EN ISO 16923:2026

Natural gas fuelling stations - Compressed natural gas (CNG) stations for fuelling vehicles (ISO 16923:2026)

This document specifies requirements for the design, construction, operation, maintenance and inspection of stations for fuelling compressed natural gas (CNG) to vehicles, including equipment, safety and control devices up to the fuelling nozzle to the vehicle.
This document applies to fuelling stations supplied with natural gas as defined in local applicable gas composition regulations or ISO 13686. It also applies to other gases meeting these requirements.
This document also applies to portions of a fuelling station where natural gas is in a gaseous state and dispensing CNG derived from liquefied natural gas (LCNG) according to ISO 16924.
This document covers all equipment for downstream gas supply connection (i.e. point of separation between the CNG fuelling station piping and the pipeline network). Fuelling station nozzle are not defined in this document.
This document covers fuelling stations with the following characteristics:
—     slow fill;
—     fast fill;
—     private access;
—     public access (self-service or assisted);
—     fuelling stations with fixed storage;
—     fuelling stations with mobile storage (daughter station);
—     multi-fuel stations.
This document is not applicable to vehicle to vehicle transfer or vehicle refuelling appliances (VRA).
NOTE            This document is based on the condition that the gas entering the fuelling station is odorized. For unodorized gas fuelling stations, additional safety requirements are included in Clause 10.

Gasfüllanlagen - CNG-Füllanlagen zur Betankung von Fahrzeugen (ISO 16923:2026)

Stations-service de gaz naturel - Stations de gaz naturel comprimé (GNC) pour le ravitaillement de véhicules (ISO 16923:2026)

Le présent document spécifie les exigences relatives à la conception, à la construction, à l’exploitation, à la maintenance et à l’inspection des stations de ravitaillement au gaz naturel comprimé (GNC) pour véhicules, y compris les appareils et les dispositifs de sécurité et de contrôle jusqu’au pistolet de distribution au véhicule.
Le présent document s’applique aux stations-service alimentées par gaz naturel comme cela est défini par les réglementations locales applicables en matière de composition des gaz ou par l’ISO 13686. Il s’applique également aux autres gaz qui répondent à ces exigences.
Le présent document s’applique également aux parties d’une station-service où le gaz naturel se trouve à l’état gazeux et où le GNC dérivé d’un gaz naturel liquéfié (GNLC) est distribué conformément à l’ISO 16924.
Le présent document couvre tous les appareils en aval de la connexion d’alimentation en gaz (c’est-à-dire le point de séparation entre les conduites de la station-service GNC et le réseau de canalisations). Les pistolets de distribution des stations-service ne sont pas définis dans le présent document.
Le présent document comprend les stations-service avec les caractéristiques suivantes:
remplissage lent;
remplissage rapide;
accès privé;
accès public (libre-service ou avec assistance);
stations-service avec stockage fixe;
stations-service avec stockage mobile (station secondaire);
stations multi-carburants.
Le présent document ne s’applique pas aux dispositifs de transfert de véhicule à véhicule ou de ravitaillement de véhicules (VRA).
NOTE            Le présent document repose sur la condition que les gaz fournis à la station-service soient odorisés. Pour les stations-service utilisant des gaz non odorisés, des exigences de sécurité supplémentaires sont spécifiées à l’Article 10.

Polnilne postaje za oskrbo z zemeljskim plinom - Postaje za oskrbo vozil s stisnjenim zemeljskim plinom (CNG) (ISO 16923:2026)

