prEN ISO 18082

• Abstract:

  ISO 18082:2014 specifies the dimensions, the allocation and marking of non-interchangeable screw-threaded (NIST) connectors intended to be used at operating pressures up to 1 400 kPa, and for vacuum systems at pressures not greater than 60 kPa absolute.; ISO 18082:2014 specifies NIST connectors intended for use with the following medical gases:; oxygen;; nitrous oxide;; medical air;; helium;; carbon dioxide;; xenon;; specified mixtures of the gases listed above;; oxygen-enriched air;; air for driving surgical tools;; nitrogen for driving surgical tools;; use with vacuum.

• Status: Not Published
• Publication Date: 16-Mar-2028
• ICS: 11.040.10 - Anaesthetic, respiratory and reanimation equipment
• Technical Committee: CEN/TC 215 - Respiratory and anaesthetic equipment
• Drafting Committee: CEN/TC 215/WG 1 - Anaesthetic machines, medical breathing systems and anaesthetic gas scavenging systems
• Current Stage: 4020 - Submission to enquiry - Enquiry
• Start Date: 24-Sep-2026
• Completion Date: 24-Sep-2026
• Ref Project: oSIST prEN ISO 18082:2026 - Anaesthetic and respiratory equipment - Dimensions of non-interchangeable screw-threaded (NIST) low-pressure connectors for medical gases (ISO/DIS 18082:2026)

• Revises: EN ISO 18082:2014/A1:2017 - Anaesthetic and respiratory equipment - Dimensions of non-interchangeable screw-threaded (NIST) low-pressure connectors for medical gases - Amendment 1 (ISO 18082:2014/Amd 1:2017)
• Effective Date: 08-Oct-2025
• Revises: EN ISO 18082:2014 - Anaesthetic and respiratory equipment - Dimensions of non-interchangeable screw-threaded (NIST) low-pressure connectors for medical gases (ISO 18082:2014)
• Effective Date: 08-Oct-2025

prEN ISO 18082 is a draft CEN/ISO standard for anaesthetic and respiratory equipment. It specifies the dimensions, allocation and marking of non-interchangeable screw-threaded (NIST) low-pressure connectors for medical gases and vacuum services, so manufacturers and system specifiers can match the right connector to the right gas service. It applies to connectors used at operating pressures up to 1 400 kPa and to vacuum systems at pressures not greater than 60 kPa absolute.

What does prEN ISO 18082 specify?

prEN ISO 18082 covers the geometry, gas-service allocation, marking and marking durability for NIST connectors. The document is arranged into six clauses: Scope, Normative references, Terms and definitions, Dimensions and allocation of NIST connectors, Marking, and Test for durability of markings, followed by a bibliography.

The scope ties the document to medical gases and to vacuum use in medical equipment. It also points readers to ISO 5359 for low-pressure hose assemblies used with medical gases and vacuum.

What are the key requirements of prEN ISO 18082?

prEN ISO 18082 is mainly about preventing misconnection by controlling the connector form, the assigned gas service and the identification marking.

• Pressure and service range - Clause 1 limits use to low-pressure medical gas connections up to 1 400 kPa and vacuum at no more than 60 kPa absolute. In practice, this keeps the document focused on the connector types used between cylinders, pipeline services and medical devices.
• Gas-specific allocation - Clause 4 and Table 1 assign each NIST connector range to a particular gas or service, such as oxygen, nitrous oxide, medical air, helium, carbon dioxide, xenon, specified mixtures, oxygen 90+ (O 90+), air or nitrogen for driving surgical tools, and vacuum. The allocation is what helps avoid cross-connection between incompatible services.
• No left-hand thread allocation - Table 1 states that left-hand threads have not been allocated. This matters because the thread direction is part of the gas-specific design and the standard keeps the system deliberately incompatible across services.
• Dimensional conformity - Clause 4 requires the NIST body, nipple and nut to comply with Figures 1 to 4 and Tables 2 to 4. Compliance is checked by measurement and visual inspection, so manufacturers need controlled dimensions and inspection methods, not just general fit.
• Sealing components - Clause 4 includes “O” ring dimensions in Table 4 and shows how they relate to the nipple design in Figure 2. The notes explain that the seal is chosen and compressed so the connector stays gas-tight and operates smoothly.
• Marking - Clause 5 requires durable, legible marking with the gas symbol from Table 5, and allows the gas name to be added. The marking must be readable by a person with corrected visual acuity from 0.5 m under 215 lux, which gives a practical readability target for production and inspection.
• Marking durability test - Clause 6 checks the marking by rubbing it with water, methylated spirit and isopropyl alcohol. In practice, this is a simple production or incoming-inspection test to confirm that the identification will survive normal handling and cleaning.

What terms does prEN ISO 18082 define?

• gas-specific - Having characteristics that prevent connections between different gas services or vacuum services.
• medical gas - A gas or gas mixture intended for patient administration or as a source of pneumatic power for medical or surgical tools.
• non-interchangeable screw-threaded connector (NIST connector) - A threaded connector system that keeps services separate by using different diameters and left- or right-hand threads for each gas or service.
• oxygen 90+ (O 90+) - A named oxygen service listed in the scope, allocation table and marking table.
• LFT - The symbol used in Table 5 for medical air/helium/carbon monoxide, identified in the table as lung function test.

Who uses prEN ISO 18082?

Manufacturers of anaesthetic and respiratory equipment use prEN ISO 18082 when designing and marking connectors fitted to medical devices. Test laboratories and quality teams use it to check dimensions, allocation and marking durability. Hospital engineering, procurement and regulatory staff use it when specifying or assessing medical gas equipment where cross-connection prevention matters.

