SIST EN ISO 18777-1:2026

SLOVENSKI STANDARD
01-maj-2026
Nadomešča:
SIST EN ISO 18777:2009
Prenosni sistemi tekočega kisika za medicinsko uporabo - 1. del: Splošne in
posebne zahteve za osnovne enote (ISO 18777-1:2026)
Transportable liquid oxygen systems for medical use - Part 1: Common requirements
and particular requirements for base units (ISO 18777-1:2026)
Flüssigsauerstoffsysteme für medizinische Anwendungen - Teil 1: Allgemeine
Anforderungen und besondere Anforderungen für Basiseinheiten (ISO 18777-1:2026)
Systèmes transportables d'oxygène liquide à usage médical - Exigences particulières -
Partie 1: unités de base (ISO 18777-1:2026)
Ta slovenski standard je istoveten z: EN ISO 18777-1:2026
ICS:
11.040.10 Anestezijska, respiratorna in Anaesthetic, respiratory and
reanimacijska oprema reanimation equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 18777-1
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2026
EUROPÄISCHE NORM
ICS 11.040.10 Supersedes EN ISO 18777:2009
English Version
Transportable liquid oxygen systems for medical use - Part
1: Common requirements and particular requirements for
base units (ISO 18777-1:2026)
Systèmes transportables d'oxygène liquide à usage Flüssigsauerstoffsysteme für medizinische
médical - Partie 1: Exigences communes et exigences Anwendungen - Teil 1: Allgemeine Anforderungen und
particulières s'appliquant aux unités de base (ISO besondere Anforderungen für Basiseinheiten (ISO
18777-1:2025) 18777-1:2025)
This European Standard was approved by CEN on 3 January 2026.

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
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 18777-1:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 18777-1:2026) has been prepared by Technical Committee ISO/TC 121
"Anaesthetic and respiratory equipment" in collaboration with Technical Committee CEN/TC 215
“Respiratory and anaesthetic equipment” the secretariat of which is held by BSI.
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 September 2026, and conflicting national standards
shall be withdrawn at the latest by September 2026.
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 18777:2009.
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 18777-1:2026 has been approved by CEN as EN ISO 18777-1:2026 without any
modification.
International
Standard
ISO 18777-1
First edition
Transportable liquid oxygen
2026-02
systems for medical use —
Part 1:
Common requirements and
particular requirements for base
units
Systèmes transportables d'oxygène liquide à usage médical —
Partie 1: Exigences communes et exigences particulières
s'appliquant aux unités de base
Reference number
ISO 18777-1:2026(en) © ISO 2026

ISO 18777-1:2026(en)
© ISO 2026
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: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 18777-1:2026(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General requirements . 2
4.1 Risk management .2
4.2 Usability .3
4.3 Materials .3
4.4 Environmental conditions .3
4.4.1 Transport and storage .3
4.4.2 Operational .4
5 Design requirements . 4
5.1 Cryogenic vessels .4
5.2 Contents level indication .4
5.3 Transfilling devices and filling port connectors .4
5.4 Interoperability between the base unit and the portable unit .6
5.5 Flow outlets .6
5.6 Oxygen temperature at the flow outlet .6
5.7 Flow control device .6
5.8 Pressure at the flow outlet.6
5.9 Oxygen conserving device .6
5.10 Venting of gaseous oxygen .6
5.11 Pressure control .7
5.12 Evaporation rate .7
5.13 Leakage .7
5.14 Excessive temperatures of accessible surfaces .7
5.15 Electrical safety .7
5.16 Protection of components and controls .7
5.17 Stability .8
5.18 Battery compartments .8
6 Construction requirements . 8
7 Information to be supplied by the manufacturer . 8
7.1 General .8
7.2 Marking .8
7.3 Instructions for use for the intended user .9
7.3.1 General information .9
7.3.2 Safety information .9
7.3.3 Pre use checks .9
7.3.4 Filling instructions .9
7.3.5 General warning statements .10
Annex A (informative) Rationale .11
Annex B (Normative) Test Methods .13
Annex C (Normative) Opening sequence between the base unit transfilling device and the
portable unit filling port connector . 17
Annex D (informative) Guidance on the requirements in IEC 60601-1 that can be applicable .18
Annex E (informative) Hazard identification for risk management assessment .21
Bibliography .22

iii
ISO 18777-1:2026(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 121 Anaesthetic and respiratory equipment
Subcommittee SC 6, Medical gas supply systems in collaboration with the European Committee for
Standardization (CEN) Technical Committee CEN/TC 215, Respiratory and anaesthetic equipment, in
accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This first edition together with ISO 18777-2 cancels and replaces ISO 18777:2005 which has been technically
revised.
The main changes are as follows:
— part 1 includes requirements that are common to both base units and portable units.
— requirements for the transfilling device have been included.
A list of all parts in the ISO 18777 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.