Ta dokument določa zahteve za načrtovanje, gradnjo, obratovanje, vzdrževanje in pregledovanje postaj za polnjenje vozil s stisnjenim zemeljskim plinom (CNG), vključno z opremo, varnostnimi in kontrolnimi napravami do polnilne šobe za vozilo.
Ta dokument se uporablja za polnilne postaje, ki so oskrbovane z zemeljskim plinom, kot je opredeljeno v lokalnih veljavnih predpisih o sestavi plina ali ISO 13686. Prav tako se uporablja za druge pline, ki izpolnjujejo te zahteve.
Ta dokument se uporablja tudi za dele polnilne postaje, kjer je zemeljski plin v plinastem stanju in kjer se razdeljuje CNG, pridobljen iz utekočinjenega zemeljskega plina (LCNG) v skladu z ISO 16924.
Ta dokument zajema vso opremo za priključitev na plinovodno omrežje (tj. točko ločitve med cevovodom polnilne postaje CNG in plinovodnim omrežjem). Polnilne šobe postaje niso opredeljene v tem dokumentu.
Ta dokument zajema polnilne postaje z naslednjimi značilnostmi:
- počasno polnjenje;
- hitro polnjenje;
- zasebni dostop;
- javni dostop (samooskrba ali pomoč);
- polnilne postaje s fiksnim skladiščenjem;
- polnilne postaje z mobilnim skladiščenjem (hčerinska postaja);
- večgorivne postaje.
Ta dokument ni uporaben za prenos med vozili ali naprave za polnjenje vozil (VRA).
OPOMBA Ta dokument temelji na pogoju, da je plin, ki vstopa v polnilno postajo, odišavljen. Za polnilne postaje z neodišavljenim plinom so dodatne varnostne zahteve vključene v 10. člen.

General Information

• Status: Published
• Publication Date: 20-Jan-2026
• ICS: 75.200 - Petroleum products and natural gas handling equipment
• Technical Committee: CEN/TC 326 - Gas supply for Natural Gas Vehicles (NGV)
• Drafting Committee: CEN/TC 326/WG 4 - LNG Fuelling Stations
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 21-Jan-2026
• Completion Date: 21-Jan-2026
• Directive: Not Harmonized2014/94/EU - Directive 2014/94/EU of The European Parliament and of The Council of 22 October 2014 on the deployment of alternative fuels infrastructure
• Mandate: M/533 - [C(2015)1330] Standardisation request addressed to CEN, CENELEC and ETSI in support of the implementation of the Directive 2014/94/EU on the deployment of alternative fuels infrastructure
• Ref Project: SIST EN ISO 16923:2026 - Natural gas fuelling stations - Compressed natural gas (CNG) stations for fuelling vehicles (ISO 16923:2026)

Relations

• Replaces: EN ISO 16923:2018 - Natural gas fuelling stations - CNG stations for fuelling vehicles (ISO 16923:2016)
• Effective Date: 18-Jan-2023
• Refers: ISO 11119-3:2020 - Gas cylinders — Design, construction and testing of refillable composite gas cylinders and tubes — Part 3: Fully wrapped fibre reinforced composite gas cylinders and tubes up to 450 l with non-load-sharing metallic or non-metallic liners or without liners
• Effective Date: 11-Mar-2026
• Refers: ISO 23684:2023 - Road vehicles — Technical personnel dealing with natural gas vehicles (NGVs) — Training and qualification
• Effective Date: 11-Mar-2026
• Refers: IEC 60079-25:2020 - Explosive atmospheres - Part 25: Intrinsically safe electrical systems
• Effective Date: 11-Mar-2026
• Refers: ISO 15500-17:2021 - Road vehicles — Compressed natural gas (CNG) fuel system components — Part 17: Flexible fuel line
• Effective Date: 11-Mar-2026
• Refers: IEC 60079-7:2015 - Explosive atmospheres - Part 7: Equipment protection by increased safety "e"
• Effective Date: 11-Mar-2026
• Refers: ISO 9809-2:2019 - Gas cylinders — Design, construction and testing of refillable seamless steel gas cylinders and tubes — Part 2: Quenched and tempered steel cylinders and tubes with tensile strength greater than or equal to 1 100 MPa
• Effective Date: 11-Mar-2026
• Refers: ISO 20607:2019 - Safety of machinery — Instruction handbook — General drafting principles
• Effective Date: 11-Mar-2026
• Refers: ISO 15500-2:2016 - Road vehicles — Compressed natural gas (CNG) fuel system components — Part 2: Performance and general test methods
• Effective Date: 11-Mar-2026
• Refers: IEC 62443-3-2:2020 - Security for industrial automation and control systems - Part 3-2: Security risk assessment for system design
• Effective Date: 11-Mar-2026
• Refers: ISO 14120:2015 - Safety of machinery — Guards — General requirements for the design and construction of fixed and movable guards
• Effective Date: 11-Mar-2026
• Refers: ISO 30013:2011 - Rubber and plastics hoses — Methods of exposure to laboratory light sources — Determination of changes in colour, appearance and other physical properties
• Effective Date: 11-Mar-2026
• Refers: ISO 11439:2013 - Gas cylinders — High pressure cylinders for the on-board storage of natural gas as a fuel for automotive vehicles
• Effective Date: 11-Mar-2026
• Refers: IEC 60079-14:2024 - Explosive atmospheres - Part 14: Electrical installation design, selection and installation of equipment, including initial inspection
• Effective Date: 11-Mar-2026
• Refers: IEC 61511-1:2016 - Functional safety - Safety instrumented systems for the process industry sector - Part 1: Framework, definitions, system, hardware and application programming requirements
• Effective Date: 11-Mar-2026

