SIST EN ISO 21009-2:2025

Cryogenic vessels - Static vacuum insulated vessels - Part 2: Operational requirements (ISO 21009-2:2024)

This document specifies operational requirements for static vacuum insulated vessels designed for a maximum allowable pressure of more than 50 kPa (0,5 bar). It can also be used as a guideline for vessels designed for a maximum allowable pressure of less than 50 kPa (0,5 bar).
This document applies to vessels designed for cryogenic fluids specified in ISO 21009-1.
Static cryogenic vessels are often partly equipped by the manufacturer, but can be installed or re- installed by another party, such as the operator, user or owner.
NOTE 1        For the installation of these vessels, additional requirements can apply.
NOTE 2        Some requirements of this document can be covered by local regulations, e.g. safety distances, occupational safety and health.
NOTE 3        Additional requirements can apply to the operation of large scale and field-fabricated vessels.

Kryo-Behälter - Ortsfeste vakuumisolierte Behälter - Teil 2: Betriebsanforderungen (ISO 21009-2:2024)

Dieses Dokument legt Betriebsanforderungen für ortsfeste vakuumisolierte Kryo-Behälter fest, die für den Betrieb mit einem maximal zulässigen Druck von über 50 kPa (0,5 bar) ausgelegt sind. Es kann auch als Richtlinie für Behälter mit einem maximal zulässigen Druck von weniger als 50 kPa (0,5 bar) angewendet werden.
Dieses Dokument gilt für Behälter, die für in ISO 21009 1 festgelegte tiefkalte Fluide ausgelegt sind.
Ortsfeste Kryo-Behälter werden oft teilweise vom Hersteller ausgerüstet, können jedoch von einer anderen Partei wie Betreiber, Anwender oder Eigentümer aufgestellt oder wieder aufgestellt werden.
ANMERKUNG 1   Es können zusätzliche Anforderungen an die Installation dieser Behälter gelten.
ANMERKUNG 2   Einige Anforderungen dieses Dokuments können durch regionale Vorschriften abgedeckt sein, z. B. Sicherheitsabstände, Arbeitsschutzbestimmungen.
ANMERKUNG 3   Für den Betrieb von großen und vor Ort hergestellten Behältern können zusätzliche Anforderungen gelten.

Récipients cryogéniques - Récipients fixes isolés sous vide - Partie 2: Exigences de fonctionnement (ISO 21009-2:2024)

Le présent document spécifie les exigences de fonctionnement pour les récipients fixes isolés sous vide, conçus pour une pression maximale admissible supérieure à 50 kPa (0,5 bar). Il peut également être utilisé comme guide pour les récipients conçus pour une pression maximale admissible inférieure à 50 kPa (0,5 bar).
Le présent document s'applique à des récipients conçus pour des fluides cryogéniques tels que spécifiés dans l'ISO 21009-1.
Les récipients cryogéniques fixes sont souvent partiellement équipés par le fabricant, mais ils peuvent être installés ou réinstallés par une autre partie, comme par exemple l'opérateur, l'utilisateur ou le propriétaire.
NOTE 1        Pour l'installation des récipients en question, des exigences supplémentaires peuvent s'appliquer.
NOTE 2        Certaines exigences du présent document peuvent être couvertes par des réglementations locales, par exemple distances de sécurité, sécurité et santé au travail.
NOTE 3        Des exigences supplémentaires peuvent s'appliquer pour l'exploitation de récipients de grande capacité et fabriqués sur site.

Kriogene posode - Stabilne, vakuumsko izolirane posode - 2. del: Zahteve za obratovanje (ISO 21009-2:2024)

Ta dokument določa zahteve za obratovanje za stabilne, vakuumsko izolirane posode, zasnovane za največji dovoljeni tlak, ki presega 50 kPa (0,5 bara). Uporabljati ga je mogoče tudi kot smernico za posode, zasnovane za največji dovoljeni tlak, ki ne presega 50 kPa (0,5 bara).
Ta dokument se uporablja za posode za kriogene tekočine, kot je določeno v standardu ISO 21009-1.
Stabilne kriogene posode pogosto delno opremi proizvajalec, vendar jih lahko namesti oziroma znova namesti druga oseba, npr. upravljavec, uporabnik ali lastnik.
OPOMBA 1: Za namestitev teh posod lahko veljajo dodatne zahteve.
OPOMBA 2: Nekatere zahteve tega dokumenta so lahko zajete v lokalnih predpisih (npr. varnostne razdalje, varnost in zdravje pri delu).
OPOMBA 3: Za obratovanje velikih posod in posod, izdelanih na mestu uporabe, lahko veljajo dodatne zahteve.

