SIST EN ISO 15761:2020

Steel gate, globe and check valves for sizes DN 100 and smaller, for the petroleum and natural gas industries (ISO 15761:2020)

This document specifies the requirements for a series of compact steel gate, globe and check valves for
petroleum and natural gas industry applications.
It is applicable to valves of:
— nominal sizes DN 8, 10, 15, 20, 25, 32, 40, 50, 65, 80 and 100,
— corresponding to nominal pipe sizes NPS ¼, ⅜, ½, ¾, 1, 1¼, 1½, 2, 2½, 3 and 4,
— pressure designations PN 16, 25, 40, 63, 100, 250 and 400, and
— pressure designations Class 150, 300, 600, 800, 1 500 and 2 500.
Class 800 is not a listed class designation, but is an intermediate Class number widely used for socket
welding and threaded end compact valves covered by this document. There is no equivalent PN
designation.
This document includes provisions for the following valve characteristics:
— outside screw with rising stems (OS & Y): in sizes 8 ≤ DN ≤ 100;
— inside screw with rising stems (ISRS): in sizes 8 ≤ DN ≤ 65 with a pressure designation PN ≤ 100 or
Class ≤ 800;
— socket welding or threaded ends: in sizes 8 ≤ DN ≤ 65;
— flanged or butt-welding ends excluding flanged end Class 800;
— bonnet joint construction that is bolted, welded or threaded with seal weld;
— bonnet joint construction that uses a union nut with a pressure designation PN ≤ 45 or Class ≤ 800;
— body seat openings;
— materials: as specified;
— testing and inspection.
This document covers valve end flanges in accordance with EN 1092-1 and ASME B16.5 and valve
body ends having tapered pipe threads in accordance with ISO 7-1 or ASME B1.20.1. It is applicable to
extended body construction in sizes 15 ≤ DN ≤ 50 with pressure designations Class 800 and Class 1 500
and to bellows and bellows assembly construction adaptable to gate or globe valves in sizes 8 ≤ DN ≤ 50.
Also covered are requirements for bellows stem seal type testing.

Schieber, Kugel- und Rückschlagventile aus Stahl mit Nennweiten DN 100 und kleiner für die Erdöl- und Erdgasindustrie (ISO 15761:2020)

Robinets-vannes, robinets à soupape et clapets de non retour en acier de dimensions DN 100 et inférieures, pour les industries du pétrole et du gaz naturel (ISO 15761:2020)

Le présent document spécifie les exigences pour une série de robinets-vannes, robinets à soupape et clapets de non-retour, en acier massif, pour des applications dans les industries du pétrole et du gaz naturel.
Elle est applicable aux appareils de robinetterie:
—     de diamètres nominaux DN 8, 10, 15, 20, 25, 32, 40, 50, 65, 80 et 100,
—     correspondant aux dimensions nominales de tuyauterie NPS ¼, ⅜, ½, , 1, 1¼, 1½, 2, 2½, 3 et 4,
—     affichant des désignations de pression PN 16, 25, 40, 63, 100, 250 et 400, et
—     affichant des désignations de pression Class 150, 300, 600, 800, 1 500 et 2 500.
Class 800 n'est pas une désignation de pression Class énumérée. C'est un numéro Class intermédiaire largement utilisé pour les appareils de robinetterie en acier massif à extrémités à emboîter et à souder et extrémités filetées couverts par le présent document. Il n'existe pas de désignation PN équivalente.
Le présent document contient des dispositions relatives aux caractéristiques des appareils de robinetterie suivants:
—     tiges montantes à filetage extérieur (OS & Y): de dimensions 8 ≤ DN ≤ 100;
—     tiges montantes à filetage intérieur (ISRS): de dimensions 8 ≤ DN ≤ 65 avec une désignation de la pression PN ≤ 100 ou Class ≤ 800;
—     extrémités à emboîter et à souder ou extrémités filetées, de dimensions 8 ≤ DN ≤ 65;
—     extrémités à brides ou extrémités à souder en bout, excepté les extrémités à brides de Class 800;
—     assemblage du chapeau qui est boulonné, soudé ou fileté avec une soudure d'étanchéité;
—     assemblage du chapeau utilisant un écrou de raccord union avec une désignation de pression correspondant à PN ≤ 45 ou Class ≤ 800;
—     ouvertures au siège de l'appareil de robinetterie;
—     matériaux: comme spécifié;
—     essais et contrôle.
Le présent document couvre les extrémités à brides des appareils de robinetterie conformes à l'EN 1092-1 et à l'ASME B16.5, ainsi que les extrémités de corps des appareils de robinetterie avec des filetages de tuyauterie coniques conformes à l'ISO 7-1 ou à l'ASME B1.20.1. Il s'applique aux constructions à corps rallongés de dimensions 15 ≤ DN ≤ 50 avec des désignations de pression Class 800 et Class 1 500, et aux constructions à soufflets et aux joints à soufflets adaptables aux robinets-vannes ou aux robinets à soupape de dimensions 8 ≤ DN ≤ 50. Il couvre également des exigences applicables aux essais de type des étanchéités de tige par soufflet.