Overview

EN ISO 16923:2026 is a comprehensive international standard specifying the requirements for the design, construction, operation, maintenance, and inspection of compressed natural gas (CNG) fuelling stations for vehicles. Developed by CEN and based on ISO 16923:2026, this standard provides guidance for facilities dispensing CNG derived from natural gas or liquefied natural gas (LCNG), ensuring safe and efficient operation across various types of fuelling stations.

This standard applies to public and private CNG fuelling stations, including those with slow fill, fast fill, fixed or mobile storage, and multi-fuel configurations. It addresses natural gas quality per local regulations or ISO 13686 and incorporates sections on equipment, safety, and control devices up to the nozzle. The document specifically excludes vehicle-to-vehicle gas transfer and vehicle refuelling appliances (VRAs). Additional safety requirements are outlined for stations using unodorized natural gas.

Key Topics

EN ISO 16923:2026 covers crucial aspects for CNG station stakeholders, including:

• Design and Construction: Guidelines for planning, constructing, and modifying CNG fuelling stations. Requirements cover site layout, equipment selection, ventilation, and structural safety.
• Operation and Maintenance: Standards for fuelling procedures, routine operations, documentation, and training for competent personnel to maximize safety and efficiency.
• Equipment and Safety Devices: Requirements for compressors, buffer storage, dispensers, dryers, pressure safety systems, emergency shutdown devices, and gas detection.
• Inspection Protocols: Procedures for regular inspection and maintenance, gas detection system checks, and performance testing to ensure ongoing compliance.
• Hazardous Area Classification: Guidance for assessing and mitigating risks in station design and operation, including detailed responsibilities for zone classification and explosion protection.
• Special Configurations: Provisions for slow fill, fast fill, mobile daughter stations, fixed storage, and multi-fuel operations within the scope of applicable regulations.

Applications

This standard serves as a vital resource for diverse stakeholders in the natural gas vehicle (NGV) eco-system, including:

• CNG Fuelling Station Operators: Ensures stations comply with safety, operational reliability, and maintenance best practices.
• Designers and Engineers: Provides foundational guidance for planning new stations or upgrading existing facilities to international benchmarks.
• Equipment Manufacturers: Sets requirements for compressors, dispensers, storage vessels, and safety controls, supporting product certification and market access.
• Inspectors and Regulatory Authorities: Offers a unified framework for safety audits and regulatory compliance across the European Union and internationally.
• Transport and Logistics Companies: Facilitates expansion into CNG-powered fleets by ensuring fuelling infrastructure meets rigorous quality and safety standards.

By adhering to EN ISO 16923:2026, organizations benefit from harmonized practices, improved risk management, and the promotion of safe, reliable CNG fuelling solutions aligned with sustainability and energy transition goals.

Related Standards

EN ISO 16923:2026 references and aligns with leading international and European standards in the field, supporting comprehensive compliance. Relevant documents include:

• ISO 13686: Natural gas - Quality designation
• ISO 16924: LNG fuelling stations for vehicles (LCNG)
• ISO 834-1: Fire-resistance tests for building elements
• ISO 12100: Safety of machinery – Risk assessment
• IEC 60079 series: Explosive atmospheres protection
• ISO 15500 series: CNG fuel system components
• ISO/IEC 62443 series: Network and system security for industrial automation

Organizations planning, operating, or regulating CNG refuelling stations can utilize these standards together with EN ISO 16923:2026 to establish robust, safe, and future-ready natural gas vehicle infrastructure.

Keywords: EN ISO 16923:2026, CNG fuelling stations, natural gas vehicles, compressed natural gas, LCNG, fuelling station safety, CEN standards, station maintenance, risk management, equipment requirements.

