SIST EN ISO 10434:2020

SLOVENSKI STANDARD
01-november-2020
Nadomešča:
SIST EN ISO 10434:2004
Jekleni zasuni s prirobničnim zgornjim delom za naftno industrijo, petrokemijo in
podobno industrijo (ISO 10434:2020)
Bolted bonnet steel gate valves for the petroleum, petrochemical and allied industries
(ISO 10434:2020)
Schieber aus Stahl mit geflanschtem Oberteil für die Erdöl-, petrochemische und
verwandte Industrien (ISO 10434:2020)
Robinets-vannes en acier à chapeau boulonné pour les industries du pétrole, de la
pétrochimie et les industries connexes (ISO 10434:2020)
Ta slovenski standard je istoveten z: EN ISO 10434:2020
ICS:
23.060.30 Zapirni ventili (zasuni) Gate valves
75.180.01 Oprema za industrijo nafte in Equipment for petroleum and
zemeljskega plina na splošno natural gas industries in
general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 10434
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2020
EUROPÄISCHE NORM
ICS 75.180.20 Supersedes EN ISO 10434:2004
English Version
Bolted bonnet steel gate valves for the petroleum,
petrochemical and allied industries (ISO 10434:2020)
Robinets-vannes en acier à chapeau boulonné pour les Schieber aus Stahl mit geflanschtem Oberteil für die
industries du pétrole, de la pétrochimie et les Erdöl-, petrochemische und verwandte Industrien (ISO
industries connexes (ISO 10434:2020) 10434:2020)
This European Standard was approved by CEN on 21 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 10434:2020 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 10434:2020) has been prepared by Technical Committee ISO/TC 153 "Valves"
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 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 10434:2004.
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 10434:2020 has been approved by CEN as EN ISO 10434:2020 without any modification.

INTERNATIONAL ISO
STANDARD 10434
Third edition
2020-08
Bolted bonnet steel gate valves for the
petroleum, petrochemical and allied
industries
Robinets-vannes en acier à chapeau boulonné pour les industries du
pétrole, de la pétrochimie et les industries connexes
Reference number
ISO 10434:2020(E)
©
ISO 2020
ISO 10434:2020(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
CP 401 • Ch. de Blandonnet 8
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 10434:2020(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Pressure/temperature ratings . 3
5 Design . 4
5.1 Body wall thickness . 4
5.2 Bonnet wall thickness . 5
5.3 Body dimensions . 6
5.3.1 Flanged ends . . 6
5.3.2 Butt-welding ends. 7
5.3.3 Body seats . 9
5.4 Bonnet dimensions .10
5.5 Bonnet-to-body joint.11
5.6 Gate .12
5.7 Yoke .13
5.8 Stem and stem nut .13
5.9 Packing and packing box .15
5.10 Bolting .16
5.11 Operation .16
5.12 Auxiliary connections .17
6 Materials .19
6.1 Materials other than trim materials .19
6.2 Trim materials .20
6.3 Welding for fabrication and repair .22
7 Testing, inspection and examination .23
7.1 Pressure tests .23
7.1.1 General.23
7.1.2 Shell test .23
7.1.3 Closure tightness test . .23
7.1.4 Optional backseat tightness test .25
7.1.5 Optional closure tightness test .25
7.1.6 Fugitive emission testing .25
7.2 Inspection .26
7.2.1 Extent of inspection.26
7.2.2 Site inspection .26
7.3 Examination.26
7.4 Supplementary examination .26
8 Marking .26
8.1 Legibility .26
8.2 Body marking .27
8.3 Ring joint marking .27
8.4 Identification plate marking .27
8.5 Special marking for unidirectional valves .27
9 Preparation for despatch .28
Annex A (informative) Information to be specified by the purchaser .29
Annex B (informative) Identification of valve terms .31
Annex C (informative) Valve material combinations .34
ISO 10434:2020(E)
Bibliography .38
iv © ISO 2020 – All rights reserved

ISO 10434:2020(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 69, Industrial valves, in
accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 10434:2004), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— Clause 2 “Normative references” was updated;
— higher PN and Class designations have been added, including PN 63, 160, 250 and 400;
— design and manufacturing requirements for the stem to wedge connection have been added.
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 10434:2020(E)
Introduction
The purpose of this document is to establish the basic requirements and practices for flanged and butt-
welding end steel gate valves of bolted bonnet construction that is parallel to those given in American
Petroleum Institute API Standard 600, eleventh edition.
vi © ISO 2020 – All rights reserved

