EN ISO 15761:2002

SLOVENSKI STANDARD
01-maj-2004
Steel gate, globe and check valves for sizes DN 100 and smaller, for the petroleum
and natural gas industries (ISO 15761:2002)
Steel gate, globe and check valves for sizes DN 100 and smaller, for the petroleum and
natural gas industries (ISO 15761:2002)
Schieber, Kugel- und Rückschlagventile aus Stahl mit Nennweiten DN 100 und kleiner
für die Erdöl- und Erdgasindustrie (ISO 15761:2002)
Robinets-vannes, robinets a soupape et clapets de non-retour en acier de dimensions
DN 100 et inférieures, pour les industries du pétrole et du gaz naturel (ISO 15761:2002)
Ta slovenski standard je istoveten z: EN ISO 15761:2002
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.

INTERNATIONAL ISO
STANDARD 15761
First edition
2002-12-15
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 15761:2002(E)
ISO 15761:2002(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be
edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file,
parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters
were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event
that a problem relating to it is found, please inform the Central Secretariat at the address given below.
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's
member body in the country of the requester.
ISO copyright office
Case postale 56  CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.ch
Web www.iso.ch
Printed in Switzerland
©
ii ISO 2002 – All rights reserved

ISO 15761:2002(E)
Contents Page
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 . 4
5.3 Wall thickness . 4
5.4 Valve body . 5
5.5 Valve bonnet or cover . 9
5.6 Obturator . 10
5.7 Stem . 11
5.8 Stem nut or stem bushing . 12
5.9 Packing, packing chamber and gland . 13
5.10 Packing retention . 13
5.11 Hand wheel . 13
6 Materials . 14
6.1 Trim materials . 14
6.2 Materials other than trim . 14
7 Marking . 14
7.1 Legibility . 14
7.2 Body marking . 17
7.3 Ring joint groove marking . 17
7.4 Identification plate marking . 17
8 Testing and inspection . 17
8.1 Pressure tests . 17
8.2 Inspection . 19
9 Preparation for despatch . 19
Annexes
A Requirements for extended body gate valve bodies . 21
B Requirements for valves with bellows stem seals. 25
C Type testing of bellows stem seals. 28
D Identification of valve parts . 31
E Information to be specified by the purchaser . 34
Bibliography. 36
©
ISO 2002 – All rights reserved iii

ISO 15761:2002(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 15761 was prepared by Technical Committee ISO/TC 153, Valves, Subcommittee SC 1,
Design, manufacture, marking and testing.
Annexes A, B and C form a normative part of this International Standard. Annexes D and E are for information only.
©
iv ISO 2002 – All rights reserved

ISO 15761:2002(E)
Introduction
The purpose of this International Standard is to establish basic requirements and practices for socket-welding, butt-
welding, threaded and flanged end, steel gate, globe and check valves with reduced body seat openings, whose
[1]
general construction parallels that specified by the American Petroleum Institute standard API 602 and the British
[2]
Standard BS 5352 .
[3] [4]
The form of this International Standard corresponds to ISO 6002 and ISO 10434 . However, it is not the purpose
of this International Standard to replace ISO 6002, ISO 10434 or any other International Standard not identified with
petroleum or natural gas industry applications.
©
ISO 2002 – All rights reserved v

INTERNATIONAL STANDARD ISO 15761:2002(E)
Steel gate, globe and check valves for sizes DN 100 and smaller, for
the petroleum and natural gas industries
1 Scope
This International Standard 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,
1/4 3/8 1/2 3/4 1 1/4 1 1/2 2 1/2
— corresponding to nominal pipe sizes NPS , , , , 1, , , 2, , 3 and 4,
and to pressure designations of Class 150, Class 300, Class 600, Class 800 and Class 1500.
Class 800 is not a listed class designation, but is an intermediate class number widely used for socket welding and
threaded end compact valves.
It includes provisions for the following valve characteristics:
— outside screw with rising stems (OS&Y), in sizes 8� DN� 100 and pressure designations
150� Class� 1500 including Class 800;
— inside screw with rising stems (ISRS), in sizes 8� DN� 65 and pressure designations of Class � 800;
— socket welding or threaded ends, in sizes 8� DN� 65 and pressure designations of Class800 and
Class 1500;
— flanged or butt-welding ends, in sizes 15� DN� 100 and pressure designations of 150� Class� 1500,
excluding flanged end Class 800;
— bonnet joint construction — bolted, welded, threaded with seal weld, and union nut for nominal pressure rating
Class ;� 800
— body seat openings;
— materials, as specified;
— testing and inspection.
This International Standard is applicable to valve end flanges in accordance with ASME B16.5 and valve body ends
having tapered pipe threads to ISO 7-1 or ASME B1.20.1. It is applicable to extended body construction in sizes
15� DN� 50 and pressure designations of Class 800 and Class 1500, and to bellows and bellows assembly
construction as may be adaptable to gate or globe valves in sizes 8� DN� 50. It covers bellows stem seal type
testing requirements.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
©
ISO 2002 – All rights reserved 1

