ASTM E741-00

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

SCOPE
1.1 This test method describes 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 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.  
1.3 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.  
1.4 Determination of the contribution to air change by individual components of the zone enclosure is beyond the scope of this test method.  
1.5 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.  
1.6 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.  
1.7 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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-Dec-2000
• ICS: 13.040.01 - Air quality in general
• Technical Committee: E06 - Performance of Buildings
• Drafting Committee: E06.41 - Air Leakage and Ventilation Performance

Relations

• Replaced By: ASTM E741-00(2006) - Standard Test Method for Determining Air Change in a Single Zone by Means of a Tracer Gas Dilution
• Effective Date: 01-Oct-2006
• Referred By: ASTM D6669-19 - Standard Practice for Selecting and Constructing Exposure Scenarios for Assessment of Exposures to Alkyd and Latex Interior Paints
• Effective Date: 10-Dec-2000
• Referred By: ASTM D6670-18 - Standard Practice for Full-Scale Chamber Determination of Volatile Organic Emissions from Indoor Materials/Products
• Effective Date: 10-Dec-2000
• Referred By: ASTM E779-19 - Standard Test Method for Determining Air Leakage Rate by Fan Pressurization
• Effective Date: 10-Dec-2000
• Referred By: ASTM D7911-19 - Standard Guide for Using Reference Material to Characterize Measurement Bias Associated with Volatile Organic Compound Emission Chamber Test
• Effective Date: 10-Dec-2000
• Referred By: ASTM D7297-21 - Standard Practice for Evaluating Residential Indoor Air Quality Concerns
• Effective Date: 10-Dec-2000
• Referred By: ASTM E1827-22 - Standard Test Methods for Determining Airtightness of Buildings Using an Orifice Blower Door
• Effective Date: 10-Dec-2000
• Referred By: ASTM E1333-22 - Standard Test Method for Determining Formaldehyde Concentrations in Air and Emission Rates from Wood Products Using a Large Chamber
• Effective Date: 10-Dec-2000
• Referred By: ASTM D6245-18 - Standard Guide for Using Indoor Carbon Dioxide Concentrations to Evaluate Indoor Air Quality and Ventilation
• Effective Date: 10-Dec-2000
• Referred By: ASTM D7663-12(2018)e1 - Standard Practice for Active Soil Gas Sampling in the Vadose Zone for Vapor Intrusion Evaluations
• Effective Date: 10-Dec-2000
• Referred By: ASTM D8445-22a - Standard Practice for Measuring Chemical Emissions from Spray Polyurethane Foam (SPF) Insulation Samples in a Large-scale Ventilated Enclosure
• Effective Date: 10-Dec-2000
• Referred By: ASTM E1186-22 - Standard Practices for Air Leakage Site Detection in Building Envelopes and Air Barrier Systems
• Effective Date: 10-Dec-2000

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
Designation: E 741 – 00
Standard Test Method for
Determining Air Change in a Single Zone by Means of a
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.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope of Wind Vanes and Rotating Anemometers
E260 Practice for Packed Column Gas Chromatography
1.1 This test method describes techniques using tracer gas
E779 Test Method for Determining Air Leakage Rate by
dilution for determining a single zone’s air change with the
Fan Pressurization
outdoors, as induced by weather conditions and by mechanical
E1186 Practice forAir Leakage Site Detection in Building
ventilation. These techniques are: (1) concentration decay, ( 2)
Envelopes
constant injection, and (3) constant concentration.
2.2 Other Documents:
1.2 This test method is restricted to any single tracer gas.
ASHRAE Handbook of Fundamentals, Chapter 23
The associated data analysis assumes that one can characterize
ASHRAE Standard62
thetracergasconcentrationwithinthezonewithasinglevalue.
The zone shall be a building, vehicle, test cell, or any
3. Terminology
conforming enclosure.
