prEN ISO 21011

Cryogenic vessels - Valves for cryogenic service

This document specifies the requirements for the design, manufacture and testing of valves for a rated temperature of -40 °C and below (cryogenic service), i.e. for operation with cryogenic fluids in addition to operation at temperatures from ambient to cryogenic.
It applies to all types of cryogenic valves, including vacuum jacketed cryogenic valves up to size DN 150.
This document is not applicable to pressure relief valves covered by ISO 21013-1 or EN

Kryo Behälter - Ventile für den Kryo Betrieb

Dieses Dokument legt die Anforderungen an die Konstruktion, Herstellung und Prüfung von Absperrarmaturen bei einer Bemessungstemperatur von −40 °C (Kryo-Betrieb) fest, d. h. für den Betrieb mit tiefkalten Fluiden zusätzlich zum Betrieb bei Umgebungstemperaturen bis zu tiefkühlen Temperaturen.
Es gilt für alle Arten von tiefkalten Absperrarmaturen, einschließlich vakuum-isolierter Absperrarmaturen mit Nennweiten bis DN 200. Dieses Dokument kann als Anleitung für Absperrarmaturen mit größeren Nennweiten angewendet werden. Dieses Dokument gilt nicht für in ISO 21013-1 enthaltene Druck-Ablass-Einrichtungen.

Récipients cryogéniques - Robinets pour service cryogénique

Kriogene posode - Ventili za kriogeno območje (ISO/DIS 21011:2021)

General Information

• Status: Not Published
• Publication Date: 26-Oct-2023
• ICS: 23.020.40 - Cryogenic vessels
• Technical Committee: CEN/TC 268 - Cryogenic vessels
• Drafting Committee: CEN/TC 268 - Cryogenic vessels
• Current Stage: 3098 - Decision to reject - Consensus building
• Completion Date: 11-Jun-2020
• Directive: 2008/68/EC - Directve 2008/68/EC of the European Parliament and of the council of 24 September 2008 on the inland transport of the dangerous goods
• Directive: 2014/68/EU - Directive 2014/68/EU of the European Parliament and of the Council of 15 May 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of pressure equipment
• Directive: 94/55/EC - Transport of dangerous goods by road
• Directive: 96/49/EC - Transport of dangerous goods by rail
• Directive: 96/86/EC - Transport of dangerous goods by road (94/55/EC Dir. amendment)
• Directive: 96/87/EC - Transport of dangerous goods by rail (96/49/EC Dir. amendment)
• Mandate: M/071 - Mandate to CEN for standardization in the field of Pressure equipment
• Ref Project: oSIST prEN ISO 21011:2021 - Cryogenic vessels - Valves for cryogenic service (ISO/DIS 21011:2021)

Relations

• Revises: EN 1626:2008 - Cryogenic vessels - Valves for cryogenic service
• Effective Date: 19-Jan-2023

Standards Content (Sample)

SLOVENSKI STANDARD
oSIST prEN ISO 21011:2021
01-maj-2021
Kriogene posode - Ventili za kriogeno območje (ISO/DIS 21011:2021)
Cryogenic vessels - Valves for cryogenic service (ISO/DIS 21011:2021)
Kryo-Behälter - Ventile für den Kryo-Betrieb (ISO/DIS 21011:2021)
Récipients cryogéniques - Robinets pour usage cryogénique (ISO/DIS 21011:2021)
Ta slovenski standard je istoveten z: prEN ISO 21011
ICS:
23.020.40 Proti mrazu odporne posode Cryogenic vessels
(kriogenske posode)
23.060.01 Ventili na splošno Valves in general
oSIST prEN ISO 21011:2021 en,fr,de

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

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oSIST prEN ISO 21011:2021
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oSIST prEN ISO 21011:2021
DRAFT INTERNATIONAL STANDARD
ISO/DIS 21011
ISO/TC 220 Secretariat: AFNOR
Voting begins on: Voting terminates on:
2021-03-22 2021-06-14
Cryogenic vessels — Valves for cryogenic service
ICS: 23.020.40
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 21011:2021(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. ISO 2021
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oSIST prEN ISO 21011:2021
ISO/DIS 21011:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