General Information

• Status: Published
• Public Enquiry End Date: 09-Sep-2023
• Publication Date: 11-Dec-2024
• ICS: 23.020.40 - Cryogenic vessels
• Technical Committee: TLP - Pressure vessels
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 07-Oct-2024
• Due Date: 12-Dec-2024
• Completion Date: 12-Dec-2024
• 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
• Mandate: M/071 - Mandate to CEN for standardization in the field of Pressure equipment
• Mandate: M/601 - COMMISSION IMPLEMENTING DECISION of 1.3.2024 on a standardisation request to the European Committee for Standardization and the European Committee for Electrotechnical Standardization as regards pressure equipment and assemblies in support of Directive 2014/68/EU of the European Parliament and of the Council
• Ref Project: EN ISO 21009-2:2024 - Cryogenic vessels - Static vacuum-insulated vessels - Part 2: Operational requirements (ISO 21009-2:2024)

Relations

• Replaces: SIST EN ISO 21009-2:2016 - Cryogenic vessels - Static vacuum insulated vessels - Part 2: Operational requirements (ISO 21009-2:2015)
• Effective Date: 01-Jul-2025

Overview

EN ISO 21009-2:2024 - Cryogenic vessels - Static vacuum-insulated vessels - Part 2: Operational requirements - specifies operational requirements for static vacuum‑insulated cryogenic vessels. The standard is intended primarily for vessels with a maximum allowable pressure > 50 kPa (0.5 bar) and can be used as a guideline for lower‑pressure vessels. It applies to vessels intended for the cryogenic fluids defined in ISO 21009-1 and complements design and fabrication requirements with practical rules for safe operation, installation, inspection and maintenance.

Key topics

The document covers practical, safety‑focused topics operators and installers need to follow:

• Personnel training and competency requirements for operating and maintaining cryogenic vessels
• General safety requirements and safety considerations for static vacuum‑insulated vessels
• Installation rules, including indoor/outdoor considerations and safety distances for siting vessels
• Inspection regime: pre‑service checks, periodic inspections, marking and labelling, handover documentation and inspection equipment
• Pressure‑relief devices: certificates, marking, visual inspection and performance checks, including guidance on bursting disc replacement
• Operational procedures: putting into service, filling, taking out of service, maintenance and repair
• Special requirements for flammable gases, covering electrical equipment, grounding (earthing), installation and filling precautions
• Emergency equipment and procedures, plus an informative annex on safety distances

Applications and users

EN ISO 21009-2:2024 is directly useful for:

• Manufacturers and suppliers of static vacuum‑insulated cryogenic vessels (to provide operational guidance and handover documentation)
• Operators, owners and maintenance teams who install, commission, operate and service vessels on site
• Safety managers, inspectors and regulatory authorities responsible for compliance, periodic inspection and emergency preparedness
• Plant and project engineers specifying storage and handling procedures for cryogenic fluids in industrial gas, LNG, laboratory, and process applications

Practical benefits include improved operational safety, clearer inspection schedules, compliant installation practices, and harmonized documentation to support maintenance and handover.

Related standards

• ISO 21009-1 - Design, fabrication, inspection and tests for static vacuum‑insulated cryogenic vessels
• ISO 23208 - Cleanliness for cryogenic service (referenced in the standard)
• Relationship to EU Pressure Equipment Directive (2014/68/EU) is described in Annex ZA; applying the normative clauses can contribute to presumption of conformity where cited in the Official Journal.

Keywords: EN ISO 21009-2:2024, cryogenic vessels, static vacuum‑insulated vessels, operational requirements, inspection, installation, safety distances, pressure‑relief devices.