3.1 Definitions of Terms Specific to This Standard:
1.3 Use of this test method requires a knowledge of the
3.1.1 air change flow, Q, n—the total volume of air passing
principles of gas analysis and instrumentation. Correct use of
throughthezonetoandfromtheoutdoorsperunittime(m /s,
the formulas presented here requires consistent use of units,
3 3
m /h, ft /h).
especially those of time.
3.1.2 air change rate, A, n—the ratio of the total volume of
1.4 Determination of the contribution to air change by
air passing through the zone to and from the outdoors per unit
individual components of the zone enclosure is beyond the
of time to the volume of the zone (1/s, 1/h).
scope of this test method.
3.1.3 envelope, n—the system of barriers between a condi-
1.5 The results from this test method pertain only to those
tioned building zone and the outdoors.
conditionsofweatherandzonaloperationthatprevailedduring
3.1.3.1 Discussion—This includes exterior doors, windows,
themeasurement.Theuseoftheresultsfromthistesttopredict
roofs, walls, floors and ductwork. It excludes interior parti-
air change under other conditions is beyond the scope of this
tions, ducts, etc., that separate conditioned zones.
test method.
3.1.4 tracer gas, n—a gas that is mixed with air and
1.6 The text of this test method references notes and
measured in very small concentrations in order to study air
footnoteswhichprovideexplanatorymaterial.Thesenotesand
movement.
footnotes (excluding those in tables and figures) shall not be
3.1.5 tracer gas analyzer, n—a device used to measure the
considered requirements of this test method.
concentration of tracer gas in an air sample.
1.7 This standard does not purport to address all of the
3.1.6 tracer gas concentration, C, n—the ratio of the
safety concerns, if any, associated with its use. It is the
quantity of tracer gas in air to the quantity of that air
responsibility of the user of this standard to establish appro-
3 3
(moles/mole or m /m ).
priate safety and health practices and determine the applica-
3.1.7 single zone, n—a space or set of spaces wherein the
bility of regulatory limitations prior to use.
concentration of a tracer gas is maintained uniformly through-
2. Referenced Documents out and that only exchanges air with the outside.
3.1.7.1 Discussion—Multizone buildings are difficult to
2.1 ASTM Standards:
treat as single zones and meet the uniformity of tracer gas
D4480 TestMethodforMeasuringSurfaceWindbyMeans
Annual Book of ASTM Standards, Vol 11.03.
1 3
This test method is under the jurisdiction of ASTM Committee E06 on Annual Book of ASTM Standards, Vol 14.02.
Performance of Buildings and is the direct responsibility of Subcommittee E06.41 Annual Book of ASTM Standards, Vol 04.11.
on Air Leakage and Ventilation. Available from American Society of Heating, Refrigerating, and Air-
Current edition approved Dec. 10, 2000. Published January 2001. Originally Conditioning Engineers, Inc., 1791 Tullie Circle, N.E., Atlanta, GA 30329.
published as E741–80. Last previous edition E741–95. A common way of expressing air change rate units is ACH=air changes per
hour=1/h.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
E741–00
concentration required in this test method. Single zones within
multizone buildings are difficult to isolate such that they
Dt = time interval between periodic samples.
exchange air only with the outside and not to other zones
(t) = function of time t.
within the building via ventilation ducts, electrical conduits, (t, i) = function of time t and location i.
t(n, = t-distribution value for n degrees of freedom
elevator shafts, stairs, and other pathways.
1−a) and a two-sided probability of a.
3.2 Symbols:
3.2.1 Variables:
4. Summary of Test Method
4.1 This test method uses the measurement of tracer gas
A = air change rate (1/s, 1/h).
dilution to determine air change within a building or other
C = concentration (dimensionless).
enclosure that is characterized as a single zone. The measure-
CONF = confidence limit value (units of the variable mea-
sured). ment of the concentration, and sometimes the volume rate of
d = desired precision (dimensionless). the tracer gas that is injected into the zone, allows calculation
ESE = estimated standard error.
of the volume rate of outgoing air from the zone. From this,
i = location number.
onecaninferthevolumerateofincomingair.Threetechniques
k = constant.
are presented: (1) concentration decay, ( 2) constant injection,
n = number of data points.
and (3) constant concentration. Each technique employs spe-
N = number of sampling locations in the zone.
cific tracer gas injection and sampling strategies. Other tech-
3 3 3
Q = flow (m /s, m /h, ft /h).
niquesexistbutarebeyondthescopeofthistestmethod.Table
s = sample standard deviation (units of the variable
1 summarizes the three techniques.
estimated).
