1、December 2016 English price group 17No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 13.240!%V3“2595116www.din.deDIN
2、 EN ISO 4126-7Safety devices for protection against excessive pressure Part 7: Common data (ISO 41267:2013 + Amd 1:2016);English version EN ISO 41267:2013 + A1:2016,English translation of DIN EN ISO 4126-7:2016-12Sicherheitseinrichtungen gegen unzulssigen berdruck Teil 7: Allgemeine Daten (ISO 41267
3、:2013 + Amd 1:2016);Englische Fassung EN ISO 41267:2013 + A1:2016,Englische bersetzung von DIN EN ISO 4126-7:2016-12Dispositifs de scurit pour protection contre les pressions excessives Partie 7: Donnes communes (ISO 41267:2013 + Amd 1:2016);Version anglaise EN ISO 41267:2013 + A1:2016,Traduction an
4、glaise de DIN EN ISO 4126-7:2016-12SupersedesDIN EN ISO 41267:201312www.beuth.deDocument comprises 42 pagesDTranslation by DIN-Sprachendienst.In case of doubt, the German-language original shall be considered authoritative.12.16 DIN EN ISO 4126-7:2016-12 2 A comma is used as the decimal marker. Nati
5、onal foreword This document (EN ISO 4126-7:2013 + A1:2016) has been prepared by Technical Committee ISO/TC 185 “Safety devices for protection against excessive pressure” in collaboration with Technical Committee CEN/TC 69 “Industrial valves” (Secretariat: AFNOR, France). The responsible German body
6、involved in its preparation was DIN-Normenausschuss Armaturen (DIN Standards Committee Valves), Working Committee NA 003-01-10 AA Sicherheitseinrichtungen gegen Druckberschreitungen. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights.
7、 DIN and/or DKE shall not be held responsible for identifying any or all such patent rights. Amendment A1:2016 has been incorporated in this standard and indicated in the text by tags !“. Amendments This standard differs from DIN EN ISO 4126-7:2013-12 as follows: a) in Subclause 5.3.1 “Discharge cap
8、acity for steam”, Equation (9) has been amended; b) in Subclause 7.4, the inscription on the estimating chart for the compressibility factor Z has been corrected; c) Example 1 in A.1 has been amended. Previous editions DIN EN ISO 4126-7: 2004-05; 2013-12 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE
9、NORM EN ISO 4126-7:2013 July 2013 + A1 June 2016 ICS 13.240 English Version Safety devices for protection against excessive pressure Part 7: Common data (ISO 4126-7:2013 + Amd 1:2016) Dispositifs de scurit pour protection contre les pressions excessives Partie 7: Donnes communes (ISO 4126-7:2013 + A
10、md 1:2016) Sicherheitseinrichtungen gegen unzulssigen berdruck Teil 7: Allgemeine Daten (ISO 4126-7:2013 + Amd 1:2016) EN ISO 4126-7:2013 was approved by CEN on 2013-04-25 and Amendment A1:2016 on 2016-05-19. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate t
11、he conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member. This European Standar
12、d exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the nation
13、al standards bodies of 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, Slovak
14、ia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2016 CEN All rights of exploitation in any form and by any means
15、reserved worldwide for CEN national Members. Ref. No. EN ISO 4126-7:2013 + A1:2016 EEN ISO 4126-7:2013 + A1:2016 (E) 2 Contents Page Foreword to EN ISO 4126-7:2013 4 !European foreword to EN ISO 4126-7:2013/A1:2016“ 6 1 Scope 7 2 Normative references 7 3 Terms and definitions . 7 4 Symbols and units
16、 . 9 5 Determination of safety valve performance. 10 5.1 Determination of coefficient of discharge . 10 5.2 Critical and subcritical flow 10 5.3 Discharge capacity at critical flow . 10 5.4 Discharge capacity for any gas at subcritical flow . 11 5.5 Discharge capacity for non-flashing liquid as the
17、test medium in the turbulent zone where the Reynolds number Re is equal to or greater than 80 000 11 6 Sizing of safety valves . 12 6.1 General . 12 6.2 Valves for gas or vapour relief . 12 6.3 Calculation of capacity 12 7 Thermodynamic properties . 14 7.1 Steam data 14 7.2 Value of C as a function