Tablasti, krogelni in nepovratni ventili za velikosti DN 100 in manj za industrijo nafte in zemeljskega plina (ISO 15761:2020)

General Information

• Status: Published
• Public Enquiry End Date: 29-Feb-2020
• Publication Date: 27-Sep-2020
• ICS: 23.060.01 - Valves in general
• ICS: 75.180.20 - Processing equipment
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 24-Sep-2020
• Due Date: 29-Nov-2020
• Completion Date: 28-Sep-2020
• Ref Project: EN ISO 15761:2020 - Steel gate, globe and check valves for sizes DN 100 and smaller, for the petroleum and natural gas industries (ISO 15761:2020)

Relations

• Revised: SIST EN ISO 15761:2004 - Steel gate, globe and check valves for sizes DN 100 and smaller, for the petroleum and natural gas industries (ISO 15761:2002)
• Effective Date: 08-May-2019
• Replaces: SIST EN ISO 15761:2004 - Steel gate, globe and check valves for sizes DN 100 and smaller, for the petroleum and natural gas industries (ISO 15761:2002)
• Effective Date: 23-Sep-2020

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 15761:2020
01-november-2020
Nadomešča:
SIST EN ISO 15761:2004

Tablasti, krogelni in nepovratni ventili za velikosti DN 100 in manj za industrijo

nafte in zemeljskega plina (ISO 15761:2020)

Steel gate, globe and check valves for sizes DN 100 and smaller, for the petroleum and

natural gas industries (ISO 15761:2020)

Schieber, Kugel- und Rückschlagventile aus Stahl mit Nennweiten DN 100 und kleiner

für die Erdöl- und Erdgasindustrie (ISO 15761:2020)

Robinets-vannes, robinets à soupape et clapets de non retour en acier de dimensions

DN 100 et inférieures, pour les industries du pétrole et du gaz naturel (ISO 15761:2020)

Ta slovenski standard je istoveten z: EN ISO 15761:2020
ICS:
23.060.01 Ventili na splošno Valves in general
75.180.20 Predelovalna oprema Processing equipment
SIST EN ISO 15761:2020 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 15761:2020
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SIST EN ISO 15761:2020
EN ISO 15761
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2020
EUROPÄISCHE NORM
ICS 75.180.20 Supersedes EN ISO 15761:2002
English Version
Steel gate, globe and check valves for sizes DN 100 and
smaller, for the petroleum and natural gas industries (ISO
15761:2020)

Robinets-vannes, robinets à soupape et clapets de non Schieber, Kugel- und Rückschlagventile aus Stahl mit

retour en acier de dimensions DN 100 et inférieures, Nennweiten DN 100 und kleiner für die Erdöl- und

pour les industries du pétrole et du gaz naturel (ISO Erdgasindustrie (ISO 15761:2020)

15761:2020)
This European Standard was approved by CEN on 22 August 2020.

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, Turkey 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

© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 15761:2020 E

worldwide for CEN national Members.
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SIST EN ISO 15761:2020
EN ISO 15761:2020 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 15761:2020
EN ISO 15761:2020 (E)
European foreword

This document (EN ISO 15761:2020) has been prepared by Technical Committee ISO/TC 153 "Valves"

in collaboration with Technical Committee CEN/TC 12 “Materials, equipment and offshore structures

for petroleum, petrochemical and natural gas industries” the secretariat of which is held by NEN.

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 March 2021, and conflicting national standards shall

be withdrawn at the latest by March 2021.

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 supersedes EN ISO 15761:2002.

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, Turkey and the

United Kingdom.
Endorsement notice

The text of ISO 15761:2020 has been approved by CEN as EN ISO 15761:2020 without any modification.