ISO 15761:2002(E)
ISO 7-1, Pipe threads where pressure-tight joints are made on the threads — Part 1: Dimensions, tolerances and
designation
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 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 6708:1995, Pipework components — Definition and selection of DN (nominal size)
ISO 9606-1, Approval testing of welders — Fusion welding — Part 1: Steels
ISO 9956-1, Specification and approval of welding procedures for metallic materials — Part 1: General rules for
fusion welding
ISO 9956-2, Specification and approval of welding procedures for metallic materials — Part 2: Welding procedure
specification for arc welding
ISO 9956-3, Specification and approval of welding procedures for metallic materials — Part 3: Welding procedure
tests for arc welding of steels
ISO 9956-4, Specification and approval of welding procedures for metallic materials — Part 4: Welding procedure
tests for the arc welding of aluminium and its alloys
ISO 9956-5, Specification and approval of welding procedures for metallic materials — Part 5: Approval by using
approved welding consumables for arc welding
EN 10269, Steels and nickel alloys for fasteners with specified elevated and/or low temperature properties
1)
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
ASME B16.10, Face-to-face and end-to-end dimensions of valves
ASME B16.34:1996, Valves — Flanged, threaded and welding end
ASME, Boiler and Pressure Vessel Code, Section IX, Qualification standard for welding and brazing procedures,
welders, brazers, and welding and brazing operators
ASTM A193, Standard specification for alloy-steel and stainless steel bolting materials for high-temperature service
1) American Society of Mechanical Engineers
©
2 ISO 2002 – All rights reserved

ISO 15761:2002(E)
ASTM A194, Standard specification for carbon and alloy steel nuts for bolts for high-pressure or high-temperature
service, or both
ASTM A307, Standard specification for carbon steel bolts and studs, 60 000 PSI tensile strength
3 Terms and definitions
For the purposes of this International Standard, the terms and definitions of class and nominal pipe size given in
2)
ASME B16.34 and the following term and definition apply.
3.1
nominal size
DN
alphanumeric designation of size for components of a pipe work system, used for reference purposes, comprising
the letters “DN” followed by a dimensionless whole number indirectly related to the physical size, in millimetres, of the
bore or outside diameter of the end connections
NOTE 1 The number following “DN” does not represent a measurable value and should not be used for calculation purposes
except where specified in the relevant standard.
NOTE 2 In those standards which use the DN designation system, any relationship between DN and component dimensions
should be given, e.g. DN/OD or DN/ID.
(Adapted from ISO 6708:1995, definition 2.1.)
4 Pressure/temperature ratings
4.1 Valve ratings
4.1.1 Applicability
The pressure/temperature ratings applicable to valves specified in this International Standard shall be in accordance
with those specified in the tables of ASME B16.34 for standard class for the applicable material specification and
class designation.
4.1.2 Interpolated ratings
Pressure/temperature ratings for Class 800 shall be determined by the equation:
1 2
p = p + p
8 6 9
3 3
where
3)
p is the pressure at the specified temperature, expressed in bars , 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 bars;
p is the listed pressure, at the specified temperature, for Class 900, expressed in bars.
2) Pressure designation Class 800 has been added in order to identify widely used socket welding and threaded end valves
having intermediate pressure/temperature ratings. It is not available for flanged end valves.
5 2
3) 1 bar= 0,1 MPa= 10 Pa; 1 MPa = 1 N/mm
©
ISO 2002 – All rights reserved 3

