ASTM E2029-99(2004)
(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
SIGNIFICANCE AND USE
The method presented here is a field method that may be used to determine mass and volume flow rates in ducts where flow conditions may be irregular and nonuniform. The gas flowing in the duct is considered to be an ideal gas. The method may be especially useful in those locations where conventional pitot tube or thermal anemometer velocity measurements are difficult or inappropriate due either to very low average flow velocity or the lack of a suitable run of duct upstream and downstream of the measurement location.
This test method can produce the volumetric flow rate at standard conditions without the need to determine gas stream composition, temperature, and water vapor content.
This test method is useful for determining mass or volumetric flow rates in HVAC ducts, fume hoods, vent stacks, and mine tunnels, as well as in performing model studies of pollution control devices.
This test method is based on first principles (conservation of mass) and does not require engineering assumptions.
This test method does not require the measurement of the area of the duct or stack.
The test method does not require flow straightening.
The test method is independent of flow conditions, such as angle, swirl, turbulence, reversals, and hence, does not require flow straightening.
The dry volumetric airflow can be determined by drying the air samples without measuring the water vapor concentration.
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: E2029 – 99 (Reapproved 2004)
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 E2029; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2.2 ANSI/ASME Standard:
ANSI/ASME TC 19.1–1985 (1994) Measurement Uncer-
1.1 This test method describes the measurement of the
tainty: Instrument Apparatus
volumetric and mass flow rate of a gas stream within a duct,
stack, pipe, mine tunnel, or flue using a tracer gas dilution
3. Terminology
technique. For editorial convenience all references in the text
3.1 Definitions of Terms Specific to This Standard:
will be to a duct, but it should be understood that this could
3.1.1 ideal gas, n—a gas or gas mixture for which the ratio
referequallywelltoastack,pipe,minetunnel,orflue.Thistest
of the pressure divided by product of the density and tempera-
method is limited to those applications where the gas stream
ture is a constant.
andthetracergascanbetreatedasidealgasesattheconditions
3.1.2 mass flow, n—the total mass of air passing the
of the measurement. In this test method, the gas stream will be
sampling point per unit time (kg/s, lb/min).
referred as air, though it could be any another gas that exhibits
3.1.3 tracer gas, n—a gas that can be mixed with air and
ideal gas law behavior.
measured in very low concentrations.
1.2 Thistestmethodisnotrestrictedtoanyparticulartracer
3.1.4 tracer gas analyzer, n—a device that measures the
gas although experimental experience has shown that certain
concentration of tracer gas in an air sample.
gasesareusedmorereadilythanothersassuitabletracergases.
3.1.5 tracer gas mass concentration, n—the ratio of the
It is preferable that the tracer gas not be a natural component
mass of tracer gas in air to the total mass of the air-tracer
of the gas stream.
mixture. For an ideal gas, the mass concentration is indepen-
1.3 Use of this test method requires a knowledge of the
dent of temperature and pressure.
principles of gas analysis and instrumentation. Correct use of
3.1.6 tracer gas molar concentration, n—the ratio of the
the formulas presented here requires consistent use of units.
number of moles of tracer gas in air to the total number of
1.4 This standard does not purport to address all of the
moles of the air-tracer mixture.
safety concerns, if any, associated with its use. It is the
3.1.7 tracer gas volume concentration, n—the ratio of the
responsibility of the user of this standard to establish appro-
volume of tracer gas in air to the total volume of the air-tracer
priate safety and health practices and to determine the
mixture. For an ideal gas, the volume concentration is inde-
applicability of regulatory limitations prior to use.Forspecific
pendent of temperature and pressure and is equal to the molar
precautionary statements, see Section 7.
concentration.
2. Referenced Documents 3.1.8 volumetric flow, n—thetotalvolumeofairpassingthe
3 3
sampling point per unit time (m /s, ft /min).
2.1 ASTM Standards:
3.2 Symbols:
D3154 Test Method for Average Velocity in a Duct (Pitot
Tube Method)
D3464 Test Method forAverageVelocity in a Duct Using a 4
C = mass concentration of tracer gas (ppb-mass, ppm-
Thermal Anemometer
mass, ppt-mass)
C = upstream mass concentration of tracer gas (ppb-
U
mass, ppm-mass, ppt-mass)
C = downstream mass concentration of tracer gas
This test method is under the jurisdiction of ASTM Committee E06 on
D
Performance of Buildings and is the direct responsibility of Subcommittee E06.41
(ppb-mass, ppm-mass, ppt-mass)
on Air Leakage and Ventilation Performance.
C = injection stream mass concentration of tracer gas
I
Current edition approved Oct. 1, 2004. Published October 2004. Originally
(ppb-mass, ppm-mass, ppt-mass)
approved in 1999. Last previous edition approved in 1999 as E2029–99. DOI:
10.1520/E2029-99R04.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E2029 – 99 (2004)
flowingintheductisconsideredtobeanidealgas.Themethod
c = volume concentration of tracer gas (ppb, ppm,
maybeespeciallyusefulinthoselocationswhereconventional
ppt)
pitot tube or thermal anemometer velocity measurements are
c = upstreamvolumeconcentration oftracergas(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
(ppb, ppm, ppt) downstream of the measurement location.
c = injection volume concentration of tracer gas (ppb, 5.2 Thistestmethodcanproducethevolumetricflowrateat
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 volumetricflowratesinHVACducts,fumehoods,ventstacks,
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)
pollution control devices.
std 5 3
f = volumetric flow rate at standard conditions (m /s,
5.4 This test method is based on first principles (conserva-
L/min, cfm)
tion of mass) and does not require engineering assumptions.
