EN ISO 4126-1:2004
(Main)Safety devices for protection against excessive pressure - Part 1: Safety valves (ISO 4126-1:2004)
Safety devices for protection against excessive pressure - Part 1: Safety valves (ISO 4126-1:2004)
ISO 4126-1:2004 specifies general requirements for safety valves irrespective of the fluid for which they are designed. It is applicable to safety valves having a flow diameter of 6 mm and above which are for use at set pressures of 0,1 bar gauge and above. No limitation is placed on temperature. This is a product standard and is not concerned with applications for safety valves.
Sicherheitseinrichtungen gegen unzulässigen Überdruck - Teil 1: Sicherheitsventile (ISO 4126-1:2004)
Diese Europäische Norm legt allgemeine Anforderungen an Sicherheitsventile fest, unabhängig von dem Medium, für das sie vorgesehen sind.
Die Norm gilt für Sicherheitsventile mit einem engsten Strömungsdurchmesser von mindestens 6 mm und für Ansprechdrücke von 0,1 bar und höher. Hinsichtlich der Temperatur bestehen keine Einschränkungen.
Die vorliegende Norm ist eine Produktnorm und behandelt keine Anwendungsfälle für Sicherheitsventile.
Dispositifs de sécurité pour protection contre les pressions excessives - Partie 1 : Soupapes de sûreté (ISO 4126-1:2004)
L'ISO 4126-1:2004 spécifie les prescriptions générales des soupapes de sûreté, quel que soit le fluide pour lequel elles sont conçues. Elle est applicable aux soupapes de sûreté présentant un orifice d'écoulement de diamètre supérieur ou égal à 6 mm qui sont utilisables à des pressions de début d'ouverture de 0,1 bar effectif et au-dessus. Aucune limitation en température n'est fixée. Il s'agit d'une norme de produit et elle ne s'adresse pas aux applications de soupapes de sûreté.
Naprave za varovanje pred visokim tlakom - 1. del: Varnostni ventili (ISO 4126-1:2004)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-september-2004
Naprave za varovanje pred visokim tlakom - 1. del: Varnostni ventili (ISO 4126-
1:2004)
Safety devices for protection against excessive pressure - Part 1: Safety valves (ISO
4126-1:2004)
Sicherheitseinrichtungen gegen unzulässigen Überdruck - Teil 1: Sicherheitsventile (ISO
4126-1:2004)
Dispositifs de sécurité pour protection contre les pressions excessives - Partie 1 :
Soupapes de sureté (ISO 4126-1:2004)
Ta slovenski standard je istoveten z: EN ISO 4126-1:2004
ICS:
13.240
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD
EN ISO 4126-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2004
ICS 13.240
English version
Safety devices for protection against excessive pressure - Part
1: Safety valves (ISO 4126-1:2004)
Dispositifs de sécurité pour protection contre les pressions Sicherheitseinrichtungen gegen unzulässigen Überdruck -
excessives - Partie 1 : Soupapes de sûreté (ISO 4126- Teil 1: Sicherheitsventile (ISO 4126-1:2004)
1:2004)
This European Standard was approved by CEN on 16 May 2003.
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 Central Secretariat 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 Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2004 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 4126-1:2004: E
worldwide for CEN national Members.
Contents
Page
1 Scope .4
2 Normative references .4
3 Terms and definitions.5
4 Symbols and units .8
5 Design .8
5.1 General.8
5.2 End connections .9
5.3 Minimum requirements for springs.11
5.4 Materials.11
6 Production testing .11
6.1 Purpose.11
6.2 General.11
6.3 Hydrostatic testing .12
6.4 Pneumatic testing .13
6.5 Adjustment of cold differential test pressure .14
6.6 Seat leakage test.14
7 Type testing.14
7.1 General.14
7.2 Tests to determine operating characteristics.15
7.3 Tests to determine flow characteristics .17
7.4 Determination of the coefficient of discharge .18
7.5 Certification of coefficient of discharge .19
8 Determination of safety valve performance.19
8.1 Determination of coefficient of discharge.19
8.2 Critical and subcritical flow .19
8.3 Discharge capacity at critical flow .19
8.4 Discharge capacity for any gas at subcritical flow .20
8.5 Discharge capacity for non-flashing liquid as the test medium in the turbulent zone where the
R
Reynolds number is equal to or greater than 80 000 .20
e
9 Sizing of safety valves.20
9.1 General.20
9.2 Valves for gas or vapour relief .21
9.3 Calculation of capacity.21
10 Marking and sealing .22
10.1 Marking on the shell of a safety valve .22
10.2 Marking on an identification plate.22
10.3 Sealing of a safety valve .22
Annex A (informative) Examples of sizing calculations for various fluids.23
A.1 Capacity calculations for gaseous media at critical flow (see 9.3.3.1) .23
A.2 Capacity calculations for gaseous media at subcritical flow (see 9.3.3.2) .25
A.3 Capacity calculations for liquids (see 9.3.4) .27
Annex ZA (informative) Relationship between this European Standard and the Essential Requirements
of EU Directive 97/23/EC (PED).28
Foreword
This document (EN ISO 4126-1:2004) has been prepared by Technical Committee CEN/TC 69 “Industrial valves”,
the secretariat of which is held by AFNOR, in collaboration with Technical Committee ISO/TC 185 “Safety devices
for protection against excessive pressure”.