iv
ISO 18777-1:2026(en)
Introduction
Transportable liquid oxygen systems comprise a base unit and a portable unit for use primarily in home-care
applications and without professional supervision. This document specifies requirements that are common
to both base units and portable units and requirements that are particular to base units. Base units can be
used solely to store the liquid oxygen for refilling the portable unit or can, if fitted with a flow outlet and flow
control, also be used to provide a controlled flow of oxygen for inhalation by the patient.
Base units comprise:
— a double-walled vacuum-insulated cryogenic container for storing liquid oxygen (LOX) at approximately
–180 °C;
— a content level indicator;
— a heat exchanger to convert liquid oxygen to gaseous oxygen and warming it to ambient temperature;
— a transfilling device; and
— can also include a separate filling connector.
Annex A contains rationale for some of the requirements. It is included to provide additional insight into the
committee’s reasoning that led to a particular requirement to address the identified hazards.

v
International Standard ISO 18777-1:2026(en)
Transportable liquid oxygen systems for medical use —
Part 1:
Common requirements and particular requirements for base
units
1 Scope
This document specifies requirements for transportable liquid oxygen systems that are common to both
base units and portable units and requirements that are particular to base units.
Stationary liquid oxygen systems used for oxygen pipeline supply systems are excluded from this document.
NOTE 1 Throughout this document the term “units” is used where the requirement applies to both base units and
portable units.
NOTE 2 ISO 18777 - 2 specifies those requirements particular to portable units.
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 14971, Medical devices — Application of risk management to medical devices
ISO 15001:2010, Anaesthetic and respiratory equipment — Compatibility with oxygen
ISO 17256:2024, Anaesthetic and respiratory equipment — Respiratory therapy tubing and connectors
ISO 18562-1, Biocompatibility evaluation of breathing gas pathways in healthcare applications — Part 1:
Evaluation and testing within a risk management process
ISO 20417, Medical devices — Information to be supplied by the manufacturer
ISO 21029-1:2018+A1:2019, Cryogenic vessels — Transportable vacuum insulated vessels of not more than
1 000 litres volume — Part 1: Design, fabrication, inspection and tests
ISO 21029-2, Cryogenic vessels — Transportable vacuum insulated vessels of not more than 1 000 litres volume
— Part 2: Operational requirements
ISO 23208, Cryogenic vessels — Cleanliness for cryogenic service
IEC 60601-1:2005+AMD1:2012, Medical electrical equipment — Part 1: General requirements for basic safety
and essential performance
ISO 80601-2-67, Medical electrical equipment — Part 2-67: Particular requirements for basic safety and essential
performance of oxygen conserving equipment
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO 18777-1:2026(en)
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/
NOTE the terms defined in clause 3 are delineated throughout this document by italic font.
3.1
base unit
transportable vacuum insulated cryogenic vessel for storing liquid oxygen, used for refilling the portable
unit and can also be used as the supply source for administering oxygen to the patient
3.2
conserving device
device that reduces the amount of oxygen consumed by delivering gas intermittently and synchronized with
the patient's inspiratory cycle
Note 1 to entry: Conserving devices can be electrically or pneumatically powered.
[SOURCE: ISO 80601-2-67:2020 (201.3.201), modified — “equipment/ME equipment” replaced with “device”
and “intended to conserve supplemental oxygen” replaced with “amount of oxygen consumed”.]
3.3
flow control device
FCD
device that indicates the selected flow of a specific gas
[9]
[SOURCE: ISO 15002:2023, 3.1 , modified — Note 1 to entry deleted.]
3.4
maximum allowable working pressure
MAWP
maximum effective gauge pressure permissible at the top of the vessel in its normal operating position
including the highest effective pressure during filling and discharge
1)
[SOURCE: ISO 21029-1:— , 3.17, modified — "Ps" deleted and Note 1 to entry deleted.]
3.5
portable unit
refillable, vacuum insulated cryogenic vessel for administering a controlled flow of gaseous oxygen to the
patient whilst mobile
3.6
transfilling device
device for transferring liquid oxygen from a base unit to a portable unit
Note 1 to entry: transfilling devices can also be used as the means to fill base units from liquid oxygen sources.
4 General requirements
4.1 Risk management
4.1.1 Manufacturers shall assess the risks, in accordance with ISO 14971, when the units are transported,
stored, installed and operated under normal and single fault conditions and maintained according to the
manufacturer’s instructions.
Check conformance by inspection of the risk management file.
1) Under preparation. Stage at the time of publication: ISO/DIS 21029-1:2026.

