ASHRAE 129-1997 Measuring Air-Change Effectiveness ((with minor editorial changes))《空气交换效果的测量》.pdf

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1、ANSI/ASHRAE Standard 129-1997 (RA 2002)(with minor editorial changes)MeasuringAir-ChangeEffectivenessApproved by the ASHRAE Standards Committee on June 26, 2002; by the ASHRAE Board of Directors onJune 27, 2002; and by the American National Standards Institute on March 12, 2003. ASHRAE Standards are

2、 scheduled to be updated on a five-year cycle; the date following the standard numberis the year of ASHRAE Board of Directors approval. The latest copies may be purchased from ASHRAE Cus-tomer Service, 1791 Tullie Circle, NE, Atlanta, GA 30329-2305. E-mail: ordersashrae.org. Fax: 404-321-5478. Telep

3、hone: 404-636-8400 (worldwide) or toll free 1-800-527-4723 (for orders in US and Canada). Copyright 2002 American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.ISSN 1041-2336ASHRAE STANDARDAmerican Society of Heating, Refrigeratingand Air-Conditioning Engineers, Inc.1791 Tull

4、ie Circle NE, Atlanta, GA 30329www.ashrae.orgASHRAE STANDARDS COMMITTEE 20012002Nance C. Lavvorn, ChairThomas E. Watson, Vice-ChairCharles G. ArnoldVan D. BaxterDean S. BorgesPaul W. CabotWaller S. ClementsCharles W. Coward, Jr.Brian P. DoughertyRichard A. EvansArthur D. HallstromMatt R. HaganRichar

5、d D. HermansJohn F. HoganFrederick H. KohlossWilliam J. LandmanRodney H. LewisRoss D. MontgomeryDavor NovoselDennis A. StankeMichael H. TavaresSteven T. TaylorJ. Richard WrightLee W. Burgett, COGordon V.R. Holness, ExOClaire B. Ramspeck, Manager of StandardsSPECIAL NOTEThis American National Standar

6、d (ANS) is a national voluntary consensus standard developed under the auspices of the AmericanSociety of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). Consensus is defined by the American National StandardsInstitute (ANSI), of which ASHRAE is a member and which has approved this s

7、tandard as an ANS, as “substantial agreement reached bydirectly and materially affected interest categories. This signifies the concurrence of more than a simple majority, but not necessarily unanimity.Consensus requires that all views and objections be considered, and that an effort be made toward

8、their resolution.” Compliance with thisstandard is voluntary until and unless a legal jurisdiction makes compliance mandatory through legislation.ASHRAE obtains consensus through participation of its national and international members, associated societies, and public review.ASHRAE Standards are pre

9、pared by a Project Committee appointed specifically for the purpose of writing the Standard. The ProjectCommittee Chair and Vice-Chair must be members of ASHRAE; while other committee members may or may not be ASHRAE members, allmust be technically qualified in the subject area of the Standard. Ever

10、y effort is made to balance the concerned interests on all ProjectCommittees. The Assistant Director of Technology for Standards and Special Projects of ASHRAE should be contacted for:a. interpretation of the contents of this Standard,b. participation in the next review of the Standard,c. offering c

11、onstructive criticism for improving the Standard, ord. permission to reprint portions of the Standard.DISCLAIMERASHRAE uses its best efforts to promulgate Standards and Guidelines for the benefit of the public in light of available information andaccepted industry practices. However, ASHRAE does not

12、 guarantee, certify, or assure the safety or performance of any products, components,or systems tested, installed, or operated in accordance with ASHRAEs Standards or Guidelines or that any tests conducted under itsStandards or Guidelines will be nonhazardous or free from risk.ASHRAE INDUSTRIAL ADVE

13、RTISING POLICY ON STANDARDSASHRAE Standards and Guidelines are established to assist industry and the public by offering a uniform method of testing for ratingpurposes, by suggesting safe practices in designing and installing equipment, by providing proper definitions of this equipment, and by provi

14、dingother information that may serve to guide the industry. The creation of ASHRAE Standards and Guidelines is determined by the need for them,and conformance to them is completely voluntary.In referring to this Standard or Guideline and in marking of equipment and in advertising, no claim shall be

15、made, either stated or implied,that the product has been approved by ASHRAE.ASHRAE Standard Project Committee 129-1997Cognizant TC: TC 5.3, Room Air DistributionSPLS Liaison: Frederick H. Kohloss*Denotes members of voting status when the document was approved for publication.William J. Fisk, Chair*

