Ashrae Standard 111 Pdf Free Download

Figures - uploaded by Mustafa Falih

Author content

All figure content in this area was uploaded by Mustafa Falih

Content may be subject to copyright.

Discover the world's research

20+ million members
135+ million publications
700k+ research projects

Join for free

ANSI/ASHRAE Standard 62.1-2019

(Supersedes ANSI/ASHRAE Standard 62.1-2016)

Includes ANSI/ASHRAE addenda listed in Appendix O

Ventilation

for Acceptable

Indoor Air Quality

See Appendix O for approval dates by ASHRAE and the American National Standards Institute.

This Standard is under continuous maintenance by a Standing Standard Project Committee (SSPC) for which the Standards

Committee has established a documented program for regular publication of addenda or revisions, including procedures for

timely, documented, consensus action on requests for change to any part of the Standard. Instructions for how to submit a

change can be found on the ASHRAE® website (www.ashrae.org/continuous-maintenance).

The latest edition of an ASHRAE Standard may be purchased from the ASHRAE website (www.ashrae.org) or from

ASHRAE Customer Service, 1791 Tullie Circle, NE, Atlanta, GA 30329-2305. E-mail: orders@ashrae.org. Fax: 678-539-

2129. Telephone: 404-636-8400 (worldwide), or toll free 1-800-527-4723 (for orders in US and Canada). For reprint per-

mission, go to www.ashrae.org/permissions.

ASHRAE Standing Standard Project Committee 62.1

Cognizant TC: 4.3, Ventilation Requirements and Infiltration

SPLS Liaison: Karl L. Peterman

ASHRAE Staff Liaison: Mark Weber

Jennifer A. Isenbeck, Chair (2019), Co-Vice-Chair (2017–2019)

Hoy R. Bohanon, Jr., Chair (2016–2019)

Wayne R. Thomann, Vice-Chair (2019), Co-Vice-Chair (2017–2019)

Nick H. Agopian Henry W. Ernst, Jr. Meghan K. McNulty Dennis A. Stanke

Hugo Aguilar Richard B. Fox Maria A. Menchaca Brandan Erica Stewart

William P. Bahnfleth Enrica Galasso Christopher O. Muller Drayton P. Stott

Charlene W. Bayer Elliott Gall John Nelson, Jr. Richard Taft

Robin M. Bristol Enrique T. Gonzalez Lisa C. Ng Dean T. Tompkins

Lance R. Brown Gregg Gress Laura G. Petrillo-Groh David Vigue

Tina M. Brueckner Brian J. Hafendorfer Daniel C. Pettway Ted Wayne

Brendon J. Burley Nathan L. Ho Heather L. Platt Gulledge Josiah Wiley

Mark P. Buttner Elliott Horner Stephen Ray Scott D. Williams

Jordan D. Clark Eli P. Howard, III Daniel J. Redmond Donald Weekes, Jr.

Leonard A. Damiano Zalmie Hussein Tom Rice Runming Yao

Abdel K. Darwich Jennifer Kane Chandra Sekhar Marwa Zaatari

Helen D. Davis Paul J. Kitchens Charles J. Seyffer

James E. Dennison Lauren MacGowens Abhinav Shukla

Paul L. Doppel Stephany I. Mason Jeffrey K. Smith

ASHRAE STANDARDS COMMITTEE 2019–2020

Wayne H. Stoppelmoor, Jr., Chair Susanna S. Hanson Lawrence J. Schoen

Drury B. Crawley, Vice-Chair Rick M. Heiden Steven C. Sill

Els Baert Jonathan Humble Richard T. Swierczyna

Charles S. Barnaby Srinivas Katipamula Christian R. Taber

Niels Bidstrup Essam E. Khalil Russell C. Tharp

Robert B. Burkhead Kwang Woo Kim Adrienne G. Thomle

Thomas E. Cappellin Larry Kouma Michael W. Woodford

Douglas D. Fick Cesar L. Lim Craig P. Wray

Michael W. Gallagher Karl L. Peterman Jaap Hogeling, BOD ExO

Walter T. Grondzik Erick A. Phelps Malcolm D. Knight, CO

Steven C. Ferguson, Senior Manager of Standards

SPECIAL NOTE

This American National Standard (ANS) is a national voluntary consensus Standard developed under the auspices of ASHRAE. Consensus is defined by the American

National Standards Institute (ANSI), of which ASHRAE is a member and which has approved this Standard as an ANS, as "substantial agreement reached by directly

and materially affected interest categories. This signifies the concurrence of more than a simple majority, but not necessarily unanimity. Consensus requires that all

views and objections be considered, and that an effort be made toward their resolution." Compliance with this Standard is voluntary until and unless a legal jurisdiction

makes compliance mandatory through legislation.

ASHRAE obtains consensus through participation of its national and international members, associated societies, and public review.

ASHRAE Standards are prepared by a Project Committee appointed specifically for the purpose of writing the Standard. The Project Committee Chair and

Vice-Chair must be members of ASHRAE; while other committee members may or may not be ASHRAE members, all must be technically qualified in the subject

area of the Standard. Every effort is made to balance the concerned interests on all Project Committees.

The Senior Manager of Standards of ASHRAE should be contacted for

a. interpretation of the contents of this Standard,

b. participation in the next review of the Standard,

c. offering constructive criticism for improving the Standard, or

d. permission to reprint portions of the Standard.

DISCLAIMER

ASHRAE uses its best efforts to promulgate Standards and Guidelines for the benefit of the public in light of available information and accepted industry practices.

However, ASHRAE does not guarantee, certify, or assure the safety or performance of any products, components, or systems tested, installed, or operated in

accordance with ASHRAE's Standards or Guidelines or that any tests conducted under its Standards or Guidelines will be nonhazardous or free from risk.

ASHRAE INDUSTRIAL ADVERTISING POLICY ON STANDARDS

ASHRAE Standards and Guidelines are established to assist industry and the public by offering a uniform method of testing for rating purposes, by suggesting safe

practices in designing and installing equipment, by providing proper definitions of this equipment, and by providing other information that may serve to guide the

industry. The creation of ASHRAE Standards and Guidelines is determined by the need for them, and conformance to them is completely voluntary.

In referring to this Standard or Guideline and in marking of equipment and in advertising, no claim shall be made, either stated or implied, that the product has been

approved by ASHRAE.

CONTENTS

ANSI/ASHRAE Standard 62.1-2019

Ventilation for Acceptable Indoor Air Quality

SECTION PAGE

Foreword .....................................................................................................................................................................2

1Purpose .............................................................................................................................................................2

2Scope ................................................................................................................................................................3

3Definitions .........................................................................................................................................................3

4Outdoor Air Quality ............................................................................................................................................6

5Systems and Equipment ...................................................................................................................................7

6Procedures ......................................................................................................................................................15

7Construction and System Start-Up ..................................................................................................................30

8Operations and Maintenance .......................................................................................................................... 31

9Normative References ....................................................................................................................................34

Normative Appendix A: Multiple-Zone System Ventilation Efficiency: Alternative Procedure ............................... 36

Normative Appendix B: Separation of Exhaust Outlets and Outdoor Air Intakes.................................................. 40

Normative Appendix C: Zone Air Distribution Effectiveness: Alternate Procedures..............................................43

Informative Appendix D: Information on Selected National Standards and Guidelines for

PM10, PM2.5, and Ozone .................................................................................................................45

Informative Appendix E: Acceptable Mass Balance Equations for Use with the IAQ Procedure .......................... 47

Informative Appendix F: Simplified Ventilation Rate Calculation for Multiple-Zone Recirculating Systems

Serving Only Specified Occupancy Categories in Existing Buildings ...............................................49

Informative Appendix G: Application .....................................................................................................................51

Informative Appendix H: Documentation............................................................................................................... 53

Informative Appendix I: Rate Rationale................................................................................................................. 56

Informative Appendix J: Information on Natural Ventilation ..................................................................................64

Informative Appendix K: Compliance ....................................................................................................................67

Informative Appendix L: Ventilation Rate Check Table .........................................................................................71

Informative Appendix M: Informative References .................................................................................................75

Informative Appendix N: Indoor Air Quality Procedure (IAQP)..............................................................................76

Informative Appendix O: Addenda Description Information ..................................................................................81

ASHRAE is a registered trademark of the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.

ANSI is a registered trademark of the American National Standards Institute.

2 ANSI/ASHRAE Standard 62.1-2019

(This foreword is not part of this standard. It is merely informative and does not contain

requirements necessary for conformance to the standard. It has not been processed

according to the ANSI requirements for a standard and may contain material that has

not been subject to public review or a consensus process. Unresolved objectors on infor-

mative material are not offered the right to appeal at ASHRAE or ANSI.)

FOREWORD

Standard 62.1 has undergone key changes over the years, reflecting the ever-expanding body of

knowledge, experience, and research related to ventilation and air quality. While the purpose

of the standard remains unchanged—to specify minimum ventilation rates and other measures

intended to provide indoor air quality (IAQ) that is acceptable to human occupants and that

minimizes adverse health effects—the means of achieving this goal have evolved.

In its first edition, the standard adopted a prescriptive approach to ventilation by specifying

both minimum and recommended outdoor airflow rates to obtain acceptable indoor air quality

for a variety of indoor spaces. In 1981, the standard reduced minimum outdoor airflow rates

and introduced an alternative performance-based approach, the IAQ Procedure, which allowed

for the calculation of the amount of outdoor air necessary to maintain the levels of indoor air

contaminants below recommended limits. In 2004—the last time the standard was revised in its

entirety—the IAQ Procedure was modified to improve enforceability, but more significantly the

Ventilation Rate Procedure was modified, changing both the minimum outdoor airflow rates and

the procedures for calculating both zone-level and system-level outdoor airflow rates. Today,

the standard includes three procedures for ventilation design: the IAQ Procedure, the Ventila-

tion Rate Procedure, and the Natural Ventilation Procedure.

The following are among significant changes made in the 2019 edition of the standard:

• The scope is changed to remove commentary and to more specifically identify occupancies

previously not covered.

• Informative tables of ventilation rates per unit area are included for checking existing build-

ings and design of new buildings.

• The Ventilation Rate Procedure is modified with a new simplified version for determining Ev

and a more robust option for determining values of Ez .

• The Natural Ventilation Procedure is significantly modified to provide a more accurate calcu-

lation methodology and also define the process for designing an engineered system.

• Natural ventilation now requires considering the quality of the outdoor air and interaction

of the outdoor air with mechanically cooled spaces.

• Air-cleaning devices that generate ozone are prohibited.

• Humidity control requirements are now expressed as dew point and not as relative humidity.

• The standard now defers to ANSI Z9.5 on ventilation for laboratories handling hazardous

materials.

• Patient care spaces in the scope of ASHRAE/ASHE Standard 170 now follow the require-

ments of Standard 170; ancillary spaces not previously classified have been added.

For more specific information on these and other changes made to the standard, refer to

Informative Appendix O.

Standard 62.1 is updated on a regular basis using ASHRAE's continuous maintenance

procedures. Addenda are publicly reviewed, approved by ASHRAE and ANSI, and posted on

the ASHRAE website. Change proposals can be submitted online at www.ashrae.org/continu-

ous-maintenance. The project committee for Standard 62.1 takes formal action on all change

proposals received.

1. PURPOSE

1.1 The purpose of this standard is to specify minimum ventilation rates and other measures

intended to provide indoor air quality (IAQ) that is acceptable to human occupants and that

minimizes adverse health effects.

1.2 This standard is intended for regulatory application to new buildings, additions to existing

buildings, and those changes to existing buildings that are identified in the body of the standard.

1.3 This standard is intended to be used to guide the improvement of IAQ in existing buildings.

ANSI/ASHRAE Standard 62.1-2019 3

2. SCOPE

2.1 This standard applies to spaces intended for human occupancy within buildings except

those within dwelling units in residential occupancies in which occupants are nontransient.

2.2 This standard defines requirements for ventilation and air-cleaning system design, instal-

lation, commissioning, and operation and maintenance.

2.3 In addition to ventilation, this standard contains requirements related to certain contami-

nants and contaminant sources, including outdoor air, construction processes, moisture, and

biological growth.

2.4 This standard does not prescribe specific ventilation rate requirements for the following:

a. Spaces that contain smoking or that do not meet the requirements in the standard for sepa-

ration from spaces that contain smoking

b. Patient care areas not listed in this standard

c. Laboratories with hazardous materials

3. DEFINITIONS

3.1 Terminology (See Figure 3-1 )

acceptable indoor air quality (IAQ): air in which there are no known contaminants at harmful

concentrations, as determined by cognizant authorities, and with which a substantial majority

(80% or more) of the people exposed do not express dissatisfaction.

air:

ambient air: the air surrounding a building; the source of outdoor air brought into a

building.

cool air: air whose temperature is less than the average space temperature.

exhaust air: air removed from a space and discharged to outside the building by means of

mechanical or natural ventilation systems.

indoor air: the air in an enclosed occupiable space.

makeup air: any combination of outdoor and transfer air intended to replace exhaust air

and exfiltration.

outdoor air: ambient air and ambient air that enters a building through a ventilation sys-

tem, through intentional openings for natural ventilation, or by infiltration.

primary air: air supplied to the ventilation zone prior to mixing with any locally recircu-

lated air.

recirculated air: air removed from a space and reused as supply air.

return air: air removed from a space to be recirculated or exhausted.

supply air: air delivered by mechanical or natural ventilation to a space and composed of

any combination of outdoor air, recirculated air, or transfer air.

transfer air: air moved from one indoor space to another.

ventilation air: that portion of supply air that is outdoor air plus any recirculated air that

has been treated for the purpose of maintaining acceptable IAQ.

warm air: air whose temperature is greater than the average space temperature.

air-cleaning system: a device or combination of devices applied to reduce the concentration

of airborne contaminants such as microorganisms, dusts, fumes, respirable particles, other

particulate matter, gases, vapors, or any combination thereof.

air conditioning: the process of treating air to meet the requirements of a conditioned space

by controlling its temperature, humidity, cleanliness, and distribution.

breathing zone: the region within an occupied space between planes 3 and 72 in. (75 and

1800 mm) above the floor and more than 2 ft (600 mm) from the walls or fixed air-condition-

ing equipment.

ceiling return: air removed from the space more than 4.5 ft (1.4 m) above the floor.

ceiling supply: air supplied to the space more than 4.5 ft (1.4 m) above the floor.

4 ANSI/ASHRAE Standard 62.1-2019

classroom: a space for instruction in which the instructor regularly occupies and stores sup-

plies in the space.

lecture classroom: a space for instruction in which all occupants are interim and no sup-

plies are stored in the space.

cognizant authority: an agency or organization that has the expertise and jurisdiction to estab-

lish and regulate concentration limits for airborne contaminants, or an agency or organization

that is recognized as authoritative and has the scope and expertise to establish guidelines, limit

values, or concentrations levels for airborne contaminants.

concentration: the quantity of one constituent dispersed in a defined amount of another.

conditioned space: that part of a building that is heated or cooled or both for the comfort of

occupants.

contaminant: an unwanted airborne constituent with the potential to reduce acceptability of

the air.

contaminant mixture: two or more contaminants that target the same organ system.

demand controlled ventilation (DCV): any means by which the breathing zone outdoor air-

flow (Vbz ) can be varied to the occupied space or spaces based on the actual or estimated num-

ber of occupants, ventilation requirements of the occupied zone, or both.

dwelling unit: a single unit providing complete, independent living facilities for one or more

persons, including permanent provisions for living, sleeping, eating, cooking, and sanitation.

energy recovery ventilation system: a device or combination of devices applied to provide the

outdoor air for ventilation in which energy is transferred between the intake and exhaust air-

streams.

environmental tobacco smoke (ETS): the "aged" and diluted combination of both side-stream

smoke (smoke from the lit end of a cigarette or other tobacco product) and exhaled mainstream

smoke (smoke that is exhaled by a smoker). ETS is commonly referred to as secondhand

smoke. This definition includes smoke produced from the combustion of cannabis and con-

trolled substances and the emissions produced by electronic smoking devices.

equipment well: an area (typically on the roof) enclosed on three or four sides by walls that are

less than 75% free area, and the lesser of the length and width of the enclosure is less than three

times the average height of the walls. The free area of the wall is the ratio of area of the open-

ings through the wall, such as openings between louver blades and undercuts, divided by the

gross area (length times height) of the wall.

Figure 3-1 Ventilation system.

ANSI/ASHRAE Standard 62.1-2019 5

ETS area: spaces where smoking is permitted, as well as those spaces not separated from

spaces where smoking is permitted in accordance with the requirements of Section 5 in this

standard.

ETS-free area: an area where no smoking occurs and that is separated from ETS areas accord-

ing to the requirements of this standard. (Informative Note: A no-smoking area is not neces-

sarily an ETS-free area.)

exfiltration: uncontrolled outward air leakage from conditioned spaces through unintentional

openings in ceilings, floors, and walls to unconditioned spaces or the outdoors caused by pres-

sure differences across these openings due to wind, inside-outside temperature differences

(stack effect), and imbalances between outdoor and exhaust airflow rates.

floor return: air removed from the space less than 4.5 ft (1.4 m) above the floor.

floor supply: air supplied to the space less than 4.5 ft (1.4m) above the floor.

hazardous materials: any biological, chemical, radiological, or physical item or agent that has

the potential to cause harm to humans, animals, or the environment, either by itself or through

interaction with other factors. Hazardous chemicals are any chemicals that are classified as a

health hazard or simple asphyxiant, in accordance with the Hazard Communication Standard

(29 CFR 1910.1200), and any other particularly hazardous substances, including select carcin-

ogens, reproductive toxins, and substances that have a high degree of acute toxicity. Hazardous

biological agents are any pathogenic, allergenic, or toxigenic microorganisms, including

BSL2-4 agents as defined in the National Institute for Health's Biosafety in Microbiological

and Biomedical Laboratories.

imaging room, Class 1: imaging rooms that meet the criterion of Class 1 as per the FGI Guide-

lines for Design and Construction of Outpatient Facilities, Table 2.1-5.6.2.5.1.3.

industrial space: an indoor environment where the primary activity is production or manufac-

turing processes.

infiltration: uncontrolled inward air leakage to conditioned spaces through unintentional open-

ings in ceilings, floors, and walls from unconditioned spaces or the outdoors caused by the

same pressure differences that induce exfiltration.

mechanical ventilation: ventilation provided by mechanically powered equipment such as

motor-driven fans and blowers but not by devices such as wind-driven turbine ventilators and

mechanically operated windows.

microorganism: a microscopic organism, especially a bacterium, fungus, or protozoan.

natural ventilation: ventilation provided by thermal, wind, or diffusion effects through doors,

windows, or other intentional openings in the building.

net occupiable area: the floor area of an occupiable space defined by the inside surfaces of its

walls but excluding shafts, column enclosures, and other permanently enclosed, inaccessible,

and unoccupiable areas. Obstructions in the space, such as furnishings, display or storage

racks, and other obstructions, whether temporary or permanent, are considered to be part of the

net occupiable area.

nontransient: occupancy of a dwelling unit or sleeping unit for more than 30 days.

occupant sensor: a device such as a motion detector or a captive key system that detects the

presence of one or more persons within a space.

occupiable space: an enclosed space intended for human activities excluding spaces that are

intended to be occupied occasionally and for short periods of time, such as storage rooms,

equipment rooms, and emergency exitways.

occupied mode: when a zone is scheduled to be occupied.

occupied standby mode: when a zone is scheduled to be occupied and an occupant sensor indi-

cates zero population within the zone.

odor: a quality of gases, liquids, or particles that stimulates the olfactory organ.

openable area: the net free area of an opening.

6 ANSI/ASHRAE Standard 62.1-2019

patient care area: an area used primarily for the provision of clinical care to patients. Such

care includes monitoring, evaluation, and treatment services.

readily accessible: capable of being reached quickly for operation without requiring personnel

to climb over or remove obstacles or to resort to the use of unsafe climbing aids such as tables

or chairs.

residential occupancies: occupancies that are not classified as institutional by the authority

having jurisdiction (AHJ) and that contain permanent provisions for sleeping.

sleeping unit: a room or space in which people sleep that includes permanent provisions for

living, eating, and either sanitation or kitchen facilities but not both. Such rooms and spaces

that are also part of a dwelling unit are not sleeping units.

stratified air distribution system: a device or combination

of devices applied to provide a strat-

ified thermal and pollutant distribution within a zone.

unoccupied mode: when a zone is not scheduled to be occupied.

unusual source: an item or activity that could create or emit contaminants that occurs rarely

within an occupancy category.

ventilation: the process of supplying air to or removing air from a space for the purpose of

controlling air contaminant levels, humidity, or temperature within the space.

ventilation zone: any indoor area that requires ventilation and comprises one or more spaces

with the same occupancy category (see Table 6-1 ), occupant density, zone air distribution

effectiveness (see Section 6.2.1.2 ), and design zone primary airflow (see Section 6.2.4.3.2 and

Normative Appendix A ) per unit area. (Informative Note: A ventilation zone is not necessarily

an independent thermal control zone; however, spaces that can be combined for load calcula-

tion purposes can often be combined into a single zone for ventilation calculations purposes.)

volume, space: the total volume of an occupiable space enclosed by the building envelope, plus

that of any spaces permanently open to the occupiable space, such as a ceiling attic used as a

ceiling return plenum.

zone air distribution effectiveness: the ratio of the change of contaminant concentration

between the air supply and air exhaust to the change of contaminant concentration between the

air supply and the breathing zone.

4. OUTDOOR AIR QUALITY

Outdoor air quality shall be investigated in accordance with Sections 4.1 and 4.2 prior to com-

pletion of ventilation system design. The results of this investigation shall be documented in

accordance with Section 4.3.

4.1 Regional Air Quality. The status of compliance with national ambient air quality stan-

dards shall be determined for the geographic area of the building site.

4.1.1 In the United States, compliance status shall be either in "attainment" or "nonattain-

ment" with the National Ambient Air Quality Standards (NAAQS). In the United States, areas

with no U.S. Environmental Protection Agency (USEPA) compliance status designation shall

be considered "attainment" areas.

Informative Notes:

1. The NAAQS are shown in Table D-1 of Informative Appendix D.

2. The USEPA list of nonattainment areas can be found at www.epa.gov/green-book.

3. Air quality data collected at outdoor monitors across the U.S. can be found at

www.epa.gov/outdoor-air-quality-data.

4. Internet links to detailed information on the NAAQS and contaminant levels for

other select counties and regions can be found in Informative Appendix D.

4.2 Local Air Quality. An observational survey of the building site and its immediate sur-

roundings shall be conducted during hours the building is expected to be normally occupied to

identify local contaminants from surrounding facilities that will be of concern if allowed to

enter the building.

4.3 Documentation. Documentation of the outdoor air quality investigation shall be reviewed

with building owners or their representative and shall include the following as a minimum:

ANSI/ASHRAE Standard 62.1-2019 7

a. Regional air quality compliance status

b. Local survey information

1. Date of observations

2. Time of observations

3. Site description

4. Description of facilities on site and on adjoining properties

5. Observation of odors or irritants

6. Observation of visible plumes or visible air contaminants

7. Description of sources of vehicle exhaust on site and on adjoining properties

8. Identification of potential contaminant sources on the site and from adjoining proper-

ties, including any that operate only seasonally

c. Conclusion regarding the acceptability of outdoor air quality and the information support-

ing the conclusion

5. SYSTEMS AND EQUIPMENT

5.1 Ventilation Air Distribution. Ventilating systems shall be designed in accordance with

the requirements of the following subsections.

5.1.1 Designing for Air Balancing. Ventilation air distribution systems shall be provided

that allow field verification of outdoor air intake flow (Vot ) during operation.

5.1.1.1 Designing for Varying Loads and Operating Conditions. The ventilation air dis-

tribution system for variable air volume (VAV) and multispeed constant air volume (CAV) appli-

cations shall be provided with means to adjust the system to achieve at least the minimum

ventilation airflow as required by Section 6 under any load condition or dynamic reset condition.

5.1.2 Plenum Systems. When the ceiling or floor plenum is used both to recirculate return

air and to distribute ventilation air to ceiling-mounted or floor-mounted terminal units, the sys-

tem shall be engineered such that each space is provided with its required minimum ventilation

airflow.

Informative Note: Systems with direct connection of ventilation air ducts to terminal units,

for example, comply with this requirement.

5.1.3 Documentation. The design documents shall specify minimum requirements for air

balance testing or reference applicable national standards for measuring and balancing airflow.

The design documentation shall state assumptions that were made in the design with respect to

ventilation rates and air distribution.

5.2 Exhaust Duct Location

5.2.1 Exhaust ducts that convey Class 4 air shall be negatively pressurized relative to ducts,

plenums, or occupiable spaces through which the ducts pass.

5.2.2 Exhaust ducts under positive pressure that convey Class 2 or Class 3 air shall not

extend through ducts, plenums, or occupiable spaces other than the space from which the

exhaust air is drawn.

Exception to 5.2.2: Exhaust ducts conveying Class 2 air and exhaust ducts conveying air

from residential kitchen hoods that are sealed in accordance with SMACNA Seal Class A.

5.3 Ventilation System Controls. Mechanical ventilation systems shall include controls in

accordance with the following subsections.

5.3.1 All systems shall be provided with manual or automatic controls to maintain not less

than the outdoor air intake flow (Vot ) required by Section 6 under all load conditions or

dynamic reset conditions.

5.3.2 Systems with fans supplying variable primary air (Vps ) shall be provided with any

combination of control equipment, methods, or devices to maintain no less than the outdoor air

intake flow (Vot ) required for compliance with Section 5.3.1.

5.4 Airstream Surfaces. All airstream surfaces in equipment and ducts in the HVAC system

shall be designed and constructed in accordance with the requirements of the following sub-

sections.

8 ANSI/ASHRAE Standard 62.1-2019

5.4.1 Resistance to Mold Growth. Material surfaces shall be determined to be resistant to

mold growth in accordance with a standardized test method, such as the mold growth and

humidity test in UL 181, ASTM C1338, or ASTM D3273.

Exception to 5.4.1: Sheet metal surfaces and metal fasteners.

Informative Note: Even with this resistance, any airstream surface that is continuously wet-

ted is still subject to microbial growth.

5.4.2 Resistance to Erosion. Airstream surface materials shall be evaluated in accordance

with the erosion test in UL 181 and shall not break away, crack, peel, flake off, or show evi-

dence of delamination or continued erosion under test conditions.

Exception to 5.4.2: Sheet metal surfaces and metal fasteners.

5.5 Outdoor Air Intakes. Ventilation system outdoor air intakes shall be designed in accor-

dance with the following subsections.

5.5.1 Location. Outdoor air intakes (including openings that are required as part of a natural

ventilation system) shall be located such that the shortest distance from the intake to any spe-

cific potential outdoor contaminant source listed in Table 5-1 shall be equal to or greater than

a. the separation distance in Table 5-1 or

b. the calculation methods in Normative Appendix B

and shall comply with all other requirements of this section.

5.5.1.1 Exhaust/Relief Outlets. Separation criteria for Class 2 and Class 3 exhaust/relief

outlets apply to the distance from the outdoor air intakes for one ventilation system to the

exhaust outlets and relief outlets for any other ventilation system.

5.5.1.2 Fuel-Burning Equipment. The minimum distances relative to fuel-fired appli-

ances shall be as required by ANSI Z223.1/NFPA 54 for fuel-gas-burning appliances and equip-

ment, NFPA 31 for oil-burning

appliances and equipment, and NFPA 211 for other combustion

appliances and equipment.

5.5.1.3 Roof, Landscaped Grade, or Another Surface Directly Below Intake. Where

snow accumulation is expected, the surface of the snow at the expected average snow depth

shall be considered to be a surface directly below an intake.

Exception to 5.5.1.3: The minimum separation distance in Table 5-1 shall not apply where

outdoor surfaces below the air intake are sloped more than 45 degrees from horizontal

or where such surfaces are less than 1 in. (30 mm) in width.

Table 5-1 Air Intake Minimum Separation Distance

Object Minimum Distance, ft (m)

Class 2 air exhaust/relief outlet 10 (3)

Class 3 air exhaust/relief outlet 15 (5)

Class 4 air exhaust/relief outlet 30 (10)

Cooling tower exhaust 25 (7.5)

Cooling tower intake or basin 15 (5)

Driveway, street, or parking place 5 (1.5)

Garage entry, automobile loading area, or drive-in queue 15 (5)

Garbage storage/pick-up area, dumpsters 15 (5)

Plumbing vents terminating at least 3 ft (1 m) above the level of the outdoor air intake 3 (1)

Plumbing vents terminating less than 3 ft (1 m) above the level of the outdoor air intake 10 (3)

Roof, landscaped grade, or other surface directly below intake 1 (0.30)

Thoroughfare with high traffic volume 25 (7.5)

Truck loading area or dock, bus parking/idling area 25 (7.5)

Vents, chimneys, and flues from combustion appliances and equipment 15 (5)

ANSI/ASHRAE Standard 62.1-2019 9

5.5.1.4 Laboratory Exhaust. Separation criteria for fume hood exhaust shall be in com-

pliance with ANSI/AIHA Z9.5.

5.5.2 Rain Entrainment. Outdoor air intakes that are part of the mechanical ventilation sys-

tem shall be designed to manage rain entrainment in accordance with one or more of the fol-

lowing:

a. Limit water penetration through the intake to 0.07 oz/ft2 ·h (21.5 g/m2 ·h) of inlet area when

tested using the rain test apparatus described in UL 1995, Section 58.

b. Select louvers that limit water penetration to a maximum of 0.01 oz/ft2 (3 g/m2 ) of louver

free area at the maximum intake velocity. This water penetration rate shall be determined

for a minimum 15 minute test duration when subjected to a water flow rate of 0.25 gal/min

(16 mL/s) as described under the water penetration test in AMCA 500-L or equivalent.

Manage the water that penetrates the louver by providing a drainage area or moisture

removal devices.

c. Select louvers that restrict wind-driven rain penetration to less than 2.36 oz/ft2 ·h (721 g/

m2 ·h) when subjected to a simulated rainfall of 3 in. (75 mm) per hour and a 29 mph (13 m/

s) wind velocity at the design outdoor air intake rate with the air velocity calculated based

on the louver face area. ( Informative Note: This performance corresponds to Class A (99%

effectiveness) when rated according to AMCA 511 and tested per AMCA 500-L.)

d. Use rain hoods sized for no more than 500 fpm (2.5 m/s) face velocity with a downward-

facing intake such that all intake air passes upward through a horizontal plane that inter-

sects the solid surfaces of the hood before entering the system.

e. Manage the water that penetrates the intake opening by providing a drainage area or mois-

ture removal devices.

5.5.3 Rain Intrusion. Air-handling and distribution equipment mounted outdoors shall be

designed to prevent rain intrusion into the airstream when tested at design airflow and with no

airflow, using the rain test apparatus described in UL 1995, Section 58.

5.5.4 Snow Entrainment. Where climate dictates, outdoor air intakes that are part of the

mechanical ventilation system shall be designed as follows to manage water from snow that is

blown or drawn into the system:

a. Access doors to permit cleaning of wetted surfaces shall be provided.

b. Outdoor air ductwork or plenums shall pitch to drains designed in accordance with the

requirements of Section 5.12 .

5.5.5 Bird Screens. Outdoor air intakes shall include a screening device designed to prevent

penetration by a 0.5 in. (13 mm) diameter probe. The screening device material shall be corro-

sion resistant. The screening device shall be located, or other measures shall be taken, to pre-

vent bird nesting within the outdoor air intake.

Informative Note: Any horizontal surface may be subject to bird nesting.

5.6 Local Capture of Contaminants. The discharge from noncombustion equipment that

captures the contaminants generated by the equipment shall be ducted directly to the outdoors.

Exception to 5.6: Equipment specifically designed for discharge indoors in accordance with

the manufacturer recommendations.

5.7 Ozone Generating Devices. The use of ozone generating devices shall comply with the

following sections.

Exception to 5.7: Electronic devices used exclusively for the operation of HVAC equipment

and controls.

Informative Note: Ozone generation is expected from ozone generators, corona discharge

technology, some ultraviolet lights, electronic devices that create chemical reactions within the

system, and some devices using a high voltage (>480 V). Motors and relays are examples of

electronic devices that would be exempt.

5.7.1 Air-Cleaning Devices. Air-cleaning devices shall be listed and labeled in accordance

with UL 2998.

Informative Note: The use of devices not intended for air cleaning with the potential to gen-

erate ozone should be avoided.

10 ANSI/ASHRAE Standard 62.1-2019

5.7.2 Ultraviolet Devices. Ultraviolet generating devices in supply air or spaces shall not

transmit 185 nm wavelengths.

Informative Note: Ultraviolet devices used in treatment of closed water systems may pro-

duce 185 nm wavelengths, which may generate ozone.

5.8 Combustion Air. Fuel-burning appliances, both vented and unvented, shall be provided

with air for combustion and removal of combustion products in accordance with manufacturer

instructions. Products of combustion from vented appliances shall be vented directly outdoors.

5.9 Particulate Matter Removal. Particulate matter filters or air cleaners having either

a. a MERV of not less than 8 where rated in accordance with ASHRAE Standard 52.2 or

b. the minimum efficiency within ISO ePM10 where rated in accordance with ISO 16890

shall be provided upstream of all cooling coils or other devices with wetted surfaces through

which air is supplied to an occupiable space.

