1、AN AMERICAN NATIONAL STANDARDASME A112.4.1-2009Revision of ASME A112.4.1-1993 (R2008)Water Heater Relief Valve Drain TubesIntentionally left blank ASME A112.4.1-2009Revision of ASME A112.4.1-1993 (R2008)Water HeaterRelief ValveDrain TubesAN AMERICAN NATIONAL STANDARDDate of Issuance: January 11, 201
2、0This Standard will be revised when the Society approves the issuance of a new edition. There willbe no addenda or written interpretations of the requirements of this Standard issued to this edition.Periodically certain actions of the ASME A112 Committee may be published as Cases. Cases arepublished
3、 on the ASME Web site under the Committee Pages at http:/cstools.asme.org as they areissued.ASME is the registered trademark of The American Society of Mechanical Engineers.This code or standard was developed under procedures accredited as meeting the criteria for American NationalStandards. The Sta
4、ndards Committee that approved the code or standard was balanced to assure that individuals fromcompetent and concerned interests have had an opportunity to participate. The proposed code or standard was madeavailable for public review and comment that provides an opportunity for additional public i
5、nput from industry, academia,regulatory agencies, and the public-at-large.ASME does not “approve,” “rate,” or “endorse” any item, construction, proprietary device, or activity.ASME does not take any position with respect to the validity of any patent rights asserted in connection with anyitems menti
6、oned in this document, and does not undertake to insure anyone utilizing a standard against liability forinfringement of any applicable letters patent, nor assumes any such liability. Users of a code or standard are expresslyadvised that determination of the validity of any such patent rights, and t
7、he risk of infringement of such rights, isentirely their own responsibility.Participation by federal agency representative(s) or person(s) affiliated with industry is not to be interpreted asgovernment or industry endorsement of this code or standard.ASME accepts responsibility for only those interp
8、retations of this document issued in accordance with the establishedASME procedures and policies, which precludes the issuance of interpretations by individuals.No part of this document may be reproduced in any form,in an electronic retrieval system or otherwise,without the prior written permission
9、of the publisher.The American Society of Mechanical EngineersThree Park Avenue, New York, NY 10016-5990Copyright 2010 byTHE AMERICAN SOCIETY OF MECHANICAL ENGINEERSAll rights reservedPrinted in U.S.A.CONTENTSForeword ivCommittee Roster . vCorrespondence With the A112 Committee . vi1 General . 12 Req
10、uirements 13 Test Methods and Performance Requirements 1iiiFOREWORDThere are potential hazards associated with the heating of water in a closed vessel, as thepotential for excessive temperature or pressure development within such closed systems is alwayspresent. In order to reduce the hazards associ
11、ated with water heating, two special amendmentshave been added to the plumbing codes and standards over the past few decades that haveresulted in much safer installations. The first requirement involved the installation of a high limitcontrol in the water heating assembly, which deactivates the fuel
12、 gas control mechanism ifthe water heating device exceeds a specific temperature. The second requirement involved theinstallation of a temperature and pressure relief valve, which is designed to open to atmosphereif the water temperature or pressure within a vessel exceeds the defined specifications
13、 of thevalve. Properly inspected and maintained, these devices provide the “state-of-the-art“ in waterheater safety.For many years, relief valve drains were field-fabricated from metallic piping. With the increas-ing use of plastics and the need for more expedient installations of plumbing component
14、s, theASME A112 Committee undertook the task of developing criteria for the performance of waterheater relief valve drains.It is intended that this Standard serve as a uniform reference document for use by manufacturers,inspectors, contractors, and installers to identify criteria applicable to water
15、 heater relief valvedrain tubes.When this Standard was first developed in 1993, the standard relief valve rating of residentialwater heaters was 100,000 Btu/hr. Today the common industry rating is 105,000 Btu/hr for therelief valves. This revision reflects this change.Suggestions for improvement of
16、this Standard are welcome. They should be sent to TheAmerican Society of Mechanical Engineers, Attn: Secretary, A112 Standards Committee, ThreePark Avenue, New York, NY 10016-5990. The ASME A112 Standards Committee approved theStandard and it was subsequently adopted as an American National Standard
17、 by the AmericanNational Standards Institute on July 10, 2009.ivASME A112 COMMITTEEStandardization of Plumbing Materials and Equipment(The following is the roster of the Committee at the time of approval of this Standard.)STANDARDS COMMITTEE OFFICERSD. W. Viola, ChairS. A. Remedios, Vice ChairF. Con
