SIST EN ISO 15761:2020

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

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.

Contents Page
European foreword . 3

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.

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
ISO 15761:2020(E)
© 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
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CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

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 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

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 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

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 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

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
PN
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
DN
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 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
1)
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)
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 special soft seals, special
trim materials, packing or bellows stem seals, shall be marked on the valve identification plate (see 7.4).
4.2.3 For temperatures below the lowest temperature listed in the pressure/temperature rating tables
(see 4.1), the service pressure shall be no greater than the pressure for the lowest listed temperature. The
use of valves at lower than the lowest listed temperature is the responsibility of the user. Consideration
shall be given to the loss of ductility and toughness of many materials at low temperature.
5 Design
5.1 Reference design
5.1.1 The reference design (the design to be provided when the purchaser does not specify otherwise
or does not use Annex E) for sizes DN ≤ 100 is for bolted bonnet or cover construction, an outside stem
thread for gate and globe valves and, for globe valves having a conical disc. The reference design for
threaded end valves is to use taper pipe threads in accordance with ASME B1.20.1. In addition, for valves
DN ≤ 50 the reference design is to have the body and bonnet or cover to be forged material.
Valve parts are identified in Annex D.
5.1.2 Other configurations and types of material may be provided when specified in accordance with
Annex E. Requirements for extended body valves given in Annex A and those for bellows stem seals in
Annexes B and C shall be followed.
4 © ISO 2020 – All rights reserved

ISO 15761:2020(E)
5.2 Flow passageway
5.2.1 The flow passageway includes the seat opening and the body ports leading thereto. The body
ports are the intervening elements that link the seat opening to the end connection, e.g. socket or flange.
5.2.2 The minimum cross-sectional area requirement for the flow passageway applies for both the valve
body ports and the seat opening in the absence of the valve obturator. The minimum flow passageway
cross-sectional area shall not be less than that obtained using the equivalent diameters shown in Table 1
for standard bore and Table 2 for full bore valves.
Table 1 — Minimum equivalent flow passageway diameter for a standard-bore valve
PN
16, 25, 40, 63, 100 250 400
designation
Class
150, 300, 600, 800 1 500 2 500
designation
Gate, globe Globe Globe and
Gate Gate
or check or check check
Minimum equivalent diameter
DN NPS
(mm)
8 6 6 5 6 5 ¼
10 6 6 5 6 4 ⅜
15 9 9 8 9 8 ½
20 12 12 9 10 9 ¾
25 17 15 14 13 13 1
32 23 22 20 18 18 1¼
40 28 27 25 25 25 1½
50 36 34 27 26 25 2
65 44 38 34 — — 2½
80 50 47 42 — — 3
100 69 63 58 — — 4
Table 2 — Minimum equivalent flow passageway diameter for a full-bore valve
PN
16, 25, 40, 63, 100 250 400
designation
Class
150, 300, 600, 800 1 500 2 500
designation
Gate, globe Globe Globe and
Gate Gate
or check or check check
Minimum equivalent diameter
DN NPS
(mm)
8 6 6 4 6 4 ¼
10 6 9 7 9 7 ⅜
15 12 12 9 10 9 ½
20 17 15 14 13 13 ¾
25 22 22 19 18 18 1
32 28 26 25 25 25 1¼
40 35 34 26 26 25 1½
50 44 38 34 35 30 2
65 50 47 42 — — 2½
ISO 15761:2020(E)
Table 2 (continued)
PN
16, 25, 40, 63, 100 250 400
designation
Class
150, 300, 600, 800 1 500 2 500
designation
Gate, globe Globe Globe and
Gate Gate
or check or check check
Minimum equivalent diameter
DN NPS
(mm)
80 69 63 58 — — 3
100 95 92 87 — — 4
5.3 Wall thickness
5.3.1 Except as provided in 5.3.2 and 5.3.3, the minimum wall thickness values for valve bodies and
bonnets are given in Table 3. The manufacturer, taking into account such factors as bonnet bolting
loads, rigidity needed for stem alignment, valve design details and the specified operating conditions, is
responsible for determining if a larger wall thickness is required.
5.3.2 Valve body end connection minimum wall thickness shall be in accordance with 5.4.2, 5.4.3, 5.4.4,
or 5.4.5 as applicable. Valves identified as extended body valves shall have body extension minimum wall
thickness in accordance with A.3. Valves having bellows stem seals with a bellows enclosure shall have a
bellows enclosure extension minimum wall thickness in accordance with B.4.
5.3.3 The bonnet minimum wall thickness for gate or globe valves, except for the neck extension
that forms the packing chamber entryway, shall be in accordance with Table 3. The packing chamber
extension shall have a local minimum wall thickness as specified in Table 4, based on the local inside
diameter of the packing and stem hole.
Table 3 — Minimum wall thickness for valve bodies and bonnets
PN 16, 25, 40,
― 250 ― 400
designation 63, 100
Class 150, 300,
1 500 ― 2 500 ―
designation 600, 800
Minimum wall thickness
DN NPS
(mm)
8 3,1 3,8 4,5 5,6 6,1 ¼
10 3,3 4,3 4,7 5,9 6,5 ⅜
15 4,1 4,8 5,8 7,7 8,5 ½
20 4,8 6,1 7,0 9,4 10,4 ¾
25 5,6 7,1 8,1 11,1 12,4 1
32 5,8 8,4 9,4 13,1 14,8 1¼
40 6,1 9,7 11,4 16,2 18,3 1½
50 7,1 11,9 13,6 19,6 22,3 2
65 8,4 14,2 16,9 — — 2½
80 9,7 16,5 20,2 — — 3
100 11,9 21,3 24,6 — — 4
6 © ISO 2020 – All rights reserved