Exception to 5.9: Cooling coils that are designed, controlled, and operated to provide sensible

cooling only.

5.10 Maximum Indoor Air Dew Point in Mechanically Cooled Buildings. Buildings or

spaces equipped with or served by mechanical cooling equipment shall be provided with dehu-

midification components and controls that limit the indoor humidity to a maximum dew point

of 60°F (15°C) during both occupied and unoccupied hours whenever the outdoor air dew

point is above 60°F (15°C). The dew-point limit shall not be exceeded when system perfor-

mance is analyzed with outdoor air at the dehumidification design condition (that is, design

dew point and mean coincident dry-bulb temperatures) and with the space interior loads (both

sensible and latent) at cooling design values and space solar loads at zero.

Exceptions to 5.10:

1. Buildings or spaces that are neither equipped with nor served by mechanical cooling

equipment.

2. Buildings or spaces equipped with materials, assemblies, coatings, and furnishings that

resist microbial growth and that are not damaged by continuously high indoor air dew

points.

3. During overnight unoccupied periods not exceeding 12 hours, the 60°F (15°C) dew-

point limit shall not apply, provided that indoor relative humidity does not exceed 65%

at any time during those hours.

Informative Notes:

1. Examples of spaces are shower rooms, swimming pool enclosures, kitchens, spa

rooms, or semicooled warehouse spaces that contain stored contents that are not

damaged by continuously high indoor air dew points or microbial growth.

2. This requirement reduces the risk of microbial growth in buildings and their intersti-

tial spaces because it limits the mass of indoor water vapor that can condense or be

absorbed into mechanically cooled surfaces. The dew-point limit is explicitly

extended to unoccupied hours because of the extensive public record of mold

growth in schools, apartments, dormitories, and public buildings that are intermit-

tently cooled during unoccupied hours when the outdoor air dew point is above

60°F (15°C).

5.11 Building Exfiltration. Ventilation systems for a building equipped with or served by

mechanical cooling equipment shall be designed such that the total building outdoor air intake

equals or exceeds the total building exhaust under all load and dynamic reset conditions.

Exceptions to 5.11:

1. Where an imbalance is required by process considerations and approved by the

authority having jurisdiction (AHJ), such as in certain industrial facilities.

2. When outdoor air dry-bulb temperature is below the indoor space dew-point design

temperature.

Informative Note: Although individual zones within a building may be neutral or negative

with respect to outdoors or to other zones, net positive mechanical intake airflow for the build-

ing as a whole reduces infiltration of untreated outdoor air.

ANSI/ASHRAE Standard 62.1-2019 11

5.12 Drain Pans. Drain pans, including their outlets and seals, shall be designed and con-

structed in accordance with this section.

5.12.1 Drain Pan Slope. Pans intended to collect and drain liquid water shall be sloped at

least 0.125 in./ft (10 mm/m) from the horizontal toward the drain outlet or shall be otherwise

designed such that water drains freely from the pan whether the fan is ON or OFF.

5.12.2 Drain Outlet. The drain pan outlet shall be located at the lowest point(s) of the drain

pan and shall be sized to preclude drain pan overflow under any normally expected operating

condition.

5.12.3 Drain Seal. For configurations that result in negative static pressure at the drain pan

relative to the drain outlet (such as a draw-through unit), the drain line shall include a P-trap or

other sealing device designed to maintain a seal against ingestion of ambient air, while allow-

ing complete drainage of the drain pan under any normally expected operating condition,

whether the fan is ON or OFF.

5.12.4 Pan Size. The drain pan shall be located under the water producing device. Drain pan

width shall be sized to collect water droplets across the entire width of the water producing

device or assembly. For horizontal airflow configurations, the drain pan length shall begin at

the leading face or edge of the water producing device or assembly and extend downstream

from the leaving face or edge to a distance of either

a. one half of the installed vertical dimension of the water producing device or assembly or

b. as necessary to limit water droplet carryover beyond the drain pan to 0.0044 oz/ft2

(1.5 mL/m2 ) of face area per hour under peak sensible and peak dew-point design condi-

tions, accounting for both latent load and coil face velocity.

5.13 Finned-Tube Coils and Heat Exchangers

5.13.1 Drain Pans. A drain pan, in accordance with Section 5.12, shall be provided beneath

all dehumidifying cooling-coil assemblies and all condensate producing heat exchangers.

5.13.2 Finned-Tube-Coil Selection for Cleaning. Individual finned-tube coils or multiple

finned-tube coils in series without intervening access spaces of at least 18 in. (457 mm) shall

be selected to result in no more than 0.75 in. of water (187 Pa) combined dry-coil pressure drop

at 500 fpm (2.54 m/s) face velocity.

5.14 Humidifiers and Water Spray Systems. Steam and direct-evaporative humidifiers, air

washers, direct-evaporative coolers, and other water spray systems shall be designed in accor-

dance with this section.

5.14.1 Water Quality. Water purity shall meet or exceed potable water standards at the point

where it enters the ventilation system, space, or water vapor generator. Water vapor generated

shall contain no chemical additives other than those chemicals in a potable water system.

Exceptions to 5.14.1:

1. Water spray systems that use chemical additives that meet NSF/ANSI Standard 60,

Drinking Water Treatment Chemicals—Health Effects.

2. Boiler water additives that meet the requirements of 21 CFR 173.310, Secondary

Direct Food Additives Permitted In Food For Human Consumption, and include auto-

mated dosing devices.

5.14.2 Obstructions. Air cleaners or ductwork obstructions, such as turning vanes, volume

dampers, and duct offsets greater than 15 degrees, that are installed downstream of humidifiers

or water spray systems shall be located a distance equal to or greater than the absorption dis-

tance recommended by the humidifier or water spray system manufacturer.

Exception 5.14.2: Equipment such as eliminators, coils, or evaporative media shall be per-

mitted to be located within the absorption distance recommended by the manufacturer,

provided a drain pan complying with the requirements of Section 5.12 is used to capture

and remove any water that drops out of the airstream due to impingement on these

obstructions.

5.15 Access for Inspection, Cleaning, and Maintenance

5.15.1 Equipment Clearance. Ventilation equipment shall be installed with working space

that will allow for inspection and routine maintenance, including filter replacement and fan

belt adjustment and replacement.

12 ANSI/ASHRAE Standard 62.1-2019

5.15.2 Ventilation Equipment Access. Access doors, panels, or other means shall be pro-

vided and sized to allow unobstructed access for inspection, maintenance, and calibration of all

ventilation system components for which routine inspection, maintenance, or calibration is

necessary. Ventilation system components include air-handling units, fan-coil units, water-

source heat pumps, other terminal units, controllers, and sensors.

5.15.3 Air Distribution System. Access doors, panels, or other means shall be provided in

ventilation equipment, ductwork, and plenums, located and sized to allow convenient and

unobstructed access for inspection, cleaning, and routine maintenance of the following:

a. Outdoor air intake areaways or plenums

b. Mixed-air plenums

c. Upstream surface of each heating, cooling, and heat-recovery coil or coil assembly having

a total of four rows or fewer

d. Both upstream and downstream surface of each heating, cooling, and heat-recovery coil

having a total of more than four rows, and air washers, evaporative coolers, heat wheels,

and other heat exchangers

e. Air cleaners

f. Drain pans and drain seals

g. Fans

h. Humidifiers

5.16 Building Envelope and Interior Surfaces. The building envelope and interior surfaces

within the building envelope shall be designed in accordance with the following subsections.

5.16.1 Building Envelope. The building envelope, including roofs, walls, fenestration sys-

tems, and foundations, shall comply with the following:

a. A weather barrier or other means shall be provided to prevent liquid-water penetration into

the envelope.

Exception to 5.16.1(a): When the envelope is engineered to allow incidental water pene-

tration to occur without resulting in damage to the envelope construction.

b. An appropriately placed vapor retarder or other means shall be provided to limit water

vapor diffusion to prevent condensation on cold surfaces within the envelope.

Exception to 5.16.1(b): When the envelope is engineered to manage incidental condensa-

tion without resulting in damage to the envelope construction.

c. Exterior joints, seams, or penetrations in the building envelope that are pathways for air

leakage shall be caulked, gasketed, weather stripped, provided with a continuous air bar-

rier, or otherwise sealed to limit infiltration through the envelope to reduce uncontrolled

entry of outdoor air moisture and pollutants.

Informative Note: In localities where soils contain high concentrations of radon or other soil-

gas contaminants, the AHJ might impose additional measures such as subslab depressurization.

5.16.2 Condensation on Interior Surfaces. Pipes, ducts, and other surfaces within the build-

ing whose surface temperatures are expected to fall below the surrounding dew-point tempera-

ture shall be insulated. The insulation system thermal resistance and material characteristics shall

prevent condensate from forming on the exposed surface and within the insulating material.

Exception to 5.16.2: Where condensate will wet only surfaces that will be managed to pre-

vent or control mold growth. A management plan must be submitted along with the

design specifying design assumptions and limits of the plan. The plan must be provided

to the owner.

5.17 Buildings with Attached Parking Garages. In order to limit the entry of vehicular

exhaust into occupiable spaces, buildings with attached parking garages shall be designed to

a. maintain the garage pressure at or below the pressure of the adjacent occupiable spaces,

b. use a vestibule to provide an airlock between the garage and the adjacent occupiable spaces,

c. otherwise limit migration of air from the attached parking garage into the adjacent occupia-

ble spaces of the building in a manner acceptable to the AHJ.

5.18 Air Classification and Recirculation. Air shall be classified, and its recirculation shall

be limited in accordance with the following subsections.

ANSI/ASHRAE Standard 62.1-2019 13

5.18.1 Classification. Air (return, transfer, or exhaust air) leaving each space or location shall

be designated at an expected air-quality classification not less than that shown in Table 6-1 , 6-2 ,

or 6-3 or as approved by the AHJ. Air leaving spaces or locations that are not listed in Table 6-1 ,

6-2, or 6-3 shall be designated with the same classification as air from the most similar space or

location listed in terms of occupant activities and building construction.

Exception to 5.18.1: Air from spaces where environmental tobacco smoke (ETS) is present.

(Classification of air from spaces where ETS is present is not addressed. Spaces that are

expected to include ETS do not have a classification listed in Table 6-1.)

Informative Note: Classifications in Tables 6-1 , 6-2 , and 6-3 are based on relative contami-

nant concentration using the following subjective criteria:

1. Class 1: Air with low contaminant concentration, low sensory-irritation intensity,

and inoffensive odor.

2. Class 2: Air with moderate contaminant concentration, mild sensory-irritation inten-

sity, or mildly offensive odors. (Class 2 air also includes air that is not necessarily

harmful or objectionable but that is inappropriate for transfer or recirculation to

spaces used for different purposes.)

3. Class 3: Air with significant contaminant concentration, significant sensory-irritation

intensity, or offensive odor.

4. Class 4: Air with highly objectionable fumes or gases or with potentially dangerous

particles, bioaerosols, or gases, at concentrations high enough to be considered as

harmful.

5.18.2 Redesignation

5.18.2.1 Air Cleaning. If air leaving a space or location passes through an air-cleaning

system, redesignation of the cleaned air to a cleaner classification shall be permitted per the

following requirements:

a. Class 2 air where

based on the subjective criteria in the informative note for Section

5.18.1 and where approved by the AHJ.

b. Class 3 and Class 4 air when all requirements of Sections 6.3.1 through 6.3.4 are followed.

5.18.2.2 Transfer. A mixture of air that has been transferred through or returned from

spaces or locations with different air classes shall be redesignated with the highest classifica-

tion among the air classes mixed.

Informative Note: For example, mixed return air to a common system serving both a Class 1

space and a Class 2 space is designated as Class 2 air.

5.18.2.3 Ancillary Spaces. Redesignation of Class 1 air to Class 2 air shall be permitted

for Class 1 spaces that are ancillary to Class 2 spaces.

Informative Note: For example, an office within a restaurant might be designated as a space

ancillary to a Class 2 space, thus enabling the office to receive Class 2 air.

5.18.3 Recirculation Limitations. When the Ventilation Rate Procedure of Section 6 is used

to determine ventilation airflow values, recirculation of air shall be limited in accordance with

the requirements of this section.

5.18.3.1 Class 1 Air. Recirculation or transfer of Class 1 air to any space shall be permitted.

5.18.3.2 Class 2 Air

5.18.3.2.1 Recirculation of Class 2 air within the space of origin shall be permitted.

5.18.3.2.2 Recirculation or transfer of Class 2 air to other Class 2 or Class 3 spaces shall

be permitted, provided that the other spaces are used for the same or similar purpose or task

and involve the same or similar pollutant sources as the Class 2 space.

5.18.3.2.3 Transfer of Class 2 air to toilet rooms shall be permitted.

5.18.3.2.4 Recirculation or transfer of Class 2 air to Class 4 spaces shall be permitted.

5.18.3.2.5 Class 2 air shall not be recirculated or transferred to Class 1 spaces.

Exception to 5.18.3.2.5: When using any energy recovery device, recirculation from leak-

age, carryover, or transfer from the exhaust side of the energy recovery device is per-

mitted. Recirculated Class 2 air shall not exceed 10% of the outdoor air intake flow.

5.18.3.3 Class 3 Air

5.18.3.3.1 Recirculation of Class 3 air within the space of origin shall be permitted.

14 ANSI/ASHRAE Standard 62.1-2019

5.18.3.3.2 Class 3 air shall not be recirculated or transferred to any other space.

Exception to 5.18.3.3.2: When using any energy recovery device, recirculation from

leakage, carryover, or transfer from the exhaust side of the energy recovery device is

permitted. Recirculated Class 3 air shall not exceed 5% of the outdoor air intake flow.

5.18.3.4 Class 4 Air. Class 4 air shall not be recirculated or transferred to any space or

recirculated within the space of origin.

5.18.4 Documentation. Design documentation shall indicate the justification for classification

of air from any occupancy category, airstream, or location not listed in Table 6-1 , 6-2, or 6-3 .

5.19 Requirements for Buildings Containing ETS Areas and ETS-Free Areas. The

requirements of this section must be met when a building contains both ETS areas and ETS-

free areas. Such buildings shall be constructed and operated in accordance with Sections 5.19.1

through 5.19.8. This section does not purport to achieve acceptable IAQ in ETS areas.

5.19.1 Classification. All spaces shall be classified as either ETS-free areas or ETS areas.

5.19.2 Pressurization. ETS-free areas shall be at a positive pressure with respect to any

adjacent or connected ETS areas.

Exceptions to 5.19.2:

1. Dwelling units, including hotel and motel guestrooms, and adjacent properties under

different ownership with separation walls that are structurally independent and that

contain no openings. This exception shall apply only when

a. the separation walls are constructed as smoke barriers in accordance with the

requirements of applicable standards;

b. the separation walls include an air barrier consisting of a continuous membrane or

surface treatment in the separation wall that has documented resistance to air leak-

age—continuity of the barrier shall be maintained at openings for pipes, ducts, and

other conduits and at points where the barrier meets the outside walls and other

barriers; and

c. interior corridors common to ETS and ETS-free areas are mechanically supplied

with outdoor air at the rate of 0.1 cfm/ft2 (0.5 L/s·m2).

2. Adjacent spaces otherwise required to be held at negative pressure and posted with

signs due to the presence of hazardous or flammable materials or vapors.

Informative Note: Examples of methods for demonstrating relative pressure include engi-

neering analysis, pressure differential measurement, and airflow measurement.

5.19.3 Separation. Solid walls, floors, ceilings, and doors equipped with automatic closing

mechanisms shall separate ETS areas from ETS-free areas.

Exception to 5.19.3: Openings without doors are permitted in the separation where engi-

neered systems are designed to provide airflow from ETS-free areas into ETS areas, not-

withstanding eddies that may occur in the immediate vicinity of the boundary between

the ETS and ETS-free areas and reverse flow that may occur due to short-term condi-

tions such as wind gusts.

Informative Note: Examples of methods for demonstrating air motion are engineering anal-

ysis and the use of a directional airflow indicator at representative locations in the opening,

such as on 1 ft (0.3 m) centers or at locations required for duct traverses in standard testing and

balancing procedures, such as those described in ASHRAE Standard 111.

5.19.4 Transfer Air. When air is transferred from ETS-free areas to ETS areas, the transfer

airflow rate shall be maintained regardless of whether operable doors or windows between

ETS-free and ETS areas are opened or closed. Acceptable means of doing so include fixed

openings in doors, walls, or floors, transfer grilles, transfer ducts, or unducted air plenums with

air pressure differentials in compliance with Section 5.19.2.

5.19.5 Recirculation. Air-handling and natural ventilation systems shall not recirculate or

transfer air from an ETS area to an ETS-free area.

5.19.6 Exhaust Systems. Exhaust or relief air from an ETS area shall be discharged such

that none of the air is recirculated back into any ETS-free area.

ANSI/ASHRAE Standard 62.1-2019 15

5.19.7 Signage. A sign shall be posted outside each entrance to each ETS area. The sign shall

state, as a minimum, "This Area May Contain Environmental Tobacco Smoke" in letters at least

1 in. (25 mm) high or otherwise in compliance with accessibility guidelines.

Exception to 5.19.7: Instead of the specified sign, equivalent notification means acceptable

to the AHJ may be used.

Informative Note: Based on the definition of "ETS area," such a sign might be posted out-

side a larger ETS area that includes the area where smoking is permitted.

5.19.8 Reclassification. An area that was previously an ETS area but now meets the require-

ments of an ETS-free area shall be permitted to be classified as such where smoke exposure

has stopped and odor and irritation from residual ETS contaminants are not apparent.

6. PROCEDURES

6.1 General. The Ventilation Rate Procedure, the IAQ Procedure, the Natural Ventilation Pro-

cedure, or a combination thereof shall be used to meet the requirements of this section. In addi-

tion, the requirements for exhaust ventilation in Section 6.5 shall be met regardless of the

method used to determine minimum outdoor airflow rates.

Informative Note: Although the intake airflow determined using each of these approaches

may differ significantly because of assumptions about the design, any of these approaches is a

valid basis for design.

6.1.1 Ventilation Rate Procedure. The prescriptive design procedure presented in Section

6.2, in which outdoor air intake rates are determined based on space type/application, occu-

pancy level, and floor area, shall be permitted to be used for any zone or system.

6.1.2 Indoor Air Quality (IAQ) Procedure. The performance-based design procedure pre-

sented in Section 6.3 , in which the building outdoor air intake rates and other system design

parameters are based on an analysis of contaminant sources, contaminant concentration limits,

and level of perceived indoor air acceptability, shall be permitted to be used for any zone or

system.

6.1.3 Natural Ventilation Procedure. The prescriptive or engineered system design proce-

dure presented in Section 6.4 , in which outdoor air is provided through openings to the out-

doors, shall be permitted to be used for any zone or portion of a zone in conjunction with

mechanical ventilation systems in accordance with Section 6.4.

6.1.4 Outdoor Air Treatment. Each ventilation system that provides outdoor air shall com-

ply with Sections 6.1.4.1 through 6.1.4.4.

Exception to 6.1.4: Systems supplying air for enclosed parking garages, warehouses, storage

rooms, janitor's closets, trash rooms, recycling areas, shipping/receiving/distribution areas.

Informative Note: Occupied spaces ventilated with outdoor air that is judged to be unac-

ceptable are subject to reduced air quality when outdoor air is not cleaned prior to introduction

to the occupied spaces.

6.1.4.1 Particulate Matter Smaller than 10 Micrometers (PM10). In buildings located

in an area where the national standard or guideline for PM10 is exceeded, particle filters or air-

cleaning devices shall be provided to clean the outdoor air at any location prior to its introduc-

tion to occupied spaces. Particulate matter filters or air cleaners shall have either

a. a MERV of not less than 8 where rated in accordance with ASHRAE Standard 52.2 or

b. the minimum efficiency within ISO ePM10 where rated in accordance with ISO 16890.

Informative Note: See Informative Appendix D for resources regarding selected PM10

national standards and guidelines.

6.1.4.2 Particulate Matter Smaller than 2.5 Micrometers (PM2.5). In buildings located

in an area where the national standard or guideline for PM2.5 is exceeded, particle filters or air-

cleaning devices shall be provided to clean the outdoor air at any location prior to its introduc-

tion to occupied spaces. Particulate matter filters or air cleaners shall have either

a. a MERV of not less than 11 where rated in accordance with ASHRAE Standard 52.2 or

b. the minimum efficiency within ISO ePM2.5 where rated in accordance with ISO 16890.

Informative Note: See Informative Appendix D for resources regarding selected PM2.5

national standards and guidelines.

16 ANSI/ASHRAE Standard 62.1-2019

6.1.4.3 Ozone. Air-cleaning devices for ozone shall be provided when the most recent

three-year average annual fourth-highest daily maximum eight-hour average ozone concentra-

tion exceeds 0.100 ppm (195  g/m3 ).

Such air-cleaning devices shall have a volumetric ozone removal efficiency of not less than

40% where installed, operated, and maintained in accordance with manufacturer recommenda-

tions and shall be approved by the authority having jurisdiction (AHJ). Such devices shall be

operated where the outdoor ozone levels are expected to exceed 0.100 ppm (195  g/m3 ).

Exceptions to 6.1.4.3: Air cleaning for ozone shall not be required where

1. the system design outdoor air intake flow is 1.5 ach or less,

2. controls are provided that sense outdoor ozone level and reduce intake airflow to

1.5 ach or less while complying with the outdoor airflow requirements of Section 6 , or

3. outdoor air is brought into the building and heated by direct-fired makeup air units.

Informative Note: In the U.S., a most recent three-year average annual

fourth-highest daily

maximum eight-hour average ozone concentration exceeding 0.100 ppm (195  g/m3 ) equates

to a USEPA eight-hour ozone classification of "Serious" or higher (Severe 15, Severe 17, or

Extreme).

6.1.4.4 Other Outdoor Contaminants. In buildings located in an area where the national

standard for one or more contaminants not addressed in Section 6.1.4 is exceeded, any design

assumptions and calculations related to the impact on IAQ shall be included in the design doc-

uments.

6.2 Ventilation Rate Procedure. The outdoor air intake flow (Vot ) for a ventilation system

shall be determined in accordance with Section 6.1.4 and Sections 6.2.1 through 6.2.6.

Informative Note: Additional explanation of terms used below is contained in Normative

Appendix A, along with a ventilation system schematic (Figure A-1).

6.2.1 Zone Calculations. Ventilation zone parameters shall be determined in accordance

with Sections 6.2.1.1 through 6.2.1.3 for ventilation zones served by the ventilation system,

except that the ventilation rates from ASHRAE/ASHE Standard 170 shall be used for the occu-

pancy categories within the scope of ASHRAE/ASHE Standard 170.

Informative Note: The ventilation rates in ASHRAE/ASHE Standard 170 are intended to

achieve asepsis and control odor migration and might not be adequate to achieve acceptable

IAQ as defined in Standard 62.1.

6.2.1.1 Breathing Zone Outdoor Airflow. The outdoor airflow required in the breathing

zone (Vbz ) of the occupiable space or spaces in a ventilation zone shall be not less than the

value determined in accordance with Equation 6-1.

Vbz = Rp × Pz + Ra × Az (6-1)

where

Az = zone floor area, the net occupiable floor area of the ventilation zone, ft2 (m2)

Pz = zone population, the number of people in the ventilation zone during use

Rp = outdoor airflow rate required per person as determined from Table 6-1

Informative Note: These values are based on adapted occupants.

Ra = outdoor airflow rate required per unit area as determined from Table 6-1

Informative Notes:

1. Equation 6-1 accounts for people-related sources and area-related sources inde-

pendently in the determination of the outdoor air rate required at the breathing zone.

The use of Equation 6-1 in the context of this standard does not necessarily imply

that simple addition of outdoor airflow rates for different sources can be applied to

any other aspect of IAQ.

2. The rates in Table 6-1 are based on all other applicable requirements of this standard

being met. If other requirements of the standard are not met, then the rates do not

apply.

6.2.1.1.1 Unlisted Occupancy. Where the occupancy category for a proposed space or

zone is not listed, the requirements for the listed occupancy category that is most similar in

terms of occupant density, activities, and building construction shall be used.

ANSI/ASHRAE Standard 62.1-2019 17

Table 6-1 Minimum Ventilation Rates in Breathing Zone

Occupancy Category

People Outdoor

Air Rate Rp

Area Outdoor

Air Rate Ra

Default Values

Air

Class

(6.2.6.1.4)

Occupant Density

cfm/

person

L/s·

person cfm/ft2 L/s·m2

#/1000 ft2

or #/100 m2

Animal Facilities

Animal exam room (veterinary office) 10 5 0.12 0.6 20 2

Animal imaging (MRI/CT/PET) 10 5 0.18 0.9 20 3

Animal operating rooms 10 5 0.18 0.9 20 3

Animal postoperative recovery room 10 5 0.18 0.9 20 3

Animal preparation rooms 10 5 0.18 0.9 20 3

Animal procedure room 10 5 0.18 0.9 20 3

Animal surgery scrub 10 5 0.18 0.9 20 3

Large-animal holding room 10 5 0.18 0.9 20 3

Necropsy 10 5 0.18 0.9 20 3

Small-animal-cage room (static cages) 10 5 0.18 0.9 20 3

Small-animal-cage room (ventilated cages) 10 5 0.18 0.9 20 3

Correctional Facilities

Booking/waiting 7.5 3.8 0.06 0.3 50 2

Cell 5 2.5 0.12 0.6 25 2

Dayroom 5 2.5 0.06 0.3 30 1

Guard stations 5 2.5 0.06 0.3 15 1

Educational Facilities

Art classroom 10 5 0.18 0.9 20 2

Classrooms (ages 5 to 8) 10 5 0.12 0.6 25 1

Classrooms (age 9 plus) 10 5 0.12 0.6 35 1

Computer lab 10 5 0.12 0.6 25 1

Daycare sickroom 10 5 0.18 0.9 25 3

Daycare (through age 4) 10 5 0.18 0.9 25 2

Lecture classroom 7.5 3.8 0.06 0.3 65 1 

Lecture hall (fixed seats) 7.5 3.8 0.06 0.3 150 1 

Libraries 5 2.5 0.12 0.6 10

Media center 10 5 0.12 0.6 25 1

Multiuse assembly 7.5 3.8 0.06 0.3 100 1 

Music/theater/dance 10 5 0.06 0.3 35 1 

Science laboratories 10 5 0.18 0.9 25 2

a. Outpatient facilities to which the rates apply are freestanding birth centers, urgent care centers, neighborhood clinics and physicians offices, Class 1 imaging facilities, outpatient

psychiatric facilities, outpatient rehabilitation facilities, and outpatient dental facilities.

b. The requirements of this table provide for acceptable IAQ. The requirements of this table do not address the airborne transmission of airborne viruses, bacteria, and other infectious

contagions.

Informative Note: These rates are intended only for outpatient dental clinics where the amount of nitrous oxide is limited. They are not intended for dental operatories in institutional

buildings where nitrous oxide is piped.

18 ANSI/ASHRAE Standard 62.1-2019

Educational Facilities (continued)

University/college laboratories 10 5 0.18 0.9 25 2

Wood/metal shop 10 5 0.18 0.9 20 2

Food and Beverage Service

Bars, cocktail lounges 7.5 3.8 0.18 0.9 100 2

Cafeteria/fast-food dining 7.5 3.8 0.18 0.9 100 2

Kitchen (cooking) 7.5 3.8 0.12 0.6 20 2

Restaurant dining rooms 7.5 3.8 0.18 0.9 70 2

Food and Beverage Service, General

Break rooms 5 2.5 0.06 0.3 25 1 

Coffee stations 5 2.5 0.06 0.3 20 1 

Conference/meeting 5 2.5 0.06 0.3 50 1 

Corridors — — 0.06 0.3 — 1 

Occupiable storage rooms for liquids or gels 5 2.5 0.12 0.6 2 2

Hotels, Motels, Resorts, Dormitories

Barracks sleeping areas 5 2.5 0.06 0.3 20 1 

Bedroom/living room 5 2.5 0.06 0.3 10 1 

Laundry rooms, central 5 2.5 0.12 0.6 10 2

Laundry rooms within dwelling units 5 2.5 0.12 0.6 10 1

Lobbies/prefunction 7.5 3.8 0.06 0.3 30 1 

Multipurpose assembly 5 2.5 0.06 0.3 120 1 

Miscellaneous Spaces

Banks or bank lobbies 7.5 3.8 0.06 0.3 15 1 

Bank vaults/safe deposit 5 2.5 0.06 0.3 5 2 

Computer (not printing) 5 2.5 0.06 0.3 4 1 

Freezer and refrigerated spaces (<50°F [10°C] )10 5 0 0 0 2

Manufacturing where hazardous materials are not

used

10 5.0 0.18 0.9 7 2

Manufacturing where hazardous materials are

used (excludes heavy industrial and chemical

processes)

10 5.0 0.18 0.9 7 3

Pharmacy (prep. area) 5 2.5 0.18 0.9 10 2

Photo studios 5 2.5 0.12 0.6 10 1

Shipping/receiving 10 5 0.12 0.6 2 2

Table 6-1 Minimum Ventilation Rates in Breathing Zone (Continued)

Occupancy Category

People Outdoor

Air Rate Rp

Area Outdoor

Air Rate Ra

Default Values

Air

Class

(6.2.6.1.4)

Occupant Density

cfm/

person

L/s·

person cfm/ft2 L/s·m2

#/1000 ft2

or #/100 m2

a. Outpatient facilities to which the rates apply are freestanding birth centers, urgent care centers, neighborhood clinics and physicians offices, Class 1 imaging facilities, outpatient

psychiatric facilities, outpatient rehabilitation facilities, and outpatient dental facilities.

b. The requirements of this table provide for acceptable IAQ. The requirements of this table do not address the airborne transmission of airborne viruses, bacteria, and other infectious

contagions.

Informative Note: These rates are intended only for outpatient dental clinics where the amount of nitrous oxide is limited. They are not intended for dental operatories in institutional

buildings where nitrous oxide is piped.

ANSI/ASHRAE Standard 62.1-2019 19

Miscellaneous Spaces (continued)

Sorting, packing, light assembly 7.5 3.8 0.12 0.6 7 2

Telephone closets — — 0.00 0.0 — 1

Transportation waiting 7.5 3.8 0.06 0.3 100 1 

Warehouses 10 5 0.06 0.3 — 2

Office Buildings

Breakrooms 5 2.5 0.12 0.6 50 1

Main entry lobbies 5 2.5 0.06 0.3 10 1 

Occupiable storage rooms for dry materials 5 2.5 0.06 0.3 2 1

Office space 5 2.5 0.06 0.3 5 1 

Reception areas 5 2.5 0.06 0.3 30 1 

Telephone/data entry 5 2.5 0.06 0.3 60 1 

Outpatient Health Care Facilities a,b

Birthing room 10 5 0.18 0.9 15 2

Class 1 imaging rooms 5 2.5 0.12 0.6 5 1

Dental operatory 10 5 0.18 0.9 20 1

General examination room 7.5 3.8 0.12 0.6 20 1

Other dental treatment areas 5 2.5 0.06 0.3 5 1

Physical therapy exercise area 20 10 0.18 0.9 7 2

Physical therapy individual room 10 5 0.06 0.3 20 1

Physical therapeutic pool area — — 0.48 2.4 — 2

Prosthetics and orthotics room 10 5 0.18 0.9 20 1

Psychiatric consultation room 5 2.5 0.06 0.3 20 1

Psychiatric examination room 5 2.5 0.06 0.3 20 1

Psychiatric group room 5 2.5 0.06 0.3 50 1

Psychiatric seclusion room 10 5 0.06 0.3 5 1

Speech therapy room 5 2.5 0.06 0.3 20 1

Urgent care examination room 7.5 3.8 0.12 0.6 20 1

Urgent care observation room 5 2.5 0.06 0.3 20 1

Urgent care treatment room 7.5 3.8 0.18 0.9 20 1

Urgent care triage room 10 5 0.18 0.9 20 1

Table 6-1 Minimum Ventilation Rates in Breathing Zone (Continued)

Occupancy Category

People Outdoor

Air Rate Rp

Area Outdoor

Air Rate Ra

Default Values

Air

Class

(6.2.6.1.4)

Occupant Density

cfm/

person

L/s·

person cfm/ft2 L/s·m2

#/1000 ft2

or #/100 m2

a. Outpatient facilities to which the rates apply are freestanding birth centers, urgent care centers, neighborhood clinics and physicians offices, Class 1 imaging facilities, outpatient

psychiatric facilities, outpatient rehabilitation facilities, and outpatient dental facilities.

b. The requirements of this table provide for acceptable IAQ. The requirements of this table do not address the airborne transmission of airborne viruses, bacteria, and other infectious

contagions.

Informative Note: These rates are intended only for outpatient dental clinics where the amount of nitrous oxide is limited. They are not intended for dental operatories in institutional

buildings where nitrous oxide is piped.