ISO 15761:2002(E)
NOTE Pressure designation Class 900 is not specifically referenced in this International Standard 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.
5Design
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, has a conical disc. The reference design for threaded-end valves uses taper pipe
threads in accordance with ASME B1.20.1. In addition, for valves DN� 50, the reference design is to have a body
and bonnet or cover of 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 are given in annex A and those for bellows stem seals in annexes B and C.
5.2 Flow passageway
5.2.1 The flow passageway includes the seat opening and the body ports leading to that opening. 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. The minimum equivalent flow passageway cross-sectional area shall not be less than that
obtained using the equivalent diameters in Table 1.
5.3 Wall thickness
5.3.1 Minimum wall thickness values for valve bodies and bonnets are given in Tables 2 and 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 The valve-body specified minimum wall thickness, except for the valve end connections and body extensions
for bellows enclosures, shall be in accordance with Table 2.
5.3.3 The bonnet specified 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 2. The packing chamber extension shall have
a local minimum wall thickness as specified in Table 3, based on the local inside diameter of the packing and stem
hole.
©
4 ISO 2002 – All rights reserved

ISO 15761:2002(E)
Table 1 — Minimum diameter of equivalent flow passageway
Minimum diameter
mm
DN NPS
Class 150, Class 300, Class 600, Class 800 Class 1500
Gate, globe or check Gate Globe
8665 1/4
10 6 6 5 3/8
15 9 9 8 1/2
20 12 12 9 3/4
25 17 15 14 1
32 23 22 20 1 1/4
40 28 27 25 1 1/2
50 36 34 27 2
65 44 38 2 1/2
80 50 47 3
100 70 63 4
Table 2 — Minimum wall thickness for valve bodies
Minimum wall thickness
DN mm NPS
Class 150, Class 300, Class 600, Class 800 Class 1500
83,1 3,8 1/4
10 3,3 4,3 3/8
15 4,1 4,8 1/2
20 4,8 6,1 3/4
25 5,6 7,1 1
32 5,8 8,4 1 1/4
40 6,1 9,7 1 1/2
50 7,1 11,9 2
65 8,4 14,2 2 1/2
80 9,7 16,5 3
100 11,9 21,3 4
NOTE Wall thickness values listed for Class 150, Class 300, and Class 600 are those required for Class 800
on the assumption that flanged end and butt-welding end valve bodies of these lower nominal pressures would
have extensions added (integral or welded) to Class800 valve bodies. See ISO6002, ISO10434, or
ASME B16.34 for flanged end or butt-welding end valves having wall thickness requirements aligned to these
lower nominal pressures.
5.4 Valve body
5.4.1 General
Requirements for a basic valve body and associated end connections are given here. See annex A for requirements
for gate valve bodies having extended ends.
©
ISO 2002 – All rights reserved 5

ISO 15761:2002(E)
Table 3 — Minimum wall thickness for bonnet and bellows extensions
Extension Class 150 Class 300 Class 600 Class 800 Class 1500
Inside diameter Minimum wall thickness
mm mm
15 2,8 3,0 3,6 4,0 5,3
16 2,8 3,1 3,6 4,1 5,6
17 2,8 3,2 3,7 4,3 5,8
18 2,9 3,5 3,9 4,4 5,9
19 3,0 3,8 4,1 4,8 6,1
20 3,3 4,0 4,2 4,9 6,3
25 4,0 4,8 4,8 5,8 7,1
30 4,6 4,8 4,8 5,9 8,2
35 4,8 4,8 5,1 6,4 9,7
40 4,9 5,0 5,7 6,9 10,2
50 5,5 6,2 6,3 7,4 11,6
60 5,6 6,4 6,8 8,2 13,4
70 5,6 6,9 7,4 9,1 15,8
80 5,8 7,2 8,1 10,0 17,4
90 6,4 7,4 8,8 10,4 19,1
100 6,4 7,7 9,5 11,7 20,8
110 6,4 8,1 10,3 12,8 22,9
120 6,6 8,6 10,9 13,6 24,8
130 7,1 8,8 11,3 14,6 26,5
140 7,1 9,2 12,0 15,5 28,3
NOTE For bellows extension, see B.4.
5.4.2 Socket-welding ends
5.4.2.1 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 4.
Table 4 — Socket diameter and depth
a b
Diameter Depth
DN NPS
mm
814,1 10 1/4
10 17,6 10 3/8
15 21,7 10
1/2
20 27,0 13 3/4
25 33,8 13 1
32 42,5 13
1 1/4
40 48,6 13 1 1/2
50 61,1 16 2
65 73,8 16 2 1/2
+0,5
a
mm
The applicable diametral tolerance is .
−0
b
The depth dimension is a minimum value.
©
6 ISO 2002 – All rights reserved