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SIST EN ISO 15761:2020
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SIST EN ISO 15761:2020
INTERNATIONAL ISO
STANDARD 15761
Second edition
2020-08
Steel gate, globe and check valves
for sizes DN 100 and smaller, for the
petroleum and natural gas industries
Robinets-vannes, robinets à soupape et clapets de non retour en acier
de dimensions DN 100 et inférieures, pour les industries du pétrole et
du gaz naturel
Reference number
ISO 15761:2020(E)
ISO 2020
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SIST EN ISO 15761:2020
ISO 15761:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
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SIST EN ISO 15761:2020
ISO 15761:2020(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 3

4 Pressure/temperature ratings .............................................................................................................................................................. 3

4.1 Valve ratings .............................................................................................................................................................................................. 3

4.2 Temperature constraints ................................................................................................................................................................ 4

5 Design .............................................................................................................................................................................................................................. 4

5.1 Reference design ................................................................................................................................................................................... 4

5.2 Flow passageway .................................................................................................................................................................................. 5

5.3 Wall thickness .......................................................................................................................................................................................... 6

5.4 Valve body ................................................................................................................................................................................................... 7

5.4.1 General...................................................................................................................................................................................... 7

5.4.2 Socket welding ends ..................................................................................................................................................... 7

5.4.3 Threaded ends ................................................................................................................................................................... 8

5.4.4 Flanged ends ...................................................................... .................................................................................................. 9

5.4.5 Butt-welding ends........................................................................................................................................................10

5.4.6 Body seats ...........................................................................................................................................................................11

5.5 Valve bonnet or cover .....................................................................................................................................................................11

5.6 Obturator ..................................................................................................................................................................................................13

5.6.1 Seating surfaces .............................................................................................................................................................13

5.6.2 Gate valve obturators ................................................................................................................................................13

5.6.3 Globe valve obturators .............................................................................................................................................13

5.6.4 Check valve obturators ............................................................................................................................................13

5.7 Stem ...............................................................................................................................................................................................................14

5.8 Stem nut or stem bushing ...........................................................................................................................................................16

5.9 Packing, packing chamber, and gland ...............................................................................................................................16

5.10 Packing retention ...............................................................................................................................................................................17

5.11 Handwheel ...............................................................................................................................................................................................17

6 Materials ....................................................................................................................................................................................................................17

6.1 Trim materials ......................................................................................................................................................................................17

6.2 Materials other than trim ...........................................................................................................................................................17

7 Marking .......................................................................................................................................................................................................................18

7.1 Legibility ....................................................................................................................................................................................................18

7.2 Body marking ........................................................................................................................................................................................18

7.3 Ring joint groove marking ..........................................................................................................................................................20

7.4 Identification plate marking .....................................................................................................................................................20

7.5 Weld fabrication marking ...........................................................................................................................................................21

8 Testing and inspection ................................................................................................................................................................................21

8.1 Pressure tests ........................................................................................................................................................................................21

8.1.1 General...................................................................................................................................................................................21

8.1.2 Shell test ...............................................................................................................................................................................22

8.1.3 Closure leakage test ........................................................................................................................................... .........22

8.1.4 Optional closure leakage test for gate valves .......................................................................................23

8.1.5 Backseat leakage test ................................................................................................................................................23

8.1.6 Fugitive emission testing .......................................................................................................................................23

8.2 Inspection .................................................................................................................................................................................................24

9 Preparation for despatch ..........................................................................................................................................................................24

Annex A (normative) Requirements for extended body gate valve bodies ...............................................................25

© ISO 2020 – All rights reserved iii
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SIST EN ISO 15761:2020
ISO 15761:2020(E)

Annex B (normative) Requirements for valves with bellows stem seals .....................................................................30

Annex C (normative) Type testing of bellows stem seals .............................................................................................................34

Annex D (informative) Identification of valve parts ..........................................................................................................................37

Annex E (informative) Information to be specified by the purchaser ............................................................................40

Annex F (informative) Valve material combinations ........................................................................................................................42

Bibliography .............................................................................................................................................................................................................................46

iv © ISO 2020 – All rights reserved
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SIST EN ISO 15761:2020
ISO 15761:2020(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide 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 that committee. International

organizations, governmental and non-governmental, 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 document 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, 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 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 of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to

the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see

www .iso .org/ iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 153, Valves, in collaboration with the

European Committee for Standardization (CEN) Technical Committee CEN/TC 12, Materials, equipment

and offshore structures for petroleum, petrochemical and natural gas industries, in accordance with the

Agreement on technical cooperation between ISO and CEN (Vienna Agreement).