ISO 15761:2020(E)
5.4 Valve body
5.4.1 General
Requirements for a basic valve body and associated end connections are given here. The requirement
for gate valve bodies having extended end present in Annex A shall be followed.
5.4.2 Socket welding ends
5.4.2.1 Except as may be required herein, socket welding ends shall be in accordance with ASME B16.11.
5.4.2.2 The socket bore axis shall coincide with the end entry axis. Socket end faces shall be
perpendicular to the socket bore axis. The socket bore diameter and its depth shall be in accordance with
Table 5.
Table 4 — Minimum wall thickness for bonnet and bellows extensions
PN designation 16 25 and 40 63, 100 ― 250 400
Class designation 150 300 600 800 1 500 2 500
Extension inside diameter Minimum wall thickness
(mm) (mm)
15 3,1 3,3 3,6 4,0 4,8 7,7
16 3,2 3,4 3,8 4,3 5,1 8,0
17 3,2 3,4 3,8 4,3 5,1 8,4
18 3,3 3,5 3,9 4,4 5,3 8,7
19 3,4 3,6 4,0 4,6 5,5 9,0
20 3,4 3,6 4,1 4,7 5,7 9,4
25 3,8 4,1 4,5 5,4 6,7 11,0
30 4,2 4,6 5,0 6,0 7,9 12,8
35 4,6 5,1 5,4 6,4 9,0 14,5
40 4,9 5,5 5,7 6,7 9,9 16,2
50 5,5 6,3 6,3 7,3 11,8 19,6
60 5,7 6,6 6,6 8,1 13,6 23,0
70 5,9 6,9 7,3 9,0 15,5 26,4
80 6,1 7,2 8,0 9,9 17,3 29,8
90 6,3 7,5 8,6 10,8 19,1 33,2
100 6,5 7,8 9,3 11,8 21,0 36,6
110 6,5 8,0 10,0 12,7 22,8 40,0
120 6,7 8,3 10,7 13,6 24,7 43,4
130 6,8 8,7 11,4 14,5 26,5 46,9
140 7,0 9,0 12,0 15,5 28,4 50,3
NOTE  For bellows enclosures see B.4.
ISO 15761:2020(E)
Table 5 — Socket diameter and depth
a b
DN Diameter Depth NPS
(mm) (mm)
8 14,2 10 ¼
10 17,6 10 ⅜
15 21,8 10 ½
20 27,2 13 ¾
25 33,9 13 1
32 42,7 13 1¼
40 48,8 13 1½
50 61,2 16 2
65 73,9 16 2½
+ 05,
a
The applicable diametrical tolerance is mm.
b
The depth dimension is a minimum value.
5.4.2.3 The minimum socket wall thickness, socket diameter, extending over the full socket depth shall
be in accordance with Tables 5 and 6.
5.4.2.4 End-to-end dimensions for socket welding end valves are to be established by the manufacturer.
5.4.3 Threaded ends
5.4.3.1 The threaded end thread axis shall coincide with the end entry axis. The minimum wall
thickness at the threaded end shall be in accordance with Table 6. An approximate 45° lead-in chamfer,
having an approximate depth of one-half the thread pitch, shall be applied at each threaded end.
5.4.3.2 The end threads shall be taper pipe threads that, for PN designated valves shall be in accordance
with ISO 7-1 and for Class designated valves shall be in accordance with ASME B1.20.1. However, when
specified in purchase documentation ISO 7-1 threads may be used with Class designated valves or
ASME B1.20.1 threads may be used with PN designated valves provided that this variation is identified
on the valve identification plate.
5.4.3.3 Threads shall be gauged in accordance with the requirements of ISO 7-2 or ASME B1.20.1 as
applicable.
5.4.3.4 The minimum wall thickness of the threaded ends, measured at the outermost full thread crest,
shall be in accordance with Table 6.
5.4.3.5 End to end dimensions for threaded end valves are to be established by the manufacturer.

