Ships and marine technology -- Ball valves for use in low temperature applications -- Design and testing requirements

This document specifies requirements for design, manufacture and test methods of cryogenic ball valves in order to have an excellent quality leakage stability in a very low temperature service (−196 °C to 80 °C).

Navires et technologie maritime -- Robinets à boisseau sphérique destinés aux applications à basse température -- Exigences de conception et d'essai

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Status
Published
Publication Date
28-Oct-2018
Current Stage
6060 - International Standard published
Start Date
23-Sep-2018
Completion Date
29-Oct-2018
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ISO 21157:2018 - Ships and marine technology -- Ball valves for use in low temperature applications -- Design and testing requirements
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INTERNATIONAL ISO
STANDARD 21157
First edition
2018-11
Ships and marine technology — Ball
valves for use in low temperature
applications — Design and testing
requirements
Navires et technologie maritime — Robinets à boisseau sphérique
destinés aux applications à basse température — Exigences de
conception et d'essai
Reference number
ISO 21157:2018(E)
ISO 2018
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ISO 21157:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

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Published in Switzerland
ii © ISO 2018 – All rights reserved
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ISO 21157:2018(E)
Contents Page

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

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

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

3 Terms and definitions ..................................................................................................................................................................................... 2

4 Pressure-temperature rating .................................................................................................................................................................. 3

5 Structure ....................................................................................................................................................................................................................... 3

5.1 General ........................................................................................................................................................................................................... 3

5.1.1 Structure ................................................................................................................................................................................. 3

5.1.2 Materials ................................................................................................................................................................................. 3

5.2 Design and materials of the body............................................................................................................................................ 4

5.2.1 Design ........................................................................................................................................................................................ 4

5.2.2 Materials ................................................................................................................................................................................. 4

5.2.3 Manufacturing .................................................................................................................................................................... 4

5.3 Design and materials of the extended bonnet ............................................................................................................. 5

5.3.1 Design ........................................................................................................................................................................................ 5

5.3.2 Materials ................................................................................................................................................................................. 5

5.4 Design and materials of ball ........................................................................................................................................................ 5

5.4.1 Design ........................................................................................................................................................................................ 5

5.4.2 Materials ................................................................................................................................................................................. 5

5.5 Design and materials of the stem ............................................................................................................................................ 5

5.5.1 Design ........................................................................................................................................................................................ 5

5.5.2 Materials ................................................................................................................................................................................. 5

5.6 Stem sealing ............................................................................................................................................................................................... 6

5.7 Design and materials of the seat .............................................................................................................................................. 6

5.7.1 Design ........................................................................................................................................................................................ 6

5.7.2 Materials ................................................................................................................................................................................. 6

5.8 Design and materials of bolting ................................................................................................................................................ 6

5.8.1 Design ........................................................................................................................................................................................ 6

5.8.2 Materials ................................................................................................................................................................................. 6

5.9 Requirement of operating device and actuators ........................................................................................................ 7

5.10 Surface treatment ................................................................................................................................................................................. 7

5.11 Welding and heat treatment ........................................................................................................................................................ 7

5.11.1 Welding .................................................................................................................................................................................... 7

5.11.2 Heat treatment................................................................................................................................................................... 7

5.12 Repair welding ........................................................................................................................................................................................ 8

6 Test and inspection ............................................................................................................................................................................................ 8

6.1 General ........................................................................................................................................................................................................... 8

6.2 Material test ............................................................................................................................................................................................... 8

6.3 Non-destructive inspection .......................................................................................................................................................... 8

6.3.1 General...................................................................................................................................................................................... 8

6.3.2 Radiographic testing (RT) ........................................................................................................................................ 8

6.3.3 Penetrant testing (PT) ................................................................................................................................................. 9

6.3.4 Ultrasonic testing (UT) ............................................................................................................................................... 9

6.3.5 Retest ......................................................................................................................................................................................... 9

6.3.6 Submission of inspection results ....................................................................................................................... 9

6.4 Dimension check ................................................................................................................................................................................... 9

6.5 Visual inspection ................................................................................................................................................................................10

6.6 Heat treatment inspection .........................................................................................................................................................10

6.7 Operating tests .....................................................................................................................................................................................10

6.8 Pressure test ...........................................................................................................................................................................................10

6.8.1 Pressure test in ambient temperature .......................................................................................................10