This second edition cancels and replaces the first edition (ISO 15761:2002), which has been technically

revised:
— Clause 2 "Normative references" was updated;
— addition of ASME Class 2 500 designation and relevant dimensions;

— addition of higher PN Class designations, including PN 63, 250 and 400, and relevant dimensions.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
© ISO 2020 – All rights reserved v
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SIST EN ISO 15761:2020
ISO 15761:2020(E)
Introduction

The purpose of this document is to establish basic requirements and practices for steel gate, globe

and check valves which can be socket welded, butt welded or flanged ended with reduced body seat

openings, whose general construction parallels that described in API 602 and BS 5352.

The form of this document corresponds to ISO 6002 and ISO 10434.
vi © ISO 2020 – All rights reserved
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SIST EN ISO 15761:2020
INTERNATIONAL STANDARD ISO 15761:2020(E)
Steel gate, globe and check valves for sizes DN 100 and
smaller, for the petroleum and natural gas industries
1 Scope

This document specifies the requirements for a series of compact steel gate, globe and check valves for

petroleum and natural gas industry applications.
It is applicable to valves of:
— nominal sizes DN 8, 10, 15, 20, 25, 32, 40, 50, 65, 80 and 100,
— corresponding to nominal pipe sizes NPS ¼, ⅜, ½, ¾, 1, 1¼, 1½, 2, 2½, 3 and 4,
— pressure designations PN 16, 25, 40, 63, 100, 250 and 400, and
— pressure designations Class 150, 300, 600, 800, 1 500 and 2 500.

Class 800 is not a listed class designation, but is an intermediate Class number widely used for socket

welding and threaded end compact valves covered by this document. There is no equivalent PN

designation.
This document includes provisions for the following valve characteristics:
— outside screw with rising stems (OS & Y): in sizes 8 ≤ DN ≤ 100;

— inside screw with rising stems (ISRS): in sizes 8 ≤ DN ≤ 65 with a pressure designation PN ≤ 100 or

Class ≤ 800;
— socket welding or threaded ends: in sizes 8 ≤ DN ≤ 65;
— flanged or butt-welding ends excluding flanged end Class 800;
— bonnet joint construction that is bolted, welded or threaded with seal weld;

— bonnet joint construction that uses a union nut with a pressure designation PN ≤ 45 or Class ≤ 800;

— body seat openings;
— materials: as specified;
— testing and inspection.

This document covers valve end flanges in accordance with EN 1092-1 and ASME B16.5 and valve

body ends having tapered pipe threads in accordance with ISO 7-1 or ASME B1.20.1. It is applicable to

extended body construction in sizes 15 ≤ DN ≤ 50 with pressure designations Class 800 and Class 1 500

and to bellows and bellows assembly construction adaptable to gate or globe valves in sizes 8 ≤ DN ≤ 50.

Also covered are requirements for bellows stem seal type testing.
2 Normative references

The 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, the latest edition of the referenced document (including any amendments) applies.

ISO 7-1, Pipe threads where pressure-tight joints are made on the threads — Part 1: Dimensions, tolerances

and designation
© ISO 2020 – All rights reserved 1
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SIST EN ISO 15761:2020
ISO 15761:2020(E)

ISO 7-2, Pipe threads where pressure-tight joints are made on the threads — Part 2: Verification by means

of limit gauges
ISO 2902, ISO metric trapezoidal screw threads — General plan
ISO 2903, ISO metric trapezoidal screw threads — Tolerances
ISO 2904, ISO metric trapezoidal screw threads — Basic dimensions
ISO 5208, Industrial valves — Pressure testing of metallic valves
ISO 5209, General purpose industrial valves — Marking

ISO 5752, Metal valves for use in flanged pipe systems — Face-to-face and centre-to-face dimensions

ISO 9606-1, Qualification testing of welders — Fusion welding — Part 1: Steels

ISO 15607, Specification and qualification of welding procedures for metallic materials — General rules

ISO 15609-1, Specification and qualification of welding procedures for metallic materials — Welding

procedure specification — Part 1: Arc welding

ISO 15610, Specification and qualification of welding procedures for metallic materials — Qualification

based on tested welding consumables

ISO 15614-1, Specification and qualification of welding procedures for metallic materials — Welding

procedure test — Part 1: Arc and gas welding of steels and arc welding of nickel and nickel alloys