4.2 Choice of Technique—In choosing a technique for
t = a specific time (s, h).
measuringairchange,considerthequantitytobemeasured,the
T = a period of time (s, h).
3 3
comparative capabilities of the techniques, and the complexity
V = volume (m ,ft ).
a = probability (dimensionless). of the required equipment.
e = error (units of the variable estimated).
4.2.1 Air Change Quantity to Be Measured— Choose be-
n = coefficient of variation (dimensionless).
tweendirectmeasurementofairchangerateorairchangeflow.
3.2.2 Superscripts:
Conversions between rate and flow and vice versa are subject
to the precision and bias of the measurement of the zone
volume. To obtain air change rate directly, use the tracer gas
8 = value at the end of the test.
decay technique. To obtain air change flow, use the constant
− = mean value.
injection or constant concentration techniques.
3.2.3 Subscripts:
TABLE 1 Summary of Air Change Measurement Techniques
A = pertaining to air change rate.
NOTE 1—Speed of Measurement—A one-time measurement of air
avg = average.
change is most quickly acquired with the concentration decay technique
bias = pertaining to bias.
and least quickly with the constant concentration technique.
C = pertaining to concentration.
NOTE 2—Time-Varying Air Change—The constant concentration and
est = estimated.
constantinjectiontechniquesmaybeusefulformeasuringairchangerates
GA = pertaining to the gas analyzer.
that vary with time.
i = pertaining to time or location i.
NOTE 3—Complexity of Zone Geometry—Whereas all the techniques
inj = pertaining to the injection period. require uniform tracer gas concentration, the constant concentration
techniquemaybeusefultoachievethisinazonewithcomplexgeometry.
lower = lower limit.
NOTE 4—Equipment Complexity—The complexity of the required
meas = pertaining to the measurement.
equipment is lowest for the tracer gas decay technique and highest for the
mix = pertaining to the mixing period.
constant concentration technique.
precis = pertaining to precision.
Type of Air Steady-State Concentration
rep = pertaining to replicates.
Tech- Volume Control of
Change Mea- Assumption Measurement
sample = pertaining to a discrete tracer gas or air sample.
nique Tracer Gas
surement Required? Relative To
target = pertaining to the desired level of tracer gas.
Concentration Decay—Section 8
test = pertaining to the test period.
Average Rate No Approximate initial- Other samples
target
twt = weighted according to tracer gas flow.
Regres- Rate Yes Approximate initial Other samples
tracer = pertaining to the tracer gas.
sion target
upper = upper limit.
Constant Injection—Section 9
vol = pertaining to the volume of the zone.
Average Flow No Flow rate to within Absolute stan-
2% dard
zone = pertaining to the zone under study.
Constant Concentration—Section 10
1 = first occurrence under discussion.
Flow No Mean concentration Absolute stan-
2 = last occurrence under discussion.
within2%oftarget dard
3.2.4 Other Notations:
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
E741–00
5. Significance and Use tions. Appendix X1 also contains tracer gas target concentra-
tion levels and safety information.