6.8.2 Test procedure and method ................................................................................................................................10

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ISO 21157:2018(E)

6.8.3 Test of cavity pressure relief ...............................................................................................................................11

6.9 Fire-resistance test (if necessary) .......................................................................................................................................11

6.10 Anti-static testing...............................................................................................................................................................................11

6.11 Cryogenic tests .....................................................................................................................................................................................11

6.11.1 General...................................................................................................................................................................................11

6.11.2 Scope of tests ....................................................................................................................................................................11

6.11.3 Test procedure ................................................................................................................................................................12

6.11.4 Submission of test result ........................................................................................................................................13

7 Marking .......................................................................................................................................................................................................................13

Annex A (informative) Examples of ball valve construction .....................................................................................................14

iv © ISO 2018 – All rights reserved
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ISO 21157:2018(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 on 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 the following

URL: www .iso .org/iso/foreword .html.

This document was prepared by Technical Committee ISO/TC 8, Ships and marine technology,

Subcommittee SC 3, Piping and machinery.

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 2018 – All rights reserved v
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INTERNATIONAL STANDARD ISO 21157:2018(E)
Ships and marine technology — Ball valves for use in
low temperature applications — Design and testing
requirements
1 Scope

This document specifies requirements for design, manufacture and test methods of cryogenic ball

valves in order to have an excellent quality leakage stability in a very low temperature service (−196 °C

to 80 °C).
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 5208, Industrial valves — Pressure testing of metallic valves
ISO 5209, General purpose industrial valves — Marking
ISO 5211, Industrial valves — Part-turn actuator attachments

ISO 28921-1, Industrial valves — Isolating valves for low-temperature applications — Part 1: Design,

manufacturing and production testing

API 6D, Specification for Pipeline Valves/ Petroleum and natural gas industries — Pipeline transportation

systems — Pipeline
API 6FA, Specification for Fire Test for Valves
ASME B16.5 Pipe Flanges and Flanged Fittings
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, Butt welding Ends
ASME B16.34:2007, Valves — Flanged, Threaded, and Welding End
Sec ASME VIII, Pressure vessels

ASTM A182/A182M, Forged or Rolled Alloy-Steel Pipe Flanges, Forged Fittings and Valves and Parts for

High-temperature Service

ASTM A193/A193M, Standard Specification for Alloy-Steel and Stainless Steel Bolting for High Temperature

or High Pressure Service and Other Special Purpose Applications

ASTM A194/A194M, Carbon and Alloy Steel Nuts and Bolts for High-Pressure and High-Temperature Service

ASTM A276, Standard Specification for Stainless Steel Bars and Shapes

ASTM A312/A312M,Standard Specification for Seamless, Welded, and Heavily Cold Worked Austenitic

Stainless Steel Pipes
ASTM A320/A320M, Alloys-Steel Bolting material for Low-Temperature service
© ISO 2018 – All rights reserved 1
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ISO 21157:2018(E)

ASTM A351/A351M, Casting, Austenitic, Austenitic-Ferritic(Duplex), for Pressure-Containing Parts

ASTM E186, Reference Radiographs for Heavy-Walled(2 to 4 1/2-in) Steel Castings
ASTM E 446, Reference Radiographs for Steel Castings up to 2in. in Thickness
MSS-SP-44. Steel pipeline flanges

MSS-SP-55. Quality Standard for steel Castings for Valves, Flanges and Fittings and other Piping

Components (Visual Method)
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:

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

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 which is 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 does not represent a measure value and shall not be used

for calculation purposes except where specified in the relevant standard.

Note 2 to entry: In those standards which use the DN designation system, any relationship between DN and

component dimensions shall be given, e.g. DN/OD or DN/ID.
3.2
nominal pressure

numerical designation relating to pressure that is a convenient round number for reference purposes

Note 1 to entry: It is intended that all equipment of the same nominal size (DN) designated by the same PN

number shall have the same mating dimensions appropriate to the type of end connections. The permissible

working pressure depends upon materials, design and working temperature and has to be selected from the

pressure/temperature rating tables in corresponding standards.
3.3
nominal pipe size
NPS

alphanumeric designation of size that is common for components used in a piping system, used for

reference purposes, comprising the letters NPS followed by a dimensionless number having an indirect

correspondence to the physical size of the bore or outside diameter of the component end connections

Note 1 to entry: The dimensionless number may be used as a size identifier without the prefix NPS. The

dimensionless number does not represent a measurable value and is not used for calculation purposes.