Standards Content (Sample)

SLOVENSKI STANDARD
01-maj-2026
Nadomešča:
SIST EN ISO 16923:2018
SIST ISO 16923:2017
Polnilne postaje za oskrbo z zemeljskim plinom - Postaje za oskrbo vozil s
stisnjenim zemeljskim plinom (CNG) (ISO 16923:2026)
Natural gas fuelling stations - Compressed natural gas (CNG) stations for fuelling
vehicles (ISO 16923:2026)
Gasfüllanlagen - CNG-Füllanlagen zur Betankung von Fahrzeugen (ISO 16923:2026)
Stations-service de gaz naturel - Stations de gaz naturel comprimé (GNC) pour le
ravitaillement de véhicules (ISO 16923:2026)
Ta slovenski standard je istoveten z: EN ISO 16923:2026
ICS:
75.200 Oprema za skladiščenje Petroleum products and
nafte, naftnih proizvodov in natural gas handling
zemeljskega plina equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 16923
EUROPEAN STANDARD
NORME EUROPÉENNE
January 2026
EUROPÄISCHE NORM
ICS 75.200 Supersedes EN ISO 16923:2018
English Version
Natural gas fuelling stations - Compressed natural gas
(CNG) stations for fuelling vehicles (ISO 16923:2026)
Stations-service de gaz naturel - Stations de gaz naturel Gasfüllanlagen - CNG-Füllanlagen zur Betankung von
comprimé (GNC) pour le ravitaillement de véhicules Fahrzeugen (ISO 16923:2026)
(ISO 16923:2026)
This European Standard was approved by CEN on 4 January 2026.

This European Standard was corrected and reissued by the CEN-CENELEC Management Centre on 04 March 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 NORMALISATIO N

EUROPÄISCHES KOMITEE FÜR NORMUN G

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 16923:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Annex F (informative) A-deviation . 4

European foreword
This document (EN ISO 16923:2026) has been prepared by Technical Committee ISO/TC 340 "Natural
gas fuelling stations" in collaboration with Technical Committee CEN/TC 326 “Natural gas vehicles -
Fuelling and operation” the secretariat of which is held by TSE.
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 July 2026, and conflicting national standards shall be
withdrawn at the latest by July 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 16923:2018.
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.
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 16923:2026 has been approved by CEN as EN ISO 16923:2026 without any modification.

Annex F
(informative)
A-deviation
A-deviation: National deviation due to regulations, the alteration of which is for the time being outside
the competence of the CEN-CENELEC member.
This European standard does not fall under any Directive of the EU.
In the relevant CEN-CENELEC countries these A-deviations are valid instead of the provisions of the
European standard until they have been removed.

Country Clause Deviation
ITALY Annex B (normative) According to Italian legislation concerning rules of fire
Separation distances prevention for the design, construction and operation
of stations for fuelling compressed natural gas (CNG)

to vehicles, the internal safety distances are higher
B.3 Internal Separation
than those prescribed in the standard.
distances, Table B.1 – Internal
Ministerial Decree of 24th May 2002 by the Ministry
separation distances
of Internal Affairs (published on the Official Journal of
the Italian Republic n. 131 of 6th June 2002), as
amended by Ministerial Decree of 28th June 2002
(published on the Official Journal of the Italian
Republic n. 161 of 11th July 2002), and by Ministerial
Decree of 12th March 2019 (published on the Official
Journal of the Italian Republic n. 67 of 20th March
2019) concerning rules of fire prevention for the
design, construction and operation of stations for
fuelling compressed natural gas (CNG) to vehicles.