20 ANSI/ASHRAE Standard 62.1-2019

Public Assembly Spaces

Auditorium seating area 5 2.5 0.06 0.3 150 1 

Courtrooms 5 2.5 0.06 0.3 70 1 

Legislative chambers 5 2.5 0.06 0.3 50 1 

Libraries 5 2.5 0.12 0.6 10 1

Lobbies 5 2.5 0.06 0.3 150 1 

Museums (children's) 7.5 3.8 0.12 0.6 40 1

Museums/galleries 7.5 3.8 0.06 0.3 40 1 

Places of religious worship 5 2.5 0.06 0.3 120 1 

Retail

Sales (except as below) 7.5 3.8 0.12 0.6 15 2

Barbershop 7.5 3.8 0.06 0.3 25 2 

Beauty and nail salons 20 10 0.12 0.6 25 2

Coin-operated laundries 7.5 3.8 0.12 0.6 20 2

Mall common areas 7.5 3.8 0.06 0.3 40 1 

Pet shops (animal areas) 7.5 3.8 0.18 0.9 10 2

Supermarket 7.5 3.8 0.06 0.3 8 1 

Sports and Entertainment

Bowling alley (seating) 10 5 0.12 0.6 40 1

Disco/dance floors 20 10 0.06 0.3 100 2 

Gambling casinos 7.5 3.8 0.18 0.9 120 1

Game arcades 7.5 3.8 0.18 0.9 20 1

Gym, sports arena (play area) 20 10 0.18 0.9 7 2

Health club/aerobics room 20 10 0.06 0.3 40 2

Health club/weight rooms 20 10 0.06 0.3 10 2

Spectator areas 7.5 3.8 0.06 0.3 150 1 

Stages, studios 10 5 0.06 0.3 70 1 

Swimming (pool and deck) — — 0.48 2.4 — 2

Transient Residential

Common corridors — — 0.06 0.3 1 

Dwelling unit 5 2.5 0.06 0.3 F 1 

Table 6-1 Minimum Ventilation Rates in Breathing Zone (Continued)

Occupancy Category

People Outdoor

Air Rate Rp

Area Outdoor

Air Rate Ra

Default Values

Air

Class

(6.2.6.1.4)

Occupant Density

cfm/

person

L/s·

person cfm/ft2 L/s·m2

#/1000 ft2

or #/100 m2

a. Outpatient facilities to which the rates apply are freestanding birth centers, urgent care centers, neighborhood clinics and physicians offices, Class 1 imaging facilities, outpatient

psychiatric facilities, outpatient rehabilitation facilities, and outpatient dental facilities.

b. The requirements of this table provide for acceptable IAQ. The requirements of this table do not address the airborne transmission of airborne viruses, bacteria, and other infectious

contagions.

Informative Note: These rates are intended only for outpatient dental clinics where the amount of nitrous oxide is limited. They are not intended for dental operatories in institutional

buildings where nitrous oxide is piped.

ANSI/ASHRAE Standard 62.1-2019 21

Table 6-2 Minimum Exhaust Rates

Occupancy Category

Exhaust Rate,

cfm/unit

Exhaust Rate,

cfm/ft2Notes

Exhaust Rate,

L/s·unit

Exhaust Rate,

L/s·m2

Air

Class

Animal Facilities

Animal imaging (MRI/CT/PET) — 0.90 — 4.5 3

Animal operating rooms — 3.00 — 15 3

Animal postoperative recovery room — 1.50 — 7.5 3

Animal preparation rooms — 1.50 — 7.5 3

Animal procedure room — 2.25 — 11.3 3

Animal surgery scrub — 1.50 — 7.5 3

Large-animal holding room — 2.25 — 11.3 3

Necropsy — 2.25 — 11.3 3

Small-animal-cage room (static cages) — 2.25 — 11.3 3

Small-animal-cage room (ventilated cages) — 1.50 — 7.5 3

Arenas — 0.50 B — — 1

Art classrooms — 0.70 — 3.5 2

Auto repair rooms — 1.50 A — 7.5 2

Barber shops — 0.50 — 2.5 2

Beauty and nail salons — 0.60 — 3.0 2

Cells with toilet — 1.00 — 5.0 2

Copy, printing rooms — 0.50 — 2.5 2

Darkrooms — 1.00 — 5.0 2

Educational science laboratories — 1.00 — 5.0 2

Janitor closets, trash rooms, recycling — 1.00 — 5.0 3

Kitchenettes — 0.30 — 1.5 2

Kitchens—commercial — 0.70 — 3.5 2

Locker rooms for athletic, industrial, and health

care facilities

— 0.50 — 2.5 2

All other locker rooms — 0.25 — — 1.25 2

Shower rooms 20/50 G,I 10/25 2

Paint spray booths — — F — — 4

Parking garages — 0.75 C — 3.7 2

Pet shops (animal areas) — 0.90 — — 4.5 2

Refrigerating machinery rooms — — F — — 3

Residential kitchens 50/100 — G 25/50 — 2

Soiled laundry storage rooms — 1.00 F — 5.0 3

Storage rooms, chemical — 1.50 F — 7.5 4

Toilets—private 25/50 — E, H 12.5/25 — 2

Toilets—public 50/70 — D, H 25/35 — 2

Woodwork shop/classrooms — 0.50 — — 2.5 2

NOTES:

A Stands where engines are run shall have exhaust systems that directly connect to the engine exhaust and prevent escape of fumes.

B Where combustion equipment is intended to be used on the playing surface, additional dilution ventilation, source control, or both shall be provided.

C Exhaust shall not be required where two or more sides compose walls that are at least 50% open to the outside.

D Rate is per water closet, urinal, or both. Provide the higher rate where periods of heavy use are expected to occur. The lower rate shall be permitted to be used otherwise.

E Rate is for a toilet room intended to be occupied by one person at a time. For continuous system operation during hours of use, the lower rate shall be permitted to be used. Other-

wise the higher rate shall be used.

F See other applicable standards for exhaust rate.

G For continuous system operation, the lower rate shall be permitted to be used. Otherwise the higher rate shall be used.

H Exhaust air that has been cleaned to meet Class 1 criteria from Section 5.18.1 shall be permitted to be recirculated.

I Rate is per showerhead.

22 ANSI/ASHRAE Standard 62.1-2019

6.2.1.1.2 Source Strengths. The Ventilation Rate Procedure minimum rates are based on

contaminant sources and source

strengths that are typical for the listed occupancy categories.

Where unusual sources are expected, the additional ventilation or air cleaning required shall be

calculated using Section 6.3.6 of the IAQ Procedure or criteria established by the EHS profes-

sional responsible to the owner.

Informative Notes:

1. Zones where emissions are expected from stored hazardous materials are not typical

for any listed occupancy category.

2. Dry ice, theatrical smoke, and smoke-producing activities are not typical for any

listed occupancy categories.

6.2.1.1.3 Air Density. Volumetric airflow rates are based on dry-air density of

0.075 lbda/ft3 (1.2 kgda/m3 ) at a barometric pressure of 1 atm (101.3 kPa) and an air tempera-

ture of 70°F (21°C).

Rates shall be permitted to be adjusted for actual density.

6.2.1.1.4 Dwelling Units with Transient Occupancy. Air from one residential dwelling

shall not be recirculated or transferred to any other space outside of that dwelling.

6.2.1.1.5 Laboratories. Laboratory spaces that comply with all requirements of ANSI/

AIHA Z9.5 are not required to comply with the rates in Table 6-1.

6.2.1.1.6 Animal Facilities. Animal facilities that have completed a risk evaluation per-

formed by the environmental health and safety professional responsible to the owner or to the

owner's designee are not required to comply with the rates in Table 6-1.

6.2.1.1.7 Design Zone Population. Design zone population ( P z) shall equal the largest

(peak) number of people expected to occupy the ventilation zone during typical use.

Exceptions to 6.2.1.1.7:

1. Where the number of people expected to occupy the ventilation zone fluctuates,

zone population equal to the average number of people shall be permitted, pro-

vided such average is determined in accordance with Section 6.2.5.2.

2. Where the largest or average number of people expected to occupy the ventilation

zone cannot be established for a specific design, an estimated value for zone pop-

ulation shall be permitted, provided such value is the product of the net occupiable

area of the ventilation zone and the default occupant density listed in Table 6-1.

6.2.1.1.7.1 Design Zone Population for Dwelling Units with Transient Occupancy.

Default occupancy for dwelling units shall be two persons for studio and one-bedroom units,

with one additional person for each additional bedroom.

6.2.1.2 Zone Air Distribution Effectiveness. The zone air distribution effectiveness (Ez )

shall be determined in accordance with Table 6-4 or Normative Appendix C.

Informative Notes:

1. For some configurations, the default value depends on space and supply air tem-

perature.

2. Calculation of Ez using the procedures in Normative Appendix C may result in val-

ues greater than those listed in Table 6-4 for systems with the same description.

Table 6-3 Airstreams or Sources

Description Air Class

Commercial kitchen grease hoods 4

Commercial kitchen hoods other than grease 3

Diazo printing equipment discharge 4

Hydraulic elevator machine room 2

Laboratory hoods 4

Paint spray booths 4

Refrigerating machinery rooms 3

Residential kitchen hoods in transient occupancy 3

ANSI/ASHRAE Standard 62.1-2019 23

6.2.1.2.1 Stratified Air Distribution Systems. A stratified air distribution system shall

be designed in accordance with the following subsections, or the zone

air distribution effective-

ness (Ez ) shall be determined in accordance with Normative Appendix C.

6.2.1.2.1.1 Supply Air. Cool air shall be at least 4°F (2°C) less than the average room

air temperature.

6.2.1.2.1.2 Return Air. The return air openings or pathways shall be located more than

9 ft (2.8 m) above the floor.

6.2.1.2.1.3 Stratification. The zone shall not contain any devices that mechanically

mix the air, and shall be protected from impinging airstreams from adjacent ventilation zones.

Informative Note: Ceiling fans, blowers, air curtains, aspirating diffusers without adequate

draft separation, or other devices that disrupt the stratification cause the zone air distribution

effectiveness to be similar to a well-mixed system.

6.2.1.2.2 Personalized Ventilation Systems. A personalized ventilation system shall be

designed in accordance with the following subsections, or the zone

air distribution effectiveness

(Ez ) shall be determined in accordance with Normative Appendix C.

Informative Note: A personalized ventilation system is primarily for exposure control and

dilution of contaminants in the breathing zone and may provide some spot cooling. Personal-

ized ventilation is used when the occupant spends most of their time in one occupied space.

Table 6-4 Zone Air Distribution Effectiveness

Air Distribution Configuration Ez

Well-Mixed Air Distribution Systems

Ceiling supply of cool air 1.0

Ceiling supply of warm air and floor return 1.0

Ceiling supply of warm air 15°F (8°C) or more above space temperature and ceiling return 0.8

Ceiling supply of warm air less than 15°F (8°C) above average space temperature where the supply air-jet velocity is less than

150 fpm (0.8 m/s) within 4.5 ft (1.4 m) of the floor and ceiling return

0.8

Ceiling supply of warm air less than 15°F (8°C) above average space temperature where the supply air-jet velocity is

equal to or greater than 150 fpm (0.8 m/s) within 4.5 ft (1.4 m) of the floor and ceiling return

1.0

Floor supply of warm air and floor return 1.0

Floor supply of warm air and ceiling return 0.7

Makeup supply outlet located more than half the length of the space from the exhaust, return, or both 0.8

Makeup supply outlet located less than half the length of the space from the exhaust, return, or both 0.5

Stratified Air Distribution Systems (Section 6.2.1.2.1)

Floor supply of cool air where the vertical throw is greater than or equal to 60 fpm (0.25 m/s) at a height of 4.5 ft (1.4 m)

above the floor and ceiling return at a height less than or equal to 18 ft (5.5 m) above the floor

1.05

Floor supply of cool air where the vertical throw is less than or equal to 60 fpm (0.25 m/s) at a height of 4.5 ft (1.4 m)

above the floor and ceiling return at a height less than or equal to 18 ft (5.5 m) above the floor

1.2

Floor supply of cool air where the vertical throw is less than or equal to 60 fpm (0.25 m/s) at a height of 4.5 ft (1.4 m)

above the floor and ceiling return at a height greater than 18 ft (5.5 m) above the floor

1.5

Personalized Ventilation Systems (Section 6.2.1.2.2)

Personalized air at a height of 4.5 ft (1.4 m) above the floor combined with ceiling supply of cool air and ceiling return 1.40

Personalized air at a height of 4.5 ft (1.4 m) above the floor combined with ceiling supply of warm air and ceiling return 1.40

Personalized air at a height of 4.5 ft (1.4 m) above the floor combined with a stratified air distribution system with

nonaspirating floor supply devices and ceiling return

1.20

Personalized air at a height of 4.5 ft (1.4 m) above the floor combined with a stratified air distribution system with

aspirating floor supply devices and ceiling return

1.50

24 ANSI/ASHRAE Standard 62.1-2019

The ventilation outlet is usually incorporated into or mounted on the furniture. It is used in

conjunction with another air distribution system that handles the area ventilation requirements

and thermal loads in the space.

6.2.1.2.2.1 Personalized Air. The personalized air shall be distributed in the breathing

zone and designed such that the velocity is equal to or less than 50 fpm (0.25 m/s) at the head/

facial region of the occupant.

6.2.1.2.2.2 Return Air. The return air openings or pathways shall be located more than

9 ft (2.8 m) above the floor.

6.2.1.3 Zone Outdoor Airflow. The zone outdoor airflow (Voz ) provided to the ventilation

zone by the supply air distribution system shall be determined in accordance with Equation 6-2.

Voz = Vbz /Ez (6-2)

6.2.2 Single-Zone Systems. For ventilation systems wherein one or more air handler sup-

plies a mixture of outdoor air and recirculated air to only one ventilation zone, the outdoor air

intake flow (Vot ) shall be determined in accordance with Equation 6-3.

Vot = Voz (6-3)

6.2.3 100% Outdoor Air Systems. For ventilation systems wherein one or more air handler

supplies only outdoor air to one or more ventilation zones, the outdoor air intake flow (Vot ) shall

be determined in accordance with Equation 6-4.

Vot =  all zonesV oz (6-4)

6.2.4 Multiple-Zone Recirculating Systems. For ventilation systems wherein one or

more air handler supplies a mixture of outdoor air and recirculated air to more than one ven-

tilation zone, the outdoor air intake flow (Vot ) shall be determined in accordance with Sec-

tions 6.2.4.1 through 6.2.4.4 .

6.2.4.1 Uncorrected Outdoor Air Intake. The uncorrected outdoor air intake ( Vou ) flow

shall be determined in accordance with Equation 6-5.

Vou = D all zones(R p × P z ) +  all zones(R a × A z) (6-5)

6.2.4.1.1 Occupant Diversity. The occupant diversity ratio (D ) shall be determined in

accordance with Equation 6-6 to account for variations in population within the ventilation

zones served by the system.

D = P

s/ all zones P z(6-6)

where the system population (Ps ) is the total population in the area served by the system.

Exception to 6.2.4.1.1: Alternative methods to account for occupant diversity shall be

permitted, provided the resulting Vou value is not less than that determined using

Equation 6-5.

6.2.4.1.2 Design System Population. Design system population (Ps ) shall equal the larg-

est (peak) number of people expected to occupy all ventilation zones served by the ventilation

system during use.

Informative Note: Design system population is always equal to or less than the sum of design

zone population for all zones in the area served by the system because all zones may not be

simultaneously occupied at design population.

6.2.4.1.3 Other Ventilation Requirements. When a zone ventilation rate is obtained from

criteria other than this standard, the ventilation rate shall be converted to cfm or L/s and the value

added to Vou for use in system design calculations.

6.2.4.2 System Ventilation Efficiency. The system ventilation efficiency (Ev ) shall be

determined in accordance with Section 6.2.4.3 for the Simplified Procedure or Normative

Appendix A for the Alternative Procedure.

Informative Note: These procedures also establish zone minimum primary airflow rates for

VAV systems.

6.2.4.3 Simplified Procedure

6.2.4.3.1 System Ventilation Efficiency. System ventilation efficiency (Ev ) shall be

determined in accordance with Equation 6-7 or 6-8.

ANSI/ASHRAE Standard 62.1-2019 25

Ev = 0.88 × D + 0.22 for D < 0.60 (6-7)

Ev = 0.75 for D  0.60 (6-8)

6.2.4.3.2 Zone Minimum Primary Airflow. For each zone, the minimum primary air-

flow (Vpz-min ) shall be determined in accordance with Equation 6-9.

Vpz-min = Voz × 1.5 (6-9)

6.2.4.4 Outdoor Air Intake. The design outdoor air intake flow (Vot ) shall be determined

in accordance with Equation 6-10.

Vot = Vou /Ev (6-10)

6.2.5 Design for Varying Operating Conditions

6.2.5.1 Variable Load Conditions. Ventilation systems shall be designed to be capable of

providing not less than the minimum ventilation rates required in the breathing zone where the

zones served by the system are occupied, including all full- and part-load conditions.

Informative Note: The minimum outdoor air intake flow may be less than the design value

at part-load conditions.

6.2.5.2 Short-Term Conditions. Where it is known that peak occupancy will be of short

duration, ventilation will be varied or interrupted for a short period of time, or both, the design

shall be permitted to be based on the average conditions over a time period (T ) determined by

Equation 6-11a (I-P) or 6-11b (SI).

T = 3v/Vbz (6-11a)

T = 50v/Vbz (6-11b)

where

T= averaging time period, min

v= the volume of the ventilation zone where averaging is being applied, ft3 (m3)

Vbz = the breathing zone outdoor airflow calculated using Equation 6-1 and the design value

of the zone population (Pz ), cfm (L/s)

Acceptable design adjustments based on this optional provision include the following:

a. Zones with fluctuating occupancy: The zone population (Pz ) shall be permitted to be aver-

aged over time ( T).

b. Zones with intermittent interruption of supply air: The average outdoor airflow supplied to

the breathing zone over time (T ) shall be not less than the breathing zone outdoor airflow

(Vbz ) calculated using Equation 6-1.

c. Systems with intermittent closure of the outdoor air intake: The average outdoor air intake

over time (T) shall be not less than the minimum outdoor air intake (Vot ) calculated using

Equation 6-3, 6-4, or 6-5 as appropriate.

6.2.6 Dynamic Reset. The system shall be permitted to be designed to reset the outdoor air

intake flow (Vot ), the space or ventilation zone airflow (Voz ) as operating conditions change, or

both.

6.2.6.1 Demand Control Ventilation (DCV). DCV shall be permitted as an optional

means of dynamic reset.

Exception to 6.2.6.1: CO2 -based DCV shall not be applied in zones with indoor sources

of CO2 other than occupants, or with CO2 removal mechanisms, such as gaseous air

cleaners.

6.2.6.1.1 For DCV zones in the occupied mode, breathing zone outdoor airflow (Vbz )

shall be reset in response to current population. Current population estimates used in DCV

control calculations shall not result in ventilation rates that are less than those required by the

actual population during any one-hour time period.

6.2.6.1.2 For DCV zones in the occupied mode, breathing zone outdoor airflow (Vbz )

shall be not less than the building component (Ra × Az ) for the zone.

6.2.6.1.3 Where CO2 sensors are used for DCV, the CO 2 sensors shall be certified by the

manufacturer to be accurate within ±75 ppm at concentrations of both 600 and 1000 ppm when

26 ANSI/ASHRAE Standard 62.1-2019

measured at sea level at 77°F (25°C). Sensors shall be factory calibrated and certified by the

manufacturer to require calibration not more frequently than once every five years. Upon detec-

tion of sensor failure, the system shall provide a signal that resets the ventilation system to sup-

ply the required minimum quantity of outdoor air (Vbz ) to the breathing zone for the design zone

population (Pz ).

6.2.6.1.4 For DCV zones in the occupied standby mode, breathing zone outdoor airflow

shall be permitted to be reduced to zero for the occupancy categories indicated "OS" in Table

6-1, provided that airflow is restored to Vbz whenever occupancy is detected.

6.2.6.1.5 Documentation. A written description of the equipment, methods, control

sequences, set points, and the intended operational functions shall be provided. A table shall be

provided that shows the minimum and maximum outdoor intake airflow for each system.

6.2.6.2 Ventilation Efficiency. Variations in the efficiency with which outdoor air is dis-

tributed to the occupants under different ventilation system airflows and temperatures shall be

permitted as an optional basis of dynamic reset.

6.2.6.3 Outdoor Air Fraction. A higher fraction of outdoor air in the air supply due to

intake of additional outdoor air for free cooling or exhaust air makeup shall be permitted as an

optional basis of dynamic reset.

6.3 Indoor Air Quality (IAQ) Procedure. Breathing zone outdoor airflow (Vbz ) shall be

determined in accordance with Sections 6.3.1 through 6.3.5.

6.3.1 Contaminant Sources. Each contaminant of concern, for purposes of the design, shall

be identified. For each contaminant of concern, indoor sources and outdoor sources shall be

identified, and the emission rate for each contaminant of concern from each source shall be

determined. Where two or more contaminants of concern target the same organ system, these

contaminants shall be considered to be a contaminant mixture.

6.3.2 Contaminant Concentration. For each contaminant of concern, a concentration limit

and its corresponding exposure period and an appropriate reference to a cognizant authority

shall be specified. For each contaminant mixture of concern, the ratio of the concentration of

each contaminant to its concentration limit shall be determined, and the sum of these ratios

shall be not greater than one.

Exception to 6.3.2: Consideration of odors in determining concentration limits shall not be

required.

Informative Note: Odors are addressed in Section 6.3.4.2.

6.3.3 Perceived Indoor Air Quality. The design level of indoor air acceptability shall be

specified in terms of the percentage of building occupants, visitors, or both expressing satis-

faction with perceived IAQ.

6.3.4 Design Approach. Zone and system outdoor airflow rates shall be the larger of those

determined in accordance with Section 6.3.4.1 and either Section 6.3.4.2 or 6.3.4.3 , based on

emission rates, concentration limits, and other relevant design parameters.

6.3.4.1 Mass Balance Analysis. Using a steady-state or dynamic mass-balance analysis,

the minimum outdoor airflow rates required to achieve the concentration limits specified in Sec-

tion 6.3.2 shall be determined for each contaminant or contaminant mixture of concern within

each zone served by the system.

Informative Notes:

1. Informative Appendix E includes steady-state mass-balance equations that describe

the impact of air cleaning on outdoor air and recirculation rates for ventilation sys-

tems serving a single zone.

2. In the completed building, measurement of the concentration of contaminants or

contaminant mixtures of concern may be useful as a means of checking the accu-

racy of the design mass-balance analysis, but such measurement is not required for

compliance.

6.3.4.2 Subjective Evaluation. Using a subjective occupant evaluation conducted in the

completed building, the minimum outdoor airflow rates required to achieve the level of accept-

ability specified in Section 6.3.3 shall be determined within each zone served by the system.

ANSI/ASHRAE Standard 62.1-2019 27

Informative Note: Level of acceptability often increases in response to increased outdoor

airflow rates, increased level of indoor or outdoor air cleaning, or decreased indoor or outdoor

contaminant emission rate.

6.3.4.3 Similar Zone. The minimum outdoor airflow rates shall be not less than those

found in accordance with Section 6.3.4.2 for a substantially similar zone.

6.3.5 Combined IAQ Procedure and Ventilation Rate Procedure. The IAQ Procedure in

conjunction with the Ventilation Rate Procedure shall be permitted to be applied to a zone or

system. In this case, the Ventilation Rate Procedure shall be used to determine the required

zone minimum outdoor airflow, and the IAQ Procedure shall be used to determine the addi-

tional outdoor air or air cleaning necessary to achieve the concentration limits of the contami-

nants and contaminant mixtures of concern.

Informative Note: The improvement of IAQ through the use of air cleaning or provision of

additional outdoor air in conjunction with minimum ventilation rates may be quantified using

the IAQ Procedure.

6.3.6 Documentation. Where the IAQ Procedure is used, the following information shall be

included in the design documentation: the contaminants and contaminant mixtures of concern

considered in the design process, the sources and emission rates of the contaminants of con-

cern, the concentration limits and exposure periods and the references for these limits, and the

analytical approach used to determine ventilation rates and air-cleaning requirements. The con-

taminant monitoring and occupant or visitor evaluation plans shall also be included in the doc-

umentation.

6.4 Natural Ventilation Procedure. Natural ventilation systems shall comply with the

requirements of either Section 6.4.1 or 6.4.2 . Designers shall provide interior air barriers, insu-

lation, or other means that separate naturally ventilated spaces from mechanically cooled

spaces to prevent high-dew-point outdoor air from coming into contact with mechanically

cooled surfaces.

6.4.1 Prescriptive Compliance Path. Any zone designed for natural ventilation shall

include a mechanical ventilation system designed in accordance with Section 6.2 , Section 6.3,

or both.

Exceptions to 6.4.1:

1. Zones in buildings that have all of the following:

a. Natural ventilation openings that comply with the requirements of Section 6.4.1.

b. Controls that prevent the natural ventilation openings from being closed during peri-

ods of expected occupancy, or natural ventilation openings that are permanently open.

2. Zones that are not served by heating or cooling equipment.

6.4.1.1 Ceiling Height. For ceilings that are parallel to the floor, the ceiling height (H ) to

be used in Sections 6.4.1.3 through 6.4.1.5 shall be the minimum ceiling height in the zone.

For zones wherein ceiling height increases as distance from the ventilation increases, the

ceiling height shall be the average height of the ceiling determined over a distance not greater

than 6 m (20 ft) from the openings.

6.4.1.2 Floor Area to be Ventilated. The naturally ventilated area in zones or portions of

zones shall extend from the openings to a distance determined by Sections 6.4.1.3, 6.4.1.4, or

6.4.1.5. Openings shall meet the requirements of Section 6.4.1.6 . For zones where ceilings are

not parallel to the floor, the ceiling height shall be determined in accordance with Section

6.4.1.1.

6.4.1.3 Single Side Opening. For zones with openings on only one side of the zone, the

naturally ventilated area shall extend to a distance not greater that two times the height of the

ceiling from the openings.

6.4.1.4 Double Side Opening. For zones with openings on two opposite sides of the zone,

the naturally ventilated area shall extend between the openings separated by a distance not

greater than five times the height of the ceiling.

6.4.1.5 Corner Openings. For zones with openings on two adjacent sides of a zone, the

naturally ventilated area shall extend to a distance not greater than five times the height of the

ceiling along a line drawn between the outside edges of the two openings that are the farthest

28 ANSI/ASHRAE Standard 62.1-2019

apart. Floor area outside that line shall comply with Section 6.4.1.3 as a zone having openings

on only one side of the zone.

Informative Note: Floor area outside that line refers to the remaining area of the zone that

is not bounded by the walls that have the openings and the line drawn between the openings.

6.4.1.6 Location and Size of Openings. Zones or portions of zones to be naturally venti-

lated shall have a permanently open airflow path to openings directly connected to the outdoors.

The minimum flow rate to the zone shall be determined in accordance with Section 6.2.1.1.

This flow rate shall be used to determine the required openable area of openings, accounting

only for buoyancy-driven flow. Wind-driven flow shall be used only where it can be demon-

strated that the minimum flow rate is provided during all occupied hours. Openings shall be

sized in accordance with Section 6.4.1.6.1 (Path A) or Section 6.4.1.6.2 (Path B).

Informative Note: Permanently open airflow path refers to pathways that would allow air-

flow unimpeded by partitions, walls, furnishings, etc.

6.4.1.6.1 Sizing Openings—Path A. Where the zone is ventilated using a single open-

ing or multiple single openings located at the same elevation, the openable area as a percent of

the net occupiable floor area shall be greater than or equal to the value indicated in Table 6-5.

Where the zone is ventilated using two openings located at different elevations or multiple

pairs of such openings, the openable area as a percent of the net occupiable floor area shall be

greater than or equal to the value indicated in Table 6-6 .

Where openings are obstructed by louvers or screens, the openable area shall be based on

the net free area of the opening. Where interior zones, or portions of zones, without direct

openings to the outdoors are ventilated through adjoining zones, the opening between zones

shall be permanently unobstructed and have a free area of not less than twice the percent of

occupiable floor area used to determine the opening size of adjacent exterior zones, or 25 ft2

(2.3 m2), whichever is greater.

Informative Note: Tables 6-5 and 6-6 are based solely on buoyancy-driven flow and have

not been created to address thermal comfort.

6.4.1.6.2 Sizing Openings—Path B. The required openable area for a single zone shall

be calculated using CIBSE AM10, Section 4.3.

6.4.2 Engineered System Compliance Path. For an engineered natural ventilation system,

the designer shall

a. determine hourly environmental conditions, including outdoor air dry-bulb temperature;

dew-point temperature; outdoor concentration of contaminants, including PM2.5, PM10,

and ozone where data are available; wind speed and direction; and internal heat gains

during expected hours of natural ventilation operation.

b. determine the effect of pressure losses along natural ventilation airflow paths on the result-

ing flow rates, including inlet openings, air transfer grills, ventilation stacks, and outlet

openings during representative conditions of expected natural ventilation system use.

c. quantify natural ventilation airflow rates of identified airflow paths accounting for wind

induced and thermally induced driving pressures during representative conditions of

expected natural ventilation system use.

d. design to provide outdoor air in quantities sufficient to result in acceptable IAQ as estab-

lished under Section 6.2.1.1 or 6.3 during representative conditions of expected natural

ventilation system use.

6.4.3 Control and Accessibility. The means to open required openings shall be readily

accessible to building occupants whenever the space is occupied. Controls shall be designed to

coordinate operation of the natural and mechanical ventilation systems.

6.4.4 Documentation. Where the Natural Ventilation Procedure is used, the designer shall

document the values and calculations that demonstrate conformance with the compliance path

and the controls systems and sequences required for operation of the natural ventilation system,

including coordination with mechanical ventilation systems. Where the Prescriptive Compli-

ance Path is used for buildings

located in an area where the national standard for one or more

contaminants is exceeded, any design assumptions and calculations related to the impact on

IAQ shall be included in the design documents.

ANSI/ASHRAE Standard 62.1-2019 29

6.5 Exhaust Ventilation. The Prescriptive Compliance Path or the Performance Compliance

Path shall be used to meet the requirements of this section. Exhaust makeup air shall be permit-

ted to be any combination of outdoor air, recirculated air, or transfer air.

6.5.1 Prescriptive Compliance Path. The design exhaust airflow shall be determined in

accordance with the requirements in Tables 6-2 and 6-3.

Exception to 6.5.1: Laboratory spaces that comply with all requirements of ANSI/AIHA

Z9.5.

6.5.1.1 Laboratory Hoods. Exhaust from laboratory hoods shall be Air Class 4 unless

determined otherwise by the Environmental Health and Safety

professional responsible to the

owner or to the owner's designee.

6.5.1.2 Pressure Requirements. While the required exhaust systems are operating, the

exhaust airflow of zones listed in Table 6-2 shall be larger than their respective supply airflow.

Table 6-5 Minimum Openable Areas: Single Openings a

Vbz/Az 

([L/s]/m2)

Vbz/Az 

(cfm/ft2)

Total Openable Areas in Zone as a Percentage of Az

HS/WS  0.1 0.1 < HS/WS  1 H S/WS > 1

1.0 0.2 4.0 2.9 2.5

2.0 0.4 6.9 5.0 4.4

3.0 0.6 9.5 6.9 6.0

4.0 0.8 12.0 8.7 7.6

5.5 1.1 15.5 11.2 9.8

where

Vbz = breathing zone outdoor airflow, per Table 6-1.

Az = zone floor area, the net occupiable floor area of the ventilation zone.

WS = aggregated width of all single outdoor openings located at the same elevation.

HS = vertical dimension of the single opening or the least vertical dimension of the openings where there are multiple openings.

a. Volumetric airflow rates used to estimate required openable area are based on the following:

• Dry-air density of 0.075 lbda/ft3 (1.2 kgda/m3) at a barometric pressure of 1 atm (101.3 kPa) and an air temperature of 70°F (21°C)

• Temperature difference between indoors and outdoors of 1.8°F (1°C)

• Gravity constant of 32.2 ft/s2 (9.81 m/s2)

• Window discharge coefficient of 0.6

Table 6-6 Minimum Openable Areas: Two Vertically Spaced Openings a

Vbz /Az 

(L/s/m2)

Vbz /Az 

(cfm/ft2)

Total Openable Areas in Zone as a Percentage of Az

Hvs  8.2 ft (2.5 m) 8.2 ft (2.5m) < Hvs  16.4 ft (5 m) 16.4 ft (5 m) < Hvs

As /Al  0.5 As /Al > 0.5 A s /Al  0.5 As / A l > 0.5 As /Al  0.5 A s /Al > 0.5

1.0 0.2 2.0 1.3 1.3 0.8 0.9 0.6

2.0 0.4 4.0 2.6 2.5 1.6 1.8 1.2

3.0 0.6 6.0 3.9 3.8 2.5 2.7 1.7

4.0 0.8 8.0 5.2 5.0 3.3 3.6 2.3

5.5 1.1 11.0 7.1 6.9 4.5 4.9 3.2

where

Vbz = breathing zone outdoor airflow, per Table 6-1.

Az = zone floor area, the net occupiable floor area of the ventilation zone.

Hvs = vertical separation between the center of the top and bottom openings' free operable area; in case of multiple horizontally spaced pairs of openings, use shortest distance

encountered.

As = openable area of smallest opening (top or bottom); in case of multiple horizontally spaced pairs of top-and-bottom openings, use aggregated areas.