ISO 15761:2002(E)
5.4.2.2 The minimum socket wall thickness, extending over the full socket depth, shall be in accordance with
Table 5.
Table 5 — Socket and threaded end minimum wall thickness
Minimum wall thickness
DN mm NPS
Class 800 Class 1500
83,3 4,1 1/4
10 3,6 4,3 3/8
15 4,1 5,3 1/2
20 4,3 6,1 3/4
25 5,1 6,9 1
32 5,3 8,1 1 1/4
40 5,8 8,9 1 1/2
50 6,9 10,7 2
65 7,9 12,4 2 1/2
5.4.2.3 End-to-end dimensions for socket welding end valves shall 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 5. 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 meeting the requirements of ASME B1.20.1. When specified in
the purchase order, taper pipe threads in accordance with ISO 7-1 may be substituted.
5.4.3.3 Threads shall be gauged in accordance with ISO 7-2 or ASME B1.20.1, as applicable.
5.4.3.4 End-to-end dimensions for threaded end valves shall be established by the manufacturer.
5.4.4 Flanged ends
5.4.4.1 End flanges shall comply with the dimensional requirements of ASME B16.5. Unless otherwise specified,
raised face end flanges shall be provided.
This International Standard does not provide for flanged ends for Class 800 valves.
5.4.4.2 End flanges and bonnet flanges shall be cast or forged integral with the body, except that cast or forged
flanges attached by full penetration butt-welding or by inertia welding may be used. A purchaser requiring an integral
flange body shall so specify. When a flange is attached by welding, the welding operator and welding procedure shall
be qualified in accordance with ISO 9606-1 and ISO 9956-1 to ISO 9956-5, or ASME-BPVC, Section IX. Alignment
rings, integral or loose, used as a welding aid shall be completely removed following welding, while care shall be
taken that the minimum wall thickness is maintained. 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 the
material specification.
5.4.4.3 Face-to-face dimensions for flanged end valves, Class150, Class300 and Class600, shall be in
accordance with ISO 5752 — Basic Series 3, 4 and 5 for gate valves, and 5, 10 and 21 for globe and check valves —
except that the applicable tolerance shall be in accordance with Table 6. For Class 1500, the face-to-face dimensions
shall be as shown in Table 6.
©
ISO 2002 – All rights reserved 7

ISO 15761:2002(E)
Table 6 — Face-to-face dimensions for Class 1500
Dimensions
DN NPS
mm
15 216 1/2
20 229 3/4
25 254 1
32 279 1 1/4
40 305 1 1/2
50 368 2
65 419 2 1/2
80 470 3
100 546 4
The applicable length tolerance shall be ± 1,6 mm (see 5.4.4.3).
NOTE These dimensions and tolerances are in accordance with ASME B16.10.
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 7.
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.
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 hard
facing material may be weld-deposited either directly on a valve body or on a separate body seat ring. Weld-
deposited seating surfaces shall have a minimum finished facing material thickness of 1mm. 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 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 be in accordance with Table 1.
©
8 ISO 2002 – All rights reserved

ISO 15761:2002(E)
Dimensions in millimetres
Key
A is the nominal outside diameter of the welding end.
B is the nominal inside diameter of the pipe.
T is the nominal wall thickness of the pipe.
Figure 1 — Butt-welding ends
Table 7 — Butt-welding end diameters
DN 8 101520 25 32405065 80 100
A
15 19 23 28 35 44 50 62 78 91 117
mm
The tolerance for diameter A shall be ±1mm for DN� 20 and +2,5/−1mm for DN� 25.
The tolerance for diameter B shall be ±1mm (see Figure 1).
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 the
requirements of 5.5.2 to 5.5.8, by one of the following methods:
— bolting;
— welding;
— threaded with a seal weld;
— threaded union nut, provided it is of 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 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 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 of type 18Cr-8Ni or 18Cr-8Ni-Mo and of either regular or low carbon grade.
©
ISO 2002 – All rights reserved 9