INTERNATIONAL STANDARD ISO 10434:2020(E)
Bolted bonnet steel gate valves for the petroleum,
petrochemical and allied industries
1 Scope
This document specifies the requirements for a heavy-duty series of bolted bonnet steel gate valves for
petroleum refinery and related applications where corrosion, erosion and other service conditions can
indicate a need for full port openings, heavy wall sections and large stem diameters.
This document sets forth the requirements for the following gate valve features:
— bolted bonnet;
— outside screw and yoke;
— rising stems;
— non-rising handwheels;
— single or double gate;
— wedge or parallel seating;
— metallic seating surfaces;
— flanged or butt-welding ends.
It covers valves of the nominal sizes DN:
— 25; 32; 40; 50; 65; 80; 100; 150; 200; 250; 300; 350; 400; 450; 500; 600;
corresponding to nominal pipe sizes NPS:
— 1; 1¼; 1½; 2; 2½; 3; 4; 6; 8; 10; 12; 14; 16; 18; 20; 24;
applies for pressure Class designations:
— 150; 300; 600; 900; 1 500; 2 500;
and applies for pressure PN designations:
— 16, 25, 40, 63, 100, 160, 250 and 400.
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 5208, Industrial valves — Pressure testing of metallic valves
ISO 5209, General purpose industrial valves — Marking
ISO 5210, Industrial valves — Multi-turn valve actuator attachments
ISO 10434:2020(E)
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 15848-1, Industrial valves — Measurement, test and qualification procedures for fugitive emissions —
Part 1: Classification system and qualification procedures for type testing of valves
ISO 15848-2, Industrial valves — Measurement, test and qualification procedures for fugitive emissions —
Part 2: Production acceptance test of valves
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 B1.12, Class 5 Interference-Fit Thread
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 B16.25, Buttwelding Ends
ASME B16.34, Valves Flanged, Threaded and Welding End
ASME B18.2.2, Nuts for General Applications: Machine Screw Nuts, Hex, Square, Hex Flange, and Coupling
Nuts (Inch Series)
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
EN 1092-1, Flanges and their joints — Circular flanges for pipes, valves, fittings and accessories, PN
designated — Part 1: Steel flanges
EN 12516-1:2014+A1: 2018, Industrial valves — Shell design strength — Part 1: Tabulation method for
steel valve shells
MSS-SP-55, Quality Standard for Steel Castings for Valves, Flanges and Fittings, and Other Piping
Components — Visual Method for Evaluation of Surface Irregularities
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/
2 © ISO 2020 – All rights reserved

ISO 10434:2020(E)
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 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.
4.2 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.
4.3 Restrictions of temperature or pressure, for example those imposed by valve special soft seals or
special trim materials, shall be marked on the valve identification plate, see 8.4.
4.4 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.
4.5 For temperatures below the lowest temperature listed in the pressure/temperature tables (see 4.1,
4.2 and 4.3), the service pressure shall be no greater than the pressure for the lowest listed temperature.
The use of valves at lower temperatures is the responsibility of the user. Consideration should be given to
the loss of ductility and impact strength of many materials at low temperature.
4.6 Double seated valves, in some design configurations, may be capable of trapping liquid in the centre
cavity of the valve when in the closed position. If subjected to an increase in temperature, an excessive
build-up of pressure may occur leading to a pressure boundary failure. Where such condition is possible,
ISO 10434:2020(E)
it is the responsibility of the user to provide, or require to be provided, means in design, installation
or operating procedure to ensure that the pressure in the valve does not exceed that allowed by this
document for the resultant temperature.
5 Design
5.1 Body wall thickness
5.1.1 A valve body schematic is shown in Figure 1. The minimum body wall thickness, T , at the time
m
of manufacture shall be as given in Table 1, except as indicated in 5.1.2 for butt-welding valve ends.
Additional metal thickness needed for assembly stresses, stress concentrations, and shapes other than
circular shall be determined by individual manufacturers, since these factors vary widely. The body
inside diameter (Figure 1, key 3) shall not be less than that specified in Table 6 for the body seat.
Key
1 junction of body run and body neck 6 body neck
2 body end flange 7 axis of body run
3 body port inside diameter 8 butt-welding end
4 axis of body neck 9 body run
5 body/bonnet flange
Figure 1 — Identification of terms

