ASTM E741-23

Standard Test Method for Determining Air Change in a Single Zone by Means of a Tracer Gas Dilution

SIGNIFICANCE AND USE
5.1 Effects of Air Change—Air change often accounts for a significant portion of the heating or air-conditioning load of a building. It also affects the moisture and contaminant balances in the building. Moisture-laden air passing through the building envelope can permit condensation and cause material degradation. An appropriate level of ventilation is required in all buildings; one should consult ASHRAE Standard 62 to determine the ventilation requirements of a building.  
5.2 Prediction of Air Change—Air change depends on the size and distribution of air leakage sites, pressure differences induced by wind and temperature, mechanical system operation, and occupant behavior. Air change may be calculated from this information, however, many of the needed parameters are difficult to determine. Tracer gas testing permits direct measurement of air change.  
5.3 Utility of Measurement—Measurements of air change provide useful information about ventilation and air leakage. Measurements in buildings with the ventilation system closed are used to determine whether natural air leakage rates are higher than specified. Measurements with the ventilation system in operation are used to determine whether the air change meets or exceeds requirements.  
5.4 Known Conditions—Knowledge of the factors that affect air change makes measurement more meaningful. Relating building response to wind and temperature requires repetition of the test under varying meteorological conditions. Relating building response to the ventilation system or to occupant behavior requires controlled variation of these factors.  
5.5 Applicability of Results—The values for air change obtained by the techniques used in this test method apply to the specific conditions prevailing at the time of the measurement. Air change values for the same building will differ if the prevailing wind and temperature conditions have changed, if the operation of the building is different, or if the envelope changes between m...
SCOPE
1.1 This test method covers techniques using tracer gas dilution for determining a single zone's air change with the outdoors, as induced by weather conditions and by mechanical ventilation. These techniques are: (1) concentration decay, (2) constant injection, and (3) constant concentration.  
1.2 This test method is restricted to a single tracer gas.  
1.3 The associated data analysis assumes that one can characterize the tracer gas concentration within the zone with a single value. The zone shall be a building, vehicle, test cell, or any conforming enclosure.  
1.4 Use of this test method requires a knowledge of the principles of gas analysis and instrumentation. Correct use of the formulas presented here requires consistent use of units, especially those of time.  
1.5 Determination of the contribution to air change by individual components of the zone enclosure is beyond the scope of this test method.  
1.6 The results from this test method pertain only to those conditions of weather and zonal operation that prevailed during the measurement. The use of the results from this test to predict air change under other conditions is beyond the scope of this test method.  
1.7 The text of this test method references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered requirements of this test method.  
1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.9 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Reco...

General Information

• Status: Published
• Publication Date: 30-Jun-2023
• ICS: 13.040.01 - Air quality in general
• Technical Committee: E06 - Performance of Buildings
• Drafting Committee: E06.41 - Air Leakage and Ventilation Performance