Al = openable area of largest opening (top or bottom); in case of multiple horizontally spaced pairs of top-and-bottom openings, use aggregated areas.

a. Volumetric airflow rates used to estimate required operable area are based on the following:

• Dry-air density of 0.075 lbda/ft3 (1.2 kgda/m3) at a barometric pressure of 1 atm (101.3 kPa) and an air temperature of 70°F (21°C)

• Temperature difference between indoors and outdoors of 1.8°F (1°C)

• Gravity constant of 32.2 ft/s2 (9.81 m/s2)

• Window discharge coefficient of 0.6

30 ANSI/ASHRAE Standard 62.1-2019

If zones listed in Table 6-2 are adjacent, the difference between the exhaust and the supply air-

flow shall be larger for the zone with the higher number class of air.

Exception to 6.5.1.2: Where airflow offset requirements are established by the Environ-

mental Health and Safety professional responsible to the owner or owner's designee.

Informative Notes:

1. Exhaust systems are required for any occupancy category listed in Table 6-2.

2. Where intermittent operation is allowed in Table 6-2 , exhaust equipment is intended

to be operated when the space is in use.

6.5.2 Performance Compliance Path. The exhaust airflow shall be determined in accor-

dance with the following subsections.

6.5.2.1 Contaminant Sources. Contaminants or mixtures of concern for purposes of the

design shall be identified. For each contaminant or mixture of concern, indoor sources (occu-

pants, materials, activities, and processes) and outdoor sources shall be identified, and the

emission rate for each contaminant of concern from each source shall be determined.

6.5.2.2 Contaminant Concentration. For each contaminant of concern, a concentration

limit and its corresponding exposure period and an appropriate reference to a cognizant author-

ity shall be specified.

6.5.2.3 Monitoring and control systems shall be provided to automatically detect contami-

nant levels of concern and modulate exhaust airflow such that contaminant levels are main-

tained at not greater than the specified contaminant concentration limits.

6.6 Design Documentation Procedures. Design criteria and assumptions shall be docu-

mented and made available for operation of the system after installation. See Sections 4.3 ,

5.1.3, 5.18.4, 6.2.6.1.5, 6.3.6, and 6.4.4 regarding assumptions to be detailed in the documen-

tation.

7. CONSTRUCTION AND SYSTEM START-UP

7.1 Construction Phase

7.1.1 Application. The requirements of this section apply to ventilation systems and the

spaces they serve in new buildings and additions to or alterations in existing buildings.

7.1.2 Filters. Systems designed with particle filters shall not be operated without filters in

place.

7.1.3 Protection of Materials. When recommended by the manufacturer, building materials

shall be protected from rain and other sources of moisture by appropriate in-transit and on-site

procedures. Porous materials with visible microbial growth shall not be installed. Nonporous

materials with visible microbial growth shall be decontaminated.

7.1.4 Protection of Occupied Areas

7.1.4.1 Application. The requirements of Section 7.1.4 apply when construction requires

a building permit and entails sanding, cutting, grinding, or other activities that generate sig-

nificant amounts of airborne particles or procedures that generate significant amounts of gas-

eous contaminants.

7.1.4.2 Protective Measures. Measures shall be employed to reduce the migration of con-

struction-generated contaminants to occupied areas.

Informative Note: Examples of acceptable measures include, but are not limited to, sealing

the construction area using temporary walls or plastic sheathing, exhausting the construction

area, or pressurizing contiguous occupied areas.

7.1.5 Air Duct System Construction. Air duct systems shall be constructed in accordance

with the following standards, as applicable:

a. The following sections of ANSI/SMACNA 006, HVAC Duct Construction Standards—

Metal and Flexible:

• Section S1.9 of Section 1.3.1, "Duct Construction and Installation Standards"

• Section 7.4, "Installation Standards for Rectangular Ducts Using Flexible Liner"

• Section 3.5, "Duct Installation Standards"

• Section 3.6, "Specification for Joining and Attaching Flexible Duct"

• Section 3.7, "Specification for Supporting Flexible Duct"

ANSI/ASHRAE Standard 62.1-2019 31

• Sections S6.1, S6.3, S6.4, and S6.5 of Section 9.1, "Casing and Plenum Construction

Standards"

b. All sections of SMACNA's Fibrous Glass Duct Construction Standards

c. NFPA 90A, Standard for the Installation of Air-Conditioning and Ventilating Systems

d. NFPA 90B, Standard for the Installation of Warm Air Heating and Air-Conditioning Sys-

tems

7.2 System Start-Up

7.2.1 Application. The requirements of this section apply to the following ventilation sys-

tems:

a. Newly installed air-handling systems

b. Existing air-handling systems undergoing supply air or outdoor airflow reduction (Only the

requirements of Section 7.2.2 shall apply to these altered systems.)

c. Existing air-handling distribution systems undergoing alterations affecting more than 25%

of the floor area served by the systems (Only the requirements of Section 7.2.2 shall apply

to these altered systems.)

7.2.2 Air Balancing and Verification of Outdoor Air Performance. Ventilation systems

shall be balanced in accordance with ASHRAE Standard 111 or another applicable national

standards so as to verify conformance with the total outdoor airflow requirements of this stan-

dard (Vot ).

7.2.3 Testing of Drain Pans. To minimize conditions of water stagnation that may result in

microbial growth, drain pans shall be field tested under operating conditions that are the most

restrictive to condensate flow to demonstrate proper drainage.

Exception to 7.2.3: Field testing of drain pans is not required if units with factory-installed

drain pans have been certified (attested in writing) by the manufacturer for proper drain-

age when installed as recommended.

Informative Note: Above conditions usually occur at full fan airflow for draw-through fans

and minimum fan airflow for blow-through fans.

7.2.4 Ventilation System Start-Up. Ventilation air distribution systems shall be clean of

dirt and debris.

7.2.5 Outdoor Air Dampers. Prior to occupancy, each ventilation system shall be tested to

demonstrate that outdoor air dampers operate in accordance with the system design.

7.2.6 Documentation. The following ventilation system documentation shall be provided to

the building owner or his/her designee, retained within the building, and made available to the

building operating personnel:

a. An operations and maintenance manual describing basic data relating to the operation and

maintenance of ventilation systems and equipment as installed

b. HVAC controls information consisting of diagrams, schematics, control sequence narra-

tives, and maintenance and/or calibration information

c. An air balance report documenting the work performed for Section 7.2.2

d. Construction drawings of record, control drawings, and final design drawings

e. Design criteria and assumptions

8. OPERATIONS AND MAINTENANCE

8.1 General

8.1.1 Application. The requirements of this section apply to buildings and their ventilation

systems and their components constructed or renovated after the adoption date of this section.

8.1.2 Building Alterations or Change of Use. When buildings are altered or when changes

in building use, occupant category, significant change in occupant density, or other changes

inconsistent with system design assumptions are made, the ventilation system design, opera-

tion, and maintenance shall be reevaluated and the operations and maintenance (O&M) manual

updated as necessary.

8.2 O&M Manual. An O&M manual, either written or electronic, shall be developed and

maintained on site or in a centrally accessible location for the working life of the applicable

ventilation system equipment or components. This manual shall be updated as necessary. The

32 ANSI/ASHRAE Standard 62.1-2019

Table 8-1 Minimum Maintenance Activity and Frequency for Ventilation System Equipment

and Associated Components

Inspection/Maintenance Task Frequency a

a. Investigate system for water intrusion or accumulation. Rectify as necessary. As necessary

b. Verify that the space provided for routine maintenance and inspection of open cooling tower water systems, closed

cooling tower water systems, and evaporative condensers is unobstructed.

Monthly

c. Open cooling tower water systems, closed cooling tower water systems, and evaporative condensers shall be treated

to limit the growth of microbiological contaminants, including legionella sp.

Monthly

d. Verify that the space provided for routine maintenance and inspection of equipment and components is unobstructed. Quarterly

e. Check pressure drop and scheduled replacement date of filters and air-cleaning devices. Clean or replace as

necessary to ensure proper operation.

Quarterly

f. Check ultraviolet lamp. Clean or replace as needed to ensure proper operation. Quarterly

g. Visually inspect dehumidification and humidification devices. Clean and maintain to limit fouling and microbial

growth. Measure relative humidity and adjust system controls as necessary.

Quarterly

h. Maintain floor drains and trap primer located in air plenums or rooms that serve as air plenums to prevent transport

of contaminants from the floor drain to the plenum.

Semiannually

i. Check ventilation and IAQ related control systems and devices for proper operation. Clean, lubricate, repair, adjust,

or replace as needed to ensure proper operation.

Semiannually

j. Check P-traps in floor drains located in plenums or rooms that serve as air plenums. Prime as needed to ensure

proper operation.

Semiannually

k. Check fan belt tension. Check for belt wear and replace if necessary to ensure proper operation. Check sheaves for

evidence of improper alignment or evidence of wear and correct as needed.

Semiannually

l. Check variable-frequency drive for proper operation. Correct as needed. Semiannually

m. Check for proper operation of cooling or heating coil for damage or evidence of leaks. Clean, restore, or replace as

required.

Semiannually

n. Visually inspect outdoor air intake louvers, bird screens, mist eliminators, and adjacent areas for cleanliness and

integrity; clean as needed; remove all visible debris or visible biological material observed and repair physical

damage to louvers, screens, or mist eliminators if such damage impairs the item from providing the required outdoor

air entry.

Semiannually

o. Visually inspect natural ventilation openings and adjacent areas for cleanliness and integrity; clean as needed.

Remove all visible debris or visible biological material observed and repair physical damage to louvers, and screens

if such damage impairs the item from providing the required outdoor air entry. Manual and/or automatic opening

apparatus shall be physically tested for proper operation and repaired or replaced as necessary.

Semiannually

p. Verify the operation of the outdoor air ventilation system and any dynamic minimum outdoor air controls. Annually

q. Check air filter fit and housing seal integrity. Correct as needed. Annually

r. Check control box for dirt, debris, and/or loose terminations. Clean and tighten as needed. Annually

s. Check motor contactor for pitting or other signs of damage. Repair or replace as needed. Annually

t. Check fan blades and fan housing. Clean, repair, or replace as needed to ensure proper operation. Annually

u. Check integrity of all panels on equipment. Replace fasteners as needed to ensure proper integrity and fit/finish of

equipment.

Annually

v. Assess field serviceable bearings. Lubricate if necessary. Annually

w. Check drain pans, drain lines, and coils for biological growth. Check adjacent areas for evidence of unintended

wetting. Repair and clean as needed.

Annually

x. Check for evidence of buildup or fouling on heat exchange surfaces. Restore as needed to ensure proper operation. Annually

y. Inspect unit for evidence of moisture carryover from cooling coils beyond the drain pan. Make corrections or repairs

as necessary.

Annually

z. Check for proper damper operation. Clean, lubricate, repair, replace, or adjust as needed to ensure proper operation. Annually

aa. Visually inspect areas of moisture accumulation for biological growth. If present, clean or disinfect as needed. Annually

a. Minimum frequencies may be increased or decreased if indicated in the O&M manual.

ANSI/ASHRAE Standard 62.1-2019 33

manual shall include the O&M procedures, ventilation system operating schedules and any

changes made thereto, final design drawings, maintenance schedules based on manufacturer

instructions, and the maintenance requirements and frequencies provided in Table 8-1.

8.3 Ventilation System Operation. Mechanical and natural ventilation systems shall be oper-

ated in a manner consistent with the O&M manual. Systems shall be operated such that spaces

are ventilated in accordance with Section 6 during periods of expected occupancy.

8.4 Ventilation System Maintenance. The building ventilation system components shall be

maintained in accordance with the O&M manual.

ab. Check condensate pump. Clean or replace as needed. Annually

ac. Visually inspect exposed ductwork and external piping for insulation and vapor barrier for integrity. Correct as

needed.

Annually

ad. Verify the accuracy of permanently mounted sensors whose primary function is outdoor air delivery monitoring,

outdoor air delivery verification, or dynamic minimum outdoor air control, such as flow stations at an air handler and

those used for demand control ventilation, including CO2 sensors. A sensor failing to meet the accuracy specified in

the O&M manual shall be recalibrated or replaced. Performance verification shall include output comparison to a

measurement reference standard consistent with those specified for similar devices in ASHRAE Standard 41.2 or

ASHRAE Standard 111.

5 years

ae. Verify the total quantity of outdoor air delivered by air handlers set to minimum outdoor air mode. If measured

minimum airflow rates are less than the design minimum rate documented in the O&M manual, ± a 10% balancing

tolerance, (1) confirm the measured rate does not conform with the provisions of this standard and (2) adjust or

modify the air-handler components to correct the airflow deficiency. Ventilation systems shall be balanced in

accordance with ASHRAE Standard 111 or its equivalent, at least to the extent necessary to verify conformance with

the total outdoor airflow and space supply airflow requirements of this standard.

Exception: Units under 2000 cfm (1000 L/s) of supply air are exempt from this requirement.

5 years

Table 8-1 Minimum Maintenance Activity and Frequency for Ventilation System Equipment

and Associated Components (Continued)

Inspection/Maintenance Task Frequency a

a. Minimum frequencies may be increased or decreased if indicated in the O&M manual.

34 ANSI/ASHRAE Standard 62.1-2019

9. NORMATIVE REFERENCES

Reference Title Section

Air Movement and Control Association International, Inc. (AMCA)

30 West University Drive

Arlington Heights, IL 60004-1893, United States

1-847-394-0150; www.amca.org

AMCA 500-L-15 Laboratory Methods of Testing Louvers for Rating 5.5.2

American Industrial Hygiene Association (AIHA)

3141 Fairview Park Drive, Suite 777

Falls Church, VA 22042, United States

(703) 849-8888; www.aiha.org

ANSI/AIHA Z9.5-2012 Standard for Laboratory Ventilation 5.5.1.4; 6.2.1.1.5;

6.5.1; B1.1

ASHRAE

1791 Tullie Circle NE

Atlanta, GA 30329, United States

1-404-636-8400; www.ashrae.org

ANSI/ASHRAE Standard 41.2 (2018) Standard Methods for Air Velocity and Airflow Measurement Table 8-1

ANSI/ASHRAE Standard 52.2 (2017) Method of Testing General Ventilation Air-Cleaning Devices for

Removal Efficiency by Particle Size

5.9; 6.1.4.1; 6.1.4.2

ANSI/ASHRAE Standard 111-2008

(RA 2017)

Measurement, Testing, Adjusting, and Balancing of

Building HVAC Systems

7.2.2; Table 8-1

ANSI/ASHRAE/ASHE Standard 170 (2017) Ventilation for Health Care Facilities 6.2.2

ASTM International

100 Barr Harbor Dr.

West Conshohocken, PA 19428-2959, United States

1-610-832-9585; www.astm.org

ASTM D3273 (2016) Standard Test Method for Resistance to Growth of Mold on the

Surface of Interior Coatings in an Environmental Chamber

5.4.1

ASTM C1338 (2014) Standard Test Method for Determining Fungi Resistance of

Insulation Materials and Facings

5.4.1

Chartered Institution of Building Services Engineers (CIBSE)

222 Balham High Road

London

SW12 9BS

United Kingdom

+44 (0)20 8675 5211; www.cibse.org

CIBSE AM10 (2005) Natural Ventilation in Non-Domestic Buildings 6.4.1.6.2

International Organization for Standardization (ISO)

ISO Central Secretariat, 1 rue de Varembee, Case postale 56

CH-1211 Geneva 20, Switzerland

+41-22-749-01-11; www.iso.org

ISO 16890 (2016) Air Filters for General Ventilation 5.9; 6.1.4.1; 6.1.4.2

National Fire Protection Association (NFPA)

1 Battery March Park

Quincy, MA 02169-7471

United States

1-617-770-0700; www.nfpa.org

ANSI Z223.1/NFPA-54 (2018) National Fuel Gas Code 5.5.1.2

NFPA-31 (2016) Standard for the Installation of Oil-Burning Equipment 5.5.1.2

ANSI/ASHRAE Standard 62.1-2019 35

NFPA-45 (2015) Standard on Fire Protection for Laboratories Using Chemicals B1.1

NFPA-90A (2018) Standard for the Installation of Air-Conditioning and

Ventilating Systems

7.1.5

NFPA-90B (2018) Standard for the Installation of Warm Air Heating and

Air-Conditioning Systems

7.1.5

NFPA-211 (2019) Standard for Chimneys, Fireplaces, Vents, and Solid

Fuel-Burning Appliances

5.5.1.2

NSF International

789 Dixboro Road

Ann Arbor, MI 48105, United States

734-769-8010; www.nsf.org; info@nsf.org

NSF/ANSI 60 (2016) Drinking Water Treatment Chemicals—Health Effects 5.14.1

Sheet Metal and Air Conditioning Contractors National Association (SMACNA)

4201 Lafayette Center Drive

Chantilly, VA 20151, Unites States

1-703-803-2980

Fibrous Glass Duct Construction Standards, 7th Edition (2003) 7.1.5

ANSI/SMACNA 006 (2006) HVAC Duct Construction Standards—Metal and Flexible, 3rd Edition 7.1.5

ANSI/SMACNA 016 (2012) HVAC Air Duct Leakage Test Manual, 2nd Edition 5.2.2

Underwriters Laboratories Inc. (UL)

333 Pfingsten Road

Northbrook, IL 60062, United States

847-272-8800; www.ul.com; cec.us@us.ul.com

UL 181 (2013) Factory-Made Air Ducts and Air Connectors, 11th Edition 5.4.1; 5.4.2

UL 1995 (2015) Heating and Cooling Equipment, 5th Edition 5.5.2; 5.5.3

UL 2998 (2016) Environmental Claim Validation Procedure (ECVP) for Zero Ozone

Emissions from Air Cleaners

5.7.1

U.S. Government Printing Office (USGPO)

732 North Capitol St. NW

Washington, DC 20401

202-512-1800; www.gpo.gov

21 CFR 173.310 (2018) Secondary Direct Food Additives Permitted in Food for Human

Consumption—Boiler Water Additives

5.14.1

40 CFR 50 (2018) National Primary and Secondary Ambient Air Quality Standards 4.1.1; 6.1.4.1;

6.1.4.2

Reference Title Section

36 ANSI/ASHRAE Standard 62.1-2019

(This is a normative appendix and is part of the standard.)

NORMATIVE APPENDIX A

MULTIPLE-ZONE SYSTEM VENTILATION

EFFICIENCY: ALTERNATIVE PROCEDURE

This appendix presents an alternative procedure for calculating the system ventilation effi-

ciency (Ev ) for multiple-zone recirculating systems that must be used when Section 6.2.4.3 is

not used. In this alternative procedure, Ev is equal to the lowest calculated value of the zone

ventilation efficiency (Evz ) (see Equation A-2).

Informative Note: Figure A-1 contains a ventilation system schematic depicting most of the

quantities used in this appendix.

A1. SYSTEM VENTILATION EFFICIENCY

For any multiple-zone recirculating system, the system ventilation efficiency (Ev ) shall be cal-

culated in accordance with Sections A1.1 through A1.3.

A1.1 Average Outdoor Air Fraction. The average outdoor air fraction (Xs ) for the ventila-

tion system shall be determined in accordance with Equation A-1.

Xs = Vou /Vps (A-1)

where the uncorrected outdoor air intake (Vou) is found in accordance with Section 6.2.4.1 , and

the system primary airflow (Vps) is found at the condition analyzed.

Informative Note: For VAV-system design purposes, Vps is the highest expected system pri-

mary airflow at the design condition analyzed. System primary airflow at design is usually less

than the sum of design zone primary airflow values because primary airflow seldom peaks

simultaneously in all VAV zones.

A1.2 Zone Ventilation Efficiency. The zone ventilation efficiency (Evz ) shall be determined

in accordance with Section A1.2.1 or A1.2.2.

A1.2.1 Single Supply Systems. For single supply systems, wherein all of the air supplied to

each ventilation zone is a mixture of outdoor air and system-level recirculated air, zone ventila-

tion efficiency (Evz ) shall be determined in accordance with Equation A-2. Examples of single

supply systems include constant-volume reheat, single-duct VAV, single-fan dual-duct, and

multiple-zone systems.

Evz = 1 + Xs – Zpz (A-2)

where the average outdoor air fraction for the system (Xs ) is determined in accordance with Equa-

tion A-1, and the primary outdoor air fraction for the zone (Zpz ) is determined in accordance with

Equation A-3.

Zpz = Voz /Vpz (A-3)

For VAV systems, Vpz is the lowest zone primary airflow value expected at the design con-

dition analyzed.

A1.2.2 Secondary Recirculation Systems. For secondary recirculation systems wherein all

or part of the supply air to each ventilation zone is recirculated air (air that has not been

directly mixed with outdoor air) from other zones, zone ventilation efficiency (Evz ) shall be

determined in accordance with Equation A-4. Examples of secondary recirculation systems

include dual-fan dual-duct and fan-powered mixing-box systems and systems that include

transfer fans for conference rooms.

Evz = ( F a + Xs × Fb – Zpz × Ep × F

c)/F a(A-4)

where system air fractions Fa , Fb , and Fc are determined in accordance with Equation A-5, A-6,

and A-7, respectively.

Fa = Ep + ( 1 – Ep ) × Er (A-5)

Fb = Ep (A-6)

Fc = 1 – ( 1 – Ez ) × (1 – Er ) × (1 – Ep ) (A-7)

ANSI/ASHRAE Standard 62.1-2019 37

Where the zone primary air fraction (Ep ) is determined in accordance with Equation A-8,

zone secondary recirculation fraction ( Er ) is determined by the designer based on system con-

figuration, and zone air distribution effectiveness (Ez ) is determined in accordance with Section

6.2.1.2.

Ep = V

pz /V dz (A-8)

where Vdz is zone discharge airflow.

Informative Notes:

1. For plenum return systems with secondary recirculation (e.g., fan-powered VAV

with plenum return), Er is usually less than 1.0, although values may range from 0.1

to 1.2 depending upon the location of the ventilation zone relative to other zones

and the air handler. For ducted return systems with secondary recirculation (e.g.,

fan-powered VAV with ducted return), Er is typically 0.0, while for those with sys-

tem-level recirculation (e.g, dual-fan dual-duct systems with ducted return), Er is

typically 1.0. For other system types, Er is typically 0.75.

2. For single-zone and single-supply systems, Ep is 1.0.

A1.3 System Ventilation Efficiency. The system ventilation efficiency shall equal the lowest

zone ventilation efficiency among all ventilation zones served by the air handler in accordance

with Equation A-9.

Ev = minimum (Evz ) (A-9)

A2. DESIGN PROCESS

The system ventilation efficiency and, therefore, the outdoor air intake flow for the system

(Vot ) determined as part of the design process are based on the design and minimum expected

Figure A-1 Ventilation system schematic.

38 ANSI/ASHRAE Standard 62.1-2019

supply airflows to individual ventilation zones as well as the design outdoor air requirements to

the zones. For VAV system design purposes, zone ventilation efficiency (Evz ) for each ventila-

tion zone shall be found using the minimum expected zone primary airflow (Vpz ) and using the

highest expected system primary airflow (Vps ) at the design condition analyzed.

Informative Note: Increasing the zone supply airflow values during the design process, par-

ticularly to the critical zones requiring the highest fraction of outdoor air, reduces the system

outdoor air intake flow requirement determined in the calculation.

A2.1 Selecting Zones for Calculation. Zone ventilation efficiency (Evz ) shall be calculated

for all ventilation zones.

Exception to A2.1: Because system ventilation efficiency (Ev ) is determined by the minimum

value of the zone ventilation efficiency (Evz ) in accordance with Equation A-9, calculation

of Evz is not required for any ventilation zone that has an Evz value that is equal to or larger

than that of the ventilation zone for which a calculation has been made.

Informative Note: The value of Evz for a ventilation zone will be equal to or larger than that

for another ventilation zone if all of the following are true relative to the other ventilation zone:

a. Floor area per occupant (Az/Pz ) is no lower.

b. Minimum zone discharge airflow rate per unit area (Vdz/Az ) is no lower.

c. Primary air fraction (Ep ) is no lower.

d. Zone air distribution effectiveness (Ez ) is no lower.

e. Area outdoor air rate (Ra ) is no higher.

f. People outdoor air rate (Rp ) is no higher.

A3. SYMBOLS

Az zone floor area: the net occupiable floor area of the ventilation zone, ft2 (m2).

Doccupant diversity: the ratio of the system population to the sum of the zone populations.

Ep primary air fraction: the fraction of primary air in the discharge air to the ventilation zone.

Er secondary recirculation fraction: in systems with secondary recirculation of return air,

the fraction of secondary recirculated air to the zone that is representative of average

system return air rather than air directly recirculated from the zone.

Ev system ventilation efficiency: the efficiency with which the system distributes air from the

outdoor air intake to the breathing zone in the ventilation-critical zone, which requires the

largest fraction of outdoor air in the primary airstream.

Evz zone ventilation efficiency: the efficiency with which the system distributes air from the

outdoor air intake to the breathing zone in any particular ventilation zone.

Ez zone air distribution effectiveness: a measure of the effectiveness of supply air

distribution to the breathing zone. Ez is determined in accordance with Section 6.2.1.2 or

Normative Appendix C.

Fa supply air fraction: the fraction of supply air to the ventilation zone that includes sources

of air from outside the zone.

Fb mixed-air fraction: the fraction of supply air to the ventilation zone from fully mixed

primary air.

Fc outdoor air fraction: the fraction of outdoor air to the ventilation zone that includes

sources of air from outside the zone.

Ps system population: the simultaneous number of occupants in the area served by the

ventilation system.

Pz zone population: see Section 6.2.1.1.

Ra area outdoor air rate: see Section 6.2.1.1.

Rp people outdoor air rate: see Section 6.2.1.1.

Vbz breathing zone outdoor airflow: see Section 6.2.1.1.

Vdz zone discharge airflow: the expected discharge (supply) airflow to the zone that includes

primary airflow and secondary recirculated airflow, cfm (L/s).

ANSI/ASHRAE Standard 62.1-2019 39

Vot outdoor air intake flow: see Sections 6.2.2, 6.2.3, and 6.2.4.4.

Vou uncorrected outdoor air intake: see Section 6.2.4.1.

Voz zone outdoor airflow: see Section 6.2.1.3.

Vps system primary airflow: the total primary airflow supplied to all zones served by the

system from the air-handling unit at which the outdoor air intake is located.

Vpz zone primary airflow: the zone primary airflow to the ventilation zone, including outdoor

air and recirculated air.

Xs average outdoor air fraction: at the primary air handler, the fraction of outdoor air intake

flow in the system primary airflow.

Zpz primary outdoor air fraction: the outdoor air fraction required in the primary air supplied

to the ventilation zone prior to the introduction of any secondary recirculation air.

40 ANSI/ASHRAE Standard 62.1-2019

(This is a normative appendix and is part of the standard.)

NORMATIVE APPENDIX B

SEPARATION OF EXHAUST OUTLETS AND OUTDOOR AIR INTAKES

B1. GENERAL

This appendix presents an alternative procedure for determining separation distance between

outdoor air intakes and exhaust air and vent outlets. This analytical method can be used instead

of Table 5-1.

Exhaust air and vent outlets, as defined in Table 5-1 , shall be located no closer to outdoor air

intakes, or to operable windows, skylights, and doors, both those on the subject property and those

on adjacent properties, than the minimum separation distance (L ) specified in this section. The

distance (L ) is defined as the shortest "stretched string" distance measured from the closest point

of the outlet opening to the closest point of the outdoor air intake opening, or to the operable

window, skylight, or door opening, along a trajectory as if a string were stretched between them.

B1.1 Application. Laboratory fume hood exhaust air outlets shall be in compliance with

NFPA 45 and ANSI/AIHA Z9.5. Nonlaboratory exhaust outlets and outdoor air intakes or

other openings shall be separated in accordance with the following.

B1.2 Outdoor Air Intakes. The minimum separation distance between exhaust air/vent out-

lets, as defined in Table 5-1 , and outdoor air intakes to mechanical ventilation systems, or to

operable windows, skylights, and doors that are required as part of natural ventilation systems,

shall be equal to distance (L) determined in accordance with Section B2.

Exception to B1.2: Separation distances do not apply when exhaust and outdoor air intake

systems are controlled such that they cannot operate simultaneously.

B1.3 Other Building Openings. The minimum separation distance between building exhaust

air/vent outlets, as defined in Table 5-1 , and operable openings to occupiable spaces shall be

half of the distance (L ) determined in accordance with Section B2. The minimum separation

distance between either Class 3, Class 4, cooling tower, or combustion appliance/equipment

exhaust air/vent outlets and operable openings to occupiable spaces shall be equal to the dis-

tance (L) determined in accordance with Section B2.

B1.4 Additional Limitations for Noxious or Dangerous Air. The minimum separation dis-

tance between exhausts located less than 65 ft (20 m) vertically below outdoor air intakes or

operable windows and doors shall be equal to a horizontal separation only as determined in

accordance with Section B2; no credit may be taken for any vertical separation.

B1.5 Equipment Wells. Exhaust air outlets that terminate in an equipment well that also

encloses an outdoor air intake shall meet the separation requirements of this section and, in

addition, shall either

a. terminate at or above the highest enclosing wall and discharge air upward at a velocity

exceeding 1000 fpm (5 m/s) or

b. terminate 3 ft (1 m) above the highest enclosing wall (with no minimum velocity).

Exception to B1.5: Exhaust air designated as Class 1 or Class 2.

B1.6 Property Lines. The minimum separation distance between exhaust air/vent outlets and

property lines shall be half of the distance (L) determined in accordance with Section B2.

Exception to B1.6: For Class 3, Class 4, or combustion appliance/equipment exhaust air,

where the property line abuts a street or other public way, no minimum separation is

required if exhaust termination is at least 10 ft (3 m) above grade.

B2. DETERMINING DISTANCE L

The minimum separation distance (L ) shall be determined using one of the following three

approaches:

B2.1 Simple Method. A value of L in Table B-1 shall be used.

B2.2 Velocity Method. The value of L shall be determined using Equation B-1a (I-P) or B-1b (SI).

L = 0.09 ×  Q × ( DF – U/400) [ft] (B-1a)

L = 0.04 ×  Q × ( DF – U/2) [m] (B-1b)

ANSI/ASHRAE Standard 62.1-2019 41

where

Q=exhaust airflow rate, cfm (L/s). For gravity vents, such as plumbing vents, use an

exhaust rate of 150 cfm (75 L/s). For flue vents from fuel-burning appliances, assume

a value of 250 cfm per million Btu/h (0.43 L/s per kW) of combustion input (or obtain

actual rates from the combustion appliance manufacturer).

U= exhaust air discharge velocity, fpm (m/s). As shown in Figure B-1, U shall be

determined using Table B-2.

DF = dilution factor, which is the ratio of outdoor airflow to entrained exhaust airflow in the

outdoor air intake. The minimum dilution factor shall be determined as a function of

exhaust air class in Table B-3.

For exhaust air comprising more than one class of air, the dilution factor shall be determined

by averaging the dilution factors by the volume fraction of each class using Equation B-3:

DF =  (DFi × Qi )/ Qi (B-3)

where

DFi = dilution factor from Table B-2 for class i air

Qi = volumetric flow rate of class i air in the exhaust airstream

B2.3 Concentration Method. Determine the acceptable concentration for health (Chealth ) and

odor (Codor ) for each emitted chemical, compound, or mixture.

Design the exhaust and intake systems such that the maximum concentration at the intake

(Cmax ) is less than the acceptable concentrations of all evaluated compounds and mixtures.

Cmax < Chealth (B-4)

Cmax < Codor (B-5)

At a minimum, determination of Cmax shall consider wind speed, wind direction, exhaust

exit velocity and momentum, geometry of building and adjacent structures, and architectural

screens. Wind tunnel modeling is an acceptable design method.

Table B-1 Minimum Separation Distance

Exhaust Air Class (See Section 5.18) Separation Distance, L, ft (m)

Significant contaminant or odor intensity (Class 3) 15 (5)

Noxious or dangerous particles (Class 4) 30 (10)

Figure B-1 Exhaust air discharge velocity (U).

42 ANSI/ASHRAE Standard 62.1-2019

Table B-2 Exhaust Air Discharge Velocity

Exhaust Direction/Configuration

Exhaust Air Discharge

Velocity (U) Modifier

Exhaust is directed away from the outdoor air intake at an angle that is greater than 45 degrees from

the direction of a line drawn from the closest exhaust point to the edge of the intake.

U given a positive value.

Exhaust is directed toward the intake bounded by lines drawn from the closest exhaust point to the

edge of the intake.

U given a negative value.

Exhaust is directed at an angle between the two above cases. U is zero.

Vents from gravity (atmospheric) fuel-fired appliances, plumbing vents, and other nonpowered

exhausts, or if the exhaust discharge is covered by a cap or other device that dissipates the exhaust

airstream.

U is zero.

Hot-gas exhausts such as combustion products if the exhaust stream is aimed directly upward and

unimpeded by devices such as flue caps or louvers.

Add 500 fpm (2.5 m/s)

upward velocity to U.

Table B-3 Minimum Dilution Factors

Exhaust Air Class (See Section 5.18) Dilution Factor (DF)

Significant contaminant or odor intensity (Class 3) 15

Noxious or dangerous particles (Class 4) 50 a

a. Does not apply to fume hood exhaust. See Section B1.1.

ANSI/ASHRAE Standard 62.1-2019 43

(This is a normative appendix and is part of the standard.)

NORMATIVE APPENDIX C

ZONE AIR DISTRIBUTION EFFECTIVENESS: ALTERNATE PROCEDURES

This appendix provides a procedure for determining zone air distribution effectiveness (Ez ) for

all system types.