5.1 Effects of Air Change—Air change often accounts for a
6.2.1 Tracer Gas Concentration Standard— A known con-
significant portion of the heating or air-conditioning load of a
centration of tracer gas in air.
building. It also affects the moisture and contaminant balances
6.3 Tracer Gas Injection and Distribution Apparatus—
inthebuilding.Moisture-ladenairpassingthroughthebuilding
There are several means for releasing the appropriate volume
envelope can permit condensation and cause material degrada-
of tracer gas and distributing it in the zone.
tion. An appropriate level of ventilation is required in all
6.3.1 Tracer Gas Metering and Injection Devices—These
buildings; one should consult ASHRAE Standard62 to deter-
include (1) a graduated syringe or other container of known
mine the ventilation requirements of a building.
volume with a means for controlled release of its contents and
5.2 Prediction of Air Change—Air change depends on the
(2) a compressed tracer gas supply with a critical orifice, a
size and distribution of air leakage sites, pressure differences
criticalorificemeteringvalve,anelectronicmassflowcontrol-
induced by wind and temperature, mechanical system opera-
ler, or other tracer gas flow rate measurement and control
tion, and occupant behavior. Air change may be calculated
device.
from this information, however, many of the needed param-
6.3.2 Tracer Gas Distribution Devices— These include (1)
etersaredifficulttodetermine.Tracergastestingpermitsdirect
fans that permit good mixing of tracer gases injected manually
measurement of air change.
within the zone (oscillating or hassock fans, or, ducted forced
5.3 Utility of Measurement—Measurements of air change
air systems can serve this purpose), ( 2) tubing networks that
provide useful information about ventilation and air leakage.
dispensetracergasviamanifoldsandautomatedvalvesand(3)
Measurements in buildings with the ventilation system closed
pressure-operated valves that stop the flow from a tubing
are used to determine whether natural air leakage rates are
network when the tubing is not pressurized. (Note that leaks in
higher than specified. Measurements with the ventilation sys-
tubing networks release tracer gas at unintended locations.)
tem in operation are used to determine whether the air change
6.4 Tracer Gas Sampling Apparatuses— Examples include
meets or exceeds requirements.
containers for manual sampling and automatic samplers that
5.4 Known Conditions—Knowledge of the factors that af-
employ containers or networks.
fectairchangemakesmeasurementmoremeaningful.Relating
6.4.1 Materials for Sampling Apparatuses— Select and
building response to wind and temperature requires repetition
check materials used in tracer gas sampling systems carefully
of the test under varying meteorological conditions. Relating
for their reactivity and absorption of the tracer gas in use.
building response to the ventilation system or to occupant
Depending on the tracer gas, desirable materials include glass,
behavior requires controlled variation of these factors.
copper,andstainlesssteel.Metalfoilisappropriateforflexible
5.5 Applicability of Results—The values for air change
containers. Other acceptable materials include polypropylene,
obtainedbythetechniquesusedinthistestmethodapplytothe
polyethylene, and nylon. Materials that absorb tracer gas
specific conditions prevailing at the time of the measurement.
degrade the accuracy of the measurement. Other materials
Air change values for the same building will differ if the
release substances that interfere with tracer gas analyzer
prevailing wind and temperature conditions have changed, if
accuracy. Depending on the tracer gas, materials to avoid
the operation of the building is different, or if the envelope
include soft plastics, like vinyl and TFE-fluorocarbon.
changes between measurements because of construction or
6.4.2 Manual Samplers—These include syringes, flexible
deterioration. To determine air leakage sites, follow Practice
bottles, or air sample bags with a capacity of at least three
E1186.
timestheminimumsamplesizeofthegasanalyzerused.These
5.6 Fan Pressurization—A related technique (Test Method
containers shall have an airtight seal to assure that the sample
E779) uses a fan to pressurize the building envelope. Mea-
is not diluted or contaminated. Each container shall have a
surements of corresponding air flows and pressure differences
labelthatkeysittoarecordofthetimeandlocationthatitwas
acrosstheenvelopecharacterizeenvelopeairtightnessaseither
used. Do not reuse sample containers without first confirming
the air leakage rate under specified induced pressure differ-
that they are not contaminated with tracer gas.
ences or the equivalent leakage area of the envelope. These
6.4.3 Automatic Samplers—These apparatuses comprise ei-
factors permit modeling natural air change due to wind and
ther a sampling network or automated samplers.
temperaturedifferences.However,directmeasurementofn
...