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

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
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Phone: [phone]
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Published in Switzerland
ii © ISO 2021 – All rights reserved
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oSIST prEN ISO 21011:2021
ISO/DIS 21011:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

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

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

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Requirements .......................................................................................................................................................................................................... 4

4.1 Materials ....................................................................................................................................................................................................... 4

4.1.1 General...................................................................................................................................................................................... 4

4.1.2 Metallic materials ............................................................................................................................................................ 4

4.1.3 Non-metallic materials ............................................................................................................................................... 4

4.1.4 Corrosion resistance ..................................................................................................................................................... 4

4.1.5 Gas material compatibility ...................................................................................................................................... 5

4.2 Design ............................................................................................................................................................................................................. 5

4.2.1 General...................................................................................................................................................................................... 5

4.2.2 Packing gland ...................................................................................................................................................................... 6

4.2.3 Operating positions ....................................................................................................................................................... 6

4.2.4 Cavities ..................................................................................................................................................................................... 6

4.2.5 Valve bonnet ........................................................................................................................................................................ 6

4.2.6 Securing of gland extension ................................................................................................................................... 6

4.2.7 Seat .............................................................................................................................................................................................. 6

4.2.8 Stem securement ............................................................................................................................................................. 6

4.2.9 Torque ....................................................................................................................................................................................... 7

4.2.10 Electric continuity and explosion proofness ........................................................................................... 7

4.2.11 Fire resistance .................................................................................................................................................................... 7

5 Testing ............................................................................................................................................................................................................................. 7

5.1 Type approval .......................................................................................................................................................................................... 7

5.1.1 Verification of the design .......................................................................................................................................... 7

5.1.2 Model number .................................................................................................................................................................... 7

5.1.3 Type approval tests........................................................................................................................................................ 7

5.2 Production tests ..................................................................................................................................................................................... 9

5.3 Test report ................................................................................................................................................................................................... 9

6 Cleanliness .................................................................................................................................................................................................................. 9

7 Marking .......................................................................................................................................................................................................................... 9

7.1 Marking on the body of the valve ............................................................................................................................................ 9

7.2 Marking on an identification plate ......................................................................................................................................10

Annex A (informative) Recommended methods for leak tightness testing of cryogenic valves ..........11

Annex B (informative) Thermal shock test for valves used in LNG service ...............................................................13

Annex ZA (informative) Relationship between this European Standard and the essential

requirements of Directive 2014/68/EU (Pressure Equipment Directive) aimed to

be covered ......... ........................................................................................................................................................................................................14

Bibliography .............................................................................................................................................................................................................................15

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oSIST prEN ISO 21011:2021
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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 220, Cryogenic vessels,

This second edition cancels and replaces the first edition (ISO 21011:2008), which has been technically

revised.
The main changes compared to the previous edition are as follows:
— Update of the scope;
— Clarification of the use of pressure units;
— Revision of the type approval tests;
— Revision of Clause 7 Marking.

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.
iv © ISO 2021 – All rights reserved
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oSIST prEN ISO 21011:2021
DRAFT INTERNATIONAL STANDARD ISO/DIS 21011:2021(E)
Cryogenic vessels — Valves for cryogenic service
1 Scope

This document specifies the requirements for the design, manufacture and testing of valves for a rated

temperature of −40 °C and below (cryogenic service), i.e. for operation with cryogenic fluids in addition

to operation at temperatures from ambient to cryogenic.

It applies to all types of cryogenic valves, including vacuum jacketed cryogenic valves up to size DN

200. This document can be used as guidance for larger size valves. This document is not applicable to

pressure relief valves covered by ISO 21013-1.
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 5208:2015, Industrial valves — Pressure testing of metallic valves

ISO 10434:2020, Bolted bonnet steel gate valves for the petroleum, petrochemical and allied industries

ISO 10497:2010, Testing of valves — Fire type-testing requirements

ISO 15761:2020, Steel gate, globe and check valves for sizes DN 100 and smaller, for the petroleum and

natural gas industries

ISO 17292:2015, Metal ball valves for petroleum, petrochemical and allied industries

ISO 21010:2017, Cryogenic vessels — Gas/material compatibility

ISO 21028-1:2016, Cryogenic vessels — Toughness requirements for materials at cryogenic temperature —

Part 1: Temperatures below -80 degrees C

ISO 21028-2:2018, Cryogenic vessels — Toughness requirements for materials at cryogenic temperature —

Part 2: Temperatures between -80 degrees C and -20 degrees C
ISO 23208:2017, Cryogenic vessels — Cleanliness for cryogenic service
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/
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3.1
nominal size
DN or NPS

alphanumeric designation of size for components of a pipe work system, which is used for reference

purposes.