Informative Note: Table 6-4 provides default values of Ez that are be permitted to be used

for the air distribution configurations described in the table. The reference Ez value of 1 is typ-

ical of ideal mixing in the zone. The strategy of removing contaminants or displacing contami-

nants from the breathing zone may result in an effective Ez value greater than unity, which is

typical of stratified systems.

C1. ZONE AIR DISTRIBUTION EFFECTIVENESS

Zone air distribution effectiveness shall be calculated in accordance with Equation C-1:

Ez = (Ce – Cs )/(C – Cs ) (C-1)

where

Ez = zone air distribution effectiveness

C = average contaminant concentration at the breathing zone

Ce = average contaminant concentration at the exhaust

Cs = average contaminant concentration at the supply

C1.1 Personalized Ventilation Systems. For the purpose of calculating zone air distribution

effectiveness for personalized ventilation systems, the breathing zone shall be 9 ft2 (0.8 m2)

centered on each occupant with a height of 4.5 ft (1.4 m) from the floor.

C2. MODELED AIR DISTRIBUTION SYSTEM

C2.1 Computational Model. The computational fluid dynamics (CFD) model for calculating

zone air distribution effectiveness shall be in accordance with the following subsections.

C2.1.1 Computational Domain. The computational domain shall comprise all sensible heat

sources, all major obstructions to airflow, and all air distribution devices. The calculation

domain shall include all boundary walls.

C2.1.2 Solution Variables. Analysis shall include the solutions for fluid flow, heat transfer,

and chemical species transport. The buoyancy (gravitational) effects shall be included in the

calculation procedure.

C2.1.3 Boundary Conditions. Sensible heat sources shall be permitted to be modeled as

volumetric heat sources to allow the air to pass through the source or as hollow blocks (no

mesh inside) specified with either heat flux or constant temperature on the surfaces of the

blocks. Boundary walls shall be modeled as adiabatic (zero heat flux), specified heat flux, or

specified temperature boundary.

C2.1.4 Species Transport. The sources shall be modeled as volumetric source or a bound-

ary flux with known generation rate with zero release velocity. The analysis shall be performed

with a uniformly distributed source at the breathing zone level of the occupants. All the bound-

ary walls shall be modeled as impermeable to the chemical species.

Informative Note: The species modeled should be a tracer gas, such as CO2. Discretion is

left to the modeler to determine the appropriate model depending on the design compounds in

the zone.

C2.1.5 Turbulence Model. Reynolds (ensemble) averaging turbulence models shall be used.

Informative Note: RNG and realizable k- models meet the requirements of this section.

C2.1.6 Computational Mesh. A fine mesh shall be generated near the sensible heat

sources, such as occupants and computers, to resolve the thermal plume surrounding these

sources. The fine mesh shall be generated on all supply air and return air locations.

C2.1.7 Solution Convergence. The solution convergence levels shall include the monitoring

of relevant physical quantities, such as temperature or species concentration, at strategic loca-

tions. The globally scaled residuals shall be decreased to10–3 for all equations except the

44 ANSI/ASHRAE Standard 62.1-2019

energy and species equations, for which the residuals shall be decreased to 10–7 . The mass and

energy balance shall be calculated up to at least four (4) decimal places.

Informative Note: Review of the thermal comfort of occupants in the computational model

may be desirable.

C2.2 Zone Air Distribution Effectiveness. Zone air distribution effectiveness (Ez ) shall be

computed in accordance with Equation C-1 for each computational cell in the breathing zone.

The zone air distribution effectiveness (Ez ) of the system shall be the average value of the zone

air distribution effectiveness of each computational cell within the breathing zone. The analysis

shall be performed for both summer cooling conditions and winter heating conditions.

Informative Note: Validation of the computational model with physical measurements

during design can improve the accuracy of the computational model and the zone air distribu-

tion effectiveness of the system. Field measurements could also be performed post building

occupancy to verify zone air distribution effectiveness.

ANSI/ASHRAE Standard 62.1-2019 45

(This appendix is not part of this standard. It is merely informative and does not contain

requirements necessary for conformance to the standard. It has not been processed

according to the ANSI requirements for a standard and may contain material that has

not been subject to public review or a consensus process. Unresolved objectors on infor-

mative material are not offered the right to appeal at ASHRAE or ANSI.)

INFORMATIVE APPENDIX D

INFORMATION ON SELECTED NATIONAL STANDARDS

AND GUIDELINES FOR PM10, PM2.5, AND OZONE

Standard 62.1, Section 4 , requires that the status of compliance with National Ambient Air

Quality Standards (NAAQS) shall be determined for the geographical area of the building site.

Table D-1 is a representative table presenting the NAAQS information for the United States.

Links to detailed information on the ambient air quality standards and contaminant levels for

other select counties and regions are as follows:

• U.S. National Ambient Air Quality Standards (NAAQS): www.epa.gov/green-book and

www.epa.gov/criteria-air-pollutants/naaqs-table

• Canadian Ambient Air Quality Standards: www.ccme.ca/en/current_priorities/air/

caaqs.html

• Hong Kong Air Quality Objectives: www.epd.gov.hk/epd/english/environmentinhk/air/

air_quality_objectives/air_quality_objectives.html

• Singapore Air quality Targets: www.nea.gov.sg/our-services/pollution-control/air-pollution/

air-quality

• European Commission Air Quality Standards: ec.europa.eu/environment/air/quality/stan-

dards.htm

• Brazil Air Quality Standards: transportpolicy.net/index.php?title=Brazil:_Air_Quality_-

Standards

• World Health Organization (WHO) Air Quality Guideline Values: www.who.int/mediacen-

tre/factsheets/fs313/en

The Clean Air Act (www.epa.gov/clean-air-act-overview), which was last amended in

1990, requires the U.S. Environmental Protection Agency (USEPA) to set national ambient air

quality standards (40 CFR part 50) for pollutants considered harmful to public health and the

environment. The Clean Air Act identifies two types of national ambient air quality standards.

Primary standards provide public health protection, including protecting the health of "sensi-

tive" populations, such as asthmatics, children, and the elderly. Secondary standards provide

public welfare protection, including protection against decreased visibility and damage to ani-

mals, crops, vegetation, and buildings.

USEPA has set NAAQS for six principal pollutants, which are called "criteria" air pollut-

ants (www.epa.gov/criteria-air-pollutants ). Periodically, the standards are reviewed and may be

revised. The current standards are listed in Table D-1 . Units of measure for the standards are

parts per million (ppm) by volume, parts per billion (ppb) by volume, and micrograms per

cubic metre of air ( g/m3).

46 ANSI/ASHRAE Standard 62.1-2019

Table D-1 National Ambient Air Quality Standards for the Unites States

(www.epa.gov/criteria-air-pollutants/naaqs-table)

Pollutant

Primary/

Secondary

Averaging

Time Level Form

Carbon Monoxide (CO)

www.epa.gov/co-pollution/table-historical-

carbon-monoxide-co-national-ambient-air-

quality-standards-naaqs

Primary Eight (8) hours 9 ppm Not to be exceeded more

than once per year

One (1) hour 35 ppm

Lead (Pb)

www.epa.gov/lead-air-pollution/table-

historical-lead-pb-national-ambient-air-

quality-standards-naaqs

Primary and

secondary

Rolling three (3)

month average

0.15  g/m 3

(Note 1)

Not to be exceeded

Nitrogen Dioxide (NO2)

www.epa.gov/no2-pollution/table-historical-

nitrogen-dioxide-national-ambient-air-

quality-standards-naaqs

Primary One (1) hour 100 ppb Ninety-eighth (98th)

percentile of

one-hour daily

maximum

concentrations, averaged

over three years

Primary and

secondary

One (1) year 53 ppb

(Note 2)

Annual mean

Ozone (O3 )

www.epa.gov/ozone-pollution/table-

historical-ozone-national-ambient-air-

quality-standards-naaqs

Primary and

secondary

Eight (8) hours 0.070 ppm

(Note 3)

Annual fourth-highest

daily maximum eight-

hour concentration,

averaged over three

years

Particle Pollution (PM)

www.epa.gov/pm-pollution/

table-historical-particulate-

matter-pm-national-ambient-air-

quality-standards-naaqs

PM2.5 Primary One (1) year 12.0  g/m3 Annual mean, averaged

over three years

Secondary One (1) year 15.0  g/m3 Annual mean, averaged

over three years

Primary and

secondary

Twenty-four

(24) hours

35  g/m3 Ninety-eight (98th)

percentile, averaged

over three years

PM10 Primary and

secondary

Twenty-four

(24) hours

150  g/m3 Not to be exceeded more

than once per year on

average over three years

Sulfur Dioxide (SO2)

www.epa.gov/so2-pollution/table-historical-

sulfur-dioxide-national-ambient-air-quality-

standards-naaqs

Primary One (1) hour 75 ppb

(Note 4)

Ninety-ninth (99th)

percentile of

one-hour daily

maximum

concentrations, averaged

over three years

Secondary Three (3) hours 0.5 ppm Not to be exceeded more

than once per year

Note 1: In areas designated "nonattainment" for the Pb standards prior to the promulgation of the current (2008) standards, and for which implementation plans to attain

or maintain the current (2008) standards have not been submitted and approved, the previous standards (1.5  g/m3 as a calendar quarter average) also remain in effect.

Note 2: The level of the annual NO2 standard is 0.053 ppm. It is shown here in terms of ppb for the purpose of clearer comparison to the one-hour standard level.

Note 3: Final rule signed October 1, 2015, and effective December 28, 2015. The previous (2008) O3 standards additionally remain in effect in some areas. Revocation

of the previous (2008) O3 standards and transitioning to the current (2015) standards will be addressed in the implementation rule for the current standards.

Note 4: The previous SO2 standards (0.14 ppm 24-hour and 0.03 ppm annual) will additionally remain in effect in certain areas: (a) any area for which it is not yet one

year since the effective date of designation under the current (2010) standards, and (b) any area for which an implementation plan providing for attainment of the current

(2010) standard has not been submitted and approved and that is designated "nonattainment" under the previous SO2 standards or is not meeting the requirements of an

SIP call under the previous SO2 standards (40 CFR 50.4[3). An SIP call is an EPA action requiring a state to resubmit all or part of its State Implementation Plan to demon-

strate attainment of the required NAAQS.

ANSI/ASHRAE Standard 62.1-2019 47

(This appendix is not part of this standard. It is merely informative and does not contain

requirements necessary for conformance to the standard. It has not been processed

according to the ANSI requirements for a standard and may contain material that has

not been subject to public review or a consensus process. Unresolved objectors on infor-

mative material are not offered the right to appeal at ASHRAE or ANSI.)

INFORMATIVE APPENDIX E

ACCEPTABLE MASS BALANCE EQUATIONS

FOR USE WITH THE IAQ PROCEDURE

When applying the IAQ Procedure from Section 6.3, mass balance analysis may be employed

to determine outdoor air ventilation requirements to control concentrations to meet design tar-

gets.

Table E-1 presents mass balance equations for analysis of single-zone systems. Figures E-1

and E-2 show representative single-zone systems. A filter may be located in the recirculated air-

stream (location A) or in the supply (mixed) airstream (location B). The equations do not account

for sources within the HVAC system that may occur, such as filter off-gassing, energy recovery

carryover of specific gases, or generation of particles or compounds.

Variable-air-volume (VAV) single-zone systems reduce the circulation rate when the ther-

mal load is lower than the design load. This is accounted for by a flow reduction fraction (Fr ).

A mass balance equation for each design compound or PM2.5 may be written and used to

determine the required outdoor airflow or the breathing zone resultant concentration for the var-

ious system arrangements. Six permutations for air-handling and single-zone air distribution

systems are described in Table E-1 . The mass balance equations for computing the required out-

door airflow and the breathing-zone contaminant concentration at steady-state conditions for

each single-zone system are presented in Table E-1.

If the allowable breathing zone design target is specified, the equations in Table E-1 may

be solved for the zone outdoor airflow rate (Voz ). When the zone outdoor airflow rate is speci-

fied, the equations may be solved for the resulting breathing zone design compound or PM2.5

concentration.

While the calculation methods in this appendix are based on single-zone systems and

steady-state analysis, calculation methods that account for multiple-zone and transient effects

are also available (see Dols and Walton [2002] in Informative Appendix M).

48 ANSI/ASHRAE Standard 62.1-2019

Table E-1 Required Zone Outdoor Airflow or Space Breathing Zone Contaminant Concentration with

Recirculation and Filtration for Single-Zone Systems

Required Recirculation Rate

Required Zone Outdoor Airflow

(Voz in Section 6)

Space Breathing Zone

Contaminant Concentration

Filter

Location Flow

Outdoor

Airflow

None VAV 100%

A Constant Constant

A VAV Constant

B Constant Constant

B VAV 100%

B VAV Constant

Symbol or Subscript Definition

A, B filter location

V volumetric flow

C contaminant concentration

Ez zone air distribution effectiveness

Ef filter efficiency

Fr design flow reduction fraction factor

N contaminant generation rate

R recirculation flow factor

Subscript: o outdoor

Subscript: r return

Subscript: bbreathing

Subscript: zzone

Voz

Ez Fr Cbz Co

– 

-------------------------------------- =Cbz Co

Ez Fr Voz

-------------------- - +=

Voz

zRV rE fC bz

–

Ez Cbz Co

– 

------------------------------------------- =Cbz

zV ozC o

Ez Voz RV r Ef

+ 

------------------------------------------- =

Voz

zF rRV rE fC bz

–

Ez Cbz Co

– 

------------------------------------------------- - =Cbz

zV ozC o

Ez Voz Fr RV r Ef

+ 

------------------------------------------------- - =

Voz

zRV rE fC bz

–

Ez Cbz 1 Ef

–  Co

 – 

--------------------------------------------------------- - =Cbz

zV oz 1E f

–  Co

Ez Voz RV r Ef

+ 

----------------------------------------------------- - =

Voz

Ez Fr Cbz 1 Ef

–  Co

 – 

---------------------------------------------------------------- =Cbz

zF rV oz 1E f

–  Co

Ez Fr Voz

------------------------------------------------------------ =

Voz

zF rRV r E fC bz

–

Ez Cbz 1 Ef

–  Co

 – 

--------------------------------------------------------- - =Cbz

zV oz 1E f

–  Co

Ez Voz Fr RV r Ef

+ 

----------------------------------------------------- -

Figure E-1 Ventilation system schematic—constant-

volume system with no infiltration/exfiltration. (*Vot =

Voz for single-zone systems.)

Figure E-2 Ventilation system schematic—variable-

air-volume system with no infiltration/exfiltration.

(*Vot =Voz for single-zone systems).

ANSI/ASHRAE Standard 62.1-2019 49

(This appendix is not part of this standard. It is merely informative and does not contain

requirements necessary for conformance to the standard. It has not been processed

according to the ANSI requirements for a standard and may contain material that has

not been subject to public review or a consensus process. Unresolved objectors on infor-

mative material are not offered the right to appeal at ASHRAE or ANSI.)

INFORMATIVE APPENDIX F

SIMPLIFIED VENTILATION RATE CALCULATION FOR

MULTIPLE-ZONE RECIRCULATING SYSTEMS SERVING ONLY

SPECIFIED OCCUPANCY CATEGORIES IN EXISTING BUILDINGS

F1. USE OF THIS APPENDIX

This appendix is intended to be used to assess ventilation rates in existing buildings for third-

party building evaluation programs such as ASHRAE Building EQ (bEQ), Leadership in

Energy and Environmental Design for Existing Buildings: Operations and Maintenance

(LEED EBOM), Energy Star, etc. Zone minimum primary airflow is included as guidance in

evaluating and adjusting minimum box settings. This informative appendix is not intended to

be used as the Basis of Design or for regulatory applications.

F2. OUTDOOR AIR INTAKE

For multiple-zone recirculating systems serving only occupancy categories listed in Table F-1,

the target outdoor air intake flow (Vtarget ) is determined in accordance with Equation F-1. For

all other systems, Vtarget shall be set equal to Vot in accordance with Section 6.2.4.4 . If the min-

imum outdoor air intake flows measured at the system level meet or exceed Vtarget , then the

system meets the criteria of this informative appendix.

Vtarget = all zones Az × Rs (F-1)

where

Az = zone floor area, the net occupiable floor area of the ventilation zone, ft2 (m2)

Rs = outdoor airflow rate required per unit area as determined from Table F-1

F3. ZONE MINIMUM PRIMARY AIRFLOW

For each zone, the minimum primary airflow (Vpz-min ) is determined in accordance with Equa-

tion F-2.

Vpz-min = Az × Rpz (F-2)

where

Rpz = minimum primary airflow rate required per unit area as determined from Table F-1.

This is the minimum zone airflow required for ventilation purposes.

50 ANSI/ASHRAE Standard 62.1-2019

Table F-1 Minimum Outdoor and Primary Airflow Rates

Occupancy Category

Zone Minimum Airflow

Outdoor Airflow Rate Rs Minimum Primary Airflow Rate, Rpz

cfm/ft2L/s·m2cfm/ft2L/s·m2

Educational Facilities

Classrooms (ages 5 to 8) 0.65 3.25 1.12 5.60

Classrooms (ages 9 plus) 0.82 4.10 1.41 7.05

Computer lab 0.65 3.25 1.12 5.60

Media center 0.65 3.25 1.12 5.60

Music/theater/dance 0.72 3.60 1.24 6.20

Multiuse assembly 1.42 7.10 2.45 12.25

General

Conference/meeting 0.44 2.20 0.76 3.80

Corridors 0.11 0.55 0.19 0.95

Office Buildings

Breakrooms 0.65 3.25 1.12 5.60

Main entry lobbies 0.19 0.95 0.33 1.65

Occupiable storage rooms for dry materials 0.12 0.60 0.21 1.05

Office space 0.15 0.75 0.26 1.30

Reception areas 0.37 1.85 0.64 3.20

Telephone/data entry 0.63 3.15 1.09 5.45

Public Assembly Spaces

Libraries 0.30 1.50 0.52 2.60

ANSI/ASHRAE Standard 62.1-2019 51

(This appendix is not part of this standard. It is merely informative and does not contain

requirements necessary for conformance to the standard. It has not been processed

according to the ANSI requirements for a standard and may contain material that has

not been subject to public review or a consensus process. Unresolved objectors on infor-

mative material are not offered the right to appeal at ASHRAE or ANSI.)

INFORMATIVE APPENDIX G

APPLICATION

This appendix contains application and compliance suggestions that are intended to assist users

and enforcement agencies in applying this standard.

Although the standard may be applied to both new and

existing buildings, the provi-

sions of this standard are not

intended to be applied retroactively when the standard is used

as a mandatory regulation or code.

For the most part, Standard 62.1 is specifically written for new buildings because some of

its requirements assume that other requirements within the standard have been met. In the case

of existing buildings, retroactive application and compliance with all the requirements of this

standard may not be practical. However, the principles established in this standard may be

applied to most existing commercial and institutional buildings. Some existing buildings may

achieve acceptable IAQ despite not meeting the requirements of Standard 62.1 due to, for

example, good maintenance and capital improvement procedures; building materials that, by

virtue of their age, have very low contaminant emission rates; and many other factors.

G1. APPLICATION

G1.1 New Buildings. All sections and normative appendices should apply to new buildings

falling within the scope of this standard.

G1.2 Existing Buildings. The standard should be applied to existing buildings at least in the

circumstances described in the following subsections.

G1.2.1 Additions to Existing Buildings. All additions to existing buildings should meet the

requirements of this standard as if the addition were a new building. An exception may be made

when an existing ventilation system is extended to serve the addition. In this case, the existing

system components, such as fans and cooling and heating equipment, need not meet the require-

ments of this standard. However, the extended existing system should remain in compliance with

ventilation codes and standards that were in effect at the time it was permitted for construction.

G1.2.2 Repairs. Repairing (making operational) existing equipment or other building com-

ponents does not require the building or any of its components to retroactively comply with this

standard.

G1.2.3 Replacement. Any component of a building that is removed and replaced should

meet the applicable requirements of Section 5 , "Systems and Equipment," of this standard for

that component. An exception may be made in cases when replacing a component of like size

and kind, provided all requirements of codes and standards used at the time of original system

design and installation are met. For example, replacement of an air-conditioning unit with one

of similar capacity would not require retroactive compliance with ventilation rates and other

requirements of this standard. Unaltered components do not need to be retroactively brought

into compliance except when there are substantial alterations (as defined below).

G1.2.4 Substantial Alterations. If a building is substantially altered, the requirements of

this standard should be met as if the building were new. A building would be considered sub-

stantially altered if the cost of the revisions exceeds 50% of the building's fair market value,

excluding the cost of compliance with this standard.

G1.2.5 Change in Use. If the space application category, as listed in Table 6-1 , changes—

such as from office to retail—the minimum ventilation rates required by Section 6 , "Proce-

dures," should be met for that space.

G1.2.6 Contaminants. Ventilation requirements of this standard are based on chemical,

physical, and biological contaminants that can

affect air quality.

G1.2.7 Thermal Comfort. Control of thermal comfort is not

required by this standard.

Requirements for thermal comfort are contained in ASHRAE Standard 55. Note that there are

strong correlations between peoples' perception of IAQ and their perception of thermal comfort.

52 ANSI/ASHRAE Standard 62.1-2019

G1.2.8 Limitations. Acceptable IAQ might not be achieved in all

buildings meeting the

requirements of this standard for one or more of the following reasons:

a. Because of the diversity of sources and contaminants in

indoor air

b. Because of the many other factors that might affect occupant perception and acceptance of

IAQ, such as air temperature, humidity, noise, lighting, and psychological stress

c. Because of the range of susceptibility in the population

d. Because outdoor air brought into the building might be

unacceptable or might not be

adequately cleaned

The following section provides suggested model code language.

APPLICATION AND COMPLIANCE

Application

New Buildings. All sections and normative appendices apply to new buildings falling within

the scope of this standard.

Existing Buildings

Additions to Existing Buildings. All additions to existing buildings within the scope of this

standard shall meet the requirements of all sections and normative appendices.

Exception: When an existing ventilation system is extended to serve an addition, the existing

system components, such as fans and cooling and heating equipment, need not meet the

requirements of this standard. However, the extended existing system must remain in com-

pliance with ventilation codes and standards that were in effect at the time it was permit-

ted for construction.

Repairs. Repairing (making operational) existing equipment or other building components

shall be allowed without requiring the building or any of its components to comply with this

standard.

Replacement. Any component of a building that is removed and replaced shall meet the appli-

cable requirements of Section 5, "Systems and Equipment," of this standard for that compo-

nent. Unaltered components are not required to be brought into compliance except as required

due to a change in use.

Exception: Replacement of a building component or individual piece of equipment with a

component of like size and kind, provided that all requirements of codes effective at the

time of original system design and installation are met. For example, replacement of an

air-conditioning unit with one of similar capacity would not require that the ventilation

rate requirements and other requirements of this standard be met.

Substantial Alterations. If a building is substantially altered, all sections and normative appen-

dices of this standard shall be met as if the building were new. A building shall be considered

substantially altered if the cost of the revisions exceeds 50% of the building's fair market value,

excluding the cost of compliance with all sections and normative appendices of this standard.

Change in Use. If the space application category as listed in Table 2 changes, such as from

office to retail, the minimum ventilation rates required by Section 6, "Procedures," shall be met

for that space.

Compliance

Demonstrating that acceptable IAQ has been achieved, such as by measuring contaminant

concentrations or surveying occupants, is not required by this standard except where required

by the IAQ Procedure.

ANSI/ASHRAE Standard 62.1-2019 53

(This appendix is not part of this standard. It is merely informative and does not contain

requirements necessary for conformance to the standard. It has not been processed

according to the ANSI requirements for a standard and may contain material that has

not been subject to public review or a consensus process. Unresolved objectors on infor-

mative material are not offered the right to appeal at ASHRAE or ANSI.)

INFORMATIVE APPENDIX H

DOCUMENTATION

This appendix summarizes the requirements for documentation contained in the body of the

standard using a series of templates that summarizes the design criteria used and assumptions

made to comply with this standard. One way to comply with the documentation requirements

of the standard is to complete these templates as appropriate during the project design process.

H1. OUTDOOR AIR QUALITY

Section 4.3 of this standard requires an investigation of the outdoor air quality in the vicinity of

the project site. This template offers a means of documenting the results of both the regional

and local investigations and the conclusions reached concerning the acceptability of the out-

door air quality for indoor ventilation.

H2. BUILDING VENTILATION DESIGN CRITERIA

This template provides a means of documenting significant design criteria for the overall build-

ing. Only the last column, in accordance with Section 5.1.3 , is specifically required by the

standard. The other columns are motivated by the general documentation requirement

described in Section 6.6.

H3. VENTILATION RATE PROCEDURE

Section 6.2 permits the use of this prescription-based procedure to design ventilation systems.

This template documents the assumptions made when using this procedure as required by Sec-

tions 5.18.4 and 6.6.

H4. IAQ PROCEDURE

Section 6.3 permits the use of this performance-based procedure to design ventilation systems.

This template documents the design criteria and assumptions made when using this procedure

and justification of the design approach, as required by Section 6.3.2.

54 ANSI/ASHRAE Standard 62.1-2019

Regional Outdoor Air Quality Pollutants

Attainment or Nonattainment According to the

U.S. Environmental Protection Agency (USEPA)

Particulates (PM2.5) (Yes/No)

Particulates (PM10) (Yes/No)

Carbon monoxide—1 hour/8 hours (Yes/No)

Ozone (Yes/No)

Nitrogen dioxide (Yes/No)

Lead (Yes/No)

Sulfur dioxide (Yes/No)

Local Outdoor Air Quality Survey Date: Time:

(a) Area surveyed (Brief description of the site)

(b) Nearby facilities (Brief description type of facilities—industrial, commercial, hospitality, etc.)

(d) Visible plumes (List and describe)

(e) Nearby sources of vehicle exhaust (List and describe)

(f) Prevailing winds (Direction)

(g) Other observations

(h) Conclusions (Remarks concerning the acceptability of the outdoor air quality)

Building Ventilation Design Criteria

Total

Building

Outdoor

Air Intake

Total Building

Exhaust Air

(see Section 5.11)

Outdoor Air

Cleaning Required

(See Section 6.1.4) Indoor Air Dew Point (Section 5.10)

Air Balancing

(See Section 5.1.3)

Particulate

Matter Ozone

Peak Outdoor DP

at Dehumidification

Design Condition

Calculated Space DP

at Concurrent

Outdoor Condition

(cfm) (cfm) (Yes/No) (Yes/No) (Dew point) (Dew point) (NEBB, AABC, etc.)

ANSI/ASHRAE Standard 62.1-2019 55

Space

Identification Space Type

Occupant

Density Rate/Person Rate/SF

Zone Air

Distribution

Effectiveness

System

Ventilation

Efficiency Class of Air

(List number or

name of each

ventilation zone,

such as office

number or

name, retail

space name, or

classroom

number.)

(List occupancy

category of the

space from

Table 6-1, such as

Office Space,

Retail Sales,

Classroom Ages 5

to 8, etc.)

(People/

ft2 or m2)

(cfm or L/s) (cfm or L/s) (Table 6-4) (Section 6.2.5;

Normative

Appendix A)

(Tables 6-1 or

6-3; include

justification for

classification if not

in these tables)

IAQ Procedure Assumptions

Contaminant of

Concern

Contaminant

Source

Contaminant

Strength

Contaminant Target Concentration

Perceived

IAQ

Design

ApproachLimit

Exposure

Period

Cognizant

Authority

Reference

(Identify

and list)

(Identify

and list)

(Determine

and list)

(List) (List) (List) (Percentage of

satisfied building

occupants)

(Select from

Section 6.3.4

and include

justification.)

56 ANSI/ASHRAE Standard 62.1-2019

(This appendix is not part of this standard. It is merely

informative and does not contain requirements necessary

for confor-

mance to the standard. It has not been processed according to the ANSI requirements for a standard and may contain material

that has not been subject to public review or a consensus process. Unresolved objectors on informative material are not offered

the right to appeal at ASHRAE or ANSI.)

INFORMATIVE APPENDIX I

RATE RATIONALE

Table I-1 provides description and rationale for the Ventilation Rate Procedure rates in Table 6-1, "Minimum Ventilation Rates in Breathing

Zone." This information may be helpful to designers and other practitioners.

Table I-1 Rate Rationale (see Table 6-1)

Occupancy

Category Description/Rationale

People

Outdoor

Air Rate,

cfm/person

People

Outdoor

Air Rate,

L/s/person

Area

Outdoor

Air Rate,

cfm/ft2

Area

Outdoor

Air Rate,

L/s·m2

Air

Class

Correctional Facilities

Booking/waiting Occupant activity varies between sedentary and moderate walking. Occupants are generally more vocal.

Occupants may not be as well-groomed as typical occupants. Occupant stress levels are generally high. All of

which result in higher metabolic rates. There are no significant space-related contaminants.

7.5 3.8 0.06 0.3 2

Cell Occupant activity is primarily sedentary (seated or sleeping). There are typically higher levels of space-related

contaminants due to presence of a water closet, sink, and stored clothing. The presence of a water closet is the

primary reason why this space has an Air Class of 2.

5 2.5 0.12 0.6 2

Day room Occupant activity is primarily sedentary (seated, watching television). There are no significant space-related

contaminants.

5 2.5 0.06 0.3 1

Guard stations Occupant activity is primarily sedentary (seated). There are no significant space-related contaminants. 5 2.5 0.06 0.3 1

Educational Facilities

Art

classroom

Occupant activity is moderate. There is considerable aerobic activity in addition to the occupants being very

vocal. Also, the occupants are primarily children with higher metabolic rates. There are significant space-

related contaminants, including open paints, glues, and cleaning agents. The presence of these open

contaminants result in this space being classified as Air Class 2.

10 5 0.18 0.9 2

Classrooms

(ages 5 through 8)

Occupant activity is primarily sedentary (seated or light walking). However, occupants are generally more

vocal. Also, the occupants are primarily children with higher metabolic rates and often more bioeffluents. There

are some significant space-related contaminants, typically stored arts-and-crafts supplies and cleaning agents.

10 5 0.12 0.6 1

ANSI/ASHRAE Standard 62.1-2019 57

Classrooms

(age 9 plus)

Occupant activity is primarily sedentary (seated or light walking). However, occupants are generally more

vocal. Also, the occupants are primarily children with higher metabolic rates and often more bioeffluents. There

are some significant space-related contaminants, typically stored arts-and-crafts supplies and cleaning agents.

10 5 0.12 0.6 1

Computer lab Occupant activity is primarily sedentary (seated or light walking). However, occupants are generally more

vocal. Also, the occupants can be children/young adults with higher metabolic rates. There are some significant

space-related contaminants, typically toner cartridges and paper.

10 5 0.12 0.6 1

Daycare

(through age 4)

Occupant activity is moderate. There is considerable aerobic activity in addition to the occupants being very

vocal. Also, the occupants are primarily young children with higher metabolic rates. There are significant

space-related contaminants, including diapers, arts-and-crafts supplies, and cleaning agents. These

contaminants, particularly the diapers, result in this space being classified as Air Class 2.

10 5 0.18 0.9 2

Lecture classroom Occupant activity is primarily sedentary (seated or light walking). However, occupants are generally more

vocal, resulting in higher metabolic rates. There are no significant space-related contaminants.

7.5 3.8 0.06 0.3 1

Lecture hall

(fixed seats)

Occupant activity is primarily sedentary (seated or light walking). However, occupants are generally more

vocal, resulting in higher metabolic rates. There are no significant space-related contaminants.

7.5 3.8 0.06 0.3 1

Media center Occupant activity is primarily sedentary (seated or light walking). However, occupants are generally more

vocal. Also, the occupants are primarily children/young adults with higher metabolic rates and often more

bioeffluents. There are some significant space-related contaminants, typically toner cartridges and paper (both

loose leaf and bound).

10 5 0.12 0.6 1

Multiuse assembly Occupant activity is primarily sedentary (seated or light walking). However, occupants are generally more

vocal, resulting in higher metabolic rates. There are no significant space-related contaminants.

7.5 3.8 0.06 0.3 1

Music/theater/dance Occupant activity is high. There is considerable aerobic activity in addition to the occupants being very vocal.

There are no significant space-related contaminants.

10 5 0.06 0.3 1

Science laboratories Occupant activity is moderate. There is considerable aerobic activity in addition to the occupants being very

vocal. Also, the occupants are primarily children with higher metabolic rates. There are significant space-related

contaminants, including open chemicals and cleaning agents. The presence of these open contaminants result in

this space being classified as Air Class 2. OSHA regulated exposure limits must be maintained, ensuring Class 2

defined air is present. This condition is covered in Table 6-2 .

10 5 0.18 0.9 2

Table I-1 Rate Rationale (see Table 6-1 ) (Continued)

Occupancy

Category Description/Rationale

People

Outdoor

Air Rate,

cfm/person

People

Outdoor

Air Rate,

L/s/person

Area

Outdoor

Air Rate,

cfm/ft2

Area

Outdoor

Air Rate,

L/s·m2

Air

Class

58 ANSI/ASHRAE Standard 62.1-2019

University/college

laboratories

Occupant activity is moderate. There is considerable aerobic activity in addition to the occupants being very

vocal. Also, the occupants have higher metabolic rates. There are significant space-related contaminants,

including open chemicals and cleaning agents. The presence of these open contaminants results in this space

being classified as Air Class 2. OSHA regulated exposure limits must be maintained, ensuring Class 2 defined

air is present. This condition is covered in Table 6-2 .

