ASTM E741-11
Standard Test Method for Determining Air Change in a Single Zone by Means of a Tracer Gas Dilution
- Standard No.
- ASTM E741-11
- Release Date
- 2011
- Published By
- American Society for Testing and Materials (ASTM)
- Status
- Replace By
- ASTM E741-11(2017)
- Latest
- ASTM E741-23
- Scope
Effects of Air Change8212;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.
Prediction of Air Change8212;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.
Utility of Measurement8212;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.
Known Conditions8212;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.
Applicability of Results8212;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 measurements because of construction or deterioration. To determine air leakage sites, follow Practice E1186.
Fan Pressurization8212;A related technique (Test Method E779) uses a fan to pressurize the building envelope. Measurements of corresponding air flows and pressure differences across the envelope characterize envelope airtightness as either the air leakage rate under specified induced pressure differences or the equivalent leakage area of the envelope. These factors permit modeling natural air change due to wind and temperature differences. However, direct measurement of natural air change is not possible with Test Method E779. Test Method E779 permits comparison of different buildings, isolation of leakage sites, and evaluation of retrofit measures.
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 any single tracer......
ASTM E741-11 Referenced Document
- ASTM D4480
- ASTM E1186 Standard Practices for Air Leakage Site Detection in Building Envelopes and Air Retarder Systems
- ASTM E260 Standard Practice for Packed Column Gas Chromatography
- ASTM E631 Standard Terminology of Building Constructions
- ASTM E779 Standard Test Method for Determining Air Leakage Rate by Fan Pressurization
ASTM E741-11 history
- 2023 ASTM E741-23 Standard Test Method for Determining Air Change in a Single Zone by Means of a Tracer Gas Dilution
- 2017 ASTM E741-11(2017) Standard Test Method for Determining Air Change in a Single Zone by Means of a Tracer Gas Dilution
- 2011 ASTM E741-11 Standard Test Method for Determining Air Change in a Single Zone by Means of a Tracer Gas Dilution
- 2000 ASTM E741-00(2006)e1 Standard Test Method for Determining Air Change in a Single Zone by Means of a Tracer Gas Dilution
- 2006 ASTM E741-00(2006) Standard Test Method for Determining Air Change in a Single Zone by Means of a Tracer Gas Dilution
- 2000 ASTM E741-00 Standard Test Method for Determining Air Change in a Single Zone by Means of a Tracer Gas Dilution