International
Standard
ISO 16923
Second edition
Natural gas fuelling stations —
2026-01
Compressed natural gas (CNG)
stations for fuelling vehicles
Stations-service de gaz naturel — Stations de gaz naturel
comprimé (GNC) pour le ravitaillement de véhicules
Reference number
ISO 16923:2026(en) © ISO 2026
ISO 16923:2026(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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
ISO 16923:2026(en)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 3
4 Symbols and abbreviated terms. 9
4.1 Symbols .9
4.2 Abbreviated terms .9
5 Risk management . 9
5.1 General .9
5.2 Hazardous area classification .11
5.3 Design and safety requirements for station layout and operation .11
5.4 Site layout . 12
5.5 Pressure safety relief valves and venting . 13
6 Fuel supply to the fuelling station .13
6.1 Supply by pipeline . 13
6.2 Supply by mobile storage .14
7 Dryer .15
8 Compressors .15
8.1 General . 15
8.2 Instrumentation and control .16
8.3 Compressor design.16
8.3.1 General .16
8.4 Compressor enclosures, buildings and canopies .16
8.5 Underground compressor installations .17
8.6 Hazardous area classification .18
9 Buffer storage .18
9.1 General .18
10 Dispensers .18
10.1 General requirements .18
10.2 Breakaway devices .19
10.3 Fuelling hose assemblies . 20
10.4 Fuelling hoses . 20
10.5 Dispenser enclosure .21
10.6 Fuelling controls and instrumentation . 22
10.7 Electrical systems and interconnections .24
11 Gas odorization.24
12 Pipework.25
12.1 General . 25
12.2 Buried piping . 25
13 Electrical .26
13.1 Labelling . 26
13.2 Contact with live parts . 26
13.3 Cables . 26
13.4 Performance after power fail and restoration . 26
13.5 Electrical and grounding . 26
14 Instrumentation and control system .27
14.1 General .27
14.2 Gas detection .27
14.3 Uninterruptible power supply unit (UPS) .27

iii
ISO 16923:2026(en)
15 Emergency shutdown .28
15.1 Emergency shutdown devices (ESDs) . 28
15.2 Emergency shutdown procedure . 28
15.3 Restoration after emergency shutdown . 29
16 Indoor fuelling .29
16.1 General . 29
16.2 Ventilation . 29
16.3 Additional requirements . 29
17 Testing and commissioning .30
18 Operation .30
18.1 Fuelling procedures . 30
18.2 Safety signs . 30
18.3 Training .31
18.4 Emergency response plan . .32
18.5 Explosion protection measures .32
18.6 Operations manual .32
18.7 Documentation .32
18.7.1 Traceability .32
18.7.2 Handover documents .32
19 Installation and operating instructions .32
20 Inspection and maintenance .33
20.1 Inspection and maintenance program . 33
20.2 Maintenance and testing frequency of gas detection . 33
20.3 Maintenance operations . . 34
20.3.1 General . 34
20.4 instrument loops . 34
Annex A (informative) Examples of hazardous zone classification .35
Annex B (normative) Separation distances .42
Annex C (informative) Fuelling procedures .43
Annex D (informative) Emergency instructions example .44
Annex E (informative) Example of fuelling station periodic inspection and maintenance .45
Bibliography . 47

iv
ISO 16923:2026(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 340, Natural gas fuelling stations, in
collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/TC 326,
Natural gas vehicles – Fuelling and operation, in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
This second edition cancels and replaces the first edition (ISO 16923:2016), which has been technically
revised.
The main changes are as follows:
— clarification and expansion of the scope to explicitly exclude vehicle-to-vehicle transfer and vehicle
refuelling appliances (VRAs);
— revision of Clause 2;
— revision of Clause 3, with the inclusion of new entries;
— revision of the risk management clause to incorporate a lifecycle approach, with enhanced provisions for
ignition prevention, explosion mitigation, and equipment protection;
— revision of the design and safety provisions to strengthen them, including requirements for physical
protection of exposed gas equipment, electrical system reliability, and enhanced venting and shutdown
protocols;
— revision of Annex A (hazardous zone classification) to clarify designer responsibilities in determining
hazardous areas;
— revision of annexes to reflect current operational practices, with revised examples for fuelling procedures,
emergency instructions, and maintenance programs.
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 16923:2026(en)
Natural gas fuelling stations — Compressed natural gas (CNG)
stations for fuelling vehicles
1 Scope
This document specifies requirements for the design, construction, operation, maintenance and inspection
of stations for fuelling compressed natural gas (CNG) to vehicles, including equipment, safety and control
devices up to the fuelling nozzle to the vehicle.
This document applies to fuelling stations supplied with natural gas as defined in local applicable gas
composition regulations or ISO 13686. It also applies to other gases meeting these requirements.
This document also applies to portions of a fuelling station where natural gas is in a gaseous state and
dispensing CNG derived from liquefied natural gas (LCNG) according to ISO 16924.
This document covers all equipment for downstream gas supply connection (i.e. point of separation between
the CNG fuelling station piping and the pipeline network). Fuelling station nozzle are not defined in this
document.
This document covers fuelling stations with the following characteristics:
— slow fill;
— fast fill;
— private access;
— public access (self-service or assisted);
— fuelling stations with fixed storage;
— fuelling stations with mobile storage (daughter station);
— multi-fuel stations.
This document is not applicable to vehicle to vehicle transfer or vehicle refuelling appliances (VRA).
NOTE This document is based on the condition that the gas entering the fuelling station is odorized. For
unodorized gas fuelling stations, additional safety requirements are included in Clause 10.
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 834-1, Fire-resistance tests — Elements of building construction — Part 1: General requirements
ISO 4126-1, Safety devices for protection against excessive pressure — Part 1: Safety valves
ISO 30013, Rubber and plastics hoses — Methods of exposure to laboratory light sources — Determination of
changes in colour, appearance and other physical properties
ISO 9809-1, Gas cylinders — Design, construction and testing of refillable seamless steel gas cylinders and tubes
— Part 1: Quenched and tempered steel cylinders and tubes with tensile strength less than 1 100 MPa