10 5 0.18 0.9 2

Wood/metal shop Occupant activity is moderate. There is considerable aerobic activity in addition to the occupants being very

vocal. Also, the occupants can be children/young adults with higher metabolic rates. There are significant

space-related contaminants, including sawdust, oils, metal shavings, and chemical agents. The presence of these

open contaminants result in this space being classified as Air Class 2.

10 5 0.18 0.9 2

Food and Beverage Service

Bars,

cocktail lounges

Occupant activity is moderate (standing, talking, eating/drinking, waiting tables). The presence of large

quantities of open drinks and prepared foods creates higher levels of space-related contaminants. The associated

food and drink odors results in this space being classified as Air Class 2.

7.5 3.8 0.18 0.9 2

Cafeteria/

fast-food dining

Occupant activity is moderate (standing, talking, eating, cleaning tables). The presence of large quantities of

unpackaged, prepared foods creates higher levels of space-related contaminants. The associated food odors

result in this space being classified as Air Class 2.

7.5 3.8 0.18 0.9 2

Kitchen Occupant activity is very active (walking, talking, eating, food preparation and cooking). The presence of large

quantities of unpackaged, cooking prepared foods creates higher levels of space-related contaminants. The

associated food odors results in this space being classified as Air Class 2.

7.5 3.8 0.12 0.6 2

Restaurant

dining rooms

Occupant activity is moderate (standing, talking, eating, waiting tables). The presence of large quantities of

unpackaged, prepared foods creates higher levels of space-related contaminants. The associated food odors

result in this space being classified as Air Class 2.

7.5 3.8 0.18 0.9 2

Food and Beverage Service, General

Break rooms Occupant activity is primarily sedentary (seated). There are limited space-related contaminants. 5 2.5 0.06 0.3

Coffee stations Occupant activity is primarily sedentary. There are limited space-related contaminants. 5 2.5 0.06 0.3

Conference/meeting Occupant activity is primarily sedentary (seated). There are no significant space-related contaminants. 5 2.5 0.06 0.3 1

Corridors Persons passing through the corridor are considered to be transitory and thus not occupants. There are no

significant space-related contaminants.

— — 0.06 0.3 1

Table I-1 Rate Rationale (see Table 6-1 ) (Continued)

Occupancy

Category Description/Rationale

People

Outdoor

Air Rate,

cfm/person

People

Outdoor

Air Rate,

L/s/person

Area

Outdoor

Air Rate,

cfm/ft2

Area

Outdoor

Air Rate,

L/s·m2

Air

Class

ANSI/ASHRAE Standard 62.1-2019 59

Occupiable storage

rooms for liquids or

gels

Occupant activity is primarily sedentary (seated) The concentration of stored products increases the level of

space-related contaminants. Current ventilation rate is consistent with other minimal/transient occupancy

environments.

5 2.5 0.12 0.6 2

Hotels, Motels, Resorts, Dormitories

Barracks

sleeping areas

Occupant activity is primarily sedentary (sleeping). There are no significant space-related contaminants. 5 2.5 0.06 0.3 1

Bedroom/

living room

Occupant activity is primarily sedentary (seated or sleeping). There are no significant space-related

contaminants.

5 2.5 0.06 0.3 1

Laundry rooms,

central

Occupant activity is primarily moderate. There are often usual space-related contaminants related to cleaning. 5 2.5 0.12 0.6 2

Laundry rooms

within dwelling units

Occupant activity is primarily moderate. There are often usual space-related contaminants related to cleaning. 5 2.5 0.12 0.6 1

Lobbies/prefunction Occupant activity is primarily standing and light walking. However, occupants are generally more vocal,

resulting in higher metabolic rates. There are no significant space-related contaminants.

7.5 3.8 0.06 0.3 1

Multipurpose

assembly

Occupant activity is primarily sedentary (seated or light walking). There are no significant space-related

contaminants.

5 2.5 0.06 0.3 1

Miscellaneous Spaces

Banks or

bank lobbies

Occupant activity is primarily standing and light walking. However, occupants are generally more vocal,

resulting in higher metabolic rates. There are no significant space-related contaminants.

7.5 3.8 0.06 0.3

Bank vaults/

safe deposit

Occupant activity is light, typically standing. There are no significant space-related contaminants. 5 2.5 0.06 0.3 2

Computer

(not printing)

Occupant activity is primarily sedentary (seated). There are no significant space-related contaminants. 5 2.5 0.06 0.3 1

Freezer and

refrigerated spaces

(<50°F [10°C])

Refrigerated warehouse spaces are significantly different from conventional warehouses in a number of ways.

The low temperatures will slow the emission of contaminants, such as VOCs, from the materials stored in the

space; the characteristics of the items being stored will be different; and the amount of time spent in the space

by occupants may be shorter (particularly for spaces kept at subfreezing temperatures).

10 5 002

Table I-1 Rate Rationale (see Table 6-1 ) (Continued)

Occupancy

Category Description/Rationale

People

Outdoor

Air Rate,

cfm/person

People

Outdoor

Air Rate,

L/s/person

Area

Outdoor

Air Rate,

cfm/ft2

Area

Outdoor

Air Rate,

L/s·m2

Air

Class

60 ANSI/ASHRAE Standard 62.1-2019

General

manufacturing

(excludes heavy

industrial and

processes using

chemicals)

Occupant activity is moderate (standing, walking, assembly). Moderate levels of space-related contaminants are

expected. The unknown nature of the contaminants leads to a category of Air Class 3.

10 5 0.18 0.9 3

Pharmacy

(prep. area)

Occupant activity is primarily light work and standing. There are space-related contaminants, including open

containers of liquid medicines. The presence of these open containers results in this space being classified as

Air Class 2.

5 2.5 0.18 0.9 2

Photo studios Occupant activity is primarily standing and light work. There are large quantities of chemicals, many of them

open, resulting in higher levels of space-related contaminants.

5 2.5 0.12 0.6 1

Shipping/receiving Persons moving materials have a higher level of activity. The flow of products increases the level of space-

related contaminants in addition to the typical use of forklifts.

10 5 0.12 0.6 1

Sorting, packing,

light assembly

Occupant activity is moderate (standing, walking, assembly). There may be moderate levels of space-related

contaminants.

7.5 3.8 0.12 0.6 2

Telephone closets This should be handled as unoccupied space.

Transportation

waiting

Occupant activity is primarily standing and moderate-to-heavy walking. There are no significant space-related

contaminants.

7.5 3.8 0.06 0.3 1

Warehouses Occupant activity is moderate (standing, walking, assembly). There may be moderate levels of space-related

contaminants.

10 5 0.06 0.3 2

Office Buildings

Breakrooms Occupant activity is primarily sedentary (seated). There are limited space-related contaminants. 5 2.5 0.06 0.3 1

Main entry lobbies Occupant activity is primarily transitory light walking. There are few anticipated space-related contaminants. 5 2.5 0.06 0.3 1

Occupiable

storage rooms

for dry materials

Occupant activity is primarily sedentary (seated). The concentration of stored products increases the level of

space-related contaminants; however, dry material emissions are expected to be low.

5 2.5 0.06 0.3 1

Office space Occupant activity is primarily sedentary (seated). There are no significant space-related contaminants. 5 2.5 0.06 0.3 1

Table I-1 Rate Rationale (see Table 6-1 ) (Continued)

Occupancy

Category Description/Rationale

People

Outdoor

Air Rate,

cfm/person

People

Outdoor

Air Rate,

L/s/person

Area

Outdoor

Air Rate,

cfm/ft2

Area

Outdoor

Air Rate,

L/s·m2

Air

Class

ANSI/ASHRAE Standard 62.1-2019 61

Reception areas Occupant activity is primarily sedentary (seated). There are no significant space-related contaminants. 5 2.5 0.06 0.3 1

Telephone/

data entry

Occupant activity is primarily sedentary (seated). There are no significant space-related contaminants. 5 2.5 0.06 0.3 1

Public Assembly Spaces

Auditorium

seating area

Occupant activity is primarily sedentary (seated). There are no significant space-related contaminants. 5 2.5 0.06 0.3 1

Courtrooms Occupant activity is primarily sedentary (seated). There are no significant space-related contaminants. 5 2.5 0.06 0.3 1

Legislative chambers Occupant activity is primarily sedentary (seated). There are no significant space-related contaminants. 5 2.5 0.06 0.3 1

Libraries Occupant activity is primarily sedentary (seated or light walking). The large quantities of books create higher

levels of space-related contaminants (dust and odors).

5 2.5 0.12 0.6 1

Lobbies Occupant activity is primarily sedentary (seated or light walking). There are no significant space-related

contaminants.

5 2.5 0.06 0.3 1

Museums

(children's)

Occupant activity is moderate. There is considerable aerobic activity in addition to the occupants being very

vocal. Also, the occupants are typically young children with higher metabolic rates. There are typically some

significant space-related contaminants, such as food and drink.

7.5 3.8 0.12 0.6 1

Museums/galleries Occupant activity is primarily standing and light walking. However, occupants are generally more vocal,

resulting in higher metabolic rates. There are no significant space-related contaminants.

7.5 3.8 0.06 0.3 1

Places of

religious worship

Occupant activity is primarily sedentary (seated). There are no significant space-related contaminants. 5 2.5 0.06 0.3 1

Retail

Sales

(except as below)

Occupant activity is moderate. There is considerable occupant movement, including carrying packages and

being more vocally active. The presence of new merchandise creates higher levels of space-related

contaminants. This is primarily the reason for the space being classified as Air Class 2.

7.5 3.8 0.12 0.6 2

Barber shop Occupant activity is primarily sedentary, with moderate work being performed by the staff. Occupants are

generally more vocal, resulting in higher metabolic rates. There are some significant space-related

contaminants (shampoos, disinfecting agents, high levels of human hair). However, these are directly related to

the occupancy rather than the floor area. This is the primary reason why this space is classified as Air Class 2.

7.5 3.8 0.06 0.3 2

Table I-1 Rate Rationale (see Table 6-1 ) (Continued)

Occupancy

Category Description/Rationale

People

Outdoor

Air Rate,

cfm/person

People

Outdoor

Air Rate,

L/s/person

Area

Outdoor

Air Rate,

cfm/ft2

Area

Outdoor

Air Rate,

L/s·m2

Air

Class

62 ANSI/ASHRAE Standard 62.1-2019

Beauty and

nail salons

Occupant activity is primarily sedentary, with moderate work being performed by the staff. Occupants are

generally more vocal, resulting in higher metabolic rates. There are some significant space-related

contaminants (shampoos, disinfecting agents, high levels of hair).

20 10 0.12 0.6 2

Coin-operated

laundries

Occupant activity is primarily moderate-to-heavy walking and may include carrying packages. There are some

significant space-related contaminants (detergents, disinfecting agents, soiled laundry). However, these are

directly related to the occupancy rather than the floor area. This is the primary reason why this space is

classified as Air Class 2.

7.5 3.8 0.12 0.6 2

Mall

common areas

Occupant activity is primarily moderate to heavy walking and may include carrying packages. Occupants are

generally more vocal, resulting in higher metabolic rates. There are no significant space-related contaminants.

7.5 3.8 0.06 0.3 1

Pet shops

(animal areas)

Occupant activity is moderate (standing, talking, stooping, walking, and carrying packages). The concentration

of animals of various species in containment creates higher levels of space-related contaminants. This

concentration of animals, and the fact that they are kept in open containment, results in this space being

classified as Air Class 2.

7.5 3.8 0.18 0.9 2

Supermarket Occupant activity is primarily moderate to heavy walking and may include carrying packages. There are no

significant space-related contaminants.

7.5 3.8 0.06 0.3 1

Sports and Entertainment

Bowling alley

(seating)

Occupant activity is moderate (seated, standing, walking, talking, drinking). The presence of open food and

drink creates moderately high levels of significant contaminants.

10 5 0.12 0.6 1

Disco/dance floors Occupant activity is high. There is considerable aerobic activity. There are often considerable quantities of open

drink, creating high levels of space-related contaminants related to the people using the space.

20 10 0.06 0.3 1

Gambling casinos Occupant activity is moderate (seated, standing, walking, talking, drinking). The presence of open food and

drink creates moderately high levels of significant contaminants.

7.5 3.8 0.18 0.9 1

Game arcades Occupant activity is moderate (seated, standing, walking, talking, drinking). The presence of open food and

drink creates moderately high levels of significant contaminants.

7.5 3.8 0.18 0.9 1

Gym, stadium

(play area)

Occupant activity is high. There is considerable aerobic activity. There are no significant space-related

contaminants. Occupancy is variable, and the high area outdoor air rate compensates for the varying occupancy

and local source. CO2 -based demand controlled ventilation in these spaces should consider that the volume per

person in these spaces is typically large, which means that CO2 concentration changes will have longer than

usual lag times behind occupancy changes.

20 10 0.18 0.9 2

Table I-1 Rate Rationale (see Table 6-1 ) (Continued)

Occupancy

Category Description/Rationale

People

Outdoor

Air Rate,

cfm/person

People

Outdoor

Air Rate,

L/s/person

Area

Outdoor

Air Rate,

cfm/ft2

Area

Outdoor

Air Rate,

L/s·m2

Air

Class

ANSI/ASHRAE Standard 62.1-2019 63

Health club/

aerobics room

Occupant activity is high. There is considerable aerobic activity in addition to the occupants being very vocal.

There are significant space-related contaminants related to the people using the space.

20 10 0.06 0.3 2

Health club/

weight rooms

Occupant activity is high. There is considerable aerobic activity in addition to the occupants being very vocal.

There are significant space-related contaminants related to the people using the space.

20 10 0.06 0.3 2

Spectator areas Occupant activity is moderate. While the occupants may be primarily seated, there is considerable vocal

activity, as well as standing, cheering, and walking to concessions, etc. There are often considerable quantities

of open food and drink, creating high levels of space-related contaminants.

7.5 3.8 0.06 0.3 1

Sports arena

(play area)

Occupant activity is high. There is considerable aerobic activity. Occupancy is variable, and the high area

outdoor air rate compensates for the varying occupancy and local sources. The presence of playing surface

cleaning/resurfacing equipment results in significantly high levels of space-related contaminants.

20 10 0.18 0.9 2

Stages, studios Occupant activity is moderate. While the occupants may be primarily seated, there is considerable vocal

activity, as well as standing, cheering, and walking to concessions, etc. The stage props result in higher levels of

space-related contaminants. Contaminant level is not high enough to justify an Air Class 2.

10 5 0.06 0.3 1

Swimming

(pool and deck)

While the occupant activity (swimming) is high, it is primarily anaerobic. Occupancy is variable, and the high

area outdoor air rate compensates for the varying occupancy and local source. Also, the bioeffluents, such as

sweat are discharged into the water rather than the air. For these reasons, there is no occupancy-related outdoor

air rate. The high level of chemicals in the pool water that are absorbed into the air as the pool water evaporates

create exceptionally high levels of space-related contaminants. The presence of these chemicals, and their

noxious odor, result in the space being classified as Air Class 2.

— — 0.48 2.4 2

Transient Residential

Common corridors Persons passing through the corridor are considered to be transitory and thus not occupants. There are no

significant space-related contaminants.

— — 0.06 0.3 —

Dwelling unit Occupant activity is variable. There may be moderate levels of space-related contaminants that are under the

control of the occupants.

5 2.5 0.06 0.3 —

Table I-1 Rate Rationale (see Table 6-1 ) (Continued)

Occupancy

Category Description/Rationale

People

Outdoor

Air Rate,

cfm/person

People

Outdoor

Air Rate,

L/s/person

Area

Outdoor

Air Rate,

cfm/ft2

Area

Outdoor

Air Rate,

L/s·m2

Air

Class

64 ANSI/ASHRAE Standard 62.1-2019

(This appendix is not part of this standard. It is merely

informative and does not con-

tain requirements necessary

for conformance to the standard. It has not been pro-

cessed according to the ANSI requirements for a standard and may contain material

that has not been subject to public review or a consensus process. Unresolved objec-

tors on informative material are not offered the right to appeal at ASHRAE or ANSI.)

INFORMATIVE APPENDIX J

INFORMATION ON NATURAL VENTILATION

J1. OUTDOOR AIR QUALITY DATA

Outdoor air quality data may be considered valid if it is demonstrated that the data are both

physically representative and spatially representative.

Physically representative data accurately reflect the air quality conditions at the monitor-

ing station from which they are derived. Data are considered physically representative if they

are obtained from

a. reports of historical levels of air pollutants published by the relevant local, regional, or fed-

eral entity with statutory responsibility for collecting and reporting air quality information

in accordance with applicable air quality regulations, or

b. an on-site monitoring campaign that is verifiably comparable to local, regional, or federal

guidelines and methods for demonstration of compliance with applicable air quality regula-

tions.

Spatially representative data are collected from a monitoring site that may differ from the

proposed project location but is informative of the air quality conditions at the proposed project

location. Data may be considered spatially representative if they are

c. the same as those used by the entity charged with demonstrating regulatory compliance for

the geographic region that includes the proposed project location, or

d. derived from an on-site monitoring campaign that also meets the requirement stated by cri-

teria (b) of this annotation.

J2. NATURAL VENTILATION RATE

When calculating the ventilation rate, specific path(s) of the intended airflow passage must first

be determined along with flow directions. There are two driving forces for natural ventilation:

buoyancy and wind. The two driving forces can work cooperatively or competitively based on

the environmental conditions of wind speed, direction, indoor/outdoor air/surface tempera-

tures, as well as the intentional airflow path and mechanisms.

a. In the case of an engineered natural ventilation system that results in multiple flow scenar-

ios, each must be examined and considered separately.

b. Specific pressure-based calculation of natural ventilation flow rate is documented in

ASHRAE Handbook—Fundamentals, Chapter 16, Section 6:

1. Buoyancy-induced airflow can be calculated following Equation 38.

2. Wind-driven airflow can be calculated following Equation 37.

3. The overall pressure (driven by both wind and stack effect) converted to resulting pres-

sure difference between openings can found in Equation 36.

For obtaining wind-driven pressure, several methods are available:

a. ASHRAE Handbook—Fundamentals , Chapter 24, provides a method to convert wind speed

and direction into pressure coefficients that can be used to determine wind-driven pressure.

b. CIBSE AM10, Chapter 4, provides a method to account for wind-driven ventilation and

outlines specific challenges to it in Section 4.4.1.

c. If the building has undergone wind tunnel test for structural stress, the same test can pro-

vide detailed pressure coefficients.

d. Outdoor airflow simulation (such as computational-fluid-dynamics-based simulation) can

be used to obtain the specific flow condition at the intended openings.

For intended openings that are large, such as open atrium or open balcony, and/or when the

flow path is not well defined, such as when only single or single-side openings are available, the

pressure-based method can be invalid, and outdoor-indoor linked simulation should be used.

ANSI/ASHRAE Standard 62.1-2019 65

J3. PRESCRIPTIVE PATH A CALCULATIONS

J3.1 Ventilation Intensity. Spaces have been defined by a ventilation intensity, which rep-

resents the amount of flow rate needed per Equation 6-1, divided by the floor area of the space.

Its units are (L/s)/m2 of floor area or cfm/ft2 of floor area.

(J-1)

The ventilation intensity brackets in Table J-1 are used.

J3.2 Single Openings. The flow through a single sharp opening due to bidirectional buoy-

ancy-driven flow (Vbd_sharp ) (see Etheridge and Sandberg [1996] in Informative Appendix M)

is expressed as follows:

(J-2)

where

Aw = free unobstructed area of the window, or openable area

T = temperature difference between indoors and outdoors. Given the conservative nature of

a prescriptive path, a temperature difference of 1°C (1.8°F) is assumed for these

calculations. In reality, this temperature will depend on the internal gains in the space

and will likely be higher than 1°C (1.8°F), leading to higher airflows (and a smaller

window area requirement).

Hs = vertical dimension of the opening

g= gravity constant

Tref = reference temperature in Kelvin (or Rankine), typically equal to Tin , Tout or an expected

average. A reference temperature of 21°C (70°F, 294K) was assumed for these

calculations.

A safety factor is incorporated assuming that an awning window is used. Awning (or top-

hinged) windows are among the most common windows used for natural ventilation, and,

because of their uneven vertical area distribution, are more inefficient than a sliding window

(sharp opening) at driving flow. An efficiency  v of around 83% (value used in these calcula-

tions) when compared to sliding windows is inferred from

(J-3)

Assuming a height-to-width ratio for the window of RH/W ( R = H/W ), the window area can

be rewritten as

(J-4)

The required openable area as a fraction of the zone's floor area is therefore calculated by

equating the bidirectional buoyancy-driven flow through a single awning opening (Vso ) to the

goal flow rate (Vbz ) obtained from Table 6-1.

(J-5)

Table J-1 Ventilation Intensity Brackets

Bracket (L/s)·m2 cfm/ft2 Commonly Encountered Space Typologies Bracket

1 0.0 to 1.0 0.0 to 0.2 Office, living room, main entry lobby

2 1.0 to 2.0 0.2 to 0.4 Reception area, general manufacturing, kitchen, lobby

3 2.0 to 3.0 0.4 to 0.6 Classroom, daycare

4 3.0 to 4.0 0.6 to 0.8 Restaurant dining room, places of religious worship

5 4.0 to 5.5 0.6 to 1.1 Auditorium, health club/aerobics room, bar, gambling

Not addressed: Lecture Hall and spectator areas (6 [L/s])/m2) and disco/dance floors (10.3 [L/s]/m2)

Ventilation Intensity Vbz

-------- Rp Pz Ra Az

 + 

------------------------------------------- ==

Vso_sharp 0.21 Aw gHs

T

Tre

--------- -  =

Vso Vso_sharp  w

 =

RH/W

------------ - =

Vso Vbz

66 ANSI/ASHRAE Standard 62.1-2019

And solving for window area,

(J-6)

J3.3 Vertically Spaced Openings. The flow rate Vvs through vertically spaced openings of

areas As (the smallest sum of opening areas, either upper openings or lower openings) and Al

(the largest sum of opening areas, either upper openings or lower openings) is obtained using

the following equation:

(J-7)

where

Aeff = effective window area, defined as

(J-8)

Aw = is the total sum of all opening areas

(J-9)

R= area ratio between As and Al

(J-10)

 H is the shortest vertical distance between the center of the lowest openings and that of

the upper openings.

All other constants are the same as in the single opening scenario.

The required openable area as a fraction of the zone's floor area is therefore calculated by

equating the flow through two sets of vertically spaces openings Vvs to the goal flow rate Vbz

obtained from Table 6-1.

(J-11)

Solving for window area:

(J-12)

J4. CONTROL AND ACCESSIBILITY (MIXED-MODE VENTILATION)

Mixed-mode ventilation is a hybrid system used to maintain IAQ and internal thermal tempera-

tures year-round using both natural and mechanical ventilation systems.

a. Natural ventilation systems use natural forces such as wind and thermal buoyancy to venti-

late and cool spaces.

b. Mechanical ventilation systems use mechanical systems with fans to supply and exhaust air

from a space, provide humidity control, and, if required, filter possible contaminants.

By preferentially using natural ventilation when outdoor air conditions are suitable,

energy costs and carbon emissions can be minimized. Sensors are used to identify when natural

ventilation is less effective at providing suitable indoor temperatures, humidity levels, and con-

taminant levels, and indicate that a transition to mechanical ventilation should occur. The tran-

sition between modes can be manual or automatic, as dictated by the needs of the owner/

occupants. The use of each mode when appropriate will ensure year-round acceptable IAQ.

------ -Vbz

0.21 0.83 RHW 

4gT

Tre

--------- - 

------------------------------------------------------------------------







45 

----- 1 0 0 

Vvs Aeff Cd 2 g H  T

Tre

--------- -  =

Aeff

------ 1

------ +

----------------------- -As

1R 2

------------------- Aw

1R 2

+11

--- +







-------------------------------------------- - ===

Aw As At

RA s

----- =

Vvs Vbz

------ -Vbz

Cd 2 g H T

Tre

--------- - 

------------------------------------------- 1 R 2

+11

---





----- 1 0 0  =

ANSI/ASHRAE Standard 62.1-2019 67

(This appendix is not part of this standard. It is merely

informative and does not con-

tain requirements necessary

for conformance to the standard. It has not been pro-

cessed according to the ANSI requirements for a standard and may contain material

that has not been subject to public review or a consensus process. Unresolved objec-

tors on informative material are not offered the right to appeal at ASHRAE or ANSI.)

INFORMATIVE APPENDIX K

COMPLIANCE

This appendix contains compliance suggestions that are intended to assist users and enforce-

ment agencies in applying this standard.

K1. SECTION 4

KIs documentation of outdoor air quality included as required in Section 4.3?

K2. SECTION 5

KAre air balancing provisions included in design documentation as required in Section 5.1?

KIf the system is a plenum system, are provisions for providing minimum breathing zone

airflow specified?

KDo exhaust ducts comply with requirements of Section 5.2?

KAre ventilation systems controls specified as per Section 5.3?

KDo specifications include resistance to mold and erosion for airstream surfaces per Sec-

tion 5.4 ?

KAre separation distances between outdoor air intakes and sources listed and in compliance

with Section 5.5?

KIs there any noncombustion equipment that requires exhaust (Section 5.6)?

KIs combustion air provided for fuel-burning appliances (Section 5.8)?

KAre appropriate filters specified upstream of cooling coils or wetted surfaces (Section 5.9)?

KAre dehumidification capability and building exfiltration calculations provided (Section

5.10)?

KDo specifications for drain pans comply with requirements of Section 5.12?

KAre coils specified per requirements of Section 5.13?

KIf present, do humidifiers and water spray systems comply with requirements of Section

5.14?

KIs access provided for inspection, cleaning, and maintenance of all ventilation equipment

and air distribution equipment (Section 5.15)?

KIs moisture management (Section 5.16 ) included in building envelope design, including

specifically,

Kweather barrier;

Kvapor retarder;

Ksealing exterior joints, seams, and penetrations;

Kinsulation on pipes, ducts, or other surfaces whose temperatures are expected to fall

below dew point of surrounding air?

KIf there is an attached parking garage? Do airflow control measures comply with require-

ments of Section 5.17?

KIs recirculation from spaces containing Class 2 air limited to spaces with the same purpose

and with the same pollutants following requirements of Section 5.18.3.2?

KIs air from spaces containing Class 3 air contained and not transferred to any other space

(Section 5.18.3.3)?

KIs all air from spaces containing Class 4 air exhausted directly to the outdoors (Section

5.18.3.4)?

KIf environmental tobacco smoke is expected to be present, does the design comply with all

separation requirements of Section 5.19?

68 ANSI/ASHRAE Standard 62.1-2019

K3. SECTION 6 VRP

KAre occupancy categories consistent with the space design documents?

KAre there any unusual sources of contaminants or compounds? If yes, ventilation must be

added per Section 6.3.6.

K3.1 Filtration

KIf PM10 standard is exceeded as reported in Section 4 , is required filtration per Section

6.1.4.1 provided?

KIf PM2.5 standard is exceeded as reported in Section 4 , is required filtration per Section

6.1.4.2 provided?

KIf ozone standard is exceeded, and the area is Serious, Severe15, Severe17, or Extreme, fil-

tration per Section 6.1.4.3 is required unless an exception is documented.

K3.2 Ventilation Rates. Check compliance with the outdoor air ventilation rate at the intake

(Vot ) using the following process.

KCalculate Votdefault using Equation K-1 using the combined default rate (Rc ) from Informa-

tive Appendix L and the occupiable area (Az ) of each zone.

Votdefault =  all zones R c × A z(K-1)

KCalculate additional ventilation required by Section 6.2.1.1.2 . Additional ventilation is

Votadditional.

KCalculate Votmax using Equation K-2.

Votmax = Votdefault + Votadditional (K-2)

KCalculate Votmin using Equation K-3.

Votmin = Votmax × 0.75 (K-3)

KDesigned system ventilation rate at the outdoor air intake (Vot ) should fall between Votmin

and Votmax .

KValues of Vot for multiple-zone recirculating variable-air-volume (VAV) systems should be

close to Votmax .

KValues of Vot for 100% (dedicated) outdoor air systems providing tempered air should be

equivalent to Votmin .

KValues of Vot for other systems should fall between these values.

KIf dynamic reset is included as a part of the design, does it comply with all requirements of

Section 6.2.6?

Exceptions to K3.2:

1. Minimum outdoor airflow for multiple-zone recirculating systems designed using Nor-

mative Appendix A could be below Votmin . A calculation spreadsheet should be pro-

vided to confirm that Ev for the system is greater than 0.75.

2. Minimum outdoor airflow for systems designed using Normative Appendix C could be

below Votmin . Calculation assumptions of any modeling criteria and results should be

provided to confirm that Ez values are greater than 1.0.

K4. SECTION 6 IAQP

For the IAQ procedure:

KDo the design documents provide evaluation of the following?

KCompounds included in the design (Section 6.3.1)

KList includes all contaminants of concern

KIndoor sources and emissions rates for each compound

KOutdoor sources and expected concentrations for each compound

KExposure periods and concentration limits

KEvaluation of mixtures

KSpecification of perceived IAQ acceptability

ANSI/ASHRAE Standard 62.1-2019 69

KCalculation of resultant concentrations from the design by mass balance

KDo specifications include test methods?

KDo specifications require that the subjective evaluation process be completed during occu-

pancy?

KIf a substantially similar zone is used for subjective evaluation, are previous test

results, conditions, and system design provided to verify that the zone is substantially

similar?

KIf applicable, are appropriate specifications for dynamic reset monitoring and controls

included?

K5. SECTION 6 NATURAL VENTILATION PROCEDURE

Natural ventilation systems shall follow either the prescriptive or the engineered system com-

pliance path.

For the prescriptive compliance path:

KIs a mechanical system compliant with either Section 6.2 or 6.3 included?

KIf no, does design comply with Exceptions 1 or 2 of Section 6.4.1?

KDo maximum distances from openings comply with Sections 6.4.1.2, 6.4.1.3, or 6.4.1.4?

KDo opening sizes comply with the requirements of Section 6.4.2?

KIs net free area of openings specified?

KAre sill-to-head heights specified?

KAre aggregate widths specified?

KAre controls readily accessible?

For the engineered compliance path:

KDo the design documents provide evaluation of the following:

KHourly environmental conditions, including, but not limited to, outdoor air dry-bulb

temperature; dew-point temperature; outdoor concentration of contaminants of con-

cern (including but not limited to PM2.5, PM10, and ozone), where data are available;

wind speed and direction; and internal heat gains during expected hours of natural

ventilation operation.

KThe effect of pressure losses along airflow paths of natural ventilation airflow on the

resulting flow rates, including, but not limited to, inlet vents, air transfer grills, venti-

lation stacks, and outlet vents.

KQualification of natural ventilation airflow rates of identified airflow paths accounting

for wind and thermally induced driving pressures.

KOutdoor air is provided in sufficient quantities to ensure pollutants and odors of indoor

origin do not result in unacceptable IAQ as established under Section 6.2.1.1 and/or 6.3 .

KOutdoor air introduced into the space through natural ventilation system openings

does not result in unacceptable IAQ according to Sections 6.1.4.1 through 6.1.4.4.

KEffective interior air barriers and insulation are provided that separate naturally venti-

lated spaces from mechanically cooled spaces, ensuring that high-dew-point outdoor

air does not come into contact with mechanically cooled surfaces.

KAre controls readily accessible?

K6. SECTION 6 EXHAUST

Exhaust ventilation systems shall follow either the prescriptive or the performance compliance

path.

For the prescriptive compliance path:

KDoes airflow comply with requirements of Table 6-1 and 6-3?

KIf no for any space, does it qualify as an exception?

KHave source strengths been evaluated as required in Section 6.5.1.1?

70 ANSI/ASHRAE Standard 62.1-2019

For the performance compliance path:

KDo the design documents provide evaluation of the following?

KCompounds of interest for the design

KIndoor sources and emissions rates for each compound

KOutdoor sources and emissions rates brought in by ventilation air

KExposure periods and concentration limits

KEvaluation of mixtures

KCalculation of resultant concentrations from the design

KDo specifications require that the subjective evaluation process be completed during occu-

pancy (Section 6.3.4.2)?

KIf applicable, are appropriate specifications for dynamic reset monitoring and controls

included?

K7. VENTILATION FOR EXISTING BUILDINGS

This section provides guidance for determining compliance with the standard for existing

buildings. Many sustainability and energy programs require that ventilation rates for systems

comply with ASHRAE Standard 62.1; however, the methods for determining compliance vary

widely. This appendix is intended to provide a standardized approach and clear guidance for

practitioners who work with existing buildings.

A ventilation system in an existing building may be deemed to comply with Standard 62.1

if the system complies with all the sections in this appendix. The building may be deemed to

comply if all systems in the building comply with all the sections in this appendix (Sections

K7.1, K7.2, and K7.3).

K7.1 Filtration. Filtration shall comply with Sections K7.1.1 and K7.1.2.

K7.1.1 Filtration Before Coils. Filtration complies with Section 5.9.

K7.1.2 Filtration of Outdoor Air. Filtration complies with Section 6.1.4.

K7.2 Outdoor Airflow. The following process may be used to determine if outdoor airflow

rates comply with the standard. Occupied areas may be determined by measurement, dimen-

sioned floor plans, or from building manager's data.