18、stantino, SecretarySTANDARDS COMMITTEE PERSONNELR. H. Ackroyd, Rand EngineeringS. R. Aridi, NSF InternationalA. Ciechanowski, Alternate, NSF InternationalJ. A. Ballanco, JB Engineering however, they shouldnot contain proprietary names or information.Requests that are not in this format will be rewri
19、tten in this format by the Committee priorto being answered, which may inadvertently change the intent of the original request.ASME procedures provide for reconsideration of any interpretation when or if additionalinformation that might affect an interpretation is available. Further, persons aggriev
20、ed by aninterpretation may appeal to the cognizant ASME Committee or Subcommittee. ASME does not“approve,” “certify,” “rate,” or “endorse” any item, construction, proprietary device, or activity.Attending Committee Meetings. The A112 Standards Committee regularly holds meetings,which are open to the
21、 public. Persons wishing to attend any meeting should contact the Secretaryof the A112 Standards Committee.viASME A112.4.1-2009WATER HEATER RELIEF VALVE DRAIN TUBES1 GENERAL1.1 ScopeThis Standard establishes performance requirementsand test methods applicable to water heater relief valvedrain (or ru
22、noff) tubes for use with relief valves havinga steam rating of 105,000 Btu/hr or less.1.2 Reference StandardsThe following reference standards shall be used toevaluate the product, and are cited herein. Unless indi-cated, the latest edition of these standards shall be appli-cable for certification t
23、o this Standard.ANSI Z21.22, Relief Valves for Hot Water SupplySystemsPublisher: International Association of Plumbing andMechanical Officials (IAPMO), 20001 Walnut Drive,South Walnut, CA 91789-2825 (www.iapmo.org)ASME B1.20.1, Pipe Threads, General Purpose (Inch)Publisher: The American Society of M
24、echanicalEngineers (ASME), Three Park Avenue, New York, NY10016-5990; Order Dept: 22 Law Drive, P. O. Box 2900,Fairfield, NJ 07007-2900 (www.asme.org)2 REQUIREMENTS2.1 SizeThe drain tube shall have a minimum inside diameterof34in. and a minimum length of 48 in.2.2 MaterialThe material that is used i
25、n the composition of thedrain tube shall be capable of withstanding the tempera-ture tests cited in section 3 without collapse or perma-nent distortion. Materials shall be corrosion resistant.2.3 JointsAny joints within the tube shall be firmly affixed andshall withstand the temperature tests withou
26、t separationor leakage. Assembly of the drain tube to the relief valveshall be possible by hand-tightening only. Connectingthreads shall comply with ASME B1.20.1 for34in. NPTpipe threads.12.4 Installation InstructionsInstallation instructions, including post-installationrelief valve testing procedur
27、es, shall be provided withthe unit. A permanent tag or label relating to the reliefvalve test procedures shall be provided with the device.2.5 Marking and Identification2.5.1 The manufacturers name or trademark shallbe permanently marked on the drain tube.2.5.2 For products intended for other than O
28、EMapplications, the limitations of installation for the draintube shall be permanently marked on the tube in let-tering not less than 0.125 in. in height. For example,“HAND-TIGHTEN ONLY,” “USE ONLY ON T & PVALVES WITH 105,000 Btu/hr OR LESS RATING,” or“NO PIPE SEALANTS.”3 TEST METHODS AND PERFORMANC
29、EREQUIREMENTS3.1 Temperature Test3.1.1 Test Equipment. A steam-generating sourcecapable of producing 105,000 Btu/hr at 15 psig pressureand 250F temperature shall be used to conduct this test.The steam source shall be fitted with instruments thatmeasure pressure and temperature. The steam sourceshall
30、 be connected to a34-in. relief valve that complieswith ANSI Z21.22. The relief valve shall be mountedhorizontally and the drain tube shall be installed in adownward position. For drain tubes intended for instal-lation in relief valve locations at the top of a water heater,the test assembly shall be
31、 installed with the relief valvein a vertical position and the drain tube connected andtested accordingly.3.1.2 Test Method. Prior to conducting this test, theinside diameter and length of the drain tube shall bemeasured and recorded. A thermocouple shall beattached to the outside surface of the dra
32、in tube within3 in. 0.5 in. of the relief valve in order to measure theequilibrium temperature. The steam generator shall beASME A112.4.1-2009activated and the relief valve shall be manually lockedin an open position. Steam discharge conditions of105,000 Btu/hr 5% Btu/hr, pressure ratings of 15 psig
33、,and temperature values of 250F shall be established.When the thermocouple on the drain tube assemblyindicates equilibrium temperature has been attained, thetest shall continue for 15 min. After 15 min, the steam2generator shall be deactivated and the drain tube shallbe allowed to cool. The drain tube shall be evaluatedagainst its original baseline dimensions.3.1.3 Performance Requirements. The drain tubeshall maintain its original inside diameter and shall notexceed 0.25 in. from its original length.Intentionally left blank J13709ASME A112.4.1-2009
