EN ISO 4126-7:2013

Safety devices for protection against excessive pressure - Part 7: Common data (ISO 4126-7:2013)

ISO 4126-7:2013 specifies requirements for safety valves. It contains information which is common to ISO 4126-1 to ISO 4126-6 to avoid unnecessary repetition.

Sicherheitseinrichtungen gegen unzulässigen Überdruck - Teil 7: Allgemeine Daten (ISO 4126-7:2013)

Dieser Teil von ISO 4126 legt Anforderungen an Sicherheitsventile fest. Er enthält zur Vermeidung unnötiger Wiederholungen Daten, die den Teilen 1 bis 6 der ISO 4126 gemein sind.
Zu ausdampfenden Flüssigkeiten oder Zweiphasengemischen siehe ISO 4126-10.
Der Anwender wird darauf hingewiesen, dass die Verwendung der in 6.3 angegebenen allgemeinen Gasgleichung nicht empfohlen wird, wenn die Abblasetemperatur mehr als 90 % der thermodynamischen kritischen Temperatur und der Abblasedruck mehr als 50 % des thermodynamischen kritischen Drucks beträgt. Darüber hinaus wird die Kondensation nicht berücksichtigt. Bei Auftreten von Kondensation sollte das in 6.3 angegebene Verfahren nicht angewendet werden.

Dispositifs de sécurité pour protection contre les pressions excessives - Partie 7: Données communes (ISO 4126-7:2013)

L'ISO 4126-5:2013 spécifie des exigences pour les soupapes de sûreté. Elle contient des données qui sont communes aux parties 1 à 6 de l'ISO 4126 pour éviter les répétitions inutiles.
Pour les liquides auto-vaporisants ou les mélanges biphasiques, voir l'ISO 4126‑10.

Naprave za varovanje pred visokim tlakom - 7. del: Splošni podatki (ISO 4126-7:2013)

Ta del standarda ISO 4126 vsebuje informacije, ki so enake za dele od 1 do 6 standarda ISO 4126, da se ne ponavljajo brez potrebe. Uporabnika opozarjamo, da ni priporočena uporaba formule idealnega plina iz točke 6.3, ko je temperatura za razbremenitev večja od 90 % termodinamične kritične temperature in tlak za razbremenitev večji od 50 % termodinamičnega kritičnega tlaka. Poleg tega se kondenzacija ne upošteva. Če pride do kondenzacije, se metoda iz točke 6.3 ne sme uporabiti.

General Information

• Status: Published
• Publication Date: 16-Jul-2013
• Withdrawal Date: 30-Jan-2014
• ICS: 13.240 - Protection against excessive pressure
• Technical Committee: CEN/TC 69 - Industrial valves
• Drafting Committee: CEN/TC 69/WG 10 - Safety devices against excessive pressure
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 17-Jul-2013
• Completion Date: 17-Jul-2013
• Directive: 2014/68/EU - Directive 2014/68/EU of the European Parliament and of the Council of 15 May 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of pressure equipment
• Directive: 97/23/EC - Directive 97/23/EC of the European Parliament and of the Council of 29 May 1997 on the approximation of the laws of the Member States concerning pressure equipment
• Mandate: M/071 - Mandate to CEN for standardization in the field of Pressure equipment
• Ref Project: SIST EN ISO 4126-7:2013 - Safety devices for protection against excessive pressure - Part 7: Common data (ISO 4126-7:2013)

Relations

• Replaces: EN ISO 4126-7:2004 - Safety devices for protection against excessive pressure - Part 7: Common data (ISO 4126-7:2004)
• Effective Date: 24-Jul-2013
• Replaces: EN ISO 4126-7:2004/AC:2008 - Safety devices for protection against excessive pressure - Part 7: Common data (ISO 4126-7:2004/Cor 1:2006)
• Effective Date: 24-Jul-2013
• Amended By: EN ISO 4126-7:2013/A1:2016 - Safety devices for protection against excessive pressure - Part 7: Common data - Amendment 1 (ISO 4126-7:2013/Amd 1:2016)
• Effective Date: 25-Nov-2015

Standards Content (Sample)