ISO 15761:2002(E)
◦
5.5.4 Bonnet and body flange bolting bearing surfaces shall be parallel to the flange face within 1 . Spot facing or
back facing required to meet this requirement shall be in accordance with ASME B16.5.
5.5.5 A bolted bonnet or cover to the body joint shall be secured by a minimum of four cap screws, studs or stud
bolts. Internal socket head cap screws shall not be used. The minimum bolt size permitted is M10 (or 3/8 in).
5.5.6 The bolting shall, as a minimum, meet the following bolt cross-sectional area requirements:
A
g
P � 65,25S � 9 000
c b
A
b
where
◦
S is the allowable bolt stress at 38 C, expressed in megapascals (when > 138 MPa, use 138 MPa);
b
P is the class designation number, e.g. Class 800;
c
A is the area bounded by the effective outside periphery of the gasket, expressed in square millimetres;
g
A is the total effective bolt tensile stress area, expressed in square millimetres.
b
A
The value of is a minimum tensile cross-sectional area requirement for bonnet bolting. The manufacturer is
b
responsible for providing additional bolting area as may be required for valve design details such as gasket
compression essentials or specified service conditions.
5.5.7 Threaded pressure-retaining joints shall, as a minimum, meet the following thread shear area requirements:
A
g
P � 4 200
c
A
s
where A is the total effective thread shear stress area, expressed in square millimetres.
s
This is a minimum requirement for thread shear area for all pressure retaining joints including threaded bonnet joints.
The manufacturer is responsible for providing any additional thread engagement as may be required for valve design
details such as gasket compression essentials or specified service conditions.
5.5.8 Bonnets welded directly to valve bodies shall be secured by a full penetration weld having two or more welding
passes (layers). The welding operator and welding procedure shall be in accordance with 6.2.3. Heat treatment
following welding shall be performed as required by the material specification.
5.6 Obturator
5.6.1 Seating surfaces
Obturator seating surfaces shall be integral or have a facing of weld metal. Weld-deposited seating surfaces shall
have a minimum finished facing material thickness of 1mm.
5.6.2 Gate valve obturators
5.6.2.1 Gate valves shall be provided with a one-piece wedge gate. The installed wedge gate outer seating surfaces
shall be free of sharp edges so as not to score or gouge the body seating surfaces during opening or closing.
5.6.2.2 A slot near the top of the wedge gate shall be provided to receive the button or tee-head stem connection.
The wedge gate shall be guided in the body in a manner that prevents rotation and leads the gate re-entry between
the seats.
©
10 ISO 2002 – All rights reserved