K7.2.1 System Outdoor Airflow. Measure system outdoor airflow. Measurements may be

made directly or by installed flow measurement devices in the system that are calibrated. This

rate is Votmeasured .

K7.2.2 Determine System Type. Determine the system type and then follow the guidance

in the appropriate section.

K7.2.2.1 Single Zone Systems. Determine Votdesign using Section 6.2.3. If Votmeasured 

Votdesign , the system complies.

K7.2.2.2 100% Outdoor Air Systems. Determine Votdesign using Section 6.2.4. If Votmea-

sured  V otdesign, the system complies.

K7.2.2.3 Multiple Zone Recirculating Systems. Determine Votdesign using any process

listed in this section. If, in any calculation, Votmeasured  Votdesign , the system complies.

Informative Note: Calculations are ordered from simplest to most complex.

K7.2.2.3.1 Appendix F. Determine Votdesign using Informative Appendix F.

K7.2.2.3.1.1 Systems with Measured Zone Primary Airflow. If measured zone pri-

mary airflow is available by VAV box readings or by a testing, adjusting, and balancing (TAB)

report, one may calculate using either of the following approaches.

K7.2.2.3.1.2 Simplified Procedure. Determine Votdesign using Section 6.2.4 simplified

procedure.

K7.2.2.3.1.3 Alternative Procedure. Determine Votdesign using Section 6.2.4 alterna-

tive procedure.

Informative Note: The alternative procedure provides credit for secondary recirculation.

K7.3 Controls. Confirm that ventilation system controls comply with requirements of Sec-

tion 5.3 .

ANSI/ASHRAE Standard 62.1-2019 71

(This appendix is not part of this standard. It is merely

informative and does not contain require-

ments necessary

for conformance to the standard. It has not been processed according to the ANSI

requirements for a standard and may contain material that has not been subject to public review

or a consensus process. Unresolved objectors on informative material are not offered the right to

appeal at ASHRAE or ANSI.)

INFORMATIVE APPENDIX L

VENTILATION RATE CHECK TABLE

Table L-1 is not for design purposes. It is intended to provide check values. Default rate per unit area is

based on a multiple-zone system with default occupancy and default Ev that equals 0.75. This is the default

Ev in the simplified rate when D > 0.60.

Table L-1 Check Table for the Ventilation Rate Procedure

Occupancy Category

Combined Outdoor Air Rate (Rc )

cfm/ft2L/s·

Animal Facilities

Animal exam room (veterinary office) 0.43 2.13

Animal imaging (MRI/CT/PET) 0.51 2.53

Animal operating rooms 0.51 2.53

Animal postoperative recovery room 0.51 2.53

Animal preparation rooms 0.51 2.53

Animal procedure room 0.51 2.53

Animal surgery scrub 0.51 2.53

Large-animal holding room 0.51 2.53

Necropsy 0.51 2.53

Small-animal-cage room (static cages) 0.51 2.53

Small-animal-cage room (ventilated cages) 0.51 2.53

Correctional Facilities

Booking/waiting 0.58 2.93

Cell 0.33 1.63

Dayroom 0.28 1.40

Guard stations 0.18 0.90

Educational Facilities

Art classroom 0.51 2.53

Classrooms (ages 5 through 8) 0.49 2.47

Classrooms (ages 9 plus) 0.63 3.13

Computer lab 0.49 2.47

Daycare sickroom 0.57 2.87

Daycare (through age 4) 0.57 2.87

Lecture classroom 0.73 3.69

Lecture hall (fixed seats) 1.58 8.00

Libraries 0.23 1.13

Media center 0.49 2.47

72 ANSI/ASHRAE Standard 62.1-2019

Multiuse assembly 1.08 5.47

Music/theater/dance 0.55 2.73

Science laboratories 0.57 2.87

University/college laboratories 0.57 2.87

Wood/metal shop 0.51 2.53

Food and Beverage Service

Bars, cocktail lounges 1.24 6.27

Cafeteria/fast-food dining 1.24 6.27

Kitchen (cooking) 0.36 1.81

Restaurant dining rooms 0.94 4.75

Food and Beverage Service, General

Break rooms 0.25 1.23

Coffee stations 0.21 1.07

Conference/meeting 0.41 2.07

Corridors 0.08 0.40

Occupiable storage rooms for liquids or gels 0.17 0.87

Hotels, Motels, Resorts, Dormitories

Barracks sleeping areas 0.21 1.07

Bedroom/living room 0.15 0.73

Laundry rooms (central) 0.23 1.13

Laundry rooms within dwelling units 0.23 1.13

Lobbies/prefunction 0.38 1.92

Multipurpose assembly 0.88 4.40

Miscellaneous Spaces

Banks or bank lobbies 0.23 1.16

Bank vaults/safe deposit 0.11 0.57

Computer (not printing) 0.11 0.53

Freezer and refrigerated spaces (<50°F [10°C]) 0.03 0.13

General manufacturing (excludes heavy industrial

and processes using chemicals)

0.33 1.67

Pharmacy (prep area) 0.31 1.53

Photo studios 0.23 1.13

Shipping/receiving 0.19 0.93

Sorting, packing, light assembly 0.23 1.15

Telephone closets 0.00 0.00

Transportation waiting 1.08 5.47

Warehouses 0.09 0.47

Table L-1 Check Table for the Ventilation Rate Procedure (Continued)

Occupancy Category

Combined Outdoor Air Rate (Rc )

cfm/ft2L/s·

ANSI/ASHRAE Standard 62.1-2019 73

Office Buildings

Breakrooms 0.49 2.47

Main entry lobbies 0.15 0.73

Occupiable storage rooms for dry materials 0.09 0.47

Office space 0.11 0.57

Reception areas 0.28 1.40

Telephone/data entry 0.48 2.40

Outpatient Health Care Facilities

Birthing room 0.44 2.20

Class 1 imaging rooms 0.19 0.97

Dental operatory 0.51 2.53

General examination room 0.36 1.81

Other dental treatment areas 0.11 0.57

Physical therapy exercise area 0.43 2.13

Physical therapy individual room 0.35 1.73

Physical therapeutic pool area 0.64 3.20

Prosthetics and orthotics room 0.51 2.53

Psychiatric consultation room 0.21 1.07

Psychiatric examination room 0.21 1.07

Psychiatric group room 0.41 2.07

Psychiatric seclusion room 0.15 0.73

Urgent care examination room 0.36 1.81

Urgent care observation room 0.21 1.07

Urgent care treatment room 0.44 2.21

Urgent care triage room 0.51 2.53

Speech therapy room 0.21 1.07

Public Assembly Spaces

Auditorium seating area 1.08 5.40

Courtrooms 0.55 2.73

Legislative chambers 0.41 2.07

Libraries 0.23 1.13

Lobbies 1.08 5.40

Museums (children's) 0.56 2.83

Museums/galleries 0.48 2.43

Places of religious worship 0.88 4.40

Table L-1 Check Table for the Ventilation Rate Procedure (Continued)

Occupancy Category

Combined Outdoor Air Rate (Rc )

cfm/ft2L/s·

74 ANSI/ASHRAE Standard 62.1-2019

Retail

Sales (except as below) 0.31 1.56

Barbershop 0.33 1.67

Beauty and nail salons 0.83 4.13

Coin-operated laundries 0.36 1.81

Mall common areas 0.48 2.43

Pet shops (animal areas) 0.34 1.71

Supermarket 0.16 0.81

Sports and Entertainment

Bowling alley (seating) 0.69 3.47

Disco/dance floors 2.75 13.73

Gambling casinos 1.44 7.28

Game arcades 0.44 2.21

Gym, sports arena (play area) 0.43 2.13

Health club/aerobics room 1.15 5.73

Health club/weight rooms 0.35 1.73

Spectator areas 1.58 8.00

Stages, studios 1.01 5.07

Swimming (pool and deck) 0.64 3.20

Transient Residential

Dwelling unit 0.10 0.50

Table L-1 Check Table for the Ventilation Rate Procedure (Continued)

Occupancy Category

Combined Outdoor Air Rate (Rc )

cfm/ft2L/s·

ANSI/ASHRAE Standard 62.1-2019 75

(This appendix is not part of this standard. It is merely informative and does not contain

requirements necessary for conformance to the standard. It has not been processed

according to the ANSI requirements for a standard and may contain material that has

not been subject to public review or a consensus process. Unresolved objectors on infor-

mative material are not offered the right to appeal at ASHRAE or ANSI.)

INFORMATIVE APPENDIX M

INFORMATIVE REFERENCES

Reference Title Section

Air Movement and Control Association International (AMCA)

30 W University Dr.

Arlington Heights, IL 60004

(847) 394-0150; www.amca.org

AMCA 511 (Rev. 2016) Certified Ratings Program—Product Rating Manual for Air Control Devices 5.5.2

ASHRAE

1791 Tullie Circle NE

Atlanta, GA 30329

(800) 527-4723; www.ashrae.org

2017 ASHRAE Handbook—Fundamentals Appendix J

ASHRAE RP-1009 (2001) Simplified Diffuser Boundary Conditions for Numerical Room Airflow Models Appendix C

ASHRAE RP-1373 (2009) Air Distribution Effectiveness with Stratified Air Distribution Systems Appendix C

ASHRAE Standard 55 (2017) Thermal Environmental Conditions for Human Occupancy G1.2.7

Chartered Institution of Building Services Engineers (CIBSE)

222 Balham High Road

London

SW12 9BS

United Kingdom

+44 (0)20 8675 5211; www.cibse.org

CIBSE AM10 (2005) Natural Ventilation in Non-Domestic Buildings Appendix J

Wiley & Sons

Etheridge, D.W., and

M. Sandberg (1996)

Building Ventilation: Theory and Measurement, Vol. 50 Appendix J

Energy and Buildings 65:516–22

von Grabe, J. (2013) Flow resistance for different types of windows in the case of buoyancy ventilation Appendix J

International Journal of Environmental Research and Public Health 11(11):11753-71.

Ahn, J.H., J.E. Szulejko, K.H.

Kim, Y.H. Kim, and B.W. Kim

(2014)

Odor and VOC emissions from pan frying of mackerel at three stages: Raw, well-

done, and charred

Appendix N

National Institute of Standards and Technology (NIST)

100 Bureau Dr.,

Gaithersburg, MD 20899

(301) 975-2000; www.nist.gov

Dols, W.S., and G.N. Walton

(2002)

CONTAMW 2.0 User Manual Appendix E

76 ANSI/ASHRAE Standard 62.1-2019

(This appendix is not part of this standard. It is merely

informative and does not con-

tain requirements necessary

for conformance to the standard. It has not been pro-

cessed according to the ANSI requirements for a standard and may contain material

that has not been subject to public review or a consensus process. Unresolved objec-

tors on informative material are not offered the right to appeal at ASHRAE or ANSI.)

INFORMATIVE APPENDIX N

INDOOR AIR QUALITY PROCEDURE (IAQP)

N1. SUMMARY OF SELECTED AIR QUALITY GUIDELINES

If the Indoor Air Quality Procedure (IAQP) is used, acceptable indoor concentrations limits are

needed for design compounds (DCs) and particles. When using this procedure, these concen-

tration limits need to be referenced from a cognizant authority as defined in the standard. At

present, no single organization develops acceptable concentrations limits for all substances in

indoor air, nor are limits available for all potential DCs or particles.

Cognizant authorities, such as USEPA, California EPA, and the Committee for Health

Related Evaluation of Building Products (AgBB) publish concentration limits for compounds,

many of which may be present in the indoor environment. Compounds included in the IAQP

design need to be included if data were judged sufficient to indicate a compound was likely to

be found in buildings at concentrations that were a substantial fraction of the proposed design

target (DT). The goal is not to include every possible compound that may appear in indoor air,

but rather sufficient numbers of compounds, and diversity thereof, such that control of the

compounds is anticipated to result in air quality that meets the standard's definition of "accept-

able."

A summary of considerations is presented below:

a. Is a compound expected to be present in indoor air with reasonable frequency at concentra-

tions relevant to (but not necessarily above) the DT? Specifically, the design outdoor air

flow rate (Voz ) and design features will be controlled by the compounds with the highest

emission rates and lowest targets (taking mixtures into account); thus, compounds with low

concentrations and high targets will have little or no impact on the calculated Voz .

b. Is there a DT that has been proposed by a cognizant authority?

c. Does it seem reasonable to expect that product emissions rates may be available for the pro-

posed compound?

d. It there an established sampling and analytical method for the proposed compound?

Occupational exposure limits (e.g., permissible exposure limits and threshold limit values)

are not appropriate as DTs, as they are not established for acceptable indoor air quality or for

typical commercial buildings. In general, they were developed for industrial applications eval-

uating effects of substances on healthy adult male workers.

N2. GUIDELINE FOR EMISSION RATES

Several published peer-reviewed papers provide a reference for design teams to use to compile

reasonable DC emission rates. A nonexhaustive list of peer-reviewed papers is shown in Sec-

tion N4 . In addition, there are multiple established certification programs that include empiri-

cal measures of emission rates for construction materials as well as finishes, furniture and

equipment intended for indoor use. These include third-party programs as well as industry

trade association programs and programs in support of government regulations (e.g., the AgBB

evaluation scheme used in Germany and parts of Europe, Blue Angel, BIFMA, Green Label,

France A+, CDPH Standard Method for testing and evaluation of VOC emissions [CDPH Sec-

tion 01350], Greenguard, SCS Indoor Advantage Gold, and Floorscore). Engineers may use

the emission rates for the specific materials that a designer is including or considering for use.

The IAQP (Section 6.3 ) requires that emission rates must consider DCs emitted by occupants

and their activities, by materials, and by specific sources within the occupied spaces and intro-

duced into the building with outdoor air.

N3. SUBJECTIVE EVALUATION

Section 6.3.4.2 requires that an occupant survey be conducted. Many subjective evaluation

approaches have been used with varying degrees of success. The following is an example of

an evaluation approach that focuses on adapted occupants:

ANSI/ASHRAE Standard 62.1-2019 77

a. After the building is completed and substantially occupied, provide all occupants with an

electronic or written of survey questions, including, "Do you perceive the air quality in

your environment to be acceptable or unacceptable?"

b. Anonymous surveys with neutrally framed questions provide the best responses.

c. When conducting an evaluation of adapted occupants, respondents must record their per-

ception of zone air quality after 30 minutes residency in the occupied zone.

d. All occupants should be surveyed, if possible. Otherwise, at least 50% of typical occu-

pancy, or 300, whichever is less, should be randomly selected.

e. A minimum 30% response rate from those surveyed is desirable. Each zone must be sur-

veyed per requirements of Section 6.3 . The subjective evaluation validates the acceptabil-

ity of indoor air if 80% of respondents in the area do not express dissatisfaction. The

Center for the Built Environment at UC Berkeley has developed a survey that includes

IAQ questions and may be a useful template.

N4. BIBLIOGRAPHY

Ahn, J.H., J.E. Szulejko, K.H. Kim, Y.H. Kim, and B.W. Kim. 2014. Odor and VOC emissions

from pan frying of mackerel at three stages: Raw, well-done, and charred. International

Journal of Environmental Research and Public Health 11(11):11753–71.

Apte, M.G. 2013. Final Report: Balancing energy conservation and occupant needs in ventila-

tion rate standards for Big Box stores in California: Predicted indoor air quality and

energy consumption using a matrix of ventilation scenarios. LBNL Paper LBNL-5551E,

Lawrence Berkeley National Laboratory, University of California, Berkeley.

Assadi, A.A., J. Palau, A. Bouzaza, J. Penya-Roja, V. Martinez-Soriac, and D. Wolbert. 2014.

Abatement of 3-methylbutanal and trimethylamine with combined plasma and photocatal-

ysis in a continuous planar reactor. Journal of Photochemistry and Photobiology A: Chem-

istry 282:1–8.

Barro, R., J. Regueiro, M. Llompart, C. Garcia-Jares. 2009. Analysis of industrial contami-

nants in indoor air: Part 1. Volatile organic compounds, carbonyl compounds, polycyclic

aromatic hydrocarbons and polychlorinated biphenyls. Journal of Chromatography A

1216(3):540–66.

Batterman, S, F.C. Su, S. Li, B. Mukherjee, and C. Jia. 2014. Personal exposure to mixtures of

volatile organic compounds: modeling and further analysis of the RIOPA data. Research

report (Health Effects Institute). 181:3–63.

Bi, X.H., G.Y. Sheng, Y.L. Feng, J.M. Fu, and J.X. Xie. 2005. Gas- and particulate-phase spe-

cific tracer and toxic organic compounds in environmental tobacco smoke. Chemosphere

61(10):1512–22.

Boraphech, P., and P. Thiravetyan. 2015. Removal of trimethylamine (fishy odor) by C-3 and

CAM plants. Environmental Science and Pollution Research 22(15):11543–57.

Bradman, A., F. Gaspar, R. Castorina, J. Williams, T. Hoang, and P.L. Jenkins. 2017. Support-

ing Information: Formaldehyde and acetaldehyde exposure and risk characterization in

California early childhood education environments. Indoor Air 27(1):104–113.

CDPH. 2006. Long-term building air measurements for volatile organic compounds including

aldehydes at a California five-building sustainable office complex, (Vol. 1/2 and 2/2).

Report #CA/DHS/EHLB/R-172. California Department of Public Health, Sacramento, CA.

Chan, W.R., S. Cohn, M. Sidheswaran, D.P. Sullivan, and W.J. Fisk. 2015. Contaminant levels,

source strengths, and ventilation rates in California retail stores. Indoor Air 25(4):381–92.

Choo, C.P., and J. Jalaludin. 2015. An overview of indoor air quality and its impact on respira-

tory health among Malaysian school-aged children. Reviews on Environmental Health

30(1):9–18.

Claeson, A.S., M. Sandstrom, A.L. Sunesson. 2007. Volatile organic compounds (VOCs) emit-

ted from materials collected from buildings affected by microorganisms. Journal of Envi-

ronmental Monitoring 9(3):240–5.

Cometto-Muniz, J.E., and M.H. Abraham 2015. Compilation and analysis of types and con-

centrations of airborne chemicals measured in various indoor and outdoor human environ-

ments. Chemosphere 127:70–86.

Cometto-Muniz, J.E., and W.S. Cain. 1992. Sensory irritation. Relation to indoor air pollution.

Annals of the New York Academy of Sciences 641:137–51.

78 ANSI/ASHRAE Standard 62.1-2019

Dodson, R.E., J.I. Levy, E.A. Houseman, J.D. Spengler, and D.H. Bennett. 2009. Evaluating

methods for predicting indoor residential volatile organic compound concentration distri-

butions. Journal of Exposure Science and Environmental Epidemiology 19(7):682–93.

Dutton, S.M. 2014. Evaluation of the indoor air quality procedure for use in retail buildings.

LBNL Paper LBNL-6079E, Lawrence Berkeley National Laboratory, University of Cali-

fornia, Berkeley, CA.

Fenske, J.D., and S.E. Paulson. 1999. Human breath emissions of VOCs. Journal of the Air

and Waste Management Association 49(5):594–8.

Fischer, M.L., D. Littlejohn, M.M. Lunden, N.J. Brown. 2003. Automated measurements of

ammonia and nitric acid in indoor and outdoor air. Environmental Science and Technology

37(10):2114–9.

Godwin, C, and S. Batterman. 2007. Indoor air quality in Michigan schools. Indoor Air

17(2):109–21.

Harrison, R.M., J.M. Delgado-Saborit, S.J. Baker, N. Aquilina, C. Meddings, and S. Harrad.

2009. Measurement and modeling of exposure to selected air toxics for health effects stud-

ies and verification by biomarkers. Research report (Health Effects Institute) 143:3-96,

Discussion 7–100.

Hau, K.M., D.W. Connell, and B.J. Richardson. 2000. Use of partition models in setting health

guidelines for volatile organic compounds. Regulatory Toxicology and Pharmacology

31(1):22–9.

Hau, K.M., D.W. Connell, and B.J. Richardson. 2000. Use of partition models to evaluate

guidelines for mixtures of volatile organic compounds. Regulatory Toxicology and Phar-

macology 32(1):36–41.

Hodgson, A.T., and H. Levin. 2003. Volatile organic compounds in indoor air: A review of

concentrations measured in North America since 1990. Report No. LBNL-51715, Law-

rence Berkely National Laboratory, Berkeley, CA.

Hotchi, T., A.T. Hodgson, and W.J. Fisk. 2006. Indoor air quality impacts of a peak load shed-

ding strategy for a large retail building. LBL Contract No. 500-03-026, PIER Demand

Response Research Center, Lawrence Berkeley National Laboratory, Berkeley, CA.

Ilacqua, V., O. Hänninen, N. Kuenzli, and M.F. Jantunen. 2007. Intake fraction distributions for

indoor VOC sources in five European cities. Indoor Air 17(5):372–83.

Kinney, P.L., S.N. Chillrud, S. Ramstrom, J. Ross, and J.D. Spengler. 2002. Exposures to mul-

tiple air toxics in New York City. Environmental Health Perspectives 110:539–46.

Lamorena, R.B., and W. Lee. 2008. Influence of ozone concentration and temperature on ultra-

fine particle and gaseous volatile organic compound formations generated during the

ozone-initiated reactions with emitted terpenes from a car air freshener. Journal of Haz-

ardous Materials 158(2-3):471–7.

Lee, S.C., S. Lam, and H.K. Fai. 2001. Characterization of VOCs, ozone, and PM10 emissions

from office equipment in an environmental chamber. Building and Environment

36(7):837–42.

Lindgren, T. 2010. A case of indoor air pollution of ammonia emitted from concrete in a newly

built office in Beijing. Building and Environment 45(3):596–600.

Lioy, P.J., Z. Fan, J. Zhang, P. Georgopoulos, S.W. Wang, and P. Ohman-Strickland. 2011. Per-

sonal and ambient exposures to air toxics in Camden, New Jersey. Research report (Health

Effects Institute) (160):3–127, Discussion 9–51.

Liu W, Zhang J, Zhang L, Turpin BJ, Weisel CP, Morandi MT, et al. Estimating contributions

of indoor and outdoor sources to indoor carbonyl concentrations in three urban areas of the

United States. Atmospheric Environment. 2006;40(12):2202-14.

Nagda, N.L., and H.E. Rector. 2003. A critical review of reported air concentrations of organic

compounds in aircraft cabins. Indoor Air 13(3):292–301.

Nazaroff, W.W., and C.J. Weschler. 2004. Cleaning products and air fresheners: exposure to

primary and secondary air pollutants. Atmospheric Environment 38(18):2841–65.

Norback, D., and G. Wieslander. 2002. Biomarkers and chemosensory irritations. International

Archives Of Occupational And Environmental Health 75(5):298–304.

Ohura, T., T. Amagai, X. Shen, S. Li, P. Zhang, and L. Zhu. 2009. Comparative study on indoor

air quality in Japan and China: Characteristics of residential indoor and outdoor VOCs.

Atmospheric Environment 43(40):6352–9.

ANSI/ASHRAE Standard 62.1-2019 79

Oikawa, D., W. Takeuchi, S. Murata, K. Takahashi, and Y. Sekine. 2012. Measurement of con-

centrations of thioglycolic acid, dithiodiglycolic acid and ammonia in indoor air of a

beauty salon. Journal of Occupational Health. 54(5):370–5.

Pant, P., S.K. Guttikunda, and R.E. Peltier. 2016. Exposure to particulate matter in India: A

synthesis of findings and future directions. Environmental Research 147:480–96.

Park, J.S., and K. Ikeda. 2006. Variations of formaldehyde and VOC levels during 3 years in

new and older homes. Indoor Air 16(2):129–35.

Repace, J.L., J.N. Hyde, and D. Brugge. 2006. Air pollution in Boston bars before and after a

smoking ban. BMC Public Health 6:266.

Roda, C., I. Kousignian, C. Guihenneuc-Jouyaux, C. Dassonville, I. Nicolis, and J. Just. 2011.

Formaldehyde exposure and lower respiratory infections in infants: Findings from the

PARIS cohort study. Environmental Health Perspectives. 119(11):1653–8.

Rohr, A.C. 2013. The health significance of gas- and particle-phase terpene oxidation prod-

ucts: a review. Environment international. 60:145-62.

Saha, C.K., G.Q. Zhang, P. Kai, and B. Bjerg. 2010. Effects of a partial pit ventilation system

on indoor air quality and ammonia emission from a fattening pig room. Biosystems Engi-

neering 105(3):279–87.

Salonen, H.J., A.L. Pasanen, S.K. Lappalainen, H.M. Riuttala, T.M. Tuomi, and P.O Pasanen.

2009. Airborne concentrations of volatile organic compounds, formaldehyde and ammo-

nia in Finnish office buildings with suspected indoor air problems. Journal of Occupa-

tional and Environmental Hygiene 6(3):200–9.

Santarsiero, A., S. Fuselli, A. Piermattei, R. Morlino, G. De Blasio, and M. De Felice. 2009.

Investigation of indoor air volatile organic compounds concentration levels in dental set-

tings and some related methodological issues. Annali dell'Istituto superiore di sanita

45(1):87–98.

Sarigiannis, D.A., S.P. Karakitsios, A. Gotti, I.L. Liakos, and A. Katsoyiannis. 2011. Exposure

to major volatile organic compounds and carbonyls in European indoor environments and

associated health risk. Environment International 37(4):743–65.

Sax, S.N., D.H. Bennett, S.N. Chillrud, P.L. Kinney, and J.D. Spengler. 2004. Differences in

source emission rates of volatile organic compounds in inner-city residences of New York

City and Los Angeles. Journal of Exposure Analysis and Environmental Epidemiology

14:S95–S109.

Schripp, T., S. Langer, and T. Salthammer. 2012. Interaction of ozone with wooden building

products, treated wood samples and exotic wood species. Atmospheric Environment

54:365–72.

Siegel, J.A., J. Srebric, N. Crain, E. Nirlo, M. Zaatari, and A. Hoisington. 2012. Ventilation

and indoor air quality in retail stores (RP-1596). HVAC&R Research 20(2).

Smith, T.J., M.E. Davis, J.E. Hart, A. Blicharz, F. Laden, and E. Garshick. 2012. Potential air

toxics hot spots in truck terminals and cabs. Research report (Health Effects Institute)

(172):5–82.

Tham, K.W., M.S. Zuraimi, and S.C. Sekhar. 2004. Emission modelling and validation of

VOCs' source strengths in air-conditioned office premises. Environment International.

30(8):1075–88.

Vainiotalo, S., V. Vaananen, and R. Vaaranrinta. 2008. Measurement of 16 volatile organic

compounds in restaurant air contaminated with environmental tobacco smoke. Environ-

mental Research 108(3):280–8.

Wang, S., H.M. Ang, and M.O. Tade. 2007. Volatile organic compounds in indoor environment

and photocatalytic oxidation: state of the art. Environment International 33(5):694–705.

Wang, T.C. 1975. A study of bioeffluents in a college classroom. ASHRAE transactions

81(1):1–12.

Weisel, C.P. 2002. Assessing exposure to air toxics relative to asthma. Environmental Health

Perspectives 110 Suppl. 4:527–37.

Winkle, M.R., and P.A. Scheff. 2001. Volatile organic compounds, polycyclic aromatic hydro-

carbons and elements in the air of ten urban homes. Indoor Air 11(1):49–64.

Wolkoff, P. 2013. Indoor air pollutants in office environments: Assessment of comfort, health,

and performance. International Journal of Hygiene and Environmental Health

216(4):371–94.

80 ANSI/ASHRAE Standard 62.1-2019

Wolkoff, P., C.K. Wilkins, P.A. Clausen, and G.D. Nielsen. 2006. Organic compounds in office

environments—Sensory irritation, odor, measurements and the role of reactive chemistry.

Indoor Air 16(1):7–19.

Wu, X.M., M.G. Apte, R. Maddalena, and D.H. Bennett. 2011. Volatile organic compounds in

small- and medium-sized commercial buildings in California. Environmental Science and

Technology 45(20):9075–83.

Zaatari, M., and J. Siegel. 2014. Particle characterization in retail environments: Concentra-

tions, sources, and removal mechanisms. Indoor Air 24(4):350–61.

Zhu, J., R. Newhook, L. Marro, and C.C. Chan. 2005. Selected volatile organic compounds in

residential air in the city of Ottawa, Canada. Environmental Science and Technology

39(11):3964–71.

ANSI/ASHRAE Standard 62.1-2019 81

(This appendix is not part of this standard. It is merely informative and does not contain requirements necessary for conformance to

the standard. It has not been processed according to the ANSI requirements for a standard and may contain material that has not

been subject to public review or a consensus process. Unresolved objectors on informative material are not offered the right to

appeal at ASHRAE or ANSI.)

INFORMATIVE APPENDIX O

ADDENDA DESCRIPTION INFORMATION

ANSI/ASHRAE Standard 62.1-2019 incorporates ANSI/ASHRAE Standard 62.1-2016 and Addenda b, c, d, e, f, g, h, i, j, k, l, m, n, o, q, r,

s, t, u, v, w, z, ad, ae, af, ah, ai, aj, al, am, an, ap, aq, ar, and as to ANSI/ASHRAE Standard 62.1-2016. Table O-1 lists each addendum and

describes the way in which the standard is affected by the change. It also lists the ASHRAE and ANSI approval dates for each addendum.

Informative: Many sections and appendices have been renumbered in the 2019 edition. The designations listed below reflect those prior

to reorganization. Final designations may differ. Please refer to the Table of Contents.

Table O-1 Addenda to ANSI/ASHRAE Standard 62.1-2016

Addendum Section(s) Affected Description of Changes*

Approval Dates:

• Standards Committee

• ASHRAE BOD/

Tech Council

• ANSI

b (NEW) Informative Appendix D Addendum b adds a new Informative Appendix D, which includes a simplified ventilation rate table for use in existing

buildings where information for calculating minimum ventilation using Normative Appendix A for multiple spaces is

often unavailable.

September 14, 2018

September 28, 2018

October 1, 2018

c 6.3.1, 6.3.2, 6.3.4.2, 6.5.2.1, 6.5.2.2;

(DELETED) Informative Appendix

Addendum c deletes Informative Appendix C, "Summary of Selected Air Quality Guidelines," from Standard 62.1. June 23, 2018

June 27, 2018

July 25, 2018

d (DELETED) Informative Appendix

Addendum d deletes Informative Appendix D, "Rationale for Minimum Physiological Requirements for Respiration

Air Based on CO2 Concentration."

January 20, 2018

January 24, 2018

February 21, 2018

e 4.4.1; 6.2.1.3;

Informative Appendix F;

(DELETED) Informative Appendix I

Addendum e modifies Informative Appendix F, "Information on Selected National Standards and Guidelines for

PM10, PM2.5, And Ozone," and deletes Informative Appendix I, "National Ambient Air Quality Standards

(NAAQS)". There is no current map for when the most recent three-year average annual fourth-highest daily maximum

eight-hour average ozone concentration exceeds 0.107 ppm. Therefore, the map and reference to it are deleted by this

addendum.

January 20, 2018

January 24, 2018

January 25, 2018

* These descriptions may not be complete and are provided for information only.

82 ANSI/ASHRAE Standard 62.1-2019

f 3; 6.2.5; Normative Appendix A Addendum g replaces the Table 6.2.5.2 approach with two formulas, one to determine system ventilation efficiency and

one to determine the minimum primary airflow set point intended for use in VAV systems.

June 23, 2018

June 27, 2018

June 28, 2018

g 3 The current wording exempts "spaces that are intended primarily for other purposes," but this could be interpreted as

requiring ventilation for spaces that are seldom occupied, such as exit stairways and passageways, which are seldom

ventilated in standard practice. The key clause with respect to ventilation is whether spaces are "occupied occasionally

and for short periods of time." This change makes that clear and adds the example of emergency exit passageways to

make that application specifically exempt.

June 23, 2018

June 27, 2018

June 28, 2018

h Informative Appendix G Addendum h modifies Informative Appendix G to add informative text that is contained in the current scope. June 23, 2018

June 27, 2018

June 28, 2018

i 2; 3 This addendum removes informative text that is not part of the definition of scope and clarifies when the standard does

not provide ventilation rates. A companion Addendum h adds informative text to Informative Appendix G,

"Application."

June 22, 2019

June 26, 2019

July 24, 2019

j 4 Section 4 refers to information from USEPA. This information is subject to change, so Addendum j updates the

informative notes in this section.

June 23, 2018

June 27, 2018

June 28, 2018

k 6.2.1.3 Standard 62.1-2016 contains requirements for filtration of ozone from outdoor air under certain conditions. This

addendum changes the requirement to be consistent with current EPA ambient air quality standards.

September 14, 2018

September 28, 2018

October 1, 2018

Table O-1 Addenda to ANSI/ASHRAE Standard 62.1-2016

Addendum Section(s) Affected Description of Changes*

Approval Dates:

• Standards Committee

• ASHRAE BOD/

Tech Council

• ANSI

* These descriptions may not be complete and are provided for information only.

ANSI/ASHRAE Standard 62.1-2019 83

l 3; 6.1.3, 6.4, 6.6 This addendum provides specific requirements for the exception to the natural ventilation procedure by providing a

clear compliance path. It also recognizes that there are inherent health issues with outdoor air in many locations in the

world and updates the prescriptive requirements based on recent studies and airflow evaluations.

