EN ISO 4126-10:2024

SLOVENSKI STANDARD
01-junij-2024
Varnostne naprave za zaščito pred prekomernim tlakom - 10. del: Velikosti
varnostnih ventilov in varnostne membrane za dvofazni pretok plina/tekočine (ISO
4126-10:2024)
Safety devices for protection against excessive pressure - Part 10: Sizing of safety
valves and bursting discs for gas/liquid two-phase flow (ISO 4126-10:2024)
Sicherheitseinrichtungen gegen unzulässigen Überdruck - Teil 10: Auslegung von
Sicherheitsventilen und Berstscheiben bei Zweiphasenströmung (flüssig/gas) (ISO 4126-
10:2024)
Dispositifs de sécurité pour protection contre les pressions excessives - Partie 10:
Dimensionnement des soupapes de sûreté et des disques de rupture pour les débits
diphasiques gaz/liquide (ISO 4126-10:2024)
Ta slovenski standard je istoveten z: EN ISO 4126-10:2024
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.

EN ISO 4126-10
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2024
EUROPÄISCHE NORM
ICS 13.240
English Version
Safety devices for protection against excessive pressure -
Part 10: Sizing of safety valves and bursting discs for
gas/liquid two-phase flow (ISO 4126-10:2024)
Dispositifs de sécurité pour protection contre les Sicherheitseinrichtungen gegen unzulässigen
pressions excessives - Partie 10: Dimensionnement des Überdruck - Teil 10: Auslegung von Sicherheitsventilen
soupapes de sûreté et des disques de rupture pour les und Berstscheiben bei Zweiphasenströmung
débits diphasiques gaz/liquide (ISO 4126-10:2024) (flüssig/gas) (ISO 4126-10:2024)
This European Standard was approved by CEN on 2 October 2023.

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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 4126-10:2024 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Annex ZA (informative) Relationship between this European Standard and the essential
safety requirements of Directive 2014/68/EU (Pressure Equipment Directive)
aimed to be covered . 4

European foreword
This document (EN ISO 4126-10:2024) 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 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 October 2024, and conflicting national standards shall
be withdrawn at the latest by October 2024.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document has been prepared under a standardization request addressed to CEN by the European
Commission. The Standing Committee of the EFTA States subsequently approves these requests for its
Member States.
For the relationship with EU Legislation, see informative Annex ZA, which is an integral part of this
document.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
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, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 4126-10:2024 has been approved by CEN as EN ISO 4126-10:2024 without any
modification.
Annex ZA
(informative)
Relationship between this European Standard and the essential safety
requirements of Directive 2014/68/EU (Pressure Equipment Directive)
aimed to be covered
This European Standard has been prepared under a Commission’s standardization request M/601 to
provide one voluntary means of conforming to essential safety requirements of Directive 2014/68/EU
on the harmonisation of the laws of the Member States relating to the making available on the market of
pressure equipment.
Once this standard is cited in the Official Journal of the European Union under that Directive
2014/68/EU, compliance with the normative clauses of this standard given in Table ZA.1 and
application of the edition of the normatively referenced standards as given in Table ZA.2 confers, within
the limits of the scope of this standard, a presumption of conformity with the corresponding essential
safety requirements of that Directive 2014/68/EU, and associated EFTA regulations.
Table ZA.1 — Correspondence between this European Standard and
Annex I of Directive 2014/68/EU
Essential Safety Requirements Clause(s)/sub-clause(s) Remarks/Notes
of Directive 2014/68/EU of this EN
2.11.2 6.3.3, Pressure limiting devices
6.5.2,
6.5.3,
6.5.4 (except last paragraph),
6.5.6,
6.7 (paragraph 1)
Table ZA.2 — Applicable Standards to confer presumption of conformity as described in this
Annex ZA
Column 1 Column 2 International Column 3 Column 4
Reference in Standard Edition
Title Corresponding European
Clause 2
Standard Edition
ISO 4126-7 ISO 4126-7:2013 Safety devices for EN ISO 4126-7:2013
protection against
ISO 4126-7:2013/Amd 1:2016 EN ISO 4126-7:2013/A1:2016
excessive pressure -
Part 7: Common data
The documents listed in the Column 1 of Table ZA.2, in whole or in part, are normatively referenced in
this document, i.e. are indispensable for its application. The achievement of the presumption of
conformity is subject to the application of the edition of Standards as listed in Column 4 or, if no
European Standard Edition exists, the International Standard Edition given in Column 2 of Table ZA.2.
WARNING 1 — Presumption of conformity stays valid only as long as a reference to this European
Standard is maintained in the list published in the Official Journal of the European Union. Users of this
standard should consult frequently the latest list published in the Official Journal of the European
Union.
WARNING 2 — Other Union legislation may be applicable to the product(s) falling within the scope of
this standard.
International
Standard
ISO 4126-10
Second edition
Safety devices for protection against
2024-02
excessive pressure —
Part 10:
Sizing of safety valves and bursting
discs for gas/liquid two-phase flow
Dispositifs de sécurité pour protection contre les pressions
excessives —
Partie 10: Dimensionnement des soupapes de sûreté et des
disques de rupture pour les débits diphasiques gaz/liquide
Reference number
ISO 4126-10:2024(en) © ISO 2024

ISO 4126-10:2024(en)
© ISO 2024
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
ii
ISO 4126-10:2024(en)
Contents Page
Foreword .v
Introduction .vi
1 S c op e . 1
2 Nor m at i ve r ef er enc e s . 1
3 T erms and definitions . 1
3.1 G eneral .1
3.2 Pressure .2
3 . 3 F low r at e .4
3 .4 F low a r e a .5
3.5 F luid state .5
3.6 T emperature .5
4 S ymbols and abbreviated terms and figures . 6
4.1 Symbols .6
4.2 A bbreviated terms .8
4.3 Figures .9
5 Application range of the method .11
5.1 G eneral .11
5.2 L imitations of the method for calculating the two-phase mass flux in safety devices .11
5.2.1 Flashing flow.11
5.2.2 Condensing flow. 12
5.2.3 Flashing flow for multi-component liquids . 12
5 . 2.4 D i s s ol ve d gas e s .
...