ASTM E2029-99
(Test Method)Standard Test Method for Volumetric and Mass Flow Rate Measurement in a Duct Using Tracer Gas Dilution
Standard Test Method for Volumetric and Mass Flow Rate Measurement in a Duct Using Tracer Gas Dilution
SCOPE
1.1 This test method describes the measurement of the volumetric and mass flow rate of a gas stream within a duct, stack, pipe, mine tunnel, or flue using a tracer gas dilution technique. For editorial convenience all references in the text will be to a duct, but it should be understood that this could refer equally well to a stack, pipe, mine tunnel, or flue. This test method is limited to those applications where the gas stream and the tracer gas can be treated as ideal gases at the conditions of the measurement. In this test method, the gas stream will be referred as air, though it could be any other gas that exhibits ideal gas law behavior.
1.2 This test method is not restricted to any particular tracer gas although experimental experience has shown that certain gases are used more readily than others as suitable tracer gases. It is preferable that the tracer gas not be a natural component of the gas stream.
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.
1.4 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 to determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see Section 7.
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Designation: E 2029 – 99
Standard Test Method for
Volumetric and Mass Flow Rate Measurement in a Duct
Using Tracer Gas Dilution
This standard is issued under the fixed designation E 2029; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope tainty: Instrument Apparatus
1.1 This test method describes the measurement of the
3. Terminology
volumetric and mass flow rate of a gas stream within a duct,
3.1 Definitions of Terms Specific to This Standard:
stack, pipe, mine tunnel, or flue using a tracer gas dilution
3.1.1 ideal gas, n—a gas or gas mixture for which the ratio
technique. For editorial convenience all references in the text
of the pressure divided by product of the density and tempera-
will be to a duct, but it should be understood that this could
ture is a constant.
refer equally well to a stack, pipe, mine tunnel, or flue. This test
3.1.2 mass flow, n—the total mass of air passing the
method is limited to those applications where the gas stream
sampling point per unit time (kg/s, lb/min).
and the tracer gas can be treated as ideal gases at the conditions
3.1.3 tracer gas, n—a gas that can be mixed with air and
of the measurement. In this test method, the gas stream will be
measured in very low concentrations.
referred as air, though it could be any another gas that exhibits
3.1.4 tracer gas analyzer, n—a device that measures the
ideal gas law behavior.
concentration of tracer gas in an air sample.
1.2 This test method is not restricted to any particular tracer
3.1.5 tracer gas mass concentration, n—the ratio of the
gas although experimental experience has shown that certain
mass of tracer gas in air to the total mass of the air-tracer
gases are used more readily than others as suitable tracer gases.
mixture. For an ideal gas, the mass concentration is indepen-
It is preferable that the tracer gas not be a natural component
dent of temperature and pressure.
of the gas stream.
3.1.6 tracer gas molar concentration, n—the ratio of the
1.3 Use of this test method requires a knowledge of the
number of moles of tracer gas in air to the total number of
principles of gas analysis and instrumentation. Correct use of
moles of the air-tracer mixture.
the formulas presented here requires consistent use of units.
3.1.7 tracer gas volume concentration, n—the ratio of the
1.4 This standard does not purport to address all of the
volume of tracer gas in air to the total volume of the air-tracer
safety concerns, if any, associated with its use. It is the
mixture. For an ideal gas, the volume concentration is inde-
responsibility of the user of this standard to establish appro-
pendent of temperature and pressure and is equal to the molar
priate safety and health practices and to determine the
concentration.
applicability of regulatory limitations prior to use. For specific
3.1.8 volumetric flow, n—the total volume of air passing the
precautionary statements, see Section 7.
3 3
sampling point per unit time (m /s, ft /min).
2. Referenced Documents 3.2 Symbols:
2.1 ASTM Standards:
D 3154 Test Method for Average Velocity in a Duct (Pitot 4
C = mass concentration of tracer gas (ppb-mass, ppm-
Tube Method)
mass, ppt-mass)
D 3464 Test Method for Average Velocity in a Duct Using a
C = upstream mass concentration of tracer gas (ppb-
U
Thermal Anemometer
mass, ppm-mass, ppt-mass)
2.2 ANSI/ASME Standard:
C = downstream mass concentration of tracer gas
D
ANSI/ASME TC 19.1–1985 (1994) Measurement Uncer-
(ppb-mass, ppm-mass, ppt-mass)
C = injection stream mass concentration of tracer gas
I
(ppb-mass, ppm-mass, ppt-mass)
c = volume concentration of tracer gas (ppb, ppm,
ppt)
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.
Current edition approved June 10, 1999. Published November 1999. Available from American National Standards Institute, 11 W. 42nd Street, 13th
Annual Book of ASTM Standards, Vol 11.03. floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E2029–99
pitot tube or thermal anemometer velocity measurements are
c = upstream volume concentration of tracer gas (ppb,
U
difficult or inappropriate due either to very low average flow
ppm, ppt)
velocity or the lack of a suitable run of duct upstream and
c = downstream volume concentration of tracer gas
D
downstream of the measurement location.