ISO 18777-1:2026(en)
4.1.2 Any risks identified shall be reduced to an acceptable level.
NOTE 1 A situation in which a fault is not detected is considered a normal condition.
NOTE 2 Annex D lists known hazards for use as guidance during a risk assessment.
Check conformance by inspection of the risk management file.
4.2 Usability
[6] [7]
Manufacturers shall apply a usability engineering process, (e.g. IEC 60601-1-6 and IEC 62366-1 ), to
assess and mitigate any risks caused by usability problems associated with correct use (i.e. normal use) and
use errors.
Check conformance by inspection of the usability engineering file.
4.3 Materials
NOTE There is rationale for this clause in A.1.
4.3.1 Materials, which come in contact with liquid or gaseous oxygen under normal or single fault
conditions, shall:
a) be resistant to corrosion;
b) be compatible with oxygen in accordance with ISO 15001:2010;
c) conform with ISO 23208; and
d) if liable to shed particles, shall not be used for highly strained components and parts liable to wear, (e.g.
springs).
NOTE 1 Corrosion resistance includes resistance against moisture and surrounding materials.
NOTE 2 Oxygen compatibility is usually defined as the ability of a material to coexist with oxygen and a potential
source of ignition at an expected pressure and temperature.
NOTE 3 Many materials which do not burn in air will do so in an oxygen-enriched environment, particularly
under pressure. Similarly, materials which can be ignited in air require lower ignition energies to ignite in an oxygen
atmosphere. Many such materials can be ignited by friction at a valve seat or by adiabatic compression when oxygen at
high pressure is rapidly introduced into a system at low pressure.
NOTE 4 Design considerations and criteria for the selection of metallic and non-metallic materials that are
compatible with oxygen are given in Annexes C and D of ISO 15001:2010.
Check conformance by inspection of the technical file.
4.3.2 Components which come in contact with breathing gas pathways shall be evaluated for
biocompatibility in accordance with ISO 18562-1. Any identified risks shall be reduced to an acceptable level.
4.3.3 Units and parts thereof shall be designed and manufactured to minimize health risks due to
substances leached from the units or their components during normal use.
Check conformance by inspection of the technical file.
4.4 Environmental conditions
4.4.1 Transport and storage
Units shall conform to the performance requirements of this document after being exposed to the
environmental conditions stated by the manufacturer in their instructions for use [see 7.3.1 c)].

ISO 18777-1:2026(en)
Check conformance by exposing test samples to the environmental conditions stated in the instructions for
use prior to performing the tests given in Annex B.
4.4.2 Operational
Units shall conform with the requirements of this document and the performance stated by the manufacturer
when operated under the following environmental conditions unless a different range of environmental
conditions is stated by the manufacturer in their instructions for use, [see 7.3.1 c)]:
a) an ambient temperature range of (−10 to + 40) °C; and
b) a relative humidity range of (15 to 90) %, non-condensing.
Check conformance by performing the tests given in Annex B.
5 Design requirements
5.1 Cryogenic vessels
The units’ cryogenic vessels shall conform with ISO 21029-1:2018+A1:2019 and ISO 21029-2.
Check conformance by inspection of the technical file.
5.2 Contents level indication
5.2.1 Units shall have a means to indicate the level of the contents in the unit.
NOTE Ideally this should indicate the hours of remaining gaseous oxygen supply based on the flow setting [see
7.3.1 b)].
Check conformance by visual inspection.
5.2.2 The level at which it is recommended that units should be refilled shall be indicated by marking [see
7.2 c)] or an audible or visual alarm signal.
Check conformance by visual inspection and functional testing.
5.2.3 The means to indicate the level of the contents shall be non-user-detachable (i.e. not detachable
without the use of a tool).
Check conformance by functional testing.
5.3 Transfilling devices and filling port connectors
5.3.1 Base units shall be equipped with a transfilling device conforming with Figure 1.
NOTE Figure 1 specifies the essential dimensions necessary to ensure compatibility between different
manufacturer’s base units and portable units.
5.3.2 Transfilling devices shall be manufactured to:
a) ensure the safe transfer of liquid oxygen from the base unit to the portable unit without causing a spillage
of excess gas or liquid oxygen under normal and single fault conditions; and
b) be non-user detachable from the base unit (i.e. not detachable without the use of a tool).
5.3.3 Base units shall have means to safely drain any excess liquid oxygen during the filling of the portable
unit. These means shall be at a radius of 125 mm and 40 mm from the centre of the transfilling device.

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