Standards Content (Sample)

SLOVENSKI STANDARD
01-januar-2025
Nadomešča:
SIST EN ISO 21009-2:2016
Kriogene posode - Stabilne, vakuumsko izolirane posode - 2. del: Zahteve za
obratovanje (ISO 21009-2:2024)
Cryogenic vessels - Static vacuum insulated vessels - Part 2: Operational requirements
(ISO 21009-2:2024)
Kryo-Behälter - Ortsfeste vakuumisolierte Behälter - Teil 2: Betriebsanforderungen (ISO
21009-2:2024)
Récipients cryogéniques - Récipients fixes isolés sous vide - Partie 2: Exigences de
fonctionnement (ISO 21009-2:2024)
Ta slovenski standard je istoveten z: EN ISO 21009-2:2024
ICS:
23.020.40 Proti mrazu odporne posode Cryogenic vessels
(kriogenske posode)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 21009-2
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2024
EUROPÄISCHE NORM
ICS 23.020.40 Supersedes EN ISO 21009-2:2015
English Version
Cryogenic vessels - Static vacuum-insulated vessels - Part
2: Operational requirements (ISO 21009-2:2024)
Récipients cryogéniques - Récipients fixes isolés sous Kryo-Behälter - Ortsfeste vakuumisolierte Behälter -
vide - Partie 2: Exigences de fonctionnement (ISO Teil 2: Betriebsanforderungen (ISO 21009-2:2024)
21009-2:2024)
This European Standard was approved by CEN on 1 October 2024.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21009-2:2024 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Annex ZA (informative) Relationship between this European Standard and the essential
requirements of Directive 2014/68/EU (Pressure Equipment Directive) aimed to be
covered. 4

European foreword
This document (EN ISO 21009-2:2024) has been prepared by Technical Committee ISO/TC 220
"Cryogenic vessels" in collaboration with Technical Committee CEN/TC 268 “Cryogenic vessels and
specific hydrogen technologies applications” 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 April 2025, and conflicting national standards shall be
withdrawn at the latest by April 2025.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 21009-2:2015.
This document has been prepared under a standardization request addressed to CEN by the European
Commission. The Standing Committee of the EFTA States subsequently approves these requests for its
Member States.
For the relationship with EU Legislation, see informative Annex ZA, which is an integral part of this
document.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 21009-2:2024 has been approved by CEN as EN ISO 21009-2:2024 without any
modification.
Annex ZA
(informative)
Relationship between this European Standard and the essential
requirements of Directive 2014/68/EU (Pressure Equipment Directive)
aimed to be covered
This European Standard has been prepared under a Commission’s standardization request M/601 to
provide one voluntary means of conforming to essential requirements of 2014/68/EU (Pressure
equipment Directive).
Once this standard is cited in the Official Journal of the European Union under that Directive,
compliance with the normative clauses of this standard given in Table ZA.1 confers, within the limits of
the scope of this standard, a presumption of conformity with the corresponding essential requirements
of that Directive, and associated EFTA regulations.
Table ZA.1 — Correspondence between this European Standard and Annex I
of Directive 2014/68/EU (Pressure Equipment Directive)
Essential Requirements of Clause(s)/subclause(s) Remarks/Notes
Directive 2014/68/EU of this EN
3.4 a Clauses 5.1, 6, 7, 8, 9, 10, 11 and Operating instructions
3.4 b −
3.4 c −
Table ZA.2 — Applicable Standards to confer presumption of conformity as described
in this Annex ZA
Reference International Title Corresponding European
in Clause 2 Standard Edition Standard Edition
ISO 23208 ISO 23208:2017 Cryogenic vessels — Cleanliness EN ISO 23208:2019
for cryogenic service
ISO 21009-1 ISO 21009-1:2022 Cryogenic vessels — Static None.
vacuum-insulated vessels — Part
For applicable standard
1: Design, fabrication, inspection
edition see Column 2
and tests
The documents listed in the Column 1 of Table ZA.2, in whole or in part, are normatively referenced in
this document, i.e. are indispensable for its application. The achievement of the presumption of
conformity is subject to the application of the edition of Standards as listed in Column 4 or, if no
European Standard Edition exists, the International Standard Edition given in Column 2 of Table ZA.2.
WARNING 1 — Presumption of conformity stays valid only as long as a reference to this European
Standard is maintained in the list published in the Official Journal of the European Union. Users of this
standard should consult frequently the latest list published in the Official Journal of the European
Union.
WARNING 2 — Other Union legislation may be applicable to the product(s) falling within the scope of
this standard.
International
Standard
ISO 21009-2
Third edition
Cryogenic vessels — Static vacuum-
2024-09
insulated vessels —
Part 2:
Operational requirements
Récipients cryogéniques — Récipients fixes isolés sous vide —
Partie 2: Exigences de fonctionnement
Reference number
ISO 21009-2:2024(en) © ISO 2024

