1、Designation: E2029 11Standard Test Method forVolumetric and Mass Flow Rate Measurement in a DuctUsing Tracer Gas Dilution1This standard is issued under the fixed designation E2029; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th
2、e year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method describes the measurement of thevolumetric and mass flow rate of a gas stream within a duct
3、,stack, pipe, mine tunnel, or flue using a tracer gas dilutiontechnique. For editorial convenience all references in the textwill be to a duct, but it should be understood that this couldrefer equally well to a stack, pipe, mine tunnel, or flue.This testmethod is limited to those applications where
4、the gas streamand the tracer gas can be treated as ideal gases at the conditionsof the measurement. In this test method, the gas stream will bereferred as air, though it could be any another gas that exhibitsideal gas law behavior.1.2 This test method is not restricted to any particular tracergas al
5、though experimental experience has shown that certaingases are used more readily than others as suitable tracer gases.It is preferable that the tracer gas not be a natural componentof the gas stream.1.3 Use of this test method requires a knowledge of theprinciples of gas analysis and instrumentation
6、. Correct use ofthe formulas presented here requires consistent use of units.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and to det
7、ermine theapplicability of regulatory limitations prior to use. For specificprecautionary statements, see Section 7.2. Referenced Documents2.1 ASTM Standards:2E631 Terminology of Building Constructions2.2 ANSI/ASME Standards:3ANSI/ASME TC 19.11985 (1994) Measurement Uncer-tainty: Instrument Apparatu
8、s3. Terminology3.1 Definitions:3.1.1 For definitions of general terms related to buildingconstruction used in this test method, refer to TerminologyE631.3.2 Definitions of Terms Specific to This Standard:3.2.1 ideal gas, na gas or gas mixture for which the ratioof the pressure divided by product of
9、the density and tempera-ture is a constant.3.2.2 mass flow, nthe total mass of air passing thesampling point per unit time (kg/s, lb/min).3.2.3 tracer gas, na gas that can be mixed with air andmeasured in very low concentrations.3.2.4 tracer gas analyzer, na device that measures theconcentration of
10、tracer gas in an air sample.3.2.5 tracer gas mass concentration, nthe ratio of themass of tracer gas in air to the total mass of the air-tracermixture. For an ideal gas, the mass concentration is indepen-dent of temperature and pressure.3.2.6 tracer gas molar concentration, nthe ratio of thenumber o
11、f moles of tracer gas in air to the total number ofmoles of the air-tracer mixture.3.2.7 tracer gas volume concentration, nthe ratio of thevolume of tracer gas in air to the total volume of the air-tracermixture. For an ideal gas, the volume concentration is inde-pendent of temperature and pressure
12、and is equal to the molarconcentration.3.2.8 volumetric flow, nthe total volume of air passing thesampling point per unit time (m3/s, ft3/min).3.3 Symbols:C = mass concentration4of tracer gas (ppb-mass, ppm-mass, ppt-mass)CU= upstream mass concentration4of tracer gas (ppb-mass, ppm-mass, ppt-mass)CD
13、= downstream mass concentration4of tracer gas(ppb-mass, ppm-mass, ppt-mass)CI= injection stream mass concentration4of tracer gas(ppb-mass, ppm-mass, ppt-mass)1This test method is under the jurisdiction of ASTM Committee E06 onPerformance of Buildings and is the direct responsibility of Subcommittee
14、E06.41on Air Leakage and Ventilation Performance.Current edition approved Sept. 1, 2011. Published October 2011. Originallyapproved in 1999. Last previous edition approved in 2004 as E2029 99 (2004).DOI: 10.1520/E2029-11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact
15、 ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1Copyright AS
16、TM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.c = volume concentration4of tracer gas (ppb, ppm,ppt)cU= upstream volume concentration4of tracer gas (ppb,ppm, ppt)cD= downstream volume concentration4of tracer gas(ppb, ppm, ppt)cI= injection volum
17、e concentration4of tracer gas (ppb,ppm, ppt)F = mass flow rate5(kg/s, g/min, lb/min)FI= injection mass flow rate5(kg/s, g/min, lb/min)FU= upstream mass flow rate5(kg/s, g/min, lb/min)FD= downstream mass flow rate5(kg/s, g/min, lb/min)f = volumetric flow rate5(m3/s, L/min, cfm)fstd= volumetric flow r