Note 1 to entry: It comprises the letters “DN” or “NPS” followed by a dimensionless whole number or fractional

number which is indirectly related to the physical size of the bore or outside diameter of the end connections.

3.2
rated pressure PR

maximum pressure difference between the inside and outside of any pressure retaining boundary for

which the boundary is designed to be operated at 20 °C

Note 1 to entry: The PR of the valve is the lowest PR of any component of the valve.

3.3
PN or Class

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

and which comprises the letters PN or Class followed by the appropriate reference number

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

PN or Class number has compatible mating dimensions.

Note 2 to entry: Tables of pressure/temperature ratings in the appropriate standards provide guidance on the

maximum allowable pressure subject to materials, design and working temperature;
3.4
rated minimum temperature
lowest temperature for which the valve is rated by the manufacturer
3.5
valve category A
valves intended to be operated with normal frequency (above 20 cycles a year)
Note 1 to entry: See 5.1.3.3.
3.6
valve category B

valves intended to be operated only occasionally i.e. with a frequency below 20 cycles a year

Note 1 to entry: See 5.1.3.3.
3.7
flow coefficient

basic coefficient used to state the flow capacity of a valve under specified conditions

Note 1 to entry: Flow coefficients in current use are Kv and Cv depending upon the system of units.

Note 2 to entry: Even though the dimensions and units used with flow coefficient Kv differ from those used with

flow coefficient Cv, it is possible to relate the two flow coefficients numerically by means of the relationship.

KC=0,865

Note 3 to entry: The flow coefficient definitions given in 3.7.1 (for Kv) and in 3.7.2 (for Cv) include certain

units, nomenclature and temperature values which are not consistent with the parts of IEC 60534 other than

IEC 60534-1. These inconsistencies are limited to 3.7.1 and 3.7.2 of this document, and their sole purpose is to

illustrate the unique relationships traditionally used in the valve industry. These inconsistencies do not concern

any parts of IEC 60534 other than IEC 60534-1.
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3.7.1
flow coefficient

special volumetric flow rate calculated in cubic metres per hour (capacity) through a valve, with the

valve 100% fully open, where the static pressure loss across the valve is 1 bar (0.1 MPa) , and the fluid

is water within a temperature range 5 °C to 40 °C (278 K to 313 K)

Note 1 to entry: The value of Kv can be obtained from test results by means of the following formula:

 
 ρ 
KQ=
 
 
 
Δp ρ
  w 
where
Q is the measured volumetric flow rate, in m /h;
is the static pressure loss of 1 bar (0,1 MPa);
Δp is the measured static pressure loss across the valve, in bar (MPa);
ρ is the density of the fluid, in kg/m3;
ρ is the density of water, in kg/m3 (1 000 kg/m3).

This formula is valid when the flow is turbulent and no cavitation or flashing occurs.

3.7.2
flow coefficient C
non-SI valve coefficient which is in widespread use worldwide

Note 1 to entry: Numerically, Cv is represented as the number of US gallons of water, within a temperature range

of 40 °F to 100 °F, that will flow through a valve in 1 min, with the valve 100% fully open, when a pressure

drop of 0,068 948 bar (0,006 894 8 MPa) occurs. For conditions other than these, Cv can be obtained using the

following formula:
  
C ρ
CQ=
  
 
Δp ρ
 w 
 
where

is the measured volumetric flow rate, in US gallons per minute
1 gal (US)/min = 309 x 10-5 m3/s.

is the density of the fluid, in pounds per cubic foot
1 lb/ft3 = 16,018 kg/m3.

is the density of water within a temperature range of 4 °C to 38 °C (40 °F to 100 °F), in pounds

per cubic foot;
is the measurement state pressure loss across the valve, in psi;
Δ p = 1psi .