What changed in prEN ISO 18082 from the previous edition?

This document is presented as the first edition covering NIST connectors for medical gases as a dedicated standard. The foreword says the requirements were previously included in ISO 5359:2008 and ISO 5359:2008/Amd.1:2011.

What does the prEN ISO 18082 document contain?

The document contains dimensional figures for the NIST body, nipple, nut and assembled connector. It also contains allocation tables for gas-specific connector ranges, tables for indexing diameters and “O” ring dimensions, and a marking table that links each gas or service to its symbol.

Clause 5 gives the marking rules, and Clause 6 gives the alcohol-and-water rub test used to confirm durability. The bibliography points to related documents for low-pressure hose assemblies, vocabulary, pipeline systems, terminal units and sealing-ring dimensions.

SLOVENSKI STANDARD
01-november-2026
Anestezijska in dihalna oprema - Mere nezamenljivih nizkotlačnih priključkov z
navojem (NIST) za delo z medicinskimi plini (ISO/DIS 18082:2026)
Anaesthetic and respiratory equipment - Dimensions of non-interchangeable screw-
threaded (NIST) low-pressure connectors for medical gases (ISO/DIS 18082:2026)
Anästhesie- und Beatmungsgeräte - Maße von nichtverwechselbaren
Verbindungsstücken mit Schraubgewinde (NIST) für niedrigen Druck zur Verwendung
mit medizinischen Gasen (ISO/DIS 18082:2026)
Matériel respiratoire et anesthésique - Raccords basse pression à tête filetée non
interchangeables (NIST) pour gaz médicaux (ISO/DIS 18082:2026)
Ta slovenski standard je istoveten z: prEN ISO 18082
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.

DRAFT
International
Standard
ISO/DIS 18082
ISO/TC 121/SC 1
Anaesthetic and respiratory
Secretariat: DIN
equipment — Dimensions of non-
Voting begins on:
interchangeable screw-threaded
2026-09-25
(NIST) low-pressure connectors for
Voting terminates on:
medical gases
2026-12-18
Matériel respiratoire et anesthésique — Raccords basse pression
à tête filetée non interchangeables (NIST) pour gaz médicaux
ICS: 11.040.10
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document has not been edited by the ISO Central Secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS.
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.
Reference number
ISO/DIS 18082:2026(en)
DRAFT
ISO/DIS 18082:2026(en)
International
Standard
ISO/DIS 18082
ISO/TC 121/SC 1
Anaesthetic and respiratory
Secretariat: DIN
equipment — Dimensions of non-
Voting begins on:
interchangeable screw-threaded
(NIST) low-pressure connectors for
Voting terminates on:
medical gases
Matériel respiratoire et anesthésique — Raccords basse pression
à tête filetée non interchangeables (NIST) pour gaz médicaux
ICS: 11.040.10
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document has not been edited by the ISO Central Secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2026
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
BE CONSIDERED IN THE LIGHT OF THEIR
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
or ISO’s member body in the country of the requester.
NATIONAL REGULATIONS.
ISO copyright office
RECIPIENTS OF THIS DRAFT ARE INVITED
CP 401 • Ch. de Blandonnet 8
TO SUBMIT, WITH THEIR COMMENTS,
CH-1214 Vernier, Geneva
NOTIFICATION OF ANY RELEVANT PATENT
Phone: [phone]
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ISO/DIS 18082:2026(en)
ii
ISO/DIS 18082:2026(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Dimensions and allocation of NIST connectors. 2
5 Marking . . 9
6 Test for durability of markings . 9
Bibliography .10

iii
ISO/DIS 18082:2026(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 documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2. 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. 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 ISO/TC 121, Anaesthetic and respiratory equipment,
Subcommittee SC 1, Breathing attachments and anaesthetic machines.
This is the first edition of this International Standard that contains the requirements for non-interchangeable
screw threaded (NIST) connectors for use with medical gases previously included in ISO 5359:2008 and
ISO 5359:2008/Amd.1:2011.
iv
ISO/DIS 18082:2026(en)
Introduction
This document has been prepared in response to the need for a safe method of connecting medical equipment
intended to administer medical gases to patients or power medical devices. Medical gases are stored in
cylinders or cryogenic vessels, or can be produced on site; several medical devices (e.g. pressure regulators,
hose assemblies, flow-metering devices, lung ventilators, anaesthetic workstations) can be fitted between
the source of supply and the medical device. At each interface gas-specific connectors are needed to ensure
that the intended medical gas is administered to the patient.
While the desirability of achieving agreement on a single International Standard for screw-threaded
connectors has never been in doubt, the present pattern of usage has made such agreement impossible.
Nevertheless, fears that proliferation of individual national standards or practices will eventually result in
potentially dangerous cross-connection between components for different gases have led to the choice of
several different connector systems, all of which are intended to be incompatible with each other.
This document specifies the dimensions and the allocation of non-interchangeable screw threaded (NIST)
connectors for use with medical gases.
This document does not specify the dimensions and the allocation of
[1]
— diameter index safety system (DISS) connectors specified in CGA V-5:2019 ,
[2]
— sleeve indexed system (SIS) connectors specified in AS 2896:2021 , and
[3]
— quick connectors designed for terminal units specified in ISO 9170-1:2017 .

v
DRAFT International Standard ISO/DIS 18082:2026(en)
Anaesthetic and respiratory equipment — Dimensions of
non-interchangeable screw-threaded (NIST) low-pressure
connectors for medical gases
1 Scope
1.1 This International Standard specifies the dimensions, the allocati
...