4 © ISO 2020 – All rights reserved

ISO 10434:2020(E)
Table 1 — Minimum wall thickness for body and bonnet
PN 16 25 and 63 and ─ 160 ─ 250 ─ 400

designation 40 100
Class 150 300 600 900 ─ 1 500 ─ 2 500 ─
designation
Nominal size  Minimum wall thickness Nominal size
DN NPS
T
m
(mm)
25 6,4 6,4 7,9 12,7 7,7 12,7 8,1 15,0 12,4 1
32 6,4 6,4 8,6 14,2 8,5 14,2 9,4 17,5 14,8 1¼
40 6,4 7,9 9,4 15,0 9,7 15,0 11,4 19,1 18,3 1½
50 8,6 9,7 11,2 19,1 9,2 19,1 13,6 22,4 22,3 2
65 9,7 11,2 11,9 22,4 11,2 22,4 16,9 25,4 28,2 2½
80 10,4 11,9 12,7 19,1 13,2 23,9 20,2 30,2 34,1 3
100 11,2 12,7 16,0 21,3 15,8 28,7 42,0 35,8 42,0 4
150 11,9 16,0 19,1 26,2 22,5 38,1 61,8 48,5 61,8 6
200 12,7 17,5 25,4 31,8 29,1 47,8 81,5 62,0 81,5 8
250 14,2 19,1 28,7 36,6 35,7 57,2 101,2 67,6 101,2 10
300 16,0 20,6 31,8 42,2 42,4 66,8 121,0 86,6 121,0 12
350 16,8 22,4 35,1 46,0 49,0 69,9 140,7 — — 14
400 17,5 23,9 38,1 52,3 55,6 79,5 160,4 — — 16
450 18,3 25,4 41,4 57,2 62,3 88,9 180,2 — — 18
500 19,1 26,9 44,5 63,5 68,9 98,6 199,9 — — 20
600 20,6 30,2 50,8 73,2 82,2 114,3 239,4 — — 24
The wall thicknesses for PN 160, PN 250 and PN 400 have been taken directly from EN 12516-1.
5.1.2 The weld end preparation in butt-welding end valves (see 5.3.2) shall not reduce the body wall
thickness to less than the values specified in 5.1.1 within a region closer than T to the outside surface of
m
the body neck, measured along the run direction.
The transition to the weld preparation shall be gradual and the section shall be essentially circular
through the entire length of the transition. Sharp discontinuities or abrupt changes in section in areas
that infringe into the transition shall be avoided, except that test collars or bands, either welded or
integral, are allowed.
In no case shall the thickness be less than 0,77 T at a distance of 2 T from the weld end.
m m
5.2 Bonnet wall thickness
The minimum bonnet wall thickness at the time of manufacture, except for the neck extension that
contains the packing, shall be T as given in Table 1. For the neck extension, the local minimum wall
m
thickness shall be based on the local diameter, e.g. the inside diameter of the stem bore or packing box
bore, and shall be in accordance with Table 2.
ISO 10434:2020(E)
5.3 Body dimensions
5.3.1 Flanged ends
5.3.1.1 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.
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 resultant total flange bolting cross
sectional area is at least as great as that of the bolting being replaced.
Table 2 — Minimum wall thickness for bonnet neck extension
PN designation 16 25 and 40 63 and 100 160 250 400
Class designation 150 300 600 900 1 500 2 500
a
Bonnet neck Minimum wall thickness
extension inside (mm)
diameter
(mm)
15 2,8 3,0 3,6 4,2 5,3 7,6
16 2,8 3,1 3,6 4,4 5,6 7,9
17 2,8 3,2 3,7 4,5 5,8 8,2
18 2,9 3,5 3,9 4,7 5,9 8,5
19 3,0 3,8 4,1 5,1 6,1 8,9
20 3,3 4,0 4,2 5,2 6,3 9,2
25 4,0 4,8 4,8 6,3 7,1 11,0
30 4,6 4,8 4,8 6,5 8,2 13,1
35 4,8 4,8 5,1 7,1 9,7 14,6
40 4,9 5,0 5,7 7,5 10,2 16,4
50 5,5 6,2 6,3 7,9 11,6 19,8
60 5,6 6,4 6,8 8,9 13,4 23,2
70 5,6 6,9 7,4 9,9 15,8 26,5
80 5,8 7,2 8,1 11,0 17,4 30,1
90 6,4 7,4 8,8 12,0 19,1 33,2
100 6,4 7,7 9,5 12,8 20,8 36,7
110 6,4 8,1 10,3 14,1 22,9 40,1
120 6,6 8,6 10,9 14,9 24,8 43,5
130 7,1 8,8 11,3 16,2 26,5 46,9
140 7,1 9,2 12,0 17,3 28,3 50,2
a
See 5.2.
5.3.1.2 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 and 5;
— for Class designated valves, in accordance with ASME B16.10;
— the tolerances for all face-to-face dimensions shall be in accordance with the note in Table 5.
6 © ISO 2020 – All rights reserved