16、Paul L. Miller, Jr.Neil P. Leslie, Secretary* Francis J. Offerman, III*Ren Scott Anderson* Bjarne W. OlesenWilliam S. Apple Fred L. PaulJohn A. Carlton-Foss Andrew K. Persily*J.D. Cummins Dale O. Rammien*Daniel Int-Hout, III* Richard K. ThomasThomas M. Kenney* William J. Waeldner*Arthur E. McIvor* J

17、ames E. WoodsMilton Meckler*CONTENTSANSI/ASHRAE Standard 129-1997 (RA 2002)Measuring Air-Change EffectivenessSECTION PAGEForeword. 21 Purpose 22 Scope . 23 Definitions. 24 Criteria for Acceptable Test Space . 35 Instruments and Apparatus 36 Procedures for Measuring Air-Change Effectiveness. 67 Calcu

18、lations 98 Reporting of Information on Test Space and HVAC System. 109 References . 10Appendix A Bibliography 10Appendix B Relationship of Air-Change Effectiveness to Design Ventilation Rates inANSI/ASHRAE Standard 62-2001 . 11Appendix C Exact Equations for Calculating Age of Air from Tracer Gas Con

19、centrations 11Appendix D Determination of Average Tracer Gas Concentration from a Series of ConcentrationMeasurements with Uneven Time Intervals Between Measurements . 12Appendix E Measurement Uncertainty 12Appendix F Selecting the Tracer Decay or Tracer Step-Up Methods . 13Appendix G Estimation of

20、Tracer Gas Injection Rates. 13Appendix H Recommended Procedure for Ensuring Negligible Leakage in Sampling Systems. 15NOTEWhen addenda, interpretations, or errata to this standard have been approved, they can be downloaded free of charge from the ASHRAE Web site at www.ashrae.org. Copyright 2002 Ame

21、rican Society of Heating,Refrigerating and Air-Conditioning Engineers, Inc.1791 Tullie Circle NEAtlanta, GA 30329www.ashrae.orgAll rights reserved.2 ANSI/ASHRAE STANDARD 129-1997 (RA 2002)(This foreword is not part of this standard but is pro-vided for information only.)FOREWORDThis standard defines

22、 a method of measuring air-changeeffectiveness in mechanically ventilated buildings or spaces.The method involves an age-of-air approach to air-changeeffectiveness and employs tracer gas procedures to measurethe age of air. The age of the air at a given location is theaverage amount of time that has

23、 elapsed since the air mole-cules at that location entered the building. The definition ofair-change effectiveness is based on a comparison of the ageof air in the occupied portions of the building to the age ofair that would exist under conditions of perfect mixing of theventilation air.The need fo

24、r a test method for air-change effectivenessarose from discussions concerning ANSI/ASHRAE Stan-dard 62-1989, Ventilation for Acceptable Indoor Air Qualitywith regard to the uniformity of air distribution within build-ings and mixing within ventilated spaces. Short-circuitingairflow patterns, in whic

25、h a significant portion of supply airflows directly to the exhaust, bypassing the occupied portionof the ventilated space, have been a source of concern. Shortcircuiting could adversely impact indoor air quality andthermal comfort in the occupied space and increase energyuse. Additionally, there is

26、an increased interest in innovativeventilation, such as displacement ventilation, that may bemore effective in maintaining acceptable indoor air qualitythan ventilation that causes indoor air to be thoroughlymixed. The effective rate at which outside air is provided to theoccupied portion of the ven

27、tilated space is determined byboth the pattern of air flow within the ventilated space andby the extent of the mechanical recirculation of air by theventilation system. Increased mechanical recirculationdecreases both the adverse effect of short circuiting and thebenefits of displacement flow. The a

28、ir-change effectivenessparameter defined in this standard reflects the combinedinfluence of the indoor airflow pattern and mechanical recir-culation on the age of air at locations where people breathe.Appendix B describes how measured values of air-changeeffectiveness can be used to adjust the outdo

29、or air require-ments for ventilation determined in accordance with ANSI/ASHRAE Standard 62-2001.The test method has been used successfully in labora-tory test rooms to study the performance of different ventila-tion systems, but there is considerably less experience in thefield where many factors ca

30、n complicate the measurementprocess and increase measurement uncertainty. Therefore,the standard places strict limitations on the characteristicsof the spaces that can be tested with the method. While thetest method will not be usable in all field situations, it is gen-erally applicable in laborator

31、y test rooms. Future versions ofthe standard will benefit from additional experience with thetest method in the field, perhaps making the test methodmore widely applicable.NK mromlpbThis standard prescribes a method for measuring air-change effectiveness in mechanically ventilated spaces andbuilding

32、s that meet specified criteria. The air-change effec-tiveness is a measure of the effectiveness of outdoor air distri-bution to the breathing level within the ventilated space.OK plmbOKN The method of measuring air-change effectiveness com-pares the age of air where occupants breathe to the age of a