8 © ISO 2020 – All rights reserved

ISO 15761:2020(E)
Table 6 — Socket and threaded end minimum wall thickness
PN 16, 25, 40, 63
250 400
designation and 100
Class 150, 300, 600
1 500 2 500
designation and 800
Minimum wall thickness
DN NPS
(mm)
8 3,3 4,1 6,6 ¼
10 3,6 4,3 7,1 ⅜
15 4,1 5,3 8,1 ½
20 4,3 6,1 8,6 ¾
25 5,1 6,9 9,9 1
32 5,3 8,1 11,7 1¼
40 5,8 8,9 13,0 1½
50 6,9 10,7 15,7 2
65 7,9 12,4 18,5 2½
5.4.4 Flanged ends
5.4.4.1 Body end flanges for PN designated valves shall comply with the dimensional requirements
of EN 1092-1 and body end flanges for Class designated valves shall comply with the dimensional
requirements of ASME B16.5. This document does not cover dimensional requirements of flanged ends
for Class 800 valves. If valve end flange bolt holes are specified by the purchaser to be other than those of
the respective PN or Class flange standard, the manufacturer shall ensure that the substitute flange bolt
hole drillings will accommodate bolting having a total flange bolting cross sectional area that is at least
as great as that of the bolting being replaced.
5.4.4.2 Body end flanges and bonnet flanges shall be cast or forged integral with the body. However,
when specified by the purchaser, forged flanges may be attached by welding.
a) Welding a flange to a valve body shall be by full penetration butt-welding. The welding operator
and welding procedure shall be qualified in accordance with the rules of ISO 9606-1 or the rules of
ASME BPVC, Section IX.
b) Integral or other types of alignment rings (cantering backing rings) used to facilitate welding shall
be removed after the weld is completed, taking care that the minimum wall thickness is maintained.
c) Heat treatment, following welding, to ensure that the valve body and flange materials are suitable
for the full range of service conditions, shall be performed as required by Table A.4.
d) The weld quality shall be in accordance with the examination acceptance requirements of
ISO 15649 as specified for normal fluid service.
e) The finished end flange facings shall be parallel to each other within 2°.
5.4.4.3 Face-to-face dimensions for flanged end valves shall be as follows:
— for PN designated valves in accordance with ISO 5752, basic series 3, 4 ,5, 10 and 21 as applicable;
— for Class designated valves, Class ≤ 600 in accordance with ASME B16.10;
— for Class designated valves, Class > 600 the same as the end-to-end dimensions given in Table 7;
ISO 15761:2020(E)
— the tolerances for all face-to-face dimensions shall be ±1,5 mm (as stated in the note of Table 7).
5.4.5 Butt-welding ends
5.4.5.1 Unless otherwise specified by the purchaser, butt-welding ends shall be in accordance with
Figure 1 and Table 8. The inside and outside surfaces of valve welding ends shall be machine-finished
overall. The contour within the envelope is at the option of the manufacturer unless specifically ordered
otherwise. Intersections should be slightly rounded. For nominal outside diameters and wall thickness of
standard steel pipe, see ISO 4200.
5.4.5.2 End-to-end dimensions for butt-welding end valves shall be established by the manufacturer.
Table 7 — Face-to-face dimensions for Class 1 500 and 2 500
DN Class 1 500 Class 2 500 NPS
(mm) (mm)
15 216 264 ½
20 229 273 ¾
25 254 308 1
32 279 349 1¼
40 305 384 1½
50 368 451 2
65 419 — 2½
80 470 — 3
100 546 — 4
NOTE  The applicable length tolerance is ±1,5 mm (see 5.4.4.3).