ISO 10434:2020(E)
5.3.1.3 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.
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-IX.
Integral or other types of alignment rings (centering backing rings) used to facilitate welding shall be
removed after the weld is completed.
The body to flange weld shall be given a post-weld heat treatment in accordance with Table 3. HBN is
the Brinell Hardness number.
Table 3 — Post weld heat treatment
a
Material Thickness Temperature Holding time Weld hardness
T range
(mm) (°C) (s/mm) HBN maximum
Carbon steels T > 19 593–649 144 ─
Alloy steels: All 704–746 144 225
½ % < Cr ≤ 2 % All 704–760 144 241
2¼ % ≤ Cr ≤ 10 %
Nickel alloy steels T > 19 593–635 72 ─
b
Austenitic steels All solution anneal per the material specification
Other materials All per the material specification
a
Thickness, T, is the greater thickness of the pieces being joined by welding.
b
Except when materials being welded are L-Grades or stabilized grades.
5.3.2 Butt-welding ends
5.3.2.1 Butt-welding ends for PN designated valves shall be in accordance with Figure 2 and Table 4
and butt-welding ends for Class designated valves shall be in accordance with ASME B16.25 unless
otherwise specified by the purchaser.

ISO 10434:2020(E)
a)  Welding end for connection to pipe b)  Welding end for connection to pipe
of wall thickness T ≤ 22 mm of wall thickness T > 22 mm
Key
A nominal outside diameter of welding end
B nominal inside diameter of pipe
T nominal wall thickness of pipe
Figure 2 — Welding ends
Table 4 — Butt-welding end diameters
Nominal size, DN 25 32 40 50 65 80 100 150 200 250 300 350 400 450 500 600
Nominal size, NPS 1 1¼ 1½ 2 2½ 3 4 6 8 10 12 14 16 18 20 24
diameter 35 44 50 62 75 91 117 172 223 278 329 362 413 464 516 619
A
(mm)
tolerance +2,5 / −1,0 +4 / −1
B
tolerance +1 / −1 +2 / −2 +3 / −2
(mm)
Intersections should be slightly rounded.
Valves with minimum wall thickness equal to 3 mm or less may have ends cut square or slightly chamfered. For nominal outside diameters
and wall thickness of standard pipe, see ISO 4200.
NOTE  The inside and outside surfaces of valve welding ends are machine finished. The contour within the envelope is at the option of the
manufacturer unless specifically ordered otherwise.
5.3.2.2 End-to-end dimensions for butt-welding end PN and Class designated valves shall be in
accordance with Table 5, unless otherwise specified by the purchaser.

8 © ISO 2020 – All rights reserved

ISO 10434:2020(E)
Table 5 — End-to-end dimensions for butt-welding end valves
PN 16 25 and 63 and 160 250 400