This formula is valid when the flow is turbulent and no cavitation or flashing occurs.

1) 1 psi = 0,068 948 bar = 0,006 894 8 MPa.
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3.8
bonnet
part connecting the valve body to the seal packing chamber
4 Requirements
4.1 Materials
4.1.1 General

Materials shall be in conformance with an internationally recognized standard and compatible with the

fluid. Galling, frictional heating and galvanic corrosion shall be considered in the selection of materials.

Materials shall also be oxygen compatible, if relevant (see 4.1.5.1).

Materials not listed in an internationally recognized standard shall be controlled by the manufacturer

of the valve by a specification ensuring control of chemical content and physical properties, and

ensuring quality at least equivalent to an internally recognized standard. A test certificate providing

the chemical content and physical property test results shall be provided with the valve.

4.1.2 Metallic materials

Metallic materials to be used in the construction of cryogenic valves shall meet the toughness

requirements of ISO 21028-1 or ISO 21028-2 as appropriate for the rated minimum temperature.

These requirements apply only to the valve parts exposed to low temperatures in normal service.

Metallic materials which do not exhibit ductile/brittle transition and non-ferrous materials which can

be shown to have no ductile/brittle transition do not require additional impact tests.

Forged, rolled, wrought and fabricated valve components from raw materials from these processes need

not be impact tested if the rated minimum temperature is higher than the ductile/brittle transition

range temperatures of the material. Castings meeting the requirements of one of the applicable

mandatory Appendices I and IV or II and III of ASME B16.34 for forgings and rolled or wrought material,

or conforming to equivalent standards, need not be impact tested if the rated minimum temperature is

higher than the ductile/brittle transition range temperatures of the material. When impact testing is

required, at least one randomly selected valve body (including bonnet, if applicable) material from each

production lot castings shall be impact tested at the rated minimum temperature.
4.1.3 Non-metallic materials

Non-metallic materials are well established only for use in packing and glands and for use for inserts

within the plug/stem assembly to provide leak tightness across the seat when the valve is closed. If

such materials are to be used for structural parts, they shall have the properties appropriate to

the application and conform to ISO 21028-1 or ISO 21028-2, as appropriate to the rated minimum

temperature.
Non-metallic materials shall also:

— have mechanical properties that will allow the valve to pass the type approval test for category A

valves defined in 5.1.3.3;
— be resistant to sunlight, weather and ageing.
— be oxygen compatible, if applicable, see 4.1.5.1.
4.1.4 Corrosion resistance

In addition to resistance to normal atmospheric corrosion, particular care shall be taken to ensure that

the valve cannot be rendered inoperative by accumulation of corrosion products. Some copper alloys

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are susceptible to stress corrosion cracking; consequently, careful consideration shall be given before

selection of these materials for components under stress. Careful consideration shall be given to the

leak detection fluid that is used for leak checking copper alloys to ensure that the fluid does not cause

stress corrosion cracking in copper alloys (e.g. ASTM G186).
4.1.5 Gas material compatibility
4.1.5.1 Oxygen

If the rated minimum temperature is equal to or less than the boiling point of air (approximately – 190 °C

at atmospheric pressure), or if the valve is intended for service with oxygen or oxidizing products, the

materials in contact with liquid air or oxidizing products shall be oxygen compatible, in accordance

with ISO 21010.
4.1.5.2 Hydrogen
For hydrogen service, see ISO 11114-1 and ISO 11114-2.
4.1.5.3 Acetylene

Metallic materials shall contain less than 70 % copper if specified for use with mixtures containing

acetylene.
4.1.5.4 LNG (Liquefied Natural Gas)

The valve shall be designed to take into account the thermal stresses in transient state occurring during

the cool down operation.
NOTE Thermal stresses in transient state present the following characteristics:
— They are often much larger than static pressure stresses
— They increase with an increase in thickness of the valve body

The valve design with respect to thermal stresses in transient state shall be accepted provided that the

valve passes the thermal shock test

The optional thermal shock test defined in annex B may be performed on agreement with purchaser/

customer.
4.2 Design
4.2.1 General

The valves shall fulfil their function in a safe manner within the temperature range from +65 °C to

their rated minimum temperature and the pressure range intended for use. Valves shall be designed

to satisfy a pressure rating PR, PN, or Class. Valves shall be selected with a PR (PN or Class) equal to or

greater than the maximum allowable pressure (PS) of the equipment with which it is to be used.