Note 2 to entry: Prefix NPS usage is applicable to components bearing Class designations according to ISO 7268.

3.4
class

alphanumeric designation, used for reference purposes, related to a combination of mechanical and

dimensional characteristics of a component of a pipe-work system, comprising the word “class” followed

by a dimensionless whole number
2 © ISO 2018 – All rights reserved
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ISO 21157:2018(E)
4 Pressure-temperature rating
4.1 The types of typical fluid are shown in Table 1.
Table 1 — Types of typical fluid
Type of fluid Temperature (in atmospheric pressure) Liquid density (density)
LNG (Liquefied natural gas) −163 °C to −88 °C (434 to 478) kg/m
NG (Natural gas) −160 °C to −65 °C (0,7 to 0,89) kg/m
LN2 (Liquefied nitrogen) −196 °C 804 kg/m
N2 (Nitrogen) −196 °C to −65 °C 1,184 kg/m

4.2 The valve shall be designed to operate without failure or leakage at the extreme temperature and

pressure ranges expected in service. The maximum working pressure in ambient temperature are shown

in Table 2.
Table 2 — Maximum working pressure
PN Class Maximum working pressure Note
MPa(psi)
20 150 2,0(290)
50 300 5,2(750)
in ambient temperature
64 400 6,62(960)
100 600 10,3(1 500)

NOTE The piping design condition including, but not limited to, working pressure, service temperature and

fluid is provided by the purchasers.

4.3 The manufacturers and purchasers may reach an agreement when Class exceeds 600.

4.4 Design temperature should be between −196 °C and 80 °C.
5 Structure
5.1 General
5.1.1 Structure

The ball valve is top-entry with bolted bonnet, extended bonnet type. The end connection of the body is

‘welding ends’ type or ‘flange ends’ type. A wheel or lever is used to apply the turning torque or thrust

to open or close the valve. The ball valve may be either soft-seated or metal-seated. The sealing force

can be produced by “medium piston effect” or stem pushing. If fluid trapping is possible, then the valve

is to be provided with automatic cavity-pressure relief. Configuration and functions of the ball valve

are shown in this document. If there are some differences from this document, the manufacturers can

make a decision after reaching an agreement with the purchasers. General examples of the structure of

the valve are shown in Annex A.
5.1.2 Materials

Throughout this document, materials are specified for each of the various parts of the valve. In lieu of the

materials specified, other materials may be used provided they are manufactured by the same process

as the materials specified, such as forging, casting, bar, or seamless pipe. In addition, the material shall

be suitable for the operating temperatures and pressure of the valve and the metal materials shall have

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ISO 21157:2018(E)

mechanical properties, including low temperature impact resistance, and resistance to corrosion equal

to or better than the material specified for the specific valve part.
5.2 Design and materials of the body
5.2.1 Design
The ball valve shall be supplied with minimum internal bore as per API 6D.
5.2.2 Materials

Materials are shown in Table 3. Materials for ‘welding ends’ type valves may be used for ‘Flanged ends’

type material.
Table 3 — Materials by manufacturing method
Manufacturing method Materials
Flanged ends type Welding ends type
Forging ASTM A182 F316 ASTM A182 F316L
Casting ASTM A351 CF8M ASTM A351CF3M
5.2.3 Manufacturing

The valve shall be manufactured according to the following requirements except when there are

purchaser’s special orders.
a) Face-to-face and end-to-end dimensions of the body shall satisfy ASME B16.10.

b) The minimum wall thickness shall be equal to or thicker than the values shown in ASME

B16.34:2007 6.1.
c) The end connection of the body shall be manufactured as specified below:
1) socket welding ends:

— PN20(Class 150), PN50(Class 300), PN64(Class 400): to satisfy Class 3000 in ASME

B16.11; and
— PN100(Class 600): to satisfy Class 6000 in ASME B16.11;
2) butt welding ends:

— according to the wall thickness of connected pipes which is given by the purchasers,

manufactured according to ASME B16.25; and

— the butt welding ends may add a short stub if specified in the order. The wall thickness shall

conform to the requirement of the purchasers;
3) flange ends type:

— NPS 24(DN600) and under, except NPS22(DN550): to be manufactured in accordance with