designation 40 100
Class 150 300 600 900 1 500 2 500
designation
Nominal size End-to-end dimensions Nominal size
DN (mm) NPS
25 127 165 216 254 254 308 1
32 140 178 229 279 279 349 1¼
40 165 190 241 305 305 384 1½
50 216 216 292 368 368 451 2
65 241 241 330 419 419 508 2½
80 283 283 356 381 470 578 3
100 305 305 432 457 546 673 4
150 403 403 559 610 705 914 6
200 419 419 660 737 832 1 022 8
250 457 457 787 838 991 1 270 10
300 502 502 838 965 1 130 1 422 12
350 572 762 889 1 029 1 257 — 14
400 610 838 991 1 130 1 384 — 16
450 660 914 1 092 1 219 1 537 — 18
500 711 991 1 194 1 321 1 664 — 20
600 813 1 143 1 397 1 549 1 943 — 24
NOTE  Tolerances applicable to the dimensions:
—  for DN ≤ 250: ±1,5 mm;
—  for DN > 250: ±3 mm.
5.3.3 Body seats
5.3.3.1 The inside diameter of the body seat, except for assembly drive lugs on threaded seat rings,
shall not be less than the applicable value specified in Table 6.
5.3.3.2 Integral body seats are permitted in austenitic stainless-steel valves. When an austenitic
stainless steel or a hardfacing material is used for the body seat, this material may be weld deposited
directly on the valve body. Otherwise, valve bodies shall have separate shoulder or bottom seated seat
rings that are either threaded or welded in place, except that for DN ≤ 50, rolled or pressed-in seat rings
may be used.
5.3.3.3 Body seating surfaces shall have adequate seating area and not have sharp corners at either
the inner or outer seat circumference in order to prevent galling or damage to the wedge or disc when
operated against full differential pressure.
ISO 10434:2020(E)
5.3.3.4 Sealing compounds or greases shall not be used when assembling seat ring. However, a light
lubricant having a viscosity no greater than kerosene may be used to prevent galling of mating threaded
surfaces.
Table 6 — Body seat inside diameter
PN 16 25 and 63 and 160 250 400

designation 40 100
Class 150 300 600 900 1 500 2 500
designation
Nominal size DN Minimum body seat inside diameter Nominal
(mm) size NPS
25 25 25 25 22 22 19 1
32 31 31 31 28 28 25 1¼
40 38 38 38 34 34 28 1½
50 50 50 50 47 47 38 2
65 63 63 63 57 57 47 2½
80 76 76 76 72 69 57 3
100 100 100 100 98 92 72 4
150 150 150 150 146 136 111 6
200 200 200 199 190 177 146 8
250 250 250 247 238 222 184 10
300 305 305 298 282 263 218 12
350 336 336 326 311 288 241 14
400 387 387 374 355 330 276 16
450 438 431 419 400 371 311 18
500 489 482 463 444 415 342 20
600 590 584 558 533 498 412 24
5.4 Bonnet dimensions
5.4.1 When designing the stem, gland, lantern ring (if supplied) and backseat the manufacturer shall
take into account stem guiding and the prevention of packing extrusion.
5.4.2 The bonnet shall include a conical stem backseat in one of the following forms:
— a bushing positively secured against coming loose, i.e. not relying on friction;
— an integral surface in the case of an austenitic stainless-steel valve;
— an austenitic stainless steel or hardfaced weld deposit that is a minimum of 1,6 mm thick.
5.4.3 The restrictions of 5.12.3 on tapped openings also apply to the bonnet.
5.4.4 Bonnets shall be one-piece castings or forgings subject to the same exceptions and requirements
as specified in 5.3.1.3.
5.4.5 The gland bolting shall not be anchored to the bonnet or yoke through a fillet welded attachment
or stud welded pins. The gland bolt design shall be such that during repacking the gland bolts are
positively retained.
10 © ISO 2020 – All rights reserved