18、of k 14 7.3 Theoretical capacity correction factors for sub-critical flow (Kb) . 14 7.4 Estimating chart for compressibility factor, Z . 25 7.5 Capacity correction factor for viscosity, Kv. 27 7.6 Properties of gases 28 8 Minimum requirements for helical compression springs . 29 8.1 General . 29 8.2
19、 Materials 29 8.3 Marking 29 8.4 Dimensions . 30 8.5 Spring plates/buttons . 30 8.6 Inspection, testing and tolerances . 30 9 Minimum requirements for safety valve disc springs 33 9.1 General . 33 9.2 Materials 33 9.3 Marking 33 9.4 Dimensions . 33 9.5 Inspection, testing and tolerances . 33 DIN EN
20、ISO 4126-7:2016-12 EN ISO 4126-7:2013 + A1:2016 (E) 3 Annex A (informative) Examples of capacity calculations for various media . 34 A.1 Capacity calculations for gaseous media at critical flow (see 6.3.3.1) 34 A.2 Capacity calculations for gaseous media at subcritical flow (see 6.3.3.2) . 36 A.3 Ca
21、pacity calculations for liquids (see 6.3.4) . 37 Annex ZA (informative) Relationship between this European Standard and the Essential Requirements of EU Directive 97/23/EC (PED) 39 Bibliography . 40 DIN EN ISO 4126-7:2016-12 EN ISO 4126-7:2013 + A1:2016 (E) 4 Foreword to EN ISO 4126-7:2013 This docu
22、ment (EN ISO 4126-7:2013) has been prepared by Technical Committee ISO/TC 185 “Safety devices for protection against excessive pressure” in collaboration with the Technical Committee CEN/TC 69 “Industrial valves” the secretariat of which is held by AFNOR. This European Standard shall be given the st
23、atus of a national standard, either by publication of an identical text or by endorsement, at the latest by January 2014, and conflicting national standards shall be withdrawn at the latest by January 2014. Attention is drawn to the possibility that some of the elements of this document may be the s
24、ubject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN ISO 4126-7:2004. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and s
25、upports essential requirements of EU Directive. For relationship with EU Directive, see informative Annex ZA, which is an integral part of this document. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this Eur
26、opean 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, Slovakia, Sl
27、ovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. Endorsement notice The text of ISO 4126-7:2013 has been approved by CEN as EN ISO 4126-7:2013 without any modification. EN ISO 4126 consists of the following parts, under the general title Safety devices for protection against excess
28、ive pressure: Part 1: Safety valves Part 2: Bursting disc safety devices Part 3: Safety valves and bursting disc safety devices in combination Part 4: Pilot operated safety valves Part 5: Controlled safety pressure relief systems (CSPRS) Part 6: Application, selection and installation of bursting di
29、sc safety devices Part 7: Common data DIN EN ISO 4126-7:2016-12 EN ISO 4126-7:2013 + A1:2016 (E) 5 Part 9: Application and installation of safety devices excluding stand-alone bursting disc safety devicesN1) Part 10: Sizing of safety valves for gas/liquid two-phase flowN1) Part 11: Performance testi
30、ng1)Part 7 contains data that are common to more than one of the parts of ISO 4126 to avoid unnecessary repetition.N1)At present only available as ISO standard. 1)Under preparation DIN EN ISO 4126-7:2016-12 EN ISO 4126-7:2013 + A1:2016 (E) 6 !European foreword to EN ISO 4126-7:2013/A1:2016“ !This do
31、cument (EN ISO 4126-7:2013/A1:2016) has been prepared by Technical Committee ISO/TC 185 “Safety devices for protection against excessive pressure” in collaboration with Technical Committee CEN/TC 69 “Industrial valves” the secretariat of which is held by AFNOR. This Amendment to the European Standar
32、d EN ISO 4126-7:2013 shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by December 2016, and conflicting national standards shall be withdrawn at the latest by December 2016. Attention is drawn to the possibility that some o
33、f the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and su
34、pports essential requirements of EU Directive(s). For relationship with EU Directive, see informative Annex ZA, which is an integral part of EN ISO 4126-7:2013. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement t