ISO 16923:2026(en)
ISO 9809-2, Gas cylinders — Design, construction and testing of refillable seamless steel gas cylinders and
tubes — Part 2: Quenched and tempered steel cylinders and tubes with tensile strength greater than or equal to
1 100 MPa
ISO 11119-1, Gas cylinders — Design, construction and testing of refillable composite gas cylinders and tubes —
Part 1: Hoop wrapped fibre reinforced composite gas cylinders and tubes up to 450 l
ISO 11119-2, Gas cylinders — Design, construction and testing of refillable composite gas cylinders and tubes
— Part 2: Fully wrapped fibre reinforced composite gas cylinders and tubes up to 450 l with load-sharing metal
liners
ISO 11119-3, Gas cylinders — Design, construction and testing of refillable composite gas cylinders and tubes
— Part 3: Fully wrapped fibre reinforced composite gas cylinders and tubes up to 450 l with non-load-sharing
metallic or non-metallic liners or without liners
ISO 11439, Gas cylinders — High pressure cylinders for the on-board storage of natural gas as a fuel for
automotive vehicles
ISO 11925-3, Reaction to fire tests — Ignitability of building products subjected to direct impingement of flame
— Part 3: Multi-source test
ISO 12100, Safety of machinery — General principles for design — Risk assessment and risk reduction
ISO 13847, Petroleum and natural gas industries — Pipeline transportation systems — Welding of pipelines
ISO 14120, Safety of machinery — Guards — General requirements for the design and construction of fixed and
movable guards
ISO 15500-2, Road vehicles — Compressed natural gas (CNG) fuel system components — Part 2: Performance
and general test methods
ISO 15500-17, Road vehicles — Compressed natural gas (CNG) fuel system components — Part 17: Flexible fuel
line
ISO 15589-1, Petroleum, petrochemical and natural gas industries — Cathodic protection of pipeline systems —
Part 1: On-land pipelines
ISO 15649, Petroleum and natural gas industries — Piping
ISO 23684, Road vehicles — Technical personnel dealing with natural gas vehicles (NGVs) — Training and
qualification
ISO 20607, Safety of machinery — Instruction handbook — General drafting principles
ISO 20816-8, Mechanical vibration — Measurement and evaluation of machine vibration — Part 8: Reciprocating
compressor systems
ISO 24671, Road vehicles — Qualification and certification of technical personnel dealing with natural gas
vehicles (NGVs)
IEC 31010, Risk management — Risk assessment techniques
IEC 60079-0, Electrical apparatus for explosive gas atmospheres — Part 0: General requirements
IEC 60079-1, Explosive atmospheres — Part 1: Equipment protection by flame-proof enclosures
IEC 60079-7, Explosive atmospheres - Part 7: Equipment protection by increased safety “e”
IEC 60079-10-1, Explosive atmospheres — Part 10-1: Classification of areas — Explosive gas atmospheres
IEC 60079-11, Explosive atmospheres — Part 11: Equipment Protection by Intrinsic Safety “i”
IEC 60079-14, Electrical apparatus for explosive gas atmospheres — Part 14: Electrical installations in
hazardous areas (other than mines)