ISO 10434:2020(E)
5.5 Bonnet-to-body joint
5.5.1 The bonnet-to-body joint shall be a flange and gasket type.
5.5.2 For PN 16 and for Class 150 valves, the bonnet-to-body joint shall be one of the types illustrated
in either EN 1092-1 or ASME B16.5:
— flat face;
— raised face;
— tongue and groove;
— spigot and recess;
— ring joint.
5.5.3 For PN > 16 and for Class > 150 valves, the bonnet-to-body joint shall be as in 5.5.2, except that
the flat face joint is not permitted.
5.5.4 The bonnet flange gasket shall be one of the following:
— solid metal, corrugated or flat;
— filled metal jacketed, corrugated or flat;
— metal ring joint;
— spiral wound metal gasket with filler and a centring/compression ring;
— spiral wound metal gasket with filler, to be used only in a body-to-bonnet joint design that provides
gasket compression control.
For PN 16 and Class 150, the following is also acceptable:
— flexible graphite sheet, reinforced with a stainless-steel flat, perforated, tanged or corrugated insert.
5.5.5 Valves designated PN > 16 or Class > 150 in sizes DN > 50 shall have circular bonnet-to-body
flanges.
5.5.6 Bonnet and body flange nut bearing surfaces shall be parallel to the flange face within ±1°.
Spot facing or back facing required to meet the parallelism requirement shall be in accordance with
ASME B16.5.
5.5.7 The bonnet-to-body joint shall be secured by a minimum of four through type stud bolts. The
minimum stud bolt size for each valve size shall be as follows:
— either M10 or ⅜ when 25 ≤ DN ≤ 65;
— either M12 or ½ when 80 ≤ DN ≤ 200;
— either M16 or ⅝ when 250 ≤ DN.
5.5.8 The valve bonnet bolting shall meet the requirements of either 5.5.8 a) or 5.5.8 b).
a) For Class designated valves, the cross-sectional area of the valve bonnet bolting shall, as a minimum,
meet the requirement of Formula (1):
ISO 10434:2020(E)
A
g
P ≤≤ 65,26 S 9000 (1)
c b
A
b
where
P is the pressure Class designation number, e.g. 150;
c
S is the allowable bolt stress at 38 °C, expressed in megapascals, MPa: when its value
b
is > 138 MPa, use 138 MPa;
A is the area bounded by the effective outside periphery of the gasket — except that in the
g
case of a ring joint the bounded area is defined by the pitch diameter of the ring, in mm ;
A is the total effective bolt tensile stress area, in mm .
b
b) The value of A that satisfies Formula (1) is a minimum tensile cross-sectional area requirement
b
for bonnet bolting. The manufacturer is responsible for providing additional bolting area as may
be required for valve design details such as gasket compression essentials or special service
conditions.
c) For PN designated valves, the cross-sectional area of the valve bonnet bolting shall, as a minimum,
meet the requirements of 5.5.8 a) with the substitution of P = 150 for PN 16, P = 300 for PN 25,
c c
P = 300 for PN 40 and P = 600 for PN 100.
c c
5.5.9 At assembly, 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.
5.6 Gate
5.6.1 Gate configurations are categorized as illustrated in Annex B. The types of valve gates are given in
Figure B.2.
a) A one-piece wedge gate — as either a solid or flexible wedge design — shall be furnished, unless
otherwise specified by the purchaser.
b) A two-piece split wedge gate or parallel seat double disc gate may be furnished when specified by
the purchaser. A split wedge gate consists of two independent seating parts that conform to the
body seats when closed. A double disc gate has a spreading mechanism that forces the two parallel
discs to the body seats when closed.
5.6.2 Except for a double disc gate, in the open position, the gate shall completely clear the valve seat
openings.
5.6.3 The body guides shall be designed to minimize wear of the valve, to accurately position the gate
throughout the travel into its seat and to ensure the alignment of the gate and stem in all orientations
without the gate binding or galling.
5.6.4 Gate seating surfaces shall be integral or faced with weld metal. Unless specified, hardfaced seating
surfaces are not required. Finished thickness of any welded facing material shall be not less than 1,6 mm.
5.6.5 Wedge gates shall be designed to account for closure position seat wear. The dimensions that fix
the position of the gate seats relative to the body seats shall be such that the gate, starting from the time
of manufacture, can, as a result of seat wear, move into the seats by a distance, h, defined as wear travel.
12 © ISO 2020 – All rights reserved

ISO 10434:2020(E)
Wear travel is in a direction that is parallel with the valve stem. The required minimum wear travel varies
with valve size in accordance with Table 7.
Table 7 — Minimum wear travel
Valve size range Wear travel Valve size range
DN h NPS
(mm)
25 ≤ DN ≤ 50 2,3 1 ≤ NPS ≤ 2
65 ≤ DN ≤ 150 3,3 2½ ≤ NPS ≤ 6
200 ≤ DN ≤ 300 6,4 8 ≤ NPS ≤ 12
350 ≤ DN ≤ 450 9,7 14 ≤ NPS ≤ 18
500 ≤ DN ≤ 600 12,7 20 ≤ NPS ≤ 24
5.6.6 The lower face of the wedge tee slot shall allow the stem to transmit a balanced force to the wedge.
5.7 Yoke
5.7.1 The yoke may be either an integral part of the bonnet or a separate part. The yoke shall retain the
stem nut which links the handwheel to the stem.
5.7.2 The yoke and stem
...