SIST EN ISO 28921-2:2017

SLOVENSKI STANDARD
SIST EN ISO 28921-2:2017
01-maj-2017
1DGRPHãþD
SIST EN 12567:2001
Industrijski ventili - Zapirni ventili za uporabo pri nizki temperaturi - 2. del:
Preskušanje tipa (ISO 28921-2:2015)
Industrial valves - Isolating valves for low-temperature applications - Part 2: Type testing
(ISO 28921-2:2015)
Robinetterie industrielle - Robinets d'isolement pour application à basses températures -
Partie 2: Essais de type (ISO 28921-2:2015)
Ta slovenski standard je istoveten z: EN ISO 28921-2:2017
ICS:
23.060.01 Ventili na splošno Valves in general
SIST EN ISO 28921-2:2017 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 28921-2:2017

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SIST EN ISO 28921-2:2017


EN ISO 28921-2
EUROPEAN STANDARD

NORME EUROPÉENNE

February 2017
EUROPÄISCHE NORM
ICS 23.060.01 Supersedes EN 12567:2000
English Version

Industrial valves - Isolating valves for low-temperature
applications - Part 2: Type testing (ISO 28921-2:2015)
Robinetterie industrielle - Robinets d'isolement pour Industriearmaturen - Absperrventile für die
application à basses températures - Partie 2: Essais de Anwendung im Niedertemperaturbereich - Teil 2:
type (ISO 28921-2:2015) Typprüfung (ISO 28921-2:2015)
This European Standard was approved by CEN on 10 January 2017.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, 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: Avenue Marnix 17, B-1000 Brussels
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 28921-2:2017 E
worldwide for CEN national Members.

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SIST EN ISO 28921-2:2017
EN ISO 28921-2:2017 (E)
Contents Page
European foreword . 3

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SIST EN ISO 28921-2:2017
EN ISO 28921-2:2017 (E)
European foreword
The text of ISO 28921-2:2015 has been prepared by Technical Committee ISO/TC 153 “Valves” of the
International Organization for Standardization (ISO) and has been taken over as EN ISO 28921-2:2017
by 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 August 2017, and conflicting national standards shall
be withdrawn at the latest by August 2017.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent
rights.
EN ISO 28921-1 and EN ISO 28921-2 supersede EN 12567:2000.
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, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 28921-2:2015 has been approved by CEN as EN ISO 28921-2:2017 without any
modification.


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SIST EN ISO 28921-2:2017

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SIST EN ISO 28921-2:2017
INTERNATIONAL ISO
STANDARD 28921-2
First edition
2015-11-01
Industrial valves — Isolating valves for
low-temperature applications —
Part 2:
Type testing
Robinetterie industrielle — Robinets d’isolement pour application à
basses températures —
Partie 2: Essais de type
Reference number
ISO 28921-2:2015(E)
©
ISO 2015

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SIST EN ISO 28921-2:2017
ISO 28921-2:2015(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2015, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2015 – All rights reserved

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SIST EN ISO 28921-2:2017
ISO 28921-2:2015(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test conditions . 2
4.1 Valve selection . 2
4.2 Testing criteria and selection of valve design . 2
4.2.1 General. 2
4.2.2 Representative valve design selection. 3
4.2.3 Selection and qualification of sealing elements . 3
4.3 Requirements for test valve, direction for installation and conditions . 3
4.4 Preparation for low temperature test . 3
4.4.1 General. 3
4.4.2 Valve tests . 3
4.4.3 Test equipment . 3
5 Low temperature testing requirements . 4
5.1 Safety provisions . 4
5.2 Cooling of the valve . 4
5.3 Test gas . 4
5.4 Equipment . 4
5.4.1 General. 4
5.4.2 Test equipment . 6
5.4.3 Instruments calibration . 6
6 Information to be supplied by the purchaser. 6
Annex A (normative) Test procedure for type testing of valves at low temperature .7
Annex B (informative) Information to be supplied by the purchaser .13
Annex C (informative) Low-temperature type test record .14
Bibliography .18
© ISO 2015 – All rights reserved iii

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SIST EN ISO 28921-2:2017
ISO 28921-2:2015(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 meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is Technical Committee ISO/TC 153, Valves, Subcommittee
SC 1, Design, manufacture, marking and testing.
ISO 28921 consists of the following parts, under the general title Industrial valves — Isolating valves for
low-temperature applications:
— Part 1: Design, manufacturing and production testing
— Part 2: Type testing
iv © ISO 2015 – All rights reserved