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E741 − 23
Standard Test Method for
Determining Air Change in a Single Zone by Means of a
1
Tracer Gas Dilution
This standard is issued under the fixed designation E741; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.9 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.1 This test method covers techniques using tracer gas
ization established in the Decision on Principles for the
dilution for determining a single zone’s air change with the
Development of International Standards, Guides and Recom-
outdoors, as induced by weather conditions and by mechanical
mendations issued by the World Trade Organization Technical
ventilation. These techniques are: (1) concentration decay, (2)
Barriers to Trade (TBT) Committee.
constant injection, and (3) constant concentration.
1.2 This test method is restricted to a single tracer gas. 2. Referenced Documents
2
1.3 The associated data analysis assumes that one can 2.1 ASTM Standards:
characterize the tracer gas concentration within the zone with D4480 Test Method for Measuring Surface Wind by Means
a single value. The zone shall be a building, vehicle, test cell, of Wind Vanes and Rotating Anemometers (Withdrawn
3
or any conforming enclosure. 1999)
E260 Practice for Packed Column Gas Chromatography
1.4 Use of this test method requires a knowledge of the
E631 Terminology of Building Constructions
principles of gas analysis and instrumentation. Correct use of
E779 Test Method for Determining Air Leakage Rate by Fan
the formulas presented here requires consistent use of units,
Pressurization
especially those of time.
E1186 Practices for Air Leakage Site Detection in Building
1.5 Determination of the contribution to air change by
Envelopes and Air Barrier Systems
4
individual components of the zone enclosure is beyond the
2.2 ASHRAE Documents:
scope of this test method.
ASHRAE Handbook of Fundamentals Chapter 23
1.6 The results from this test method pertain only to those ASHRAE Standard 62 Ventilation And Acceptable Indoor
conditions of weather and zonal operation that prevailed during Air Quality
the measurement. The use of the results from this test to predict
3. Terminology
air change under other conditions is beyond the scope of this
test method.
3.1 Definitions:
3.1.1 For definitions of general terms related to building
1.7 The text of this test method references notes and
construction used in this test method, refer to Terminology
footnotes which provide explanatory material. These notes and
E631.
footnotes (excluding those in tables and figures) shall not be
3.2 Definitions of Terms Specific to This Standard:
considered requirements of this test method.
3.2.1 air change flow, Q, n—the total volume of air passing
1.8 This standard does not purport to address all of the
3
through the zone to and from the outdoors per unit time (m /s,
safety concerns, if any, associated with its use. It is the
3 3
m /h, ft /h).
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
mine the applicability of regulatory limitations prior to use.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
1
This test method is under the jurisdiction of ASTM Committee E06 on the ASTM website.
3
Performance of Buildings and is the direct responsibility of Subcommittee E06.41 The last approved version of this historical standard is referenced on
on Air Leakage and Ventilation Performance. www.astm.org.
4
Current edition approved July 1, 2023. Published July 2023. Originally approved Available from American Society of Heating, Refrigerating, and Air-
in 1980. Last previous edition approved in 2017 as E741 – 11 (2017). DOI: Conditioning Engineers, Inc. (ASHRAE), 1791 Tullie Circle, NE, Atlanta, GA
10.1520/E0741-23. 30329, http://www.ashrae.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E741 − 23
3.2.2 air change rate, A, n—the ratio of the total volume of
A = pertaining to air change rate.
air passing through the zone to and from the outdoors per unit
avg = average.
5
of time to the volu
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E741 − 11 (Reapproved 2017) E741 − 23
Standard Test Method for
Determining Air Change in a Single Zone by Means of a
1
Tracer Gas Dilution
This standard is issued under the fixed designation E741; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers techniques using tracer gas dilution for determining a single zone’s air change with the outdoors, as
induced by weather conditions and by mechanical ventilation. These techniques are: (1) concentration decay, (2) constant injection,
and (3) constant concentration.
1.2 This test method is restricted to a single tracer gas.
1.3 This test method is restricted to any single tracer gas. The associated data analysis assumes that one can characterize the tracer
gas concentration within the zone with a single value. The zone shall be a building, vehicle, test cell, or any conforming enclosure.
1.4 Use of this test method requires a knowledge of the principles of gas analysis and instrumentation. Correct use of the formulas
presented here requires consistent use of units, especially those of time.
1.5 Determination of the contribution to air change by individual components of the zone enclosure is beyond the scope of this
test method.
1.6 The results from this test method pertain only to those conditions of weather and zonal operation that prevailed during the
measurement. The use of the results from this test to predict air change under other conditions is beyond the scope of this test
method.
1.7 The text of this test method references notes and footnotes which provide explanatory material. These notes and footnotes
(excluding those in tables and figures) shall not be considered requirements of this test method.
1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.9 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
1
This test method is under the jurisdiction of ASTM Committee E06 on Performance of Buildings and is the direct responsibility of Subcommittee E06.41 on Air Leakage
and Ventilation Performance.
Current edition approved Sept. 1, 2017July 1, 2023. Published September 2017July 2023. Originally approved in 1980. Last previous edition approved in 20112017 as
E741 – 11.E741 – 11 (2017). DOI: 10.1520/E0741-11R17.10.1520/E0741-23.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E741 − 23
2. Referenced Documents
2
2.1 ASTM Standards:
3
D4480 Test Method for Measuring Surface Wind by Means of Wind Vanes and Rotating Anemometers (Withdrawn 1999)
E260 Practice for Packed Column Gas Chromatography
E631 Terminology of Building Constructions
E779 Test Method for Determining Air Leakage Rate by Fan Pressurization
E1186 Practices for Air Leakage Site Detection in Building Envelopes and Air Barrier Systems
4
2.2 ASHRAE Documents:
ASHRAE Handbook of Fundamentals Chapter 23
ASHRAE Standard 62 Ventilation And Acceptable Indoor Air Quality
3. Terminology
3.1 Definitions:
3.1.1 For definitions of general terms related to building construction used in this test method, refer to Terminology E631.
3.2 Definitions of Terms Specific to This Standard:
3 3
3.2.1 air change flow, Q, n—the total volume of air passing through the zone to and from the outdoors per unit time (m /s, m /h,
3
ft /h).
3.2.2 air change rate, A, n—the ratio of the total volume of air passing through the zone to and from the outdoors per unit of time
5
to the volume of the zone (1/s, 1/h).
3.2.3 envelope, n—the system of barriers between a conditioned building zone and the outdoors.
3.2.3.1 Discussion—
This includes exterior doors, windows, roofs, walls, floors and ductwork. It excludes interior partitions, ducts, and so forth, that
separate conditioned zones
...