ISO 21009-2:2024(en)
© ISO 2024
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
ISO 21009-2:2024(en)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Personnel training . 2
5 General safety requirements . 3
5.1 General .3
5.2 Safety considerations .3
6 Installation . 3
6.1 General requirements .3
6.2 Outdoor installation .4
6.3 Indoor installation .5
6.4 Safety distances .5
7 Inspection . 6
7.1 General .6
7.2 Inspection before putting into service .6
7.3 Marking and labelling .6
7.4 Handover documents .6
7.5 Equipment .7
7.6 Periodic inspection .7
7.6.1 General .7
7.6.2 Inspections .7
7.7 Inspection of pressure-relief devices .8
7.7.1 General .8
7.7.2 Certificates and marking .8
7.7.3 Visual inspection .8
7.7.4 Performance test .8
7.7.5 Changing bursting discs (inner vessel) .9
8 Putting into service . 9
9 Filling . 9
10 Taking out of service .10
11 Maintenance and repair .10
12 Additional requirements for flammable gases .11
12.1 General .11
12.2 Electrical equipment .11
12.3 Grounding (earthing) system . 12
12.4 Installation . 12
12.5 Filling . 13
12.6 Maintenance, repair and taking out of service . 13
13 Emergency equipment/procedures .13
Annex A (informative) Safety distances .15
Bibliography .16

iii
ISO 21009-2:2024(en)
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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, in collaboration with
the European Committee for Standardization (CEN) Technical Committee CEN/TC 268, Cryogenic vessels
and specific hydrogen technologies applications, in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 21009-2:2015), which has been technically
revised.
The main changes are as follows:
— updated definition of “authorized person”;
— updated requirements for protective clothing to prevent exposure to cryogenic fluids;
— added requirements for dealing with oxygen-enriched condensation;
— added requirements to use the results of a risk assessment for the design on underground installations;
— added requirements to use measures such as gas monitoring systems and ventilation to mitigate hazards
for underground installations;
— added requirements to consider the risks associated with spill containment (diking) for outdoor
installations if diking is needed;
— added requirements that controls for filling an indoor tank from an outdoor source shall be accessible to
the operator and that vents shall be piped to a safe location;
— added requirements that automatic control devices shall fail to a safe operating mode upon the loss of
power or pneumatic supply;
— added requirement to remove moisture as well as contaminants during a first fill;
— added option to use approved first fill procedure in place of manufacturer instructions;

iv
ISO 21009-2:2024(en)
— added requirements to ensure the fill process does not fill beyond a maximum level and pressure;
— added requirement to cap fill fittings to avoid moisture or contaminant entry to the tank;
— added separate recommended procedures for purging hydrogen tanks with helium and for other inert gases;
— updated safety distances for flammable cryogenic fluids.
A list of all parts in the ISO 21009 series can be found on the ISO website.
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.

v
International Standard ISO 21009-2:2024(en)
Cryogenic vessels — Static vacuum-insulated vessels —
Part 2:
Operational requirements
1 Scope
This document specifies operational requirements for static vacuum insulated vessels designed for a
maximum allowable pressure of more than 50 kPa (0,5 bar). It can also be used as a guideline for vessels
designed for a maximum allowable pressure of less than 50 kPa (0,5 bar).
This document applies to vessels designed for cryogenic fluids specified in ISO 21009-1.
Static cryogenic vessels are often partly equipped by the manufacturer, but can be installed or re- installed
by another party, such as the operator, user or owner.
NOTE 1 For the installation of these vessels, additional requirements can apply.
NOTE 2 Some requirements of this document can be covered by local regulations, e.g. safety distances, occupational
safety and health.
NOTE 3 Additional requirements can apply to the operation of large scale and field-fabricated vessels.
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 21009-1, Cryogenic vessels — Static vacuum-insulated vessels — Part 1: Design, fabrication, inspection and tests
ISO 23208, 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 terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
putting into service
operation by which a vessel (3.7) is prepared to be used
Note 1 to entry: It applies to either a new vessel being used for the first time or an existing vessel being returned to
service.
3.2
filling
operation by which a vessel (3.7) undergoes a prefill check, filling with a cryogenic fluid, and an after-fill check