35、his 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, Slova
36、kia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. Endorsement notice The text of ISO 4126-7:2013/Amd 1:2016 has been approved by CEN as EN ISO 4126-7:2013/A1:2016 without any modification.“ DIN EN ISO 4126-7:2016-12 1 ScopeThis part of ISO 4126 specifies requirements for safe
37、ty valves. It contains information which is common to ISO 4126-1 to ISO 4126-6 to avoid unnecessary repetition.For flashing liquids or two-phase mixtures, see ISO 4126-10.The user is cautioned that it is not recommended to use the ideal gas formula presented in 6.3 when the relieving temperature is
38、greater than 90 % of the thermodynamic critical temperature and the relieving pressure is greater than 50 % of the thermodynamic critical pressure. Additionally, condensation is not considered. If condensation occurs, the method presented in 6.3 should not be used.2 Normative referencesThe following
39、 documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 4126-1, Safety de
40、vices for protection against excessive pressure Part 1: Safety valvesISO 4126-2, Safety devices for protection against excessive pressure Part 2: Bursting disc safety devicesISO 4126-4, Safety devices for protection against excessive pressure Part 4: Pilot operated safety valvesISO 4126-5, Safety de
41、vices for protection against excessive pressure Part 5: Controlled safety pressure relief systems (CSPRS)3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 4126-1, ISO 4126-2, ISO 4126-4 ISO 4126-5 and the following apply.NOTE Pressure unit used in ISO 4
42、126-7 is the bar (1 bar = 105Pa), quoted as gauge (relative to atmospheric pressure) or absolute as appropriate.3.1safety valvevalve which automatically, without the assistance of any energy other than that of the fluid concerned, discharges a quantity of the fluid so as to prevent a predetermined s
43、afe pressure being exceeded, and which is designed to re-close and prevent further flow of fluid after normal pressure conditions of service have been restoredNote 1 to entry: The valve can be characterized either by pop action (rapid opening) or by opening in proportion (not necessarily linear) to
44、the increase in pressure over the set pressure. The use of the term safety valve in this part of ISO 4126 applies to other valve types as covered in ISO 4126-1, ISO 4126-4 and ISO 4126-5.7 EN ISO 4126-7:2013 + A1:2016 (E) DIN EN ISO 4126-7:2016-12 3.2set pressurepredetermined pressure at which a saf
45、ety valve under operating conditions commences to openNote 1 to entry: It is the gauge pressure measured at the valve inlet at which the pressure forces tending to open the valve for the specific service conditions are in equilibrium with the forces retaining the valve disc on its seat.3.3maximum al
46、lowable pressure, PSmaximum pressure for which the protected equipment is designed3.4overpressurepressure increase over set pressure, usually expressed as a percentage of the set pressure3.5relieving pressurepressure used for the sizing of a safety valve which is greater than or equal to the set pre
47、ssure plus overpressure3.6back pressurepressure that exists at the outlet of a safety valve as a result of the pressure in the discharge systemNote 1 to entry: The back pressure is the sum of the superimposed and built-up back pressures.3.7built-up back pressurepressure existing at the outlet of a s
48、afety valve caused by flow through the valve and the discharge system3.8superimposed back pressurepressure existing at the outlet of a safety valve at the time when the device is required to operateNote 1 to entry: It is the result of pressure in the discharge system from other sources.3.9flow aream
49、inimum cross-sectional flow area (but not the smallest area between the disc and seat) between inlet and seat which is used to calculate the theoretical flow capacity, with no deduction for any obstructionNote 1 to entry: The symbol is A.3.10theoretical discharge capacitycalculated capacity expressed in mass or volumetric units of a theoretically perfect nozzle having a cross-sectional flow area equal to the flow area of a safety valve3.11coeff