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SIST EN ISO 28921-2:2017
INTERNATIONAL STANDARD ISO 28921-2:2015(E)
Industrial valves — Isolating valves for low-temperature
applications —
Part 2:
Type testing
WARNING — Persons using this International Standard should be familiar with normal
laboratory practice. This International Standard does not purport to address all of the safety
issues, if any, associated with its use. It is the responsibility of the user to establish appropriate
safety and health practices and to ensure compliance with any national regulatory requirements.
1 Scope
This part of ISO 28921 specifies requirements for the type testing of isolating valves for low-temperature
applications to verify the performance of valves at a low temperature from – 50 °C down to – 196 °C.
NOTE Nominal sizes (DN), nominal pipe sizes (NPS), nominal pressure (PN) and Classes are covered in
ISO 28921-1.
This part of ISO 28921 does not evaluate valve actuators unless they are integral part of the valve.
Valves during testing can be operated manually or an actuator can be used during the testing. The effect
of cold gas vapours during testing is taken into consideration in particular if the actuator is mounted
directly over the test stand with the cold gases engulfing the actuator.
This part of ISO 28921 does not apply to valves for cryogenic services, designed in accordance with
ISO 21011, used with cryogenic vessels.
2 Normative references
The following referenced documents, in whole or in part, are normatively referenced in this document
and are indispensable for its application. 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 28921-1, Industrial valves — Isolating valves for low-temperature applications — Part 1: Design,
manufacturing and production testing
ASME B31.3, Process Piping
EN 13480-2, Metallic industrial piping — Part 2: Materials
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 28921-1 and the following apply.
3.1
symmetric seated valve
valve with an internal construction which has a plane of symmetry perpendicular to the axis of the
body ends
Note 1 to entry: This is a valve where both seat sealing elements are identical.
© ISO 2015 – All rights reserved 1

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SIST EN ISO 28921-2:2017
ISO 28921-2:2015(E)

3.2
asymmetric seated valve
valve with an internal construction which has no plane of symmetry perpendicular to the axis of
the body ends
Note 1 to entry: This is a valve with a single seat offset from the shaft centreline.
3.3
design family
valves of the same type for which the basic design for the outside pressure retaining envelope, in particular
the body construction, is the same design for all sizes of the valve range and the same stem movement
Note 1 to entry: Valves of the same type include, for example, gate, globe, ball valves.
Note 2 to entry: Examples of body construction include one piece, two piece or three piece body, bonnet extension.
Note 3 to entry: Examples of stem movement include raising and not rotating.
Note 4 to entry: Valves are considered to be of the same design family if they can all be depicted on one
dimensionless cross-sectional drawing, with all the external dimensions added in a table on the same drawing.
3.4
cold working pressure
CWP
maximum fluid pressure assigned to a valve for operation at a fluid temperature up to 38 °C
3.5
operational cycle
motion of the stem that moves a valve obturator from the fully closed position to the fully open position
and returns to the fully closed position
Note 1 to entry: For check valves, an operational cycle is when the obturator moves from the closed position to
open and back to the closed position.
4 Test conditions
4.1 Valve selection
Inspection and testing under this part of ISO 28921 shall be carried out on a randomly selected
production valve of a design family and of a particular material of construction. Size selection shall be at
mid-range of the design range, the valve PN or Class shall be selected so that it qualifies all valves of the
same PN or Class and all valves of the lower PN or Class as long as the valves are of an identical design.
Valves of the same design family and the same materials of construction tested at lower temperature
qualify valves for applications at higher temperatures up to ambient temperature.
NOTE The mid-range valve size selected for testing varies with the size range available from the valve
manufacturer. For example, if the valve offering of a particular valve design is DN 50, DN 65, DN 80, DN 100,
DN 150 and DN 200 or NPS 2, NPS 2 ½, NPS 3, NPS 4, NPS 6 and NPS 8, the mid-range valve selected for testing is
DN 80 or DN 100, and for NPS valves, it is NPS 3 or NPS 4. Either of the two sizes is acceptable. Alternatively, the
size to be tested can be decided by an agreement between the manufacturer and the purchaser.
4.2 Testing criteria and selection of valve design
4.2.1 General
The test valve submitted for this type test shall be subjected to:
— 200 operational cycles for on-off valves;
— three operational cycles only, for check valves.
2 © ISO 2015 – All rights reserved

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SIST EN ISO 28921-2:2017
ISO 28921-2:2015(E)

4.2.2 Representative valve design selection
Valve selected for this type testing shall be representative for each design family of the valve type (e.g.
gate, globe, ball valve) and closure member type (e.g. single seated, double seated, unidirectional, bi-
directional).
The test valve shall be of the same design as the other valves covered by this type test as far as the body
and bonnet configuration is concerned (e.g. one piece or multiple piece body construction, integral or
bolted on bonnet and the same gaskets types between those valve parts).
4.2.3 Selection and qualification of sealing elements
The pressure retaining seals and packing in the test valve shall be of the same design and materials of
construction as all other valves covered by extension by this type test.
4.3 Requirements for test valve, direction for installation and conditions
4.3.1 Valves designed as symmetric or asymmetric seated valves, intended for the installation in both
directions shall be tested in both directions.
4.3.2 Valves designed for unidirectional sealing shall be marked outside the valve body accordingly
and shall be tested in one direction only.
4.4 Preparation for low temperature test
4.4.1 General
Valves submitted for low temperature testing shall be internally clean and free of all water, lubricants,
sealants and oils unless otherwise agreed upon between the user and the valve manufacturer. ISO 23208
may be used as a guideline for cleaning of valve components as well as assembled valves subjected to
low temperature type testing.
4.4.2 Valve tests
Shell and seat testing shall be in accordance with ISO 5208. The shell test pressure shall be 1,1 × CWP
if tested with gas or 1,5 × CWP if tested with al
...