1、ASHRAE/SMACNA STANDARDMethod of TestingHVAC Air Ductsand FittingsANSI/ASHRAE/SMACNA Standard 126-2008(Supersedes ANSI/ASHRAE/SMACNA Standard 126-2000)Approved by the ASHRAE Standards Committee on January 19, 2008; by the ASHRAE Board of Directors onJanuary 23, 2008; by the SMACNA Board of Directors
2、on January 29, 2008; and by the American NationalStandards Institute on January 30, 2008.ASHRAE Standards are scheduled to be updated on a five-year cycle; the date following the standard number isthe year of ASHRAE Board of Directors approval. The latest copies may be purchased from ASHRAE Customer
3、Service, 1791 Tullie Circle, NE, Atlanta, GA 30329-2305. E-mail: ordersashrae.org. Fax: 404-321-5478. Tele-phone: 404-636-8400 (worldwide) or toll free 1-800-527-4723 (for orders in US and Canada). Copyright 2008 ASHRAE, Inc.ISSN 1041-2336www.ansi.orgAmerican Society of Heating, Refrigeratingand Air
4、-Conditioning Engineers, Inc.1791 Tullie Circle NE, Atlanta, GA 30329 www.ashrae.orgSheet Metal and Air ConditioningContractors National Association4201 Lafayette Center Drive, Chantilly, VA 20151 www.smacna.orgASHRAE STANDARDS COMMITTEE 20072008Stephen D. Kennedy, ChairHugh F. Crowther, Vice-ChairR
5、obert G. BakerMichael F. BedaDonald L. BrandtSteven T. BushbyPaul W. CabotKenneth W. CooperSamuel D. Cummings, Jr.K. William DeanRobert G. DoerrRoger L. HedrickEli P. Howard, IIIFrank E. JakobNadar R. JayaramanByron W. JonesJay A. KohlerJames D. LutzCarol E. MarriottR. Michael MartinMerle F. McBride
6、Frank MyersH. Michael NewmanLawrence J. SchoenBodh R. SubherwalJerry W. White, Jr.Bjarne W. Olesen, BOD ExOLynn G. Bellenger, COClaire B. Ramspeck, Assistant Director of Technology for Standards and Special ProjectsSPECIAL NOTEThis American National Standard (ANS) is a national voluntary consensus s
7、tandard 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 standard as an ANS, as “substantial agreemen
8、t 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 their resolution.” Compliance with thisstan
9、dard 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 prepared by a Project Committee appointed spec
10、ifically 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. Every effort is made to balance the concerned i
11、nterests 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 constructive criticism for improving the Sta
12、ndard, 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 guarantee, certify, or assure the safety o
13、r 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 ADVERTISING POLICY ON STANDARDSASHRAE Standards
14、 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 providingother information that may serve to gui
15、de 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 made, either stated or implied,that the pro
16、duct has been approved by ASHRAE.ASHRAE Standing Standard Project Committee 126Cognizant TC: TC 5.2, Duct DesignSPLS Liaison: Nadar R. Jayaraman*Denotes members of voting status when the document was approved for publication.Richard A. Evans, Chair* Thomas E. Ponder*Kevin J. Gebke* Bradley Lee Thoma
17、s*Eli P. Howard, III*CONTENTSANSI/ASHRAE/SMACNA Standard 126-2008Method of Testing HVAC Air Ducts and FittingsSECTION PAGEForeword. 21 Purpose 22 Scope . 23 Definitions. 24 Nomenclature . 35 Instruments. 36 Tests. 37 Leakage Test 38 Structural Tests 49 Durability Tests. 1210 Report. 1411 References
18、. 14Informative Appendix A: Commentary 14Informative Appendix B: Leakage Test Setups and Example Problem 14Informative Appendix C: Recommended Acceptance Criteria 16Informative Appendix D: Bibliography. 17NOTEWhen interpretations or errata to this standard have been approved, they can be downloaded
19、free of charge from the ASHRAE Web site at http:/www.ashrae.org. Copyright 2008 American Society of Heating,Refrigerating and Air-Conditioning Engineers, Inc.1791 Tullie Circle NEAtlanta, GA 30329www.ashrae.orgAll rights reserved.2 ANSI/ASHRAE/SMACNA Standard 126-2008(This foreword is not part of th
20、is standard. It is merelyinformative and does not contain requirements necessaryfor conformance to the standard. It has not beenprocessed according to the ANSI requirements for astandard and may contain material that has not beensubject to public review or a consensus process.Unresolved objectors on
21、 informative material are notoffered the right to appeal at ASHRAE or ANSI.)FOREWORDFirst published in 2000, Standard 126 is a joint project ofASHRAE and SMACNA, the Sheet Metal and Air ConditioningContractors National Association. It was created to providemethods of testing to determine the strengt