33、irthat would occur throughout the space if the indoor air wereperfectly mixed. OKO The standard includes measurement procedures and cri-teria for assessing the suitability of the test space for measure-ments of air-change effectiveness.PK abcfkfqflkpadjoining spaces: any ventilated or unventilated i

34、ndoor spacethat adjoins, or is surrounded by, the test space.age of air: the average time elapsed since molecules of air ina given volume of air entered the building from outside.building air infiltration: uncontrolled inward leakage of air(that may contain enriched water vapor) through cracks andin

35、terstices in any building element and around windows anddoors of a building, caused by the pressure effects of wind orthe effect of differences in the indoor and outdoor air density.calibration gas: a mixture of air and tracer gas with a tracergas concentration that is known within specified toleran

36、ces,used to calibrate tracer gas instruments.concentration: the quantity of one constituent dispersed in adefined amount of another.concentration, tracer gas: the volume or mass of tracer gasdivided by the volume or mass of air plus tracer gas.exfiltration: converse of building air infiltration.exha

37、ust air: air discharged from a space to the outdoors asdifferentiated from air transferred from one space to an adja-cent space.indoor air volume: the entire air volume of a space or build-ing in which the ventilation air is distributed, including duct-work and plenums. The volume of indoor furnishi

38、ngs,equipment, and occupants must be subtracted from the grossindoor volume that is based on interior dimensions of thespace or building.nominal time constant: the indoor air volume of a space orbuilding divided by the rate of outdoor air supply; the nominaltime constant also equals the average age

39、of air exiting fromthe space or building. The reciprocal of the nominal timeconstant is called the nominal air-change rate.outdoor air: air outside a building or taken from outdoors andnot previously circulated through the system.ANSI/ASHRAE STANDARD 129-1997 (RA 2002) 3perfect mixing: a theoretical

40、 airflow distribution patternwithin a ventilated space where the supply air is instanta-neously and uniformly mixed with the air in the space suchthat the concentration of all constituents in the air, and the ageof air, are spatially uniform.real-time measurement: In the context of this standard, ar

41、eal-time measurement of a tracer gas concentration is ameasurement that includes sample analysis by a tracer gasanalyzer during the tracer gas decay or step-up. The outputfrom the tracer gas analyzer is available within approximatelya ten-minute period after the air is sampled.return air: air extrac

42、ted from a space and totally or partiallyreturned to an air conditioner, furnace, or other heat source.supply air: air entering a space from an air-conditioning, heat-ing, or ventilating apparatus.test space: a building or portion of a building that is thesubject of the air-change effectiveness meas

43、urement.tracer gas: a gas that can be mixed in trace amounts with airfor the purpose of studying airflow patterns and measuringages of air and air-change rates.QK ofqbof=clo=bmq_ib=qbpq=pmbTo help ensure repeatable and accurate measurements, thespace or building in which air-change effectiveness ism

44、easured, hereinafter called the “test space,” must meet thefollowing criteria.QKN This standard applies to single-room or multi-room testspaces, which may be a research laboratory, an entire build-ing, or a section of a building. Test spaces may be partly orentirely surrounded by other indoor spaces

45、. In all cases, thetest space shall be representative of a space designed forhuman occupancy.QKO This standard applies to spaces that are mechanicallyventilated. During the measurement of air-change effective-ness, all airstreams of the HVAC system serving the testspace, including the supply air, re

46、turn air, outdoor air, and theairstreams exiting each supply outlet and entering each returninlet, shall have a constant flow rate to the degree practical,e.g., the difference between the maximum and minimumshould be within 10%. Fan and damper controls shall be over-ridden if necessary so that dampe

47、r positions and fan speedsare constant during the test. HVAC systems that supply air toor remove air from the test space shall not supply air to orremove air from any other space. Mechanical recirculation ofair is permitted but not required.QKP The standard applies to test spaces that have limitedte

48、mporal variation in heat loads and limited variation in theoperation of air-moving equipment according to the followingcriteria:(a) The difference between maximum and minimuminternal heat generation by equipment (e.g., lights,space heaters, computers) shall not be larger than10% during a test. (b) T

49、he difference between maximum and minimumnumber of occupants within the test space shall notbe larger than 10% or the test space shall be unoc-cupied. No restrictions are placed on occupantmovement within the test space. (c) The range of the temperature difference between allreturn airstreams and the supply airstream shall notbe larger than 2F (1.1C) during the test. The dif-ference between the maximum and minimum tem-perature of each return airstream shall not be largerthan 6F (3.3C). (d) The difference between maximum and minimumrate of airflow through fans operating within