Minimum wall thickness values for valve bodies shall be from the appropriate valve standards

ISO 10434, ISO 15761, ISO 17292 or ASME B16.34. Alternatively, the minimum wall thickness may

be determined using recognized calculation methods (e.g. EN 16668, AD2000 Merkblatt, or ASME

B31.3) for calculating the minimum shell thickness of an equivalent diameter pipe. Bonnet thickness

of extended bonnet (extended stem) valves are exempted from meeting the minimum wall thickness

requirements of these standards. These standards may be used as informative references for design

not specifically covered in this document.
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4.2.2 Packing gland

Valves can have an extended stem and/or an extended bonnet. The length of the extension 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.

Valves without an extended stem and/or an extended bonnet shall have a stem packing capable of

operating at the specified minimum temperature. The handle shall be designed to remain operable for

the duration of the sample valve test, in accordance with Clause 5.

Gland designs incorporating a gland nut with a male or female thread shall be designed in such a way

that they will not loosen unintentionally, e.g. when the valve is operated.
4.2.3 Operating positions

Unless otherwise specified by the valve manufacturer, valves with extended stem and/or an extended

bonnet shall be capable of normal operation in the liquid service with the valve stem at any position

from the vertical to 35° above the horizontal. Loads imposed by actuators shall also be considered.

4.2.4 Cavities
4.2.4.1 Trapped liquid

Cavities where liquid can be trapped and build up detrimental pressures due to evaporation of the

liquid during warming up of the valve are not permitted.

NOTE For ball and gate valves, this requirement can be met by the provision of a pressure relief hole or

passage or other means, e.g. pressure relieving seats, to relieve pressure in the bonnet and body cavities.

4.2.4.2 Debris
Cavities susceptible to trapping debris shall be avoided.
4.2.5 Valve bonnet

Valve bonnets may be brazed, welded, bolted, screwed or union type. Union nuts shall be locked to the

body. Union type bonnets shall not be used on valves greater than DN 80. Screwed bonnets shall also

be secured by a union nut or another device offering equivalent safety. For union bonnet and bolted

bonnet valves, the valve manufacturer shall calculate, apply, and indicate the torque value to guarantee

the proper sealing of the bonnet gasket.
4.2.6 Securing of gland extension

For bronze or copper alloy valves whose PR is greater than or equal to 100 bar (10 MPa), the gland

(bonnet) extensions shall be mechanically secured in the bonnet prior to brazing (e.g. by screwing).

4.2.7 Seat

Valves may have metal/metal or metal/soft seat or insert. Soft seats shall be backed by a secondary

metal seat. Soft seat materials shall be adequately supported to prevent cold flow of the seat material.

Plugs and/or soft seats shall be mechanically secured and locked (e.g. lock tight, tack welded, peening,

pinning).
4.2.8 Stem securement

The valve stem shall be secured so that it cannot be blown out of the body in the event of the gland

being removed while the valve is under pressure.
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4.2.9 Torque

The maximum torque to operate the valves manually under service conditions, when applied at the rim

of the hand wheel or lever, shall not exceed 350 × R Nm, except for valve seating and unseating, when

it shall not exceed 500 × R Nm. For a hand wheel, R is the radius of the wheel, in metres. For a lever, R is

the length of the lever, in metres, minus 0,05 m.

The valve shall be robust enough to withstand 1 000 × R Nm or equivalent in linear force as specified

above without damage. A lower value is permitted if there is a limiting torque or stroke device.

Valves intended for actuator operation may have torque or linear force requirements deviating from

the above. The sample valve tests shall then be performed using a proper actuator to operate the valve.

4.2.10 Electric continuity and explosion proofness

For valves in oxidising or flammable fluids service, the maximum electrical resistance shall not exceed

1 000 Ω with no more than 28 V between the ports, in order to ensure electrical continuity to prevent

build-up of static electricity.
Any equipment attached to, or associat
...