(ppb, ppm, ppt)
c = injection volume concentration of tracer gas (ppb,
5.2 This test method can produce the volumetric flow rate at
I
ppm, ppt)
standard conditions without the need to determine gas stream
F = mass flow rate (kg/s, g/min, lb/min)
composition, temperature, and water vapor content.
F = injection mass flow rate (kg/s, g/min, lb/min)
I
5.3 This test method is useful for determining mass or
F = upstream mass flow rate (kg/s, g/min, lb/min)
U
volumetric flow rates in HVAC ducts, fume hoods, vent stacks,
F = downstream mass flow rate (kg/s, g/min, lb/min)
D
and mine tunnels, as well as in performing model studies of
5 3
f = volumetric flow rate (m /s, L/min, cfm)
std 5 3 pollution control devices.
f = volumetric flow rate at standard conditions (m /s,
5.4 This test method is based on first principles (conserva-
L/min, cfm)
5 3
tion of mass) and does not require engineering assumptions.
f = injection volumetric flow rate (m /s, L/min, cfm)
I
5 3
f = upstream volumetric flow rate (m /s, L/min, cfm) 5.5 This test method does not require the measurement of
U
5 3
f = downstream volumetric flow rate (m /s, L/min, the area of the duct or stack.
D
cfm)
5.6 The test method does not require flow straightening.
std 5
f = injection volumetric flow rate at standard condi-
I
5.7 The test method is independent of flow conditions, such
tions (m /s, L/min, cfm)
as angle, swirl, turbulence, reversals, and hence, does not
std 5
f = upstream volumetric flow rate at standard condi-
U
require flow straightening.
tions (m /s, L/min, cfm)
5.8 The dry volumetric airflow can be determined by drying
std 5
f = downstream volumetric flow rate at standard con-
D
the air samples without measuring the water vapor concentra-
ditions (m /s, L/min, cfm)
6 3 3 tion.
r = density (kg/m , g/L, lb/ft )
6 3
r = density of gas stream without any tracer (kg/m ,
a
6. Apparatus
g/L, lb/ft )
6 3 3
r = density of the tracer gas (kg/m , g/L, lb/ft )
t 6.1 The apparatus includes a source of tracer gas, means for
6 3
r = density of the injection gas mixture (kg/m , g/L,
I distributing the tracer gas in the duct, means for obtaining air
lb/ft )
samples from the duct, and a gas analyzer to measure tracer gas
6 3
r = density of the upstream gas mixture (kg/m , g/L,
U
concentrations in the air samples.
lb/ft )
6.2 Tracer Gas—See Appendix X1 for information on
6 3
r = density of the downstream gas mixture (kg/m ,
D
tracer gases and equipment used to measure their concentra-
g/L, lb/ft )
tions. Appendix X1 also contains tracer gas target concentra-
t 6
r = density of the tracer gas at upstream conditions
U
tions and safety information.
3 3
(kg/m , g/L, lb/ft )
t 6
6.3 Tracer Gas Injection Source—This normally is a cylin-
r = density of the tracer gas at downstream conditions
D
3 3
der of compressed tracer gas either pure or diluted in a carrier
(kg/m , g/L, lb/ft )
such as air or nitrogen. Tracer release from the cylinder is
4. Summary of Test Method controlled by a critical orifice or nozzle, a metering valve, an
electronic mass flow meter or mass flow controller, or other gas
4.1 This test method describes the use of a tracer gas
flow rate measurement and control device. A rotameter is not
dilution technique to infer the volumetric flow rate through a
recommended for this measurement unless of special design,
duct. In practice, tracer gas is injected into a duct at a known
calibration, and a corresponding decrease in measurement
mass or volumetric flow rate. Downstream of the injection
accuracy is acceptable.
point gas samples are taken and are analyzed for the resulting
6.4 Tracer Gas Distribution—A single tube or a tubing
tracer concentration. The ratio of the injection flow rate and the
network is inserted into the duct to dispense tracer gas. The
downstream concentration represents the dilution volume per
tube or tubes may have either a single or multiple release points
unit time or volumetric flow rate in the duct.
for tracer gas. For large cross-section ducts a network that
5. Significance and Use
distributes tracer gas over a wide area will facilitate measure-
ment.
5.1 The method presented here is a field method that may be
6.5 Tracer Sampling—This is performed using tubing in-
used to determine mass and volume flow rates in ducts where
serted into the duct downstream of the injection point. A single
flow conditions may be irregular and nonuniform. The gas
tube is inserted into the duct. Air samples are removed from the
flowing in the duct is considered to be an ideal gas. The method
duct by means of a sampling pump to distribute tracer laden air
may be especially useful in those locations where conventional
to the analyzer either directly or by means of syringe samples.