ISO 15761:2002(E)
5.6.2.3 The wedge gate shall be designed to account for seat wear. The dimensions that fix the position of the
wedge gate seats relative to the body seats shall be such that the wedge gate, starting from the time when the valve
is new, can move into the seats, should the seats wear, a distance defined as wear travel. Wear travel is in a direction
parallel with the valve stem. The required minimum wear travel, h , varies with valve size in accordance with Table 8.
w
Table 8 — Wear travel distance for gate valve disks
Minimum wear travel
distance h
w
DN NPS
mm
8� DN� 20 1 1/4� NPS� 3/4
25� DN� 32 1,5 1� NPS� 1 1/4
40� DN� 65 2 1 1/2� NPS� 21/2
80� DN� 100 3 3� NPS� 4
5.6.3 Globe valve obturators
5.6.3.1 Globe valves shall be provided with disks that are non-integral with the stem. The disk shall have a conical
(plug) seating face or, when specified by the purchaser, a flat seating face.
5.6.3.2 When assembled, the globe valve disk-to-stem retaining design shall be such that the disk cannot become
detached from the stem as a result of vibration emanating from either flow through the valve or attached piping
movement. The means of disk-to-stem retention shall be of a design that allows the disk to align with the valve seat.
5.6.4 Check valve obturators
5.6.4.1 Check valves shall be provided with either piston, ball or swing type obturators.
5.6.4.2 Piston type and ball type check valve obturators shall be guided over the full length of their travel. The guide
and disk combination shall be designed so that a damping of the movement occurs towards the top end of the disk
travel.
5.6.4.3 Piston check and ball check valves shall be designed so that, when in the fully opened position, the net flow
area between the obturator and the body seat is greater than or equal to that of the seat opening corresponding to
the seat diameter shown in Table 1.
5.6.4.4 Obturator-to-hinge retaining nuts shall be positively secured by mechanical means.
5.7 Stem
5.7.1 Stems are designated as either inside screw (ISRS) or outside screw (OS & Y). The reference standard
design is OS & Y. Stems with inside screw shall be limited to gate and globe valves having pressure designation
Class � 800 in the nominal size range 8� DN� 65.
5.7.2 The minimum stem diameter, d , for gate and globe valves, measured where the stem passes through the
S
packing, shall be in accordance with Table 9. These are specified minimum values, not design minimum values. The
manufacturer, taking into account the stem material, the valve design and the specified operating conditions, is
responsible for determining if a larger diameter stem is required.
5.7.3 The stem shall be one-piece wrought material. Stems fabricated by welding are not permitted. The stem
surface that passes through the packing shall have a surface finish value of Ra� 0,80µm.
©
ISO 2002 – All rights reserved 11

ISO 15761:2002(E)
Table 9 — Minimum stem diameter
Minimum stem diameter, d
s
mm
DN NPS
Class 150, Class 300, Class 600, Class 800 Class 1500
Gate or globe Gate Globe
8 7,0 10,0 10,0 1/4
10 7,0 10,0 10,0 3/8
15 8,5 10,0 10,0 1/2
20 9,5 11,0 11,0 3/4
25 11,0 14,0 14,0 1
32 12,5 15,5 15,5 1 1/4
40 14,5 15,5 15,5 1 1/2
50 16,0 16,5 16,5 2
65 17,5 19,0 — 2 1/2
80 19,0 25,0 — 3
100 22,0 28,5 — 4
5.7.4 The stem threads shall be of trapezoidal form in accordance with ISO 2902, ISO 2903 and ISO 2904, or
ASME B1.5 and ASME B1.8, with nominal dimensional variations allowed. Stem threads shall be such that a direct
operated hand wheel rotated in a clockwise direction will close the valve. The major diameter of the stem threads
shall not be less than 1,5 mm below that of the actual stem diameter (see 5.7.2).
5.7.5 The means of stem-to-obturator attachment shall be designed so as to prevent the stem from becoming
disengaged from the obturator while the valve is in service. For attachment to the obturator, the stem shall have an
integral tee for outside stem thread gate valves and an integral cylindrical button for inside stem thread gate valves
and for all globe valves. Threaded or pinned stem attachment means shall not be used.
5.7.6 Valve stems, except those used in globe valves where the backseat function is with a disk component, shall
include a conical or spherical raised surface that will seat against the bonnet backseat when the obturator is at its full
open position. A back seating arrangement is a requirement for all gate and globe valves and, as such, is not meant
to imply a manufacturer's recommendation for use for the purpose of adding or replacing packing while the valve is
under pressure.
5.7.7 Gate valve stem design shall be such that, for valves with outside screw stems, the strength of the stem-to-
wedge gate connection and the part of the stem within the valve pressure boundary shall, under axial load, exceed
the strength of the stem at the root of the operating thread. For both outside and inside screw valves, the design of
the stem, wedge gate and stem connection to the wedge gate shall be such that, were mechanical failure to occur, it
would do so at a stem section outside the valve pressure boundary.
5.7.8 The means of stem disk attachment in globe valves shall be such that the disk articulates in order to permit
alignment with the seat. The stem thrust point against the disk shall be rounded and the disk components making up
the means of disk-to-stem assembly attachment shall be positively secured to prevent loosening due to fluid or piping
induced vibration.
5.8 Stem nut or stem bushing
5.8.1 The internal thread in the stem nut (yoke sleeve or stem bushing) shall be of trapezoidal form in accordance
with ISO 2902, ISO 2903 and ISO 2904, or ASME B1.5 and ASME B1.8, with nominal dimensional variations
permitted.
5.8.2 The fixed stem nut used in globe valves shall be threaded or otherwise fitted onto the yoke and positively
locked in position.
©
12 ISO 2002 – All rights reserved