ISO 16923:2026(en)
IEC 60079-17, Explosive atmospheres - Part 17: Electrical installations inspection and maintenance
IEC 60079-25, Explosive atmospheres — Part 25: Intrinsically safe electrical systems
IEC 60079-29-1, Explosive atmospheres - Part 29-1: Gas detectors - Performance requirements of detectors for
fammable gases
IEC 60079-29-4, Explosive atmospheres - Part 29-4: Gas detectors - Performance requirements of open path
detectors for fammable gases
IEC 60204-1, Safety of machinery — Electrical equipment of machines — Part 1: General requirements
IEC 60529, Degrees of protection provided by enclosures (IP Code)
IEC 61508-1, Functional safety of electrical/electronic/programmable electronic safety related systems – Part 1:
General requirements
IEC 61508-2, Functional safety of electrical/electronic/programmable electronic safety related systems – Part 2:
Requirements for electrical/electronic/programmable electronic safety related systems
IEC 61508-3, Functional safety of electrical/electronic/programmable electronic safety related systems – Part
3: Software requirements
IEC 61511-1:2016+AMD1: 2017, Functional safety – Safety instrumented systems for the process industry sector
– Part 1: Framework, definitions, system, hardware and application programming requirements
IEC 62443-2, Industrial communication networks – network and system security - Part 2: Policies and Procedures
IEC 62443-3, Industrial communication networks – network and system security – Part 3: System Level
IEC 62443-4, Industrial communication networks – network and system security – Part 4: Component Level
ISO 2615:2024, Analysis of natural gas —Biomethane — Determination of the content of compressor oil
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
assembly
sub-system of fuelling stations comprising several components
3.2
auto-extinguishing
feature of a material that ceases combustion upon removal of flame or ignition source
3.3
biomethane
methane rich gas derived from biogas or from gasification of biomass by upgrading with the properties
similar to natural gas
[SOURCE: ISO 14532:2014, 2.1.1.15]
3.4
bonding
equipotential zone where potentially live exposed metallic parts are electrically connected with at least one
point connected to the ground or earth

ISO 16923:2026(en)
3.5
breakaway device
coupling that separates at a predetermined section to protect the fuelling station from damage by vehicles
driving away while still connected to the station
3.6
buffer storage
one or more suitable pressure vessels designed for the purpose of storing compressed natural gas
3.7
building
structure, usually enclosed by walls and a roof, constructed to provide support or shelter for an intended
occupancy
3.8
bundled tube
bundles of small diameter stainless steel tubes contained within a polyethylene sheath
3.9
burst pressure
p
b
pressure that causes failure and consequential fluid loss through the component envelope
3.10
canopy
roof, overhead shelter, or hood, that affords a degree of weather protection
3.11
compresses natural gas fuelling station
CNG fuelling station
facility at which compressed natural gas is dispensed to vehicles
3.12
competent person
person having the ability, appropriate training, knowledge and experience, to supervise or carry out the
work being undertaken in a safe and proper manner with documented proof of appropriate training
3.13
compressed natural gas
CNG
natural gas which has been compressed and stored for use as a vehicle fuel
[SOURCE: ISO 15500-1:2000, 3.2]
3.14
compressor
equipment that increases the pressure of gas
3.15
conduit
casing, tubing or liner, either metallic or non-metallic
[SOURCE: ISO 14310:2008, 3.6]
3.16
cylinder
pressure vessel used for the storage of compressed natural gas
3.17
cylinder working pressure
settled pressure of a fully filled cylinder at a uniform temperature of 15 °C

