oSIST prEN ISO 18082:2026

• 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
• Public Enquiry End Date: 29-Nov-2026
• ICS: 11.040.10 - Anaesthetic, respiratory and reanimation equipment
• Technical Committee: VAZ - Healthcare
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 06-Oct-2026
• Due Date: 23-Feb-2027
• Ref Project: prEN ISO 18082 - Anaesthetic and respiratory equipment - Dimensions of non-interchangeable screw-threaded (NIST) low-pressure connectors for medical gases (ISO/DIS 18082:2026)

• Revises: SIST 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
• Revises: SIST EN ISO 18082:2014/A1:2018 - 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

oSIST prEN ISO 18082:2026 is a SIST 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, so connector interfaces stay gas-specific. It is aimed at manufacturers, designers, test labs and others who fit, inspect or verify medical devices and gas supply components.

What does oSIST prEN ISO 18082:2026 specify?

oSIST prEN ISO 18082:2026 covers NIST connectors used at operating pressures up to 1 400 kPa and for vacuum systems at pressures not greater than 60 kPa absolute. It applies to connectors for oxygen, nitrous oxide, medical air, helium, carbon dioxide, xenon, specified mixtures of those gases, oxygen 90+ (O 90+), air and nitrogen for driving surgical tools, and vacuum.

The document focuses on the connector interface itself. It leaves out manufacturer-supplied information and points users to the manufacturer of each medical device for operating information about permanently fitted connectors. The introduction also separates NIST from other connector systems such as DISS, SIS and terminal-unit quick connectors.

The standard is organized into Scope, Normative references, Terms and definitions, Dimensions and allocation of NIST connectors, Marking, Test for durability of markings, and a Bibliography.

What are the key requirements of oSIST prEN ISO 18082:2026?

oSIST prEN ISO 18082:2026 is mainly a dimensional and identification standard. The practical job is to make sure the wrong gas service cannot be connected by mistake, and that the connector can still be identified after cleaning and use.

Pressure range and gas service

Clause 1 limits the connector family to low-pressure gas services up to 1 400 kPa and vacuum up to 60 kPa absolute. Clause 1 also names the gases and mixtures covered. In practice, users must select the correct connector family for each gas service and not apply it outside those pressure conditions.

Allocation and geometry

Clause 4 assigns NIST connectors to gas services in Table 1 and states that left-hand threads have not been allocated. The body, nipple and nut dimensions are defined by Figures 1 to 4 and Tables 2 to 4. In practice, this is what keeps different gas services physically incompatible and gives manufacturers the dimensions to design, machine and inspect.

Verification method

Clause 4 says compliance is verified by measurement and visual inspection. That means dimensional checking is not optional and the connector identification must also be checked by eye. This is the basis for incoming inspection, production control and final release testing.

Marking

Clause 5 requires durable, legible marking with the gas symbol from Table 5, and it allows the gas name to be added. The marking must be readable to a person with corrected visual acuity of 1 from 0.5 m away at 215 lux. In practice, the marking has to remain visible under normal lighting and handling, not just when new.

Durability test for markings

Clause 6 gives a wipe test for marking durability: the markings are rubbed by hand with a cloth soaked in distilled water, then methylated spirit, then isopropyl alcohol, each for 15 s at ambient temperature. The marking is then checked for legibility. This gives manufacturers a simple way to show that identification survives routine cleaning.

Sealing parts

Table 4 gives the dimensions of the “O” rings used with the connector ranges. The figures also identify the position of the marking symbols and the assembly arrangement. For users, this means the sealing elements are part of the connector system and must match the defined sizes.

What terms does oSIST prEN ISO 18082:2026 define?

• gas-specific - Designed so that connectors for different gas services or vacuum services cannot be connected together.
• medical gas - A gas or gas mixture used 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 family that uses different diameters and left- or right-hand threads to preserve gas-specificity.
• NIST - The abbreviation used throughout the document for non-interchangeable screw-threaded connectors.

Who uses oSIST prEN ISO 18082:2026?

oSIST prEN ISO 18082:2026 is used by manufacturers of anaesthetic and respiratory equipment, by makers of medical devices with permanently fitted NIST connectors, and by engineers who design medical gas interfaces. It is also relevant to quality control and inspection teams that measure dimensions, check allocation and verify marking durability.

In practice, it applies to devices and systems such as pressure regulators, hose assemblies, flow-metering devices, lung ventilators and anaesthetic workstations, as well as supplies for surgical tools and vacuum services.

What changed in oSIST prEN ISO 18082:2026 from the previous edition?

oSIST prEN ISO 18082:2026 is the first edition to contain the requirements for NIST connectors for medical gases that were previously included in ISO 5359:2008 and ISO 5359:2008/Amd.1:2011. For users, that means the connector dimensions, allocation and marking are gathered in one dedicated document.

Which standards are used with oSIST prEN ISO 18082:2026?

The document cites and references several related standards and companion documents:

• ISO 5359 - low-pressure hose assemblies for medical gases and vacuum.
• ISO 4135:2022 - vocabulary for anaesthetic and respiratory equipment, including the definition of medical gas.
• ISO 4135:2022/DAmd 1.2 - will add a definition for oxygen 90+.
• ISO 7396-1:2016+Amd1:2017 - medical gas pipeline systems, including the gas-specific concept.
• ISO 9170-1:2017 - terminal units for medical gas pipeline systems, a different connector system named for comparison.
• ISO 48-2:2018 - hardness testing for rubber, used for the “O” ring notes.
• BS 4518:1982+A2:2014 - metric dimensions for toroidal sealing rings (“O” rings) and housings.
• CGA V-5:2019 and AS 2896:2021 - other non-interchangeable connector systems mentioned in the introduction.

What does the oSIST prEN ISO 18082:2026 document contain?

oSIST prEN ISO 18082:2026 is built around drawings, tables and a simple marking test. Figures 1 to 4 show the body, nipple, nut and assembled connector. Tables 1 to 3 allocate gas services and give the indexed connector dimensions, while Table 4 gives the “O” ring sizes and Table 5 gives the marking symbols.

Clause 6 provides the durability check for the markings, using water, methylated spirit and isopropyl alcohol. For readers, the document is mainly a design and inspection reference for connector geometry, identification and basic marking durability.

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
...