18、ate at standard conditions5(m3/s,L/min, cfm)fI= injection volumetric flow rate5(m3/s, L/min, cfm)fU= upstream volumetric flow rate5(m3/s, L/min, cfm)fD= downstream volumetric flow rate5(m3/s, L/min,cfm)fIstd= injection volumetric flow rate5at standard condi-tions (m3/s, L/min, cfm)fUstd= upstream vo
19、lumetric flow rate5at standard condi-tions (m3/s, L/min, cfm)fDstd= downstream volumetric flow rate5at standard con-ditions (m3/s, L/min, cfm)r = density6(kg/m3, g/L, lb/ft3)ra= density6of gas stream without any tracer (kg/m3,g/L, lb/ft3)rt= density6of the tracer gas (kg/m3, g/L, lb/ft3)rI= density6
20、of the injection gas mixture (kg/m3, g/L,lb/ft3)rU= density6of the upstream gas mixture (kg/m3, g/L,lb/ft3)rD= density6of the downstream gas mixture (kg/m3,g/L, lb/ft3)rtU= density6of the tracer gas at upstream conditions(kg/m3, g/L, lb/ft3)rtD= density6of the tracer gas at downstream conditions(kg/
21、m3, g/L, lb/ft3)4. Summary of Test Method4.1 This test method describes the use of a tracer gasdilution technique to infer the volumetric flow rate through aduct. In practice, tracer gas is injected into a duct at a knownmass or volumetric flow rate. Downstream of the injectionpoint gas samples are
22、taken and are analyzed for the resultingtracer concentration. The ratio of the injection flow rate and thedownstream concentration represents the dilution volume perunit time or volumetric flow rate in the duct.5. Significance and Use5.1 The method presented here is a field method that may beused to
23、 determine mass and volume flow rates in ducts whereflow conditions may be irregular and nonuniform. The gasflowing in the duct is considered to be an ideal gas.The methodmay be especially useful in those locations where conventionalpitot tube or thermal anemometer velocity measurements aredifficult
24、 or inappropriate due either to very low average flowvelocity or the lack of a suitable run of duct upstream anddownstream of the measurement location.5.2 This test method can produce the volumetric flow rate atstandard conditions without the need to determine gas streamcomposition, temperature, and
25、 water vapor content.5.3 This test method is useful for determining mass orvolumetric flow rates in HVAC ducts, fume hoods, vent stacks,and mine tunnels, as well as in performing model studies ofpollution control devices.5.4 This test method is based on first principles (conserva-tion of mass) and d
26、oes not require engineering assumptions.5.5 This test method does not require the measurement ofthe area of the duct or stack.5.6 The test method does not require flow straightening.5.7 The test method is independent of flow conditions, suchas angle, swirl, turbulence, reversals, and hence, does not
27、require flow straightening.5.8 The dry volumetric airflow can be determined by dryingthe air samples without measuring the water vapor concentra-tion.6. Apparatus6.1 The apparatus includes a source of tracer gas, means fordistributing the tracer gas in the duct, means for obtaining airsamples from t
28、he duct, and a gas analyzer to measure tracer gasconcentrations in the air samples.6.2 Tracer GasSee Appendix X1 for information ontracer gases and equipment used to measure their concentra-tions. Appendix X1 also contains tracer gas target concentra-tions and safety information.6.3 Tracer Gas Injec
29、tion SourceThis normally is a cylin-der of compressed tracer gas either pure or diluted in a carriersuch as air or nitrogen. Tracer release from the cylinder iscontrolled by a critical orifice or nozzle, a metering valve, anelectronic mass flow meter or mass flow controller, or other gasflow rate me
30、asurement and control device. A rotameter is notrecommended for this measurement unless of special design,calibration, and a corresponding decrease in measurementaccuracy is acceptable.6.4 Tracer Gas DistributionA single tube or a tubingnetwork is inserted into the duct to dispense tracer gas. Thetu
31、be or tubes may have either a single or multiple release pointsfor tracer gas. For large cross-section ducts a network thatdistributes tracer gas over a wide area will facilitate measure-ment.6.5 Tracer SamplingThis is performed using tubing in-serted into the duct downstream of the injection point.