ASME B16.5; and
— NPS22(DN550): to be manufactured in accordance with MSS SP-44.
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ISO 21157:2018(E)
5.3 Design and materials of the extended bonnet
5.3.1 Design
The extended bonnet shall meet the following:

a) the minimum wall thickness shall conform to ASME B16.34:2007, 6.1, and the operation torque

produced by actuators shall be considered when determining the neck thickness;

b) the minimum bonnet extension length shall satisfy ISO 28921-1 or shall be sufficient to maintain

the stem packing at a temperature high enough to permit operation within the normal temperature

range of the packing material;

c) drip pan may be installed by welding or clamping; the welding procedure of the drip pan is beyond

the requirements of 5.11;

d) lifting points are optional; the manufacturer shall ensure the necessity of lifting points and verify

the suitability.
5.3.2 Materials
Materials are shown in Table 3 for the valve body.

If short pipe is used for the extended bonnet, it shall be seamless and made of ASTM A312 or 316L.

5.4 Design and materials of ball
5.4.1 Design

The ball shall be integral forging, casting or formed of pieces, such as 2 spherical caps and one wedge.

The top and under part shall be provided with a pivot fixing device where the ball is of a fixed type.

5.4.2 Materials

The materials of the ball shall be forging as per ASTM A182 F316. The surface of the ball or sealing part

shall be adhered with hard alloy. If overlay hard surface is selected, its thickness should be at least 1,6 mm.

5.5 Design and materials of the stem
5.5.1 Design
The stem shall be as follows.
a) It shall be of an extended type.

b) The top and under parts shall be provided with a pivot fixing device where the ball is of a fixed type.

c) The critical section of the stem shall be out of the valve pressure interface and designed with

1,5 times of the calculated operating torque.
d) The ball valve shall have an anti-static device if specified by the order.

e) The ball valve shall be designed to ensure that the stem does not eject under any internal pressure

conditions or if the packing gland components and/or valve operator mounting components are

removed.
5.5.2 Materials
Materials shall be forging or bars of ASTM A182 F316 and ASTM A276 316.
© ISO 2018 – All rights reserved 5
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ISO 21157:2018(E)
5.6 Stem sealing
The requirements for stem sealing shall be as follows.

a) The stem shall be sealed with an appropriate form and structure (e.g. stem packing, lantern ring)

to prevent leakage, and shall be easily adjustable.

b) The packing materials for stem sealing may be PTFE or other materials agreed to between the

manufacturer and the purchaser. However, packing materials shall not chemically react to the

working fluid or otherwise create physical deposits.
5.7 Design and materials of the seat
5.7.1 Design
The seat shall be as follows.

a) The whole seating surface shall contact with the ball when the ball valve is in open or closed

position.

b) A soft seated valve shall be designed to ensure that the packing does not eject or shift by internal

pressure during opening or closing.
c) The bore of the seat shall conform to API 6D.
5.7.2 Materials
The materials of the seat shall be as follows.

a) The selection and use of soft seat materials shall ensure reliable performance under working

temperature, for example PCTFE, etc.

b) Where a soft seating ring is placed in a metal circle, the metal material shall be ASTM A182 F316.

c) The base material of a metal seating ring shall be ASTM A182 F316. The seating surface needs a

hard facing treatment. The thickness of a hard surface should be at least 1,6 mm.

d) Where a seating ring contains elastic metal materials, it shall have reliable performance in low

temperature conditions, such as nickel-based alloy.
5.8 Design and materials of bolting
5.8.1 Design
The types of bolting shall be as follows.

a) The design of the body bonnet bolting shall satisfy the relevant requirements of ASME B16.34. The

minimum size should be M10.

b) The design of the actuator’s bolting shall satisfy the relevant requirements of ISO 5211.

c) The tensile stress of the packing gland bolting shall not exceed 1/3 of the maximum tensile stress

of the materials.
5.8.2 Materials
The bolting materials shall be as follows.

a) The materials of a body joint bolt shall be materials of ASTM A320 Gr.B8 Class 2 and A193 Gr.B8

Class 2 up to −196 °C. The mating nut materials shall be materials of ASTM A194 Gr. 8.

6 © ISO 2018 – All rights reserved
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ISO 21157:2018(E)

b) The materials of other bolts shall be materials of ASTM A193 Gr.B8, and the mating nut materials

shall be materials of ASTM A194 Gr. 8.
5.9 Requirement of operating device and actuators
5.9.1
...

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