22、h and durabilitycharacteristics of HVAC duct and fittings under various load-ing and environmental conditions. To the project committeesknowledge, no other publication covers all of the structuraland durability tests as comprehensively as this standard,although individual tests are covered under oth
23、er standards.The intent of this standard is to cover all duct shapes andmaterials. A standardized set of comprehensive tests is used toensure that products meet minimum structural requirements aswell as to allow products to be compared to each other. Suchtests should simulate structural stresses tha
24、t the duct willexperience in service and facilitate the application of safetyfactors. These tests include pressurizing the ductwork, apply-ing superimposed loads, dropping weighted implements forimpact or puncture, applying tension to the duct, bending flex-ible duct 180 degrees, subjecting the duct
25、work to temperatureand humidity changes, and bursting or collapsing the duct-work under pressure. After an individual test or a series oftests, leakage tests may be conducted to determine the effect ofa structural or durability test on a specimen. During a test orseries of tests, the ductwork is obs
26、erved to determine if there isdegradation and permanent damage. Pass/fail criteria are determined by the sponsoringagency, code officials, or other users of this standard. Recom-mended Acceptance Criteria are provided in InformativeAppendix C.This 2008 revision of the standard clarifies the title an
27、dscope to indicate that ductwork is defined to include fittings;modifies the support points in Figures 2a, 2b, 2c, and 3 as rec-ommended by testing laboratories; adds language in Section7.1 to specifically state that the standards leakage test is notintended to determine duct-system leakage class as
28、 defined inthe ASHRAE Handbook; and updates all references to theirmost current editions. 1. PURPOSEThis standard provides laboratory test procedures for theevaluation of HVAC air ducts and fittings.2. SCOPE2.1 This standard may be used to determine the structuralstrength, dimensional stability, dur
29、ability, and leakage char-acteristics of HVAC air ducts and fittings.2.2 This standard does not cover: a. effects of aerosols, solid particulates, corrosive environ-ments, or combustibilityb. long-term effects of extended servicec. seismic qualificationsd. underground ductse. plenums and equipment c
30、asingsf. supports for ductwork and fittings3. DEFINITIONSThis section defines key terms used in this standard. Forother definitions, refer to ASHRAE Terminology of Heating,Ventilation, Air Conditioning, and Refrigeration.1accuracy (error): the ability of an instrument to indicate orrecord the true v
31、alue of a measured quantity. The error of indi-cation, which is the difference between the indicated value andthe true value of the measured quantity, expresses the accuracyof an instrument. Accuracy is usually expressed as percentageof full scale.density of standard air (s): 1.204 kg/m3.duct, HVAC:
32、 duct and fittings used for conveying air in resi-dential, commercial, institutional, and industrial heating,ventilating, and air-conditioning systems.joint: a connection of duct surface elements that is primarilyintended to connect lengths of ductwork, to join intersectingducts, or to join ducts an
33、d equipment.leakage: the volumetric flow rate required to maintain aconstant static pressure in a test specimen.precision: the closeness of agreement among repeatedmeasurements of the same physical quantity by the samemethod under the same conditions and with the same instru-ment.random error: an er
34、ror that causes readings to take randomvalues on either side of some mean value. Measurements maybe precise or imprecise depending on how well an instrumentcan reproduce subsequent readings of an unchanged input.sealant: a material or product used to seal longitudinal ductseams, transverse duct join
35、ts, and ductwork penetrations.Products include liquids, mastics, tapes, gaskets, heat-acti-vated material, and mastic with an embedded fabric.seam: a connection of duct surface elements that is primarilyoriented in the direction of airflow.sponsor: a manufacturer, trade association, or some othergro