SLOVENSKI STANDARD
01-september-2013
1DGRPHãþD
SIST EN ISO 4126-7:2004
SIST EN ISO 4126-7:2004/AC:2009
Naprave za varovanje pred visokim tlakom - 7. del: Splošni podatki (ISO 4126-
7:2013)
Safety devices for protection against excessive pressure - Part 7: Common data (ISO
4126-7:2013)
Sicherheitseinrichtungen gegen unzulässigen Überdruck - Teil 7: Allgemeine Daten (ISO
4126-7:2013)
Dispositifs de sécurité pour protection contre les pressions excessives - Partie 7:
Données communes (ISO 4126-7:2013)
Ta slovenski standard je istoveten z: EN ISO 4126-7:2013
ICS:
13.240 Varstvo pred previsokim Protection against excessive
tlakom pressure
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 4126-7
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2013
ICS 13.240 Supersedes EN ISO 4126-7:2004
English Version
Safety devices for protection against excessive pressure - Part
7: Common data (ISO 4126-7:2013)
Dispositifs de sécurité pour protection contre les pressions Sicherheitseinrichtungen gegen unzulässigen Überdruck -
excessives - Partie 7: Données communes (ISO 4126- Teil 7: Allgemeine Daten (ISO 4126-7:2013)
7:2013)
This European Standard was approved by CEN on 25 April 2013.

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 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 Standard 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 national 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, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2013 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 4126-7:2013: E
worldwide for CEN national Members.

Contents Page
Foreword .3
Annex ZA (informative) Relationship between this European Standard and the Essential
Requirements of EU Directive 97/23/EC (PED) .4

Foreword
This document (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 status 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 subject 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 supports 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 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, Slovakia, Slovenia, 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.
Annex ZA
(informative)
Relationship between this European Standard and the Essential
Requirements of EU Directive 97/23/EC (PED)
This European Standard has been prepared under a mandate given to CEN by the European Commission
and the European Free Trade Association to provide one means of conforming to Essential Requirements of
the New Approach Directive 97/23/EC (PED).
Once EN ISO 4126-7 is cited in the Official Journal of the European Communities under that Directive and has
been implemented as a national standard in at least one Member State, compliance with the normative
clauses of EN ISO 4126-7 confers, within the limits of the scope of EN ISO 4126-7, a presumption of
conformity with the corresponding Essential Requirements of that Directive and associated EFTA regulations.
Table ZA.1 — Correspondence between this European Standard and Directive 97/23/EC (PED)
Essential Requirements of Directive 97/23/EC (PED)
Sub-clauses of this EN
Essential Requirements Annex I of PED
5 and 6 Pressure Limitations 2.11.1
WARNING — Other requirements and other EU Directives may be applicable to the product(s) falling within
the scope of EN ISO 4126-7.
INTERNATIONAL ISO
STANDARD 4126-7
Second edition
2013-07-15
Safety devices for protection against
excessive pressure —
Part 7:
Common data
Dispositifs de sécurité pour protection contre les pressions excessives —
Partie 7: Données communes
Reference number
ISO 4126-7:2013(E)
©
ISO 2013
ISO 4126-7:2013(E)
© ISO 2013
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
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Published in Switzerland
ii © ISO 2013 – All rights reserved

ISO 4126-7:2013(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and units . 3
5 Determination of safety valve performance . 4
5.1 Determination of coefficient of discharge . 4
5.2 Critical and subcritical flow . 4
5.3 Discharge capacity at critical flow . 4
5.4 Discharge capacity for any gas at subcritical flow. 5
5.5 Discharge capacity for non-flashing liquid as the test medium in the turbulent zone where
the Reynolds number Re is equal to or greater than 80 000 . 5
6 Sizing of safety valves . 6
6.1 General . 6
6.2 Valves for gas or vapour relief . 6
6.3 Calculation of capacity. 6
7 Thermodynamic properties . 8
7.1 Steam data. 8
7.2 Value of C as a function of k. 8
7.3 Theoretical capacity correction factors for sub-critical flow (K ) . 8
b
7.4 Estimating chart for compressibility factor, Z .19
7.5 Capacity correction factor for viscosity, K .
v 21
7.6 Properties of gases.22
8 Minimum requirements for helical compression springs .23
8.1 General .23
8.2 Materials .23
8.3 Marking .23
8.4 Dimensions .24
8.5 Spring plates/buttons .24
8.6 Inspection, testing and tolerances .24
9 Minimum requirements for safety valve disc springs .27
9.1 General .27
9.2 Materials .27
9.3 Marking .27
9.4 Dimensions .27
9.5 Inspection, testing and tolerances .27
Annex A (informative) Examples of capacity calculations for various media .28
Bibliography .33
...