ISO 15614-2, Specification and qualification of welding procedures for metallic materials — Welding

procedure test — Part 2: Arc welding of aluminium and its alloys
ISO 15649, Petroleum and natural gas industries — Piping

EN 1092-1, Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories, PN

designated — Part 1: Steel flanges

EN 10269, Steels and nickel alloys for fasteners with specified elevated and/or low temperature properties

EN 12516-1:2014+A1: 2018, Industrial valves — Shell design strength — Part 1: Tabulation method for

steel valve shells
ASME B1.1, Unified Inch Screw Threads (UN and UNR Thread Form)
ASME B1.5, Acme Screw Threads
ASME B1.8, Stub Acme Screw Threads
ASME B1.20.1, Pipe Threads, General Purpose, Inch

ASME B16.5, Pipe Flanges and Flanged Fittings: NPS 1/2 through NPS 24 Metric/Inch Standard

ASME B16.10, Face-to Face and End-to-End Dimensions of Valves
ASME B16.11, Forged Fittings, Socket-Welding and Threaded
ASME B16.34:2017, Valves Flanged, Threaded and Welding End

ASME BPVC-IX, Boiler and Pressure Vessel Code — Section IX — Welding, Brazing, and fusing Qualifications

ASTM A307, Standard Specification for Carbon Steel Bolts, Studs, and Threaded Rod 60 000 PSI Tensile

Strength
2 © ISO 2020 – All rights reserved
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SIST EN ISO 15761:2020
ISO 15761:2020(E)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
Class

alphanumeric designation for pressure-temperature rating that is common for components used

in a piping system, used for reference purposes, comprising the letters "PN" or "Class" followed

by a dimensionless number indirectly related to the pressure retaining capability as a function of

temperature of the component

Note 1 to entry: The number following the letters PN or Class does not represent a measurable value and is not

used for calculation purposes except where specified in the relevant standard. There is no definitive correlation

that links PN designations to Class designations.

Note 2 to entry: The allowable pressure for a valve having a PN or Class number depends on the valve material

and its application temperature and is to be found in tables of pressure/temperature ratings. PN or Class usage is

applicable to steel valves bearing DN or NPS nominal size (3.2) designations.
Note 3 to entry: See ISO 7268 and ASME B16.34.
3.2
nominal size
NPS

alphanumeric designation of size for components of a pipework system, which is used for reference

purposes, comprising the letters DN or NPS followed by a dimensionless number indirectly related to

the physical size, in millimetres, of the bore or outside diameter of the end connections

Note 1 to entry: The number following the letters DN or NPS does not represent a measurable value and is

not used for calculation purposes except where specified in the relevant standard. Prefix DN or NPS usage is

applicable to steel valves bearing PN or Class (3.1) designations.
Note 2 to entry: See ISO 6708 and ASME B16.34.
4 Pressure/temperature ratings
4.1 Valve ratings

4.1.1 For Class designated valves the applicable pressure/temperature ratings shall be in accordance

with those specified in the tables of ASME B16.34 for standard Class for the applicable material

specification and the applicable Class.

4.1.2 For PN designated valves the applicable pressure/temperature ratings shall be in accordance

with those specified in the tables of EN 12516-1:2014+A1:2018 for the applicable material specification

and the applicable PN number.
© ISO 2020 – All rights reserved 3
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SIST EN ISO 15761:2020
ISO 15761:2020(E)

4.1.3 Interpolated ratings: pressure/temperature ratings for Class 800 shall be determined by

Formula (1):
1 2
pp=+ p (1)
86 9
3 3
where

p is the pressure, at the specified temperature, expressed in bar , for Class 800 rounded to

the nearest 0,1 bar (10 kPa);

p is the listed pressure, at the specified temperature, for Class 600, expressed in bar;

p is the listed pressure, at the specified temperature, for Class 900 expressed in bar.

1 bar = 0,1 MPa = 100 KPa and 1 MPa = 1 N/mm².

NOTE Pressure designation Class 900 is not specifically referenced in this document because this

designation is seldom used for the compact valves described herein. However, pressure/temperature ratings for

this designation are included in the reference given in 4.1.1.
4.2 Temperature constraints

4.2.1 The temperature for a corresponding pressure rating is the maximum temperature of the

pressure containing shell of the valve. In general, this temperature is the same as that of the contained

fluid. The use of a pressure rating corresponding to a temperature other than that of the contained fluid

is the responsibility of the user.

4.2.2 Restrictions of temperature and pressure, for example those imposed by specia

...