36、up that is funding, sponsoring, or requiring ductwork testsin compliance with this standard.systematic error: an error that persists and cannot be consid-ered due entirely to chance. A systematic error can becorrected through calibration.transverse joint: a joint that is used to assemble sections of
37、duct together or connect them to fittings. ANSI/ASHRAE/SMACNA Standard 126-2008 34. NOMENCLATUREAf= final area, mm2Ai = initial area, mm2D = diameter, mmL = length, mmLrs= reinforcement spacing, mmLus= user-specified support spacing, mmPR = percent reduction, %Qa= leakage rate at actual conditions,
38、L/sQs= leakage rate at standard air conditions, L/sR = gas constant, kJ/(kgK)W = duct width (flat surface), mmpb= barometric pressure, kPape= saturated vapor pressure of air, kPapp= partial vapor pressure of air, kPato= dry-bulb temperature, C= wet-bulb temperature, Co= density of atmospheric air, k
39、g/m3s= density of standard air, kg/m3 = relative humidity, percentage5. INSTRUMENTS5.1 Accuracy and Precision. Measurements shall be madewith an instrument or instrument system, including read-outdevices, that meets the accuracy and precision requirementsspecified in Sections 5.2 through 5.5. The sy
40、stematic error inan instrument, which affects its accuracy, can be minimizedby suitable calibration. Random error in an instrument, whichaffects its precision, may be reduced to some extent by choos-ing scale divisions to help in estimating values.5.2 Temperature Measurement5.2.1 Temperature instrum
41、ents and measurements shallcomply with ANSI/ASHRAE Standard 41.1, Standard Methodfor Temperature Measurement.25.2.2 Wet-bulb and dry-bulb thermometers, transducers,or sensors shall have an accuracy of 0.5C and a precision of0.25C or better. Wet- and dry-bulb thermometers for psy-chrometers shall be
42、matched.5.2.3 Thermometers, transducers, and sensors shall becalibrated over the range of temperatures encountered duringa test. This is done by using a reference thermometer havinga calibration traceable to the National Institute of Standardsand Technology (NIST).5.2.4 The wet-bulb thermometer shal
43、l be arranged to havea 3.5 to 10 m/s air velocity over the water-moistened wick-covered bulb or sensor. The dry-bulb thermometer shall bemounted upstream of the wet-bulb thermometer so that itsreading will not be depressed by the cooling effect of evapo-rated moisture.5.3 Pressure Measurement5.3.1 P
44、ressure instruments and measurements shall com-ply with ASHRAE Standard 41.3, Standard Method for Pres-sure Measurement.35.3.2 Multicomponent pressure-measuring systems (forexample, a system with a transducer, signal conditioner, andreadout device) shall be calibrated at both ends of the scaleand at
45、 least nine equally spaced intermediate points.5.3.3 Barometric pressure shall be measured by a mercurybarometer with an accuracy of 25 Pa. If the barometer is to beused at a temperature different from that at which the barom-eter was calibrated, expansion-of-mercury and scale-expan-sion corrections
46、 shall be made in compliance withAppendix B of ASHRAE Standard 41.3.3Local weather sta-tion and airport readings are acceptable in lieu of direct mea-surement.5.4 Flowmeters. Flowmeters shall have an accuracy of 2%(of reading).5.5 Dial Indicators. Dial indicators shall have jewel bear-ings, a suitab
47、le range, and 0.01 mm graduations.6. TESTS6.1 Tests to be conducted are listed below. A specific testspecimen may be used for more than one test at the sponsorsdiscretion.a. leakageb. deflection under pressurec. deflection under superimposed loadsd. impacte. tensionf. bendingg. pressure cyclingh. bu
48、rst/collapsei. puncturej. temperaturek. humidityThe purpose of each test is briefly explained in InformativeAppendix A.6.2 Individual tests may be omitted by the sponsor.6.3 When required by the sponsor, a leakage test shall beconducted before and after an individual test. If a specific testspecimen
49、 is to be used for a group of tests, a leakage test maybe conducted before and after the test series. Exclusive leak-age tests may be conducted on any specimen.7. LEAKAGE TESTThe leakage testing described below is intended to deter-mine the durability and tightness of ducts and connectionsrelated to the testing performed. This leakage test is not suit-able to determine the leakage class of a duct system.7.1 Test Specimen and Test Pressure. The duct assemblyand test pressure shall be specified by the sponsor. The ends ofthe duct assembly shall have sealed end caps.7.2 Test