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 August 2004, and conflicting national standards shall be withdrawn at the latest by
August 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, Cyprus, Czech Republic, Denmark,
Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
This standard for safety devices for protection against excessive pressure consists of seven parts of which this is
Part 1. The various parts are:
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 disc safety devices
Part 7 : Common data
Part 7 contains data that is common to more than one of the parts of this standard to avoid unnecessary repetition.
1 Scope
This part of this European Standard specifies general requirements for safety valves irrespective of the fluid for
which they are designed.
It is applicable to safety valves having a flow diameter of 6 mm and above which are for use at set pressures
of 0,1 bar gauge and above. No limitation is placed on temperature.
This is a product standard and is not concerned with applications for safety valves.
2 Normative references
This European Standard incorporates by dated or undated reference, provisions from other publications. These
normative references are cited at the appropriate places in the text and the publications are listed hereafter. For
dated references, subsequent amendments to or revisions of any of these publications apply to this European
Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the
publication referred to applies (including amendments).
EN 1092-1, Flanges and their joints – Circular flanges for pipes, valves, fittings and accessories PN designated –
Part 1: Steel flanges.
EN 1092-2, Flanges and their joints – Circular flanges for pipes, valves, fittings and accessories PN designated –
Part 2: Cast iron flanges.
EN 1092-3 , Flanges and their joints – Circular flanges for pipes, valves, fittings and accessories PN designated –
Part 3: Copper alloy flanges.
prEN 1759-1, Flanges and their joints - Circular flanges for pipes, valves, fittings and accessories, Class
designated - Part 1: Steel flanges NPS 1/2 to 24.
EN 12516-3, Valves – Shell design strength – Part 3: Experimental method.
EN 12627, Industrial Valves – Butt welding ends for steel valves.
EN 12760, Valves – Socket welding ends for steel valves.
EN ISO 6708, Pipework components – Definition and selection of DN (nominal size) (ISO 6708:1995).
ISO 7-1, Pipe threads where pressure-tight joints are made on the threads — Part 1: Dimensions, tolerances and
designation.
ANSI B1.20.1, NPT threads.
3 Terms and definitions
For the purposes of this European Standard, the following terms and definitions apply.
3.1
safety valve
valve 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 safe pressure being exceeded, and which is designed to
re-close and prevent further flow of fluid after normal pressure conditions of service have been restored
NOTE The valve can be characterised either by pop action (rapid opening) or by opening in proportion (not necessarily
linear) to the increase in pressure over the set pressure.
3.1.1
types of safety valve
3.1.1.1
direct loaded safety valve
safety valve in which the loading due to the fluid pressure underneath the valve disc is opposed only by a direct
mechanical loading device such as a weight, lever and weight, or a spring
3.1.1.2
assisted safety valve
safety valve which, by means of a powered assistance mechanism, may additionally be lifted at a pressure lower
than the set pressure and will, even in the event of failure of the assistance mechanism, comply with all the
requirements for safety valves given in this standard
3.1.1.3
supplementary loaded safety valve
safety valve which has, until the pressure at the inlet to the safety valve reaches the set pressure, an additional
force which increases the sealing force
NOTE 1 This additional force (supplementary load), which may be provided by means of an extraneous power source, is
reliably released when the pressure at the inlet of the safety valve reaches the set pressure. The amount of supplementary
loading is so arranged that if such supplementary loading is not released, the safety valve will attain its certified discharge
capacity at a pressure not greater than 1,1 times the maximum allowable pressure
...
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