ISO 21009-2:2024(en)
3.3
outdoor location
location outside of any building or structure and not enclosed by more than two walls
3.4
underground location
area or room whose ground or floor is on all sides lower than the adjacent ground surfaces
3.5
safety distance
minimum distance separating a piece of equipment from its inherent hazard that will mitigate the effect of a
likely foreseeable incident and prevent a minor incident escalating into a larger incident
Note 1 to entry: The safety distance also can provide protection from foreseeable external impact (e.g. roadway, flare)
or activities outside the control of the operation (e.g. plant or customer station boundary).
3.6
gas release
escape of gas due to operating conditions, or to malfunctions that cannot be reasonably excluded
Note 1 to entry: Gas release for operating reasons can be produced, for example, on vent lines and pressure-release lines.
Note 2 to entry: Gas release due to malfunctions which cannot be excluded can occur, for example, in the case of
overfilling, failure of fittings, loose connections, faulty operation, and leakages.
3.7
vessel
thermally insulated vessel intended for use with one or more cryogenic fluids in a stationary condition
[SOURCE: ISO 21009-1:2022, 3.17, modified — The term “static cryogenic vessel” was changed to “vessel”;
the Note to entry was removed.]
3.8
authorized person
trained and qualified person approved or assigned by the applicable regulations to perform specific types
of duties
4 Personnel training
Only authorized persons trained for the specific task shall be allowed to install, put into service, fill, handle,
operate or maintain the vessel and its equipment.
The training programme shall include:
— normal operating procedures;
— product and hazard identification;
— safe operating limits;
— emergency procedures;
— physical and chemical properties of the vessel's contents and their effects on the human body;
— personnel protective equipment (e.g. safety boots, goggles, gloves);
— basic risk assessment methods and techniques;
— hazards of the cryogenic liquid stored in the vessel.
Training shall be repeated as necessary to ensure that authorized personnel remain competent. A training
record shall be maintained which details the information authorized personnel have received.

ISO 21009-2:2024(en)
5 General safety requirements
5.1 General
The following requirements shall be taken into account in operating instructions:
— Identification labels and plates shall not be removed or defaced.
— Appropriate warning signs regarding product and operational hazards and personnel protective
equipment requirements shall be displayed.
— Parts under pressure shall be disconnected only if they have been previously depressurized.
— All surfaces which come in contact with the product shall be kept free from oil and grease. Cleaning shall
be in accordance with ISO 23208.
— Leaking valves or connections should be depressurized before rectification. When this is not possible,
leaking valves under pressure shall be tightened using suitable tools and procedures. Direct flame or
intense heat shall never be used to raise the pressure or de-ice frozen components.
— Valve outlets shall be kept clean, dry and free from contaminants.
— Vessels and their accessories shall not be modified without proper authorization.
5.2 Safety considerations
In all operations and training, the following safety considerations shall be taken into account:
— Systems for oxygen service shall consider the compatibility of the materials.
— Small amounts of cryogenic fluids will produce large volumes of vaporized gas. Spillage of oxygen can
result in an oxygen-enriched atmosphere; spillage of other cryogenic fluids can result in an oxygen-
deficient atmosphere. Provision shall be made for appropriate measures for this, e.g. ventilation or usage
of self-contained breathing apparatus.
— Due to the possibility of cold embrittlement, cryogenic fluids shall not come in contact with materials
(metals or plastics) which are not suitable for lower bound of the design temperatures.
— Hydrogen embrittlement shall be considered for materials exposed to hydrogen.
— Because of their extremely low temperatures, cryogenic fluids will produce cold burns when coming in
contact with the skin. Cold burns can also be produced from contact with uninsulated equipment and
pipe. When using vessels, it is necessary to use protective means for exposed areas of the face and skin,
as well as clothing which does not allow spilled cryogenic liquid to enter into the shoes.
— Oxygen enrichment due to liquefaction of ambient air can occur on the cold surfaces of equipment which
contain fluids with a boiling point lower than that of oxygen, e.g. liquid helium or liquid hydrogen. Areas
where this condensate can collect shall be considered for oxygen compatibility.
6 Installation
6.1 General requirements
The requirements in Clause 6 shall be taken into account in operating instructions.
Vessels shall be installed and operated in such a way that employees or third parties are not endangered.
Necessary minimum safety distances shall be observed.
Vessels shall be installed so that the name plate is easily readable.

ISO 21009-2:2024(en)
The installation should allow inspection of vessels on all sides. All vessel controls shall be capable of being
operated safely.
Vessels shall be installed in such a way that their filling operation can be carried out safely and easily. Vessels
shall be erected in such a way that no inadmissible misalignment or inclination can occur due to:
— the actual foundations;
— the inherent mass of the vessel inclu
...