Key
A nominal outside diameter of welding end
B nominal inside diameter of pipe
T nominal wall thickness of pipe
Figure 1 — Butt–welding ends
10 © ISO 2020 – All rights reserved

ISO 15761:2020(E)
Table 8 — Butt-welding end diameters
DN 8 10 15 20 25 32 40 50 65 80 100
A
14 17 21 27 33 42 48 60 73 89 114
(mm)
+25,
NOTE 1 The tolerance for diameter A is ±1 mm for DN ≤ 20 and mm for DN ≥ 25.
− 1
NOTE 2 The tolerance for diameter B is ±1 mm (see Figure 1).
5.4.6 Body seats
5.4.6.1 Integral body seats are permitted in austenitic stainless-steel bodies. An austenitic stainless
steel or a hardfacing material may be weld deposited either directly on a valve body or on a separate
body seat ring.
For gate valve seat rings where the hard facing is applied by a plasma arc or a laser process, seating
surfaces shall have a minimum finished facing material thickness of 0,5 mm.
All other weld deposited seating surfaces shall have a minimum finished facing material thickness
of 1 mm.
Body seating surfaces shall not have sharp corners, e.g. corners with an edge disposed to cause damage
in conjunction with gate or disc seating surfaces, at either the inner or outer seat circumference.
5.4.6.2 Except as provided in 5.4.6.1, valve bodies shall have separate removable seat rings that are
threaded, rolled or pressed in place, however rolled or pressed seat rings shall not be used with globe
valves or lift check valves unless they are seal welded.
Sealing compounds or greases shall not be used when assembling seat rings; however a light lubricant
having a viscosity no greater than kerosene may be used to prevent galling when assembling mating
surfaces.
5.4.6.3 The inside diameter of the body seat flow passageway shall not be less than the value specified
in Tables 1 and 2.
5.5 Valve bonnet or cover
5.5.1 The bonnet of a gate or globe valve or the cover of a check valve shall be secured to the body,
subject to requirements detailed below, by one of the following methods:
— bolting;
— welding;
— threaded with a seal weld;
— threaded-union nut, provided for the Class ≤ 800.
5.5.2 Gasketed joints shall be of a design that confines the gasket and prevents its
over-compression. At assembly, all gasket contact surfaces shall be free of heavy oils, grease and sealing
compounds. A light coating of a lubricant, no heavier than kerosene, may be applied if needed to assist in
proper gasket assembly. The gasket, unless otherwise specified by the purchaser, shall be suitable for a
valve operating temperature range of –29 °C to 540 °C.
5.5.3 Bonnet flange gaskets, unless otherwise specified by the purchaser, shall be spiral wound metal
with a flexible graphite filler. The wound metal shall be a type 18Cr-8Ni or 18Cr-8Ni-Mo of either a
regular or low carbon grade.
ISO 15761:2020(E)
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