32、Asingletube is inserted into the duct.Air samples are removed from theduct by means of a sampling pump to distribute tracer laden airto the analyzer either directly or by means of syringe samples.6.6 Gas AnalyzerThis device must be suited for the tracergas used and the concentrations expected in the
33、 duct beingmeasured. It should be calibrated properly and exhibit aaccuracy of better than 63 % at concentrations employed inthe measurement.4Equations in this test method assume that all mass or volume concentrations arein the same units.5Equations in this test method assume that all mass or volume
34、 flow rates are inthe same units.6Equations in this test method assume that all densities are in the same units.E2029 1127. Hazards7.1 Safety is the responsibility of the user of this testmethod. Tracer gases have safe maximum concentration limitsdue to health and, in some cases, explosive potential
35、. Table 1presents, as a guide, the maximum allowable concentration inair for some tracer gasses that can be used for airflowmeasurements. The tracer gas supplier must provide a MaterialSafety Data Sheet (MSDS) that will provide information abouthealth, fire, and explosion hazards.7.2 Health Limitati
36、onsUse current OSHA information onthe permissible exposure limit (PEL), or the ACGIH thresholdlimit value (TLV) if the particular tracer is not listed with aPEL, to determine the safe concentration for the gas chosen forthe test. Never exceed the maximum safe concentration. It isgood practice to use
37、 a concentration that is at most one tenth ofthe maximum safe concentration. Avoid using tracer gases forwhich no PEL or TLV exists.7.3 Compressed Gas EquipmentObserve the supplierssafety information and CGAinformation on the transportation,use, and storage of compressed gas cylinders, regulators, a
38、ndrelated equipment.8. Procedure for Measuring Mass and VolumetricFlowrate8.1 Inject tracer of known concentration, CI(cI), and at aknown rate, FI(fI), into a flowing duct using proceduresprovided in Section 9.8.1.1 If the tracer gas analyzer is field calibrated using asingle point method, the injec
39、tion rate, or injection concentra-tion, or a combination thereof, should be adjusted to produce aconcentration at the sample location that is the same as thecalibration concentration to within 620 %.8.1.2 If the tracer gas analyzer is field calibrated using twocalibration points, the injection rate,
40、 or injection concentration,or a combination thereof, should be adjusted to produce aconcentration at the sample location that lies between the twocalibration points.8.1.3 If the tracer gas analyzer is field calibrated using morethan two calibration points, the injection rate, or injectionconcentrat
41、ion, or a combination thereof, should be adjusted toproduce a concentration at the sample location that lies at theapproximate midpoint of the calibration range.8.2 Obtain at least N measurements of the resulting concen-trations, CiD, at least ten diameters, or equivalent hydraulicdiameters for nonr
42、ound cross section ducts, downstream of theinjection at the center of N-1 equal areas of the duct crosssection and one at the center of the duct. The number N isdetermined by Table 2 depending on the duct size.8.3 If recirculation is possible or likely, N samples CiUin thecenter of duct upstream of
43、the injection point should be takenwithin 10 s of the time a downstream sample is taken. Ifrecirculation does not exist, take at least one upstream samplebefore and after taking the downstream samples.TABLE 1 Tracer Gases and Safety IssuesTracer Gas TLVAToxicity Chemical Reactivity CommentsHydrogen
44、Asphyxiant Nontoxic Highly reactive in Fire and explosion hazardpresence of heat, when exposer to heat,flame, of O2flame, or O2Helium Asphyxiant Nontoxic InertCarbon Monoxide 25 ppm Combines with Highly reactive Fire and explosion hazardhemoglobin to with O2when exposed to heat orcause anoxia flameC
45、arbon Dioxide 5000 ppm Can be an eye Reacts vigorouslyirritant with some metals;soluble in waterSulfur Hexafluoride 1000 ppm Nontoxic Inert Thermal decompositionyields highly toxiccompoundsNitrous Oxide 25 ppm Moderately toxic Violent reaction Can form explosivewith aluminum; mixture with air; ignit
46、eswater soluble at high temperatureEthane Asphyxiant Nontoxic Flammable Incompatible withchlorine and oxidizingmaterialsMethane Asphyxiant Nontoxic Flammable Incompatible withchlorine and oxidizingmaterialsOctofluorocyclobutane 1000 ppm Low toxicity Nonflammable Thermal decomposition(Halocarbon C-31
47、8 yields highly toxiccompoundsBromotrifluoromethane 500 ppm Moderately toxid Incompatible with Dangerous in a fire(Halocarbon 13B1) by inhalation aluminumDichlorodifluoromethane 1000 ppm Central nervous Nonflammable; Thermal decomposition(Halocarbon 12) system and eye can react violently yields high
48、ly toxicirritant; can be with aluminum compoundsnarcotic at highlevelsDichlorotetrafluoromethane 1000 ppm Can be asphyxiant, Can react violently Thermal decomposition(Halocarbon 116) mildly irritating, with aluminum yields highly toxicnarcotic at high compoundslevelsAThreshold Limit Values for Chemi
49、cal Substances in the Work Environment, American Conference of Governmental Industrial Hygienists (ACGIH), 1997.E2029 1138.4 At each time a downstream sample is taken, the injec-tion flow rate FiIshall be recorded.8.5 Calculate the following quantities in either mass, vol-ume, or dry concentration depending on results desired:8.5.1 The average downstream concentration CD:CD51ND(i51NDCDi(1)where NDis the number of downstream sample locations.8.5.2 The average upstream concentration CU:CU51NU(i51NUCUi(2)where NUis the number of upstream sample locations.8.5.3 The a