5 3
f = injection volumetric flow rate (m /s, L/min, cfm)
I
5.5 This test method does not require the measurement of
5 3
f = upstream volumetric flow rate (m /s, L/min, cfm)
U
5 3 the area of the duct or stack.
f = downstream volumetric flow rate (m /s, L/min,
D
5.6 The test method does not require flow straightening.
cfm)
std 5
5.7 The test method is independent of flow conditions, such
f = injection volumetric flow rate at standard condi-
I
3 as angle, swirl, turbulence, reversals, and hence, does not
tions (m /s, L/min, cfm)
std 5
require flow straightening.
f = upstream volumetric flow rate at standard condi-
U
5.8 Thedryvolumetricairflowcanbedeterminedbydrying
tions (m /s, L/min, cfm)
std 5
the air samples without measuring the water vapor concentra-
f = downstream volumetric flow rate at standard con-
D
tion.
ditions (m /s, L/min, cfm)
6 3 3
r = density (kg/m , g/L, lb/ft )
6. Apparatus
6 3
r = density of gas stream without any tracer (kg/m ,
a
6.1 Theapparatusincludesasourceoftracergas,meansfor
g/L, lb/ft )
6 3 3
distributing the tracer gas in the duct, means for obtaining air
r = density of the tracer gas (kg/m , g/L, lb/ft )
t
6 3
samplesfromtheduct,andagasanalyzertomeasuretracergas
r = density of the injection gas mixture (kg/m , g/L,
I
concentrations in the air samples.
lb/ft )
6 3
r = density of the upstream gas mixture (kg/m , g/L, 6.2 Tracer Gas—See Appendix X1 for information on
U
tracer gases and equipment used to measure their concentra-
lb/ft )
6 3
r = density of the downstream gas mixture (kg/m ,
tions. Appendix X1 also contains tracer gas target concentra-
D
g/L, lb/ft ) tions and safety information.
t 6
r = density of the tracer gas at upstream conditions
6.3 Tracer Gas Injection Source—This normally is a cylin-
U
3 3
(kg/m , g/L, lb/ft )
der of compressed tracer gas either pure or diluted in a carrier
t 6
r = density ofthetracergasatdownstreamconditions
D such as air or nitrogen. Tracer release from the cylinder is
3 3
(kg/m , g/L, lb/ft )
controlled by a critical orifice or nozzle, a metering valve, an
electronicmassflowmeterormassflowcontroller,orothergas
4. Summary of Test Method
flow rate measurement and control device. A rotameter is not
4.1 This test method describes the use of a tracer gas
recommended for this measurement unless of special design,
dilution technique to infer the volumetric flow rate through a
calibration, and a corresponding decrease in measurement
duct. In practice, tracer gas is injected into a duct at a known
accuracy is acceptable.
mass or volumetric flow rate. Downstream of the injection
6.4 Tracer Gas Distribution—A single tube or a tubing
point gas samples are taken and are analyzed for the resulting
network is inserted into the duct to dispense tracer gas. The
tracerconcentration.Theratiooftheinjectionflowrateandthe
tubeortubesmayhaveeitherasingleormultiplereleasepoints
downstream concentration represents the dilution volume per
for tracer gas. For large cross-section ducts a network that
unit time or volumetric flow rate in the duct.
distributes tracer gas over a wide area will facilitate measure-
ment.
5. Significance and Use
6.5 Tracer Sampling—This is performed using tubing in-
5.1 Themethodpresentedhereisafieldmethodthatmaybe sertedintotheductdownstreamoftheinjectionpoint.Asingle
used to determine mass and volume flow rates in ducts where tubeisinsertedintotheduct.Airsamplesareremovedfromthe
flow conditions may be irregular and nonuniform. The gas ductbymeansofasamplingpumptodistributetracerladenair
to the analyzer either directly or by means of syringe samples.
6.6 Gas Analyzer—Thisdevicemustbesuitedforthetracer
Equationsinthistestmethodassumethatallmassorvolumeconcentrationsare
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 63% 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 (2004)
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.ThetracergassuppliermustprovideaMaterial 8.1.1 If the tracer gas analyzer is field calibrated using a
SafetyDataSheet(MSDS)thatwillprovideinformationabout 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 OSHAinformation on concentration at the sample location that is the same as the
the permissible exposure limit (PEL), or theACGIH threshold calibration concentration to within 620%.
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,todeterminethesafeconcentrationforthegaschosenfor calibrationpoints,theinjectionrate,orinjectionconcentration,
or a combination thereof, should be adjusted to produce a
the test. Never exceed the maximum safe concentration. It is
goodpracticetouseaconcentrationthatisatmostonetenthof 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 Ifthetracergasanalyzerisfieldcalibratedusingmore
7.3 Compressed Gas Equipment—Observe the supplier’s than two calibration points, the injection rate, or injection
safety information and CGAinformation 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-
i
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 (2004)
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8.3 Ifrecirculationispossibleorlikely, Nsamples C inthe 9. Procedures for Inj
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