ISO 15761:2002(E)
5.9 Packing, packing chamber and gland
h
5.9.1 The minimum uncompressed total height of the installed packing, , shall be in accordance with Table 10.
p
The packing height values in Table 10 are directly related to the stem diameters shown in Table 9. When a stem
diameter greater than that of Table 9 is used, the manufacturer shall determine if the uncompressed packing height
needs to be increased.
Table 10 — Minimum uncompressed packing height
Minimum uncompressed packing height, h
p
DN mm NPS
Class 150, Class 300, Class 600, Class 800 Class 1500
812 22 1/4
10 12 22 3/8
15 15 22 1/2
20 15 25 3/4
25 25 30 1
32 25 38 1 1/4
40 28 38 1 1/2
50 28 38 2
65 31 44 2 1/2
80 38 47 3
100 44 50 4
5.9.2 The packing chamber bore shall have a surface finish, Ra, of 3,2µm or smoother. The bottom of the packing
chamber shall be flat.
5.9.3 A gland shall be provided for packing compression. The gland may be either a self-aligning gland or an
integral part of the gland flange. The outer end of a separate gland shall have a lip whose outer diameter exceeds the
diameter of the packing chamber bore so as to block its entry into the bore.
5.9.4 Packing in the form of a single-piece spiral shall not be used.
5.10 Packing retention
5.10.1 Packing and packing gland retention for valves with outside screw stems shall be by bolting through two
holes in a gland flange that is either separate from, or integral to, the gland. Open gland flange bolt slots shall not be
used.
5.10.2 Gland flange bolts shall be hinged eyebolts, headed bolts, stud bolts or studs. Hexagon nuts shall be used.
The gland flange bolting arrangement shall be such that the bolts, after removal of the packing adjustment nuts,
remain connected to the valve.
5.10.3 The gland bolting for gate and globe valves shall not be anchored to the bonnet or yoke through a fillet
welded attachment or stud welded pins. The gland bolting design shall be such that during repacking the gland bolts
will be positively retained.
5.10.4 Packing and packing gland retention for valves with inside screw stems shall be by a packing nut threaded
directly onto the valve bonnet or in accordance with 5.10.1, 5.10.2 and 5.10.3. For application restrictions applying to
inside screw stem threads, see 5.7.
5.11 Hand wheel
5.11.1 Gate and globe valves shall be supplied with direct operated hand wheels that close the valve when turned
in a clockwise direction.
©
ISO 2002 – All rights reserved 13

ISO 15761:2002(E)
5.11.2 The hand wheel shall be a spoke and rim design that makes an effective grip possible.
5.11.3 The hand wheel shall be secured to the stem or stem nut by a threaded hand wheel nut.
6Materials
6.1 Trim materials
6.1.1 Trim items include the stem, the obturator seat surfaces and the body or seat ring seat surfaces. The trim
materials shall be in accordance with Table 11, unless other materials are agreed upon between the purchaser and
manufacturer. The trim combination number (CN) identifies both the stem material and the associated seating
surface material.
6.1.2 Trims of free machining grades of 13Cr steel (grades containing additions of elements such as lead, selenium
or sulfur to enhance machinability) are intentionally not listed in Table 11. They may be used only when specified by
the purchaser, in which case they would be identified by the appropriate trim number from Table 11 plus 100. The
affected trim CN numbers would thus be identified as CN101, 104, 105, 105A, 106, 107, 108 and 108A.
Correspondingly, HF or other material overlays shall not be applied to free machining grades of 13Cr steel unless
specified by the purchaser.
6.1.3 The trim material shall be the manufacturer's standard trim material corresponding to a listed trim CN, unless
otherwise specified in the purchase order. For a specified CN in a purchase order, an alternative CN may be
furnished in accordance with Table 12. It is not permissible to furnish a listed specified CN when an alternative CN is
specified in a purchase order without the agreement of the purchaser.
6.2 Materials other than trim
6.
...