Outdoor Air requirements specified in 6.2.1 have been applied to naturally ventilated buildings

The prescriptive path has been improved by removing the openable area requirement of 4% of net occupiable floor area

and introducing two prescriptive paths for sizing the required openable area that better respond to program in the zone

and window type.

A four-point definition of a naturally ventilated engineered system has been developed to require designers to more

fully document natural ventilation systems that do not meet prescriptive values.

July 22, 2019

August 1, 2019

August 26, 2019

m 5.8; 6.2.1.1, 6.2.1.2; 9 The current standard contains requirements for filtration of particles from outdoor air under certain conditions. It also

requires filtration upstream of wetted surfaces. Addendum m adds ISO ratings as an option to the existing MERV

requirements and makes some modifications for consistency.

January 12, 2019

January 16, 2019

February 13, 2019

n Table 6.2.2.1, (NEW) 6.2.2.1.1.3 Addendum n adds requirements for animal facilities. Ammonia is added to compounds of common interest in a

different addenda.

June 22, 2019

June 26, 2019

July 24, 2019

o 5.16.2.1 The current standard contains requirements for redesignation that are based on informative text. This addendum

clarifies and refers to mandatory requirements for Classes 3 and 4 air.

June 23, 2018

June 27, 2018

July 25, 2018

Table O-1 Addenda to ANSI/ASHRAE Standard 62.1-2016

Addendum Section(s) Affected Description of Changes*

Approval Dates:

• Standards Committee

• ASHRAE BOD/

Tech Council

• ANSI

* These descriptions may not be complete and are provided for information only.

84 ANSI/ASHRAE Standard 62.1-2019

q 5.1.1; 5.3.2; 7.2.2 Section 5 and 7 changes are intended to better satisfy the objectives of the requirements already included in the

standard and improve the language describing them. The changes differentiate the objectives fostering anticipation for

the needs of system measurements with appropriate designs and those of airflow verification.

Section 5.1.1 solicits design attention for duct layout conditions and anything that contributes to making field

measurement difficult, prone to high error rates, or sometimes impossible to perform. The new language in Section

5.3.2 is intended to provide a generalized and simpler statement of this requirement's objective and avoid the

expression of limited alternatives in subsection items (a) through (c), yet provide designers and building owners the

same flexibility and design choices.

Modification of 7.2.2 addresses the operational requirements reflected elsewhere in the standard. "Under any load or

dynamic reset condition" must also be considered when verifying the capability of the ventilation system to function as

required, particularly at the point of operation where minimum outdoor air control is the most difficult. The new

requirement identifies that direct measurement is the only method allowed to verify intake flow rates.

June 23, 2018

June 27, 2018

July 25, 2018

r 5.5.1, Table 5.5.1, 5.14.2, 5.16.1,

Table 5.16.1, "Airstream or

Surfaces" moved to Table 6.5.2,

"Airstream or Sources"

Addendum r makes several changes to Section 5. For outdoor air intakes, the alternate methods of calculation are

specified in Normative Appendix B, and the exception is eliminated. Requirements in the Table 5.5.1 footnotes are

relocated to the body of the standard. If condensation is to be managed (Exception 5.14.2), then a management plan

must be developed. If "local practice" demonstrates condensation does not grow mold, it can be included in the

management plan. Table 5.16.1, "Airstreams or Sources," is relocated to Section 6 where all other air class information

resides.

June 23, 2018

June 27, 2018

July 25, 2018

s 3; 6.1.1, 6.2.2.1, (NEW) 6.2.5.1.3,

6.2.7.1, Table 6.2.2.1

The ventilation rate procedure in Standard 62.1-2016 contains requirements in notes. This addendum relocates

requirements to the body of the standard. Another change clarifies that in the presence of unusual sources, the rates in

the VRP must be supplemented by additional ventilation to be determined by the IAQ procedure or an EHS

professional. The default values per person in Table 6.2.2.1, "Minimum Ventilation Rates in Breathing Zone," do not

contain any adjustments for Ev and, in many cases, are taken out of context. They are not used in the ventilation

calculations. These values are deleted.

June 22, 2019

June 26, 2019

July 24, 2019

t (NEW) Informative Appendix L Addendum t adds a new informative appendix that is a companion to the changes to the Natural Ventilation Procedure.

It provides information for application of the new procedure.

January 12, 2019

January 16, 2019

January 17, 2019

Table O-1 Addenda to ANSI/ASHRAE Standard 62.1-2016

Addendum Section(s) Affected Description of Changes*

Approval Dates:

• Standards Committee

• ASHRAE BOD/

Tech Council

• ANSI

* These descriptions may not be complete and are provided for information only.

ANSI/ASHRAE Standard 62.1-2019 85

u (NEW) Informative Appendix M This addendum adds a new informative appendix that provides a compliance checklist and simple calculations to

approximately check ventilation rate values. Other standards have more complex compliance documents.

June 23, 2018

June 27, 2018

July 25, 2018

v Normative Appendix B This addendum adds requirements for alternate calculation methods (current Section B2[c]) but does not describe or

prescribe a method.

June 23, 2018

June 27, 2018

July 25, 2018

w 5.5.1.4; 6.2.2.1.1.2; 6.5.1 Standard 62.1 contains minimum requirements for laboratories, but more complex laboratories should be designed

with the different approach contained in ANSI Z9.5, "Laboratory Ventilation." This addendum recognizes that

approach as valid in complying with the ventilation and exhaust requirements of Standard 62.1.

June 23, 2018

June 27, 2018

June 28, 2018

z (NEW) Informative Appendix N The default values per person in Table 6.2.2.1 do not contain adjustments for system ventilation e fficiency and, in many

cases, are taken out of context. These values are deleted in Addendum s. Addendum z provides an informative table

with a rate per unit area that incorporates the system ventilation efficiency used in the simplified procedure. This results

in a more accurate first-pass estimate of ventilation required at the outdoor air intake for many systems.

June 23, 2018

June 27, 2018

June 28, 2018

ad 6.5, 6.5.1 Table 6.5 (Minimum Exhaust Rates) lists minimum exhaust rates for certain spaces in which contaminants generation

have been deemed high enough that the contaminant cannot be diluted and thus need to be exhausted. However, the

standard does not require these spaces to be at any pressure. This addendum adds the requirement for these spaces to be

at a negative pressure with respect to adjacent spaces in order to minimize contaminants leakage to adjacent spaces

July 22, 2019

August 1, 2019

August 26, 2019

ae 5.9 This addendum establishes a 60°F (15°C) indoor air dew-point limit that avoids the microbial growth problems

frequently observed when humid outdoor air infiltrates into buildings that are mechanically cooled.

July 22, 2019

August 1, 2019

August 26, 2019

af 3; Table 6.2.2.1 The 2018 FGI (Facilities Guidelines Institute) guideline requires certain outpatient spaces to meet local ventilation

codes and not ASHRAE/ASHE Standard 170: Neither one of the two mechanical model codes (IMC and UMC) has

ventilation rates for these spaces. The IMC and UMC use ASHRAE Standard 62.1 as basis for their ventilation table.

This addendum adds ventilation rates for those spaces in order to bridge the gap with ASHRAE/ASHE Standard 170. It

was developed in consultation with FGI in order to understand the activity in each space.

July 22, 2019

August 1, 2019

August 26, 2019

Table O-1 Addenda to ANSI/ASHRAE Standard 62.1-2016

Addendum Section(s) Affected Description of Changes*

Approval Dates:

• Standards Committee

• ASHRAE BOD/

Tech Council

• ANSI

* These descriptions may not be complete and are provided for information only.

86 ANSI/ASHRAE Standard 62.1-2019

ah 3; 6.2.2.2; Table 6.2.2.2; A3;

(NEW) Normative Appendix X

Addendum ah clarifies and expands the values of zone air distribution effectiveness in Table 6.2.2.1 and adds

Normative Appendix X, "Zone Air Distribution Effectiveness—Alternate Procedures," to provide a procedure for

calculating zone air distribution effectiveness. Notes on Table 6.2.2.1 have also been removed and replaced with

definitions or specific requirements within the language of the standard.

June 22, 2019

June 26, 2019

June 27, 2019

ai 7.2.2 Addendum ai removes language published in Addendum q to Standard 62.1-2016. It reinstates the option of using

indirect measurement techniques in testing and balancing (TAB) of the ventilation system in startup.

June 22, 2019

June 26, 2019

June 27, 2019

aj (NEW) 5.7 The current standard is silent on producing ozone within HVAC equipment. In some countries, ozone generators are

accepted as air cleaners. In a recent poll of members of SSPC62.1, only 2% thought that having ozone producing

components in a ventilation system is consistent with acceptable indoor air quality.

Ozone is harmful for health, and exposure to ozone creates risk for a variety of symptoms and diseases associated with

the respiratory tract. Many products of ozone homogeneous and heterogeneous reaction processes also create risks for

health, including formaldehyde, unsaturated aldehydes (produced during the reaction of ozone with ketones and

alcohols), and ultrafine particles (secondary organic aerosols).

Ozone emission is thus undesirable. However, there is no consensus on the safe level of ozone. For example,

ASHRAE's Environmental Health Committee issued an emerging issue brief suggesting "safe ozone levels would be

lower than 10 ppb" and that "the introduction of ozone to indoor spaces should be reduced to as low as reasonably

achievable (ALARA) levels." Still, even widely used guidelines are not entirely consistent with all available

epidemiological literature on the effects of ozone, and there is relatively little known about the long-term effects of

exposure to low concentrations of ozone.

The current state of the science regarding the health effects of ozone strongly suggests that the use of air cleaners that

emit ozone by design should not be permitted; the same information and advice is given by the USEPA, among others.

There is more uncertainty about recommendations for air cleaners that do not use ozone by design for air cleaning but

produce ozone unintentionally, as a by-product of their operation. There are devices that emit ozone but at the same

time reduce concentrations of other harmful contaminants. The state of the science does not allow making highly

certain trade-offs between increased exposure to ozone and the ozone reaction byproducts and reduced exposure to

other contaminants.

June 22, 2019

June 26, 2019

July 24, 2019

al (NEW) 6.2.7.1.3;

Table 8.2

The current standard has no requirements for accuracy of CO2 sensors used for demand control ventilation.

Various research projects show wide variation in accuracy and drift. This addendum adds language from the 2013

California Title 24 Section 120.1(c)4.F.

July 22, 2019

August 1, 2019

August 26, 2019

Table O-1 Addenda to ANSI/ASHRAE Standard 62.1-2016

Addendum Section(s) Affected Description of Changes*

Approval Dates:

• Standards Committee

• ASHRAE BOD/

Tech Council

• ANSI

* These descriptions may not be complete and are provided for information only.

ANSI/ASHRAE Standard 62.1-2019 87

am (NEW) 6.5.1.1 When Addendum r to Standard 62.1-2016 was published, the footnote to old Table 5.16.1, "Airstreams or Sources," did

not transfer to new the Table 6.5.2. This addendum reinstates the note into Section 6.

June 22, 2019

June 26, 2019

June 27, 2019

an 3 This addendum clarifies that college classrooms may use Note H in Table 6.2.2.1 and have the ventilation shut off

when they are unoccupied.

July 22, 2019

August 1, 2019

August 26, 2019

ap 9; Informative Appendix J Addendum ap updates publication dates and URIs in Section 9, "References," and Informative Appendix J,

"Informative References."

June 22, 2019

June 26, 2019

June 27, 2019

aq Table 6.2.2.1 Many manufacturing occupancies do not use hazardous materials. This addendum changes the air class for those

spaces to Air Class 2, which allows the air to be recirculated to other similar manufacturing areas. Manufacturing

spaces using hazardous materials will remain Air Class 3.

June 22, 2019

June 26, 2019

July 24, 2019

ar Informative Appendix E Addendum ar modifies language in Informative Appendix E, "Acceptable Mass Balance Equations for Use with the

IAQ Procedure," to be consistent with the current IAQP. It also clarifies that the equations do not include any potential

compounds added by the HVAC system.

June 22, 2019

June 26, 2019

June 27, 2019

as 6.2.2; 9 This addendum adds a reference to ASHRAE/ASHE Standard 170 and an exception to direct users to use the

ventilation rates in ASHRAE/ASHE Standard 170 for asepsis and odor control for healthcare spaces listed in

ASHRAE/ASHE Standard 170.

July 22, 2019

August 1, 2019

August 26, 2019

NOTE

Approved addenda, errata, or interpretations for this standard can be downloaded free of charge from the

ASHRAE website at www.ashrae.org/technology .

Table O-1 Addenda to ANSI/ASHRAE Standard 62.1-2016

Addendum Section(s) Affected Description of Changes*

Approval Dates:

• Standards Committee

• ASHRAE BOD/

Tech Council

• ANSI

* These descriptions may not be complete and are provided for information only.

POLICY STATEMENT DEFINING ASHRAE'S CONCERN

FOR THE ENVIRONMENTAL IMPACT OF ITS ACTIVITIES

ASHRAE is concerned with the impact of its members' activities on both the indoor and outdoor environment.

ASHRAE's members will strive to minimize any possible deleterious effect on the indoor and outdoor environment of

the systems and components in their responsibility while maximizing the beneficial effects these systems provide,

consistent with accepted Standards and the practical state of the art.

ASHRAE's short-range goal is to ensure that the systems and components within its scope do not impact the

indoor and outdoor environment to a greater extent than specified by the Standards and Guidelines as established by

itself and other responsible bodies.

As an ongoing goal, ASHRAE will, through its Standards Committee and extensive Technical Committee structure,

continue to generate up-to-date Standards and Guidelines where appropriate and adopt, recommend, and promote

those new and revised Standards developed by other responsible organizations.

Through its Handbook , appropriate chapters will contain up-to-date Standards and design considerations as the

material is systematically revised.

ASHRAE will take the lead with respect to dissemination of environmental information of its primary interest and

will seek out and disseminate information from other responsible organizations that is pertinent, as guides to updating

Standards and Guidelines.

The effects of the design and selection of equipment and systems will be considered within the scope of the

system's intended use and expected misuse. The disposal of hazardous materials, if any, will also be considered.

ASHRAE's primary concern for environmental impact will be at the site where equipment within ASHRAE's scope

operates. However, energy source selection and the possible environmental impact due to the energy source and

energy transportation will be considered where possible. Recommendations concerning energy source selection

should be made by its members.

ASHRAE · 1791 Tullie Circle NE · Atlanta, GA 30329 · www.ashrae.org

Product code: 86170 10/19

About ASHRAE

Founded in 1894, ASHRAE is a global professional society committed to serve humanity by advancing the arts and

sciences of heating, ventilation, air conditioning, refrigeration, and their allied fields.

As an industry leader in research, standards writing, publishing, certification, and continuing education, ASHRAE

and its members are dedicated to promoting a healthy and sustainable built environment for all, through strategic

partnerships with organizations in the HVAC&R community and across related industries.

To stay current with this and other ASHRAE Standards and Guidelines, visit www.ashrae.org/standards, and

connect on LinkedIn, Facebook, Twitter, and YouTube.

Visit the ASHRAE Bookstore

ASHRAE offers its Standards and Guidelines in print, as immediately downloadable PDFs, and via ASHRAE Digital

Collections, which provides online access with automatic updates as well as historical versions of publications.

Selected Standards and Guidelines are also offered in redline versions that indicate the changes made between the

active Standard or Guideline and its previous version. For more information, visit the Standards and Guidelines

section of the ASHRAE Bookstore at www.ashrae.org/bookstore.

IMPORTANT NOTICES ABOUT THIS STANDARD

To ensure that you have all of the approved addenda, errata, and interpretations for this

Standard, visit www.ashrae.org/standards to download them free of charge.

Addenda, errata, and interpretations for ASHRAE Standards and Guidelines are no

longer distributed with copies of the Standards and Guidelines. ASHRAE provides

these addenda, errata, and interpretations only in electronic form to promote

more sustainable use of resources.

ResearchGate has not been able to resolve any citations for this publication.

Jill D. Fenske
Suzanne E. Paulson

The medical community has long recognized that humans exhale volatile organic compounds (VOCs). Several studies have quantified emissions of VOCs from human breath, with values ranging widely due to variation between and within individuals. The authors have measured human breath concentrations of isoprene and pentane. The major VOCs in the breath of healthy individuals are isoprene (12-580 ppb), acetone (1.2-1,880 ppb), ethanol (13-1,000 ppb), methanol (160-2,000 ppb) and other alcohols. In this study, we give a brief summary of VOC measurements in human breath and discuss their implications for indoor concentrations of these compounds, their contributions to regional and global emissions budgets, and potential ambient air sampling artifacts. Though human breath emissions are a negligible source of VOCs on regional and global scales (less than 4% and 0.3%, respectively), simple box model calculations indicate that they may become an important (and sometimes major) indoor source of VOCs under crowded conditions. Human breath emissions are generally not taken into account in indoor air studies, and results from this study suggest that they should be.

Little information is available about air quality in early childhood education (ECE) facilities. We collected single-day air samples in 2010-2011 from 40 ECE facilities serving children < 6 years old in California and applied new methods to evaluate cancer risk in young children. Formaldehyde and acetaldehyde were detected in 100% of samples. The median (max) indoor formaldehyde and acetaldehyde levels (μg/m(3) ) were 17.8 (48.8) and 7.5 (23.3), respectively, and were comparable to other California schools and homes. Formaldehyde and acetaldehyde concentrations were inversely associated with air exchange rates (Pearson r=-0.54 and -0.63, respectively; p<0.001). The buildings and furnishings were generally >5 years old, suggesting other indoor sources. Formaldehyde levels exceeded California 8-hour and chronic Reference Exposure Levels (both 9 μg/m(3) ) for non-cancer effects in 87.5% of facilities. Acetaldehyde levels exceeded the U.S. EPA Reference Concentration in 30% of facilities. If reflective of long-term averages, estimated exposures would exceed age-adjusted "safe harbor levels" based on California's Proposition 65 guidelines (10(-5) lifetime cancer risk). Additional research is needed to identify sources of formaldehyde and acetaldehyde and strategies to reduce indoor air levels. The impact of recent California and proposed U.S. EPA regulations to reduce formaldehyde levels in future construction should be assessed. This article is protected by copyright. All rights reserved.

J. Enrique Cometto-Muñiz
Michael H. Abraham

The main purpose of this article is to summarize and illustrate the results of a literature search on the types, levels, relative concentrations, concentration spread of individual chemicals, and number of airborne compounds (mostly volatile organic compounds, VOCs) that have been found, measured, and reported both indoors and outdoors. Two broad categories of indoor environments are considered: (1) home/school, and (2) commercial spaces. Also, two categories of outdoor environments are considered: (1) non-industrial and (2) industrial (the latter represented by the vicinity of a pig farm and the vicinity of an oil refinery). The outcome is presented as a series of graphs and tables containing the following statistics: geometric mean, arithmetic mean, median, standard deviation, variance, standard error, interquartile distance, minimum value, maximum value, and number of data (data count) for the air concentration of each reported compound in a given environment. A Supplementary Table allows interested readers to match each single value included in this compilation with its corresponding original reference. See full article at: http://escholarship.org/uc/item/51w456sw. Copyright © 2015 Elsevier Ltd. All rights reserved.

Abstract The indoor environment is a major source of human exposure to pollutants. Some pollutants can have concentrations that are several times higher indoors than outdoors. Prolonged exposure may lead to adverse biologic effects, even at low concentrations. Several studies done in Malaysia had underlined the role of indoor air pollution in affecting respiratory health, especially for school-aged children. A critical review was conducted on the quantitative literature linking indoor air pollution with respiratory illnesses among school-aged children. This paper reviews evidence of the association between indoor air quality (IAQ) and its implications on respiratory health among Malaysian school-aged children. This review summarizes six relevant studies conducted in Malaysia for the past 10 years. Previous epidemiologic studies relevant to indoor air pollutants and their implications on school-aged children's respiratory health were obtained from electronic database and included as a reference in this review. The existing reviewed data emphasize the impact of IAQ parameters, namely, indoor temperature, ventilation rates, indoor concentration of carbon dioxide (CO2), carbon monoxide (CO), particulate matters (PM), volatile organic compounds (VOCs), nitrogen dioxide (NO2) and airborne microbes, on children's respiratory health. The study found that most of the Malaysian school-aged children are exposed to the inadequate environment during their times spent either in their houses or in their classrooms, which is not in compliance with the established standards. Children living in households or studying in schools in urban areas are more likely to suffer from respiratory illnesses compared with children living in homes or studying in schools in rural areas.

Many classes of odorants and volatile organic compounds that are deleterious to our wellbeing can be emitted from diverse cooking activities. Once emitted, they can persist in our living space for varying durations. In this study, various volatile organic compounds released prior to and during the pan frying of fish (mackerel) were analyzed at three different cooking stages (stage 1 = raw (R), stage 2 = well-done (W), and stage 3 = overcooked/charred (O)). Generally, most volatile organic compounds recorded their highest concentration levels at stage 3 (O), e.g., 465 (trimethylamine) and 106 ppb (acetic acid). In contrast, at stage 2 (W), the lowest volatile organic compounds emissions were observed. The overall results of this study confirm that trimethylamine is identified as the strongest odorous compound, especially prior to cooking (stage 1 (R)) and during overcooking leading to charring (stage 3 (O)). As there is a paucity of research effort to measure odor intensities from pan frying of mackerel, this study will provide valuable information regarding the management of indoor air quality.

Introduction: Emission sources of volatile organic compounds (VOCs*) are numerous and widespread in both indoor and outdoor environments. Concentrations of VOCs indoors typically exceed outdoor levels, and most people spend nearly 90% of their time indoors. Thus, indoor sources generally contribute the majority of VOC exposures for most people. VOC exposure has been associated with a wide range of acute and chronic health effects; for example, asthma, respiratory diseases, liver and kidney dysfunction, neurologic impairment, and cancer. Although exposures to most VOCs for most persons fall below health-based guidelines, and long-term trends show decreases in ambient emissions and concentrations, a subset of individuals experience much higher exposures that exceed guidelines. Thus, exposure to VOCs remains an important environmental health concern. The present understanding of VOC exposures is incomplete. With the exception of a few compounds, concentration and especially exposure data are limited; and like other environmental data, VOC exposure data can show multiple modes, low and high extreme values, and sometimes a large portion of data below method detection limits (MDLs). Field data also show considerable spatial or interpersonal variability, and although evidence is limited, temporal variability seems high. These characteristics can complicate modeling and other analyses aimed at risk assessment, policy actions, and exposure management. In addition to these analytic and statistical issues, exposure typically occurs as a mixture, and mixture components may interact or jointly contribute to adverse effects. However most pollutant regulations, guidelines, and studies remain focused on single compounds, and thus may underestimate cumulative exposures and risks arising from coexposures. In addition, the composition of VOC mixtures has not been thoroughly investigated, and mixture components show varying and complex dependencies. Finally, although many factors are known to affect VOC exposures, many personal, environmental, and socioeconomic determinants remain to be identified, and the significance and applicability of the determinants reported in the literature are uncertain. To help answer these unresolved questions and overcome limitations of previous analyses, this project used several novel and powerful statistical modeling and analysis techniques and two large data sets. The overall objectives of this project were (1) to identify and characterize exposure distributions (including extreme values), (2) evaluate mixtures (including dependencies), and (3) identify determinants of VOC exposure. METHODS VOC data were drawn from two large data sets: the Relationships of Indoor, Outdoor, and Personal Air (RIOPA) study (1999-2001) and the National Health and Nutrition Examination Survey (NHANES; 1999-2000). The RIOPA study used a convenience sample to collect outdoor, indoor, and personal exposure measurements in three cities (Elizabeth, NJ; Houston, TX; Los Angeles, CA). In each city, approximately 100 households with adults and children who did not smoke were sampled twice for 18 VOCs. In addition, information about 500 variables associated with exposure was collected. The NHANES used a nationally representative sample and included personal VOC measurements for 851 participants. NHANES sampled 10 VOCs in common with RIOPA. Both studies used similar sampling methods and study periods. Specific Aim 1. To estimate and model extreme value exposures, extreme value distribution models were fitted to the top 10% and 5% of VOC exposures. Health risks were estimated for individual VOCs and for three VOC mixtures. Simulated extreme value data sets, generated for each VOC and for fitted extreme value and lognormal distributions, were compared with measured concentrations (RIOPA observations) to evaluate each model's goodness of fit. Mixture distributions were fitted with the conventional finite mixture of normal distributions and the semi-parametric Dirichlet process mixture (DPM) of normal distributions for three individual VOCs (chloroform, 1,4-DCB, and styrene). Goodness of fit for these full distribution models was also evaluated using simulated data. Specific Aim 2. Mixtures in the RIOPA VOC data set were identified using positive matrix factorization (PMF) and by toxicologic mode of action. Dependency structures of a mixture's components were examined using mixture fractions and were modeled using copulas, which address correlations of multiple components across their entire distributions. Five candidate copulas (Gaussian, t, Gumbel, Clayton, and Frank) were evaluated, and the performance of fitted models was evaluated using simulation and mixture fractions. Cumulative cancer risks were calculated for mixtures, and results from copulas and multivariate lognormal models were compared with risks based on RIOPA observations. Specific Aim 3. Exposure determinants were identified using stepwise regressions and linear mixed-effects models (LMMs). Results: Specific Aim 1. Extreme value exposures in RIOPA typically were best fitted by three-parameter generalized extreme value (GEV) distributions, and sometimes by the two-parameter Gumbel distribution. In contrast, lognormal distributions significantly underestimated both the level and likelihood of extreme values. Among the VOCs measured in RIOPA, 1,4-dichlorobenzene (1,4-DCB) was associated with the greatest cancer risks; for example, for the highest 10% of measurements of 1,4-DCB, all individuals had risk levels above 10(-4), and 13% of all participants had risk levels above 10(-2). Of the full-distribution models, the finite mixture of normal distributions with two to four clusters and the DPM of normal distributions had superior performance in comparison with the lognormal models. DPM distributions provided slightly better fit than the finite mixture distributions; the advantages of the DPM model were avoiding certain convergence issues associated with the finite mixture distributions, adaptively selecting the number of needed clusters, and providing uncertainty estimates. Although the results apply to the RIOPA data set, GEV distributions and mixture models appear more broadly applicable. These models can be used to simulate VOC distributions, which are neither normally nor lognormally distributed, and they accurately represent the highest exposures, which may have the greatest health significance. Specific Aim 2. Four VOC mixtures were identified and apportioned by PMF; they represented gasoline vapor, vehicle exhaust, chlorinated solvents and disinfection byproducts, and cleaning products and odorants. The last mixture (cleaning products and odorants) accounted for the largest fraction of an individual's total exposure (average of 42% across RIOPA participants). Often, a single compound dominated a mixture but the mixture fractions were heterogeneous; that is, the fractions of the compounds changed with the concentration of the mixture. Three VOC mixtures were identified by toxicologic mode of action and represented VOCs associated with hematopoietic, liver, and renal tumors. Estimated lifetime cumulative cancer risks exceeded 10(-3) for about 10% of RIOPA participants. The dependency structures of the VOC mixtures in the RIOPA data set fitted Gumbel (two mixtures) and t copulas (four mixtures). These copula types emphasize dependencies found in the upper and lower tails of a distribution. The copulas reproduced both risk predictions and exposure fractions with a high degree of accuracy and performed better than multivariate lognormal distributions. Specific Aim 3. In an analysis focused on the home environment and the outdoor (close to home) environment, home VOC concentrations dominated personal exposures (66% to 78% of the total exposure, depending on VOC); this was largely the result of the amount of time participants spent at home and the fact that indoor concentrations were much higher than outdoor concentrations for most VOCs. In a different analysis focused on the sources inside the home and outside (but close to the home), it was assumed that 100% of VOCs from outside sources would penetrate the home. Outdoor VOC sources accounted for 5% (d-limonene) to 81% (carbon tetrachloride [CTC]) of the total exposure. Personal exposure and indoor measurements had similar determinants depending on the VOC. Gasoline-related VOCs (e.g., benzene and methyl tert-butyl ether [MTBE]) were associated with city, residences with attached garages, pumping gas, wind speed, and home air exchange rate (AER). Odorant and cleaning-related VOCs (e.g., 1,4-DCB and chloroform) also were associated with city, and a residence's AER, size, and family members showering. Dry-cleaning and industry-related VOCs (e.g., tetrachloroethylene [or perchloroethylene, PERC] and trichloroethylene [TCE]) were associated with city, type of water supply to the home, and visits to the dry cleaner. These and other relationships were significant, they explained from 10% to 40% of the variance in the measurements, and are consistent with known emission sources and those reported in the literature. Outdoor concentrations of VOCs had only two determinants in common: city and wind speed. Overall, personal exposure was dominated by the home setting, although a large fraction of indoor VOC concentrations were due to outdoor sources. City of residence, personal activities, household characteristics, and meteorology were significant determinants. Concentrations in RIOPA were considerably lower than levels in the nationally representative NHANES for all VOCs except MTBE and 1,4-DCB. Differences between RIOPA and NHANES results can be explained by contrasts between the sampling designs and staging in the two studies, and by differences in the demographics, smoking, employment, occupations, and home locations. (ABSTRACT TRUNCATED)

Air pollution poses a critical threat to human health with ambient and household air pollution identified as key health risks in India. While there are many studies investigating concentration, composition, and health effects of air pollution, investigators are only beginning to focus on estimating or measuring personal exposure. Further, the relevance of exposures studies from the developed countries in developing countries is uncertain. This review summarizes existing research on exposure to particulate matter (PM) in India, identifies gaps and offers recommendations for future research. There are a limited number of studies focused on exposure to PM and/or associated health effects in India, but it is evident that levels of exposure are much higher than those reported in developed countries. Most studies have focused on coarse aerosols, with a few studies on fine aerosols. Additionally, most studies have focused on a handful of cities, and there are many unknowns in terms of ambient levels of PM as well as personal exposure. Given the high mortality burden associated with air pollution exposure in India, a deeper understanding of ambient pollutant levels as well as source strengths is crucial, both in urban and rural areas. Further, the attention needs to expand beyond the handful large cities that have been studied in detail.

Tsen C. Wang

This paper investigates the production of bioeffluents in a 434 seat auditorium, examining the types of compounds found in bioeffluents, the amount of individual compounds, its production during normal lectures, its production during examinations (a stress condition), sex differentiation, and rate of bioeffluent production. Room ventilation and air conditioning were provided by a separate unit so control over air sampling could be exercised. The volatile bioeffluent produced by classes of men and women were sampled, and large amounts were collected for subsequent identification.

Phattara Boraphech
Paitip Thiravetyan

From screening 23 plant species, it was found that Pterocarpus indicus (C3) and Sansevieria trifasciata (crassulacean acid metabolism (CAM)) were the most effective in polar gaseous trimethylamine (TMA) uptake, reaching up to 90 % uptake of initial TMA (100 ppm) within 8 h, and could remove TMA at cycles 1-4 without affecting photosystem II (PSII) photochemistry. Up to 55 and 45 % of TMA was taken up by S. trifasciata stomata and leaf epicuticular wax, respectively. During cycles 1-4, interestingly, S. trifasciata changed its stomata apertures, which was directly induced by gaseous TMA and light treatments. In contrast, for P. indicus the leaf epicuticular wax and stem were the major pathways of TMA removal, followed by stomata; these pathways accounted for 46, 46, and 8 %, respectively, of TMA removal percentages. Fatty acids, particularly tetradecanoic (C14) acid and octadecanoic (C18) acid, were found to be the main cuticular wax components in both plants, and were associated with TMA removal ability. Moreover, the plants could degrade TMA via multiple metabolic pathways associated with carbon/nitrogen interactions. In CAM plants, one of the crucial pathways enabled 78 % of TMA to be transformed directly to dimethylamine (DMA) and methylamine (MA), which differed from C3 plant pathways. Various metabolites were also produced for further detoxification and mineralization so that TMA was completely degraded by plants.

Wanyu R. Chan
Sebastian Cohn
Meera Sidheswaran
William J. Fisk

Unlabelled: This field study measured ventilation rates and indoor air quality in 21 visits to retail stores in California. Three types of stores, such as grocery, furniture/hardware stores, and apparel, were sampled. Ventilation rates measured using a tracer gas decay method exceeded the minimum requirement of California's Title 24 Standard in all but one store. Concentrations of volatile organic compounds (VOCs), ozone, and carbon dioxide measured indoors and outdoors were analyzed. Even though there was adequate ventilation according to standard, concentrations of formaldehyde and acetaldehyde exceeded the most stringent chronic health guidelines in many of the sampled stores. The whole-building emission rates of VOCs were estimated from the measured ventilation rates and the concentrations measured indoor and outdoor. Estimated formaldehyde emission rates suggest that retail stores would need to ventilate at levels far exceeding the current Title 24 requirement to lower indoor concentrations below California's stringent formaldehyde reference level. Given the high costs of providing ventilation, effective source control is an attractive alternative. Practical implications: Field measurements suggest that California retail stores were well ventilated relative to the minimum ventilation rate requirement specified in the Building Energy Efficiency Standards Title 24. Concentrations of formaldehyde found in retail stores were low relative to levels found in homes but exceeded the most stringent chronic health guideline. Looking ahead, California is mandating zero energy commercial buildings by 2030. To reduce the energy use from building ventilation while maintaining or even lowering formaldehyde in retail stores, effective formaldehyde source control measures are vitally important.

Posted by: lavadalavadakomatsue0272559.blogspot.com

Source: https://www.researchgate.net/publication/344489124_Ventilation_for_Acceptable_Indoor_Air_Quality