1、BSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06Gas welding equipment - Safety devicesPart 1: Devices incorporating a flame (flashback) arrestorBS EN ISO 51751:2017National forewordThis British Standard is the UK implementation of EN ISO 51751:2017. It is identical t
2、o ISO 51751:2017. It supersedes BS EN 7301:2002, which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee WEE/18, Gas welding and cutting appliances.A list of organizations represented on this committee can be obtained on request to its secretary.This publicati
3、on does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2017 Published by BSI Standards Limited 2017ISBN 978 0 580 92470 5ICS 25.160.30Compliance with a British Standard cannot confer immunity fro
4、m legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 December 2017.Amendments/corrigenda issued since publicationDate Text affectedBRITISH STANDARDBS EN ISO 51751:2017EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 517
5、5-1November 2017ICS 25.160.30 Supersedes EN 7301:2002EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGCEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2017 CEN Ref. No. EN ISO 51751:2017: EAll rights of exploitation in any form and by
6、any means reserved worldwide for CEN national MembersGas welding equipment Safety devices Part 1: Devices incorporating a flame (flashback) arrestor (ISO 51751:2017)Matriel de soudage au gaz Dispositifs de scurit Partie 1: Dispositifs avec arrt de flamme (ISO 51751:2017)Gasschweigerte Sicherheitsein
7、richtungen Teil 1: Mit integrierter Flammensperre (ISO 51751:2017)This European Standard was approved by CEN on 20 November 2017.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standar
8、d without any alteration. Uptodate lists and bibliographical references concerning such national standards may be obtained on application to the CENCENELEC Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any othe
9、r language made by translation under the responsibility of a CEN member into its own language and notified to the CENCENELEC Management Centre has the same status as the official versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, De
10、nmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.English V
11、ersionEN ISO 5175-1:2017 (E)European forewordThis document (EN ISO 51751:2017) has been prepared by Technical Committee ISO/TC 44 “Welding and allied processes” in collaboration with Technical Committee CEN/TC 121 “Welding and allied processes” the secretariat of which is held by DIN.This European S
12、tandard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by May 2018, and conflicting national standards shall be withdrawn at the latest by May 2018.Attention is drawn to the possibility that some of the elements of this d
13、ocument may be the subject of patent rights. CEN shall not be held responsible for identifying any or all such patent rights.This document supersedes EN 7301:2002.According to the CENCENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement
14、this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serb
15、ia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.Endorsement noticeThe text of ISO 51751:2017 has been approved by CEN as EN ISO 51751:2017 without any modification.2BS EN ISO 51751:2017ISO 5175-1:2017(E)Foreword iv1 Scope .12 Normative references 13 Terms and defini
16、tions .14 Design and materials .44.1 Connection 44.2 Materials .45 Requirements 45.1 General .45.2 Gas tightness . 55.2.1 External gas tightness . 55.2.2 Internal gas tightness. 55.3 Pressure resistance . 55.4 Flame arrestor .65.5 Flame arrestor with nonreturn valve 65.6 Flame arrestor with temperat
17、uresensitive cutoff valve 65.7 Flame arrestor with pressuresensitive cutoff valve 65.8 Other multifunctional safety devices .66 Methods for type testing .66.1 General .66.2 Accuracy of pressure and flow measurements .66.3 Test gases . 76.4 Gas tightness test 76.5 Pressure resistance test 76.6 Nonret
18、urn valve test . 76.6.1 General 76.6.2 Tests with reverse flow of gas. 76.7 Flame arrestor test 76.8 Temperaturesensitive cutoff valve test 86.9 Pressuresensitive cutoff valve test . 96.10 Internal leakage test for cutoff valves 107 Further tests .108 Manufacturers instructions 109 Marking .10Annex
19、A (informative) Gas flow measurement .12Annex B (informative) Third party testing information .14Annex C (informative) Production tests .15 ISO 2017 All rights reserved iiiContents PageBS EN ISO 51751:2017ISO 5175-1:2017(E)ForewordISO (the International Organization for Standardization) is a worldwi
20、de federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on tha
21、t committee. International organizations, governmental and nongovernmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this docume
22、nt and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives
23、, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development
24、of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the voluntary nature of sta
25、ndards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.This document was pre
26、pared by Technical Committee ISO/TC 44, Welding and allied processes, Subcommittee SC 8, Equipment for gas welding, cutting and allied processes.This first edition of ISO 51751, together with ISO 51752, cancels and replaces ISO 5175:1987, which has been technically revised. It also incorporates the
27、Amendment ISO 5175:1987/Amd 1:2015.A list of all parts in the ISO 5175 series can be found on the ISO website.Requests for official interpretations of any aspect of this document should be directed to the Secretariat of ISO/TC 44/SC 8 via your national standards body. A complete listing of these bod
28、ies can be found at www.iso.org.iv ISO 2017 All rights reservedBS EN ISO 51751:2017Gas welding equipment Safety devices Part 1: Devices incorporating a flame (flashback) arrestor1 ScopeThis document specifies the general requirements and tests for safety devices for fuel gases and oxygen or compress
29、ed air incorporating a flame (flashback) arrestor used downstream of manifold, cylinder and/or pipeline outlet regulators, and upstream of blowpipes for welding, cutting and allied processes.This document does not specify the location of these devices in the gas system.This document is not applicabl