6.6 Gas Analyzer—This device must be suited for the tracer
Equations in this test method assume that all mass or volume concentrations are
gas used and the concentrations expected in the duct being
in the same units.
measured. It should be calibrated properly and exhibit a
Equations in this test method assume that all mass or volume flow rates are in
accuracy of better than 6 3 % at concentrations employed in
the same units.
Equations in this test method assume that all densities are in the same units. the measurement.
E2029–99
TABLE 2 Minimum Number of Down Stream Sample Locations
7. Hazards
2 2
Duct Cross Sectional Area m (ft ) Number of Areas Number of Samples
7.1 Safety is the responsibility of the user of this test
Less then 0.2 (2) 4 5
method. Tracer gases have safe maximum concentration limits
0.2 to 2.3 (2 to 25) 12 13
due to health and, in some cases, explosive potential. Table 1
Greater than 2.3 (25) 20 21
presents, as a guide, the maximum allowable concentration in
air for some tracer gasses that can be used for airflow
measurements. The tracer gas supplier must provide a Material 8.1.1 If the tracer gas analyzer is field calibrated using a
Safety Data Sheet (MSDS) that will provide information about single point method, the injection rate, or injection concentra-
health, fire, and explosion hazards. tion, or a combination thereof, should be adjusted to produce a
7.2 Health Limitations—Use current OSHA information on concentration at the sample location that is the same as the
the permissible exposure limit (PEL), or the ACGIH threshold calibration concentration to within 6 20 %.
limit value (TLV) if the particular tracer is not listed with a 8.1.2 If the tracer gas analyzer is field calibrated using two
PEL, to determine the safe concentration for the gas chosen for calibration points, the injection rate, or injection concentration,
or a combination thereof, should be adjusted to produce a
the test. Never exceed the maximum safe concentration. It is
good practice to use a concentration that is at most one tenth of concentration at the sample location that lies between the two
the maximum safe concentration. Avoid using tracer gases for calibration points.
which no PEL or TLV exists. 8.1.3 If the tracer gas analyzer is field calibrated using more
7.3 Compressed Gas Equipment—Observe the supplier’s than two calibration points, the injection rate, or injection
safety information and CGA information on the transportation, concentration, or a combination thereof, should be adjusted to
use, and storage of compressed gas cylinders, regulators, and produce a concentration at the sample location that lies at the
related equipment. approximate midpoint of the calibration range.
8.2 Obtain at least N measurements of the resulting concen-
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8. Procedure for Measuring Mass and Volumetric
trations, C , at least ten diameters, or equivalent hydraulic
D
Flowrate
diameters for nonround cross section ducts, downstream of the
8.1 Inject tracer of known concentration, C (c ), and at a injection at the center of N-1 equal areas of the duct cross
I I
known rate, F (f ), into a flowing duct using procedures section and one at the center of the duct. The number N is
I I
provided in Section 9.
determined by Table 2 depending on the duct size.
TABLE 1 Tracer Gases and Safety Issues
A
Tracer Gas TLV Toxicity Chemical Reactivity Comments
Hydrogen Asphyxiant Nontoxic Highly reactive in Fire and explosion hazard
presence of heat, when exposer to heat,
flame, of O flame, or O
2 2
Helium Asphyxiant Nontoxic Inert
Carbon Monoxide 25 ppm Combines with Highly reactive Fire and explosion hazard
hemoglobin to with O when exposed to heat or
cause anoxia flame
Carbon Dioxide 5000 ppm Can be an eye Reacts vigorously
irritant with some metals;
soluble in water
Sulfur Hexafluoride 1000 ppm Nontoxic Inert Thermal decomposition
yields highly toxic
compounds
Nitrous Oxide 25 ppm Moderately toxic Violent reaction Can form explosive
with aluminum; mixture with air; ignites
water soluble at high temperature
Ethane Asphyxiant Nontoxic Flammable Incompatible with
chlorine and oxidizing
materials
Methane Asphyxiant Nontoxic Flammable Incompatible with
chlorine and oxidizing
materials
Octofluorocyclobutane 1000 ppm Low toxicity Nonflammable Thermal decomposition
(Halocarbon C-318 yields highly toxic
compounds
Bromotrifluoromethane 500 ppm Moderately toxid Incompatible with Dangerous in a fire
(Halocarbon 13B1) by inhalation aluminum
Dichlorodifluoromethane 1000 ppm Central nervous Nonflammable; Thermal decomposition
(Halocarbon 12) system and eye can react violently yields highly toxic
irritant; can be with aluminum compounds
narcotic at high
levels
Dichlorotetrafluoromethane 1000 ppm Can be asphyxiant, Can react violently Thermal decomposition
(Halocarbon 116) mildly irritating, with aluminum yields highly toxic
narcotic at high compounds
levels
A
Threshold Limit Values for Chemical Substances in the Work Environment, American Conference of Governmental Industrial Hygienists (ACGIH), 1997.
E2029–99
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8.3 If recirculation is possible or likely, N samples C in the 9. Procedures for Injecting Tracer Gas
U
center of duct upstream of the injection p
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