ISO 16923:2026(en)
3.18
dispenser
equipment through which the fuel is supplied to the vehicle
Note 1 to entry: This equipment can include metering.
3.19
dryer
item of equipment that decreases the water vapour content (moisture) of natural gas
3.20
enclosure
structure, not being a building or canopy, that encloses a component of the fuelling station
EXAMPLE Housing, container and machine cabinet.
3.21
explosive gas atmosphere
mixture of substances with air, under atmospheric conditions, in the form of gases, vapours, mists or dusts
in which, after ignition has occurred, combustion spreads to the entire unburned mixture
[SOURCE: IEC 61340-4-4:2014, 11, 3.4]
3.22
fail-safe
design feature that ensures a system or component enters or maintains a safe condition in the event of a
malfunction or loss of power supply
Note 1 to entry: A fail-safe function may involve shutdown, isolation, or deactivation of equipment to prevent hazards.
3.23
fast fill
fuelling operation which has a designed flow rate greater than 100 m (N)/h per nozzle
3.24
field piping
piping installed for interconnection between equipment at the site
3.25
fire resistant
property that prevents or retards the passage of excessive heat, hot gases or flames under specified
conditions
3.26
fire wall
wall, or separating partition erected to reduce the effects of radiated heat
3.27
fuelling
transfer of fuel from dispenser to the vehicle
3.28
fuelling pressure
pressure at which the fuel is delivered to the vehicle
3.29
fuelling station
facility at which vehicles fuels are dispensed
3.30
grounding
electrical connection of potentially live exposed metallic parts to earth

ISO 16923:2026(en)
3.31
hazardous area
area in which an explosive gas atmosphere is present, or can be expected to be present, in quantities such
as to require special precautions for the construction, installation and use of apparatus to prevent ignition
[SOURCE: IEC 60079-10-1:2008, 3.3]
3.32
hose
pipeline of flexible material with end fittings attached
3.32.1
vent hose
pipeline of flexible material through which natural gas is vented from the fuelling connection at a vehicle
3.31.2
hose assembly
hose or hoses with ancillary components, such as bend restrictors, breakaways and nozzles, attached
3.33
intrinsically safe circuit
circuit in which any spark or thermal effect is incapable of causing ignition of a mixture of flammable or
combustible material in air under specified test conditions
3.34
lower explosive limit
LEL
volume concentration of flammable gas or vapour in air, below which the mixture is not flammable
[SOURCE: ISO 19372:2015, 3.7, modified — “explosive” has been changed to “flammable”.]
3.35
maximum allowable operating pressure
MAOP
maximum pressure that the component or system is subjected to during normal operation
Note 1 to entry: MAOP is typically not greater than 90 % of the maximum allowable working pressure of the component
or system.
3.36
maximum allowable working pressure
MAWP
maximum pressure to which a component or system is designed to be subjected and which is the basis for
determining the strength of the component or system
[SOURCE: ISO 12991:2012, 3.10, modified — “or system” has been added and “under consideration” has been
removed.]
3.36.1
mobile storage
multi-cylinder or tank fixture mounted on a vehicle or trailer and used for the transportation of natural gas
to CNG fuelling stations
3.37
multi-fuel dispenser
dispenser delivering CNG and other fuels (liquid or gaseous)
3.38
multi-fuel station
fuelling station that can fuel natural gas as well as other fuels, for example diesel, petrol, LPG

ISO 16923:2026(en)
3.39
natural gas
complex gaseous mixture of hydrocarbons, primarily methane, but generally includes ethane, propane and
higher hydrocarbons, and some non-combustible gases such as nitrogen and carbon dioxide
Note 1 to entry: Natural gas can also contain components or containments such as sulfur compounds and/or other
chemical species.
[SOURCE: ISO 14532:2014, 2.1.1.1]
3.40
non-combustible
not capable of undergoing combustion under specified conditions
[SOURCE: ISO 13943:2008, 4.239]
3.41
normal operation
situation when the equipment is operating within its design parameters
[SOURCE: ISO 16110-1:2007, 3.50]
3.42
normally occupied building
building where people are regularly present for extended durations e.g. home or workplace
3.43
non-hazardous area
area in which an explosive gas is not expected to be present in quantities such as to require special
precautions for the construction, installation and use of apparatus
[SOURCE: ISO 16110-1:2007, 3.48]
3.44
odorant
intensely smelling organic chemical or combination of chemicals added to natural gas at low concentration
and capable of imparting a characteristic and distinctive (usually disagreeable) warning odour so gas leaks
can be detected at concentrations below their lower flammability limit
Note 1 to entry: ISO/TR 16922 provides guidelines for methods used in the odorization of natural gas under a safety
point of view and specifies the principles for the odorization technique (including handling and storage of odorants)
and the control of odorization of natural gas.
[SOURCE: ISO 14532:2014, 2.8.1, modified — Note 1 to entry has been added.]
3.45
o
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