30、e to safety devices not incorporating a flame arrestor, covered by ISO 51752.This document does not apply to the use of safety devices incorporating flame arrestors for applications with premixed oxy/fuel or air/fuel gas supply systems, e.g. downstream of gas mixers or a generator to produce hydroge
31、n/oxygen mixture by electrolytic decomposition of water.2 Normative referencesThe following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, t
32、he latest edition of the referenced document (including any amendments) applies.ISO 554, Standard atmospheres for conditioning and/or testing SpecificationsISO 51752, Gas welding equipment Safety devices Part 2: Not incorporating a flame (flashback) arrestorISO 7289, Gas welding equipment Quick-acti
33、on couplings with shut-off valves for welding, cutting and allied processesISO 9090, Gas tightness of equipment for gas welding and allied processesISO 9539, Gas welding equipment Materials for equipment used in gas welding, cutting and allied processesISO 10225, Gas welding equipment Marking for eq
34、uipment used for gas welding, cutting and allied processesISO 15296, Gas welding equipment VocabularyEN 560, Gas welding equipment Hose connections for equipment for welding, cutting and allied processes3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO
35、15296 and the following apply.ISO and IEC maintain terminological databases for use in standardization at the following addresses: ISO Online browsing platform: available at http:/www.iso.org/obp IEC Electropedia: available at http:/www.electropedia.org/ INTERNATIONAL STANDARD ISO 5175-1:2017(E) ISO
36、 2017 All rights reserved 1BS EN ISO 51751:2017ISO 5175-1:2017(E)3.1flame arrestordevice which arrests a flame frontEXAMPLE The good thermal conductivity, high porosity and small pore size (larger surface) of sintered metal elements lead to flame quenching. An example is given in Figure 1.Key1 norma
37、l direction of gas flow2 e.g. sintered metal element3 flameFigure 1 Flame arrestor (example)3.2maximum operating pressuremaximum pressure to which the equipment may be subjected in service3.3multifunctional safety devicedevice that incorporates two or more of the safety functionsEXAMPLE Flame arrest
38、or (3.1) with non-return valve (3.4) and cutoff valve.Note 1 to entry: The temperature-sensitive cut-off valve (3.6) is normally used in combination with a flame arrestor as its purpose is to cutoff the gas flow before the temperature at the flame arrestor reaches a point where flame transmission ac
39、ross the flame arrestor takes place. It is normal for pressure and or temperature cutoff valves only to be used in combination with flame arrestors. Due to the burning characteristics of hydrogen, it is recommended that all flame arrestors for hydrogen incorporate a temperaturesensitive cutoff valve
40、.3.4non-return valvedevice that prevents passage of gas in the direction opposite to the intended flowEXAMPLE Valve is held open by energy in gas stream and closes when downstream pressure is approximately equal to or greater than that in normal direction of flow. An example is given in Figure 2.2 I
41、SO 2017 All rights reservedBS EN ISO 51751:2017ISO 5175-1:2017(E)Key1 normal direction of gas flowFigure 2 Non-return valve (example)3.5pressure-sensitive cut-off valvedevice that stops the gas flow when the downstream pressure is higher than the upstream pressure by more than a predetermined valueE
42、XAMPLE Valve is held open, e.g. by a spring; it is actuated by a pressure wave from downstream and is then automatically held closed by a special device. An example is given in Figure 3.Key1 normal direction of gas flow2 backpressure waveFigure 3 Pressure-sensitive cut-off valve (example)3.6temperat
43、ure-sensitive cut-off valvedevice which stops the gas flow when a predetermined temperature is exceededEXAMPLE Valve is held open, e.g. by a fusible metal, and actuated by sustained temperature rise. An example is given in Figure 4. ISO 2017 All rights reserved 3BS EN ISO 51751:2017ISO 5175-1:2017(E
44、)Key1 normal direction of gas flow2 e.g. fusible metalFigure 4 Temperature-sensitive cut-off valve (example)3.7safety devicedevice which prevents the damage resulting from misuse or malfunction of gas equipment and gas installations4 Design and materials4.1 ConnectionThreaded connections up to G1 sh
45、all be in accordance with EN 560. Quick release connections shall be in accordance with ISO 7289.4.2 MaterialsMaterials used for safety devices shall conform to the requirements laid down in ISO 9539.5 Requirements5.1 GeneralRequirements for each safety device vary depending upon the device and comb
46、ination of functions in the device. A summary of the requirements and test sequence is given in Table 1.Table 1 Summary of requirements and test sequence for the most commonly available safety devicesSafety device function(s)Requirements (Subclause no.)Tests (in test order) (Subclause no.)Number of
47、devices required for each testTotal number of devices requiredFlame arrestor 5.2.1 5.3 5.46.4 External gas tightness 6.5 Pressure resistance 6.7 Flashback resistance5 1a56Flame arrestor + non return valve5.2.1 5.2.2 5.3 5.56.4 External gas tightness 6.5 Pressure resistance 6.6 Reverse flow 6.7 Flash
48、back resistance 6.6 Reverse flow5 1a5 5 56aUse a new device for this test. Do not use for any other test.4 ISO 2017 All rights reservedBS EN ISO 51751:2017ISO 5175-1:2017(E)Safety device function(s)Requirements (Subclause no.)Tests (in test order) (Subclause no.)Number of devices required for each t
49、estTotal number of devices requiredFlame arrestor + temperaturesensitive cutoff valve5.2.1 5.2.2 5.3 5.66.4 External gas tightness 6.5 Pressure resistance 6.7 Flashback resistance 6.8 Temperature cutoff 6.10 Internal leakage5 1a5 1a57Flame arrestor + non return valve + temperaturesensitive cutoff valve5.2.1 5.2.2 5.3 5.5 5.66.4 External gas tightness 6.5 Pressure resistance 6.6 Reverse flow 6.7 Flashback resistance 6.6 Reverse flow 6.8 Temperature cutoff
