EN ISO 16923:2018

Natural gas fuelling stations - CNG stations for fuelling vehicles (ISO 16923:2016)

ISO 16923:2016 covers the design, construction, operation, inspection and maintenance of stations for fuelling compressed natural gas (CNG) to vehicles, including equipment, safety and control devices.
ISO 16923:2016 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.
ISO 16923:2016 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 including biomethane, upgraded coal-bed methane (CBM) and gas supplies coming from LNG vaporization (on-site or off-site).
ISO 16923:2016 includes all equipment for downstream gas supply connection (i.e. point of separation between the CNG fuelling station piping and the pipeline network). Fuelling station nozzles are not defined in this document.
ISO 16923:2016 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.
ISO 16923:2016 is not applicable to domestic CNG fuelling devices without buffer storage.
NOTE          ISO 16923:2016  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.

Erdgastankstellen - CNG-Tankstellen zur Betankung von Fahrzeugen (ISO 16923:2016)

Dieses Dokument behandelt den Entwurf, die Konstruktion, den Betrieb, die Inspektion und die Instandhaltung von Tankstellen zur Betankung von Fahrzeugen mit komprimiertem Erdgas (CNG, en: compressed natural gas) einschließlich Ausrüstung, Sicherheit und Steuer- und Regelvorrichtungen.
Es gilt auch für Teile einer Tankstelle, wo sich das Erdgas in einem gasförmigen Zustand befindet und komprimiertes Erdgas (CNG) abgegeben wird, das nach ISO 16924 von verflüssigtem Erdgas (LCNG, en: liquefied compressed natural gas) abgeleitet wurde.
Dieses Dokument gilt für Tankstellen, die mit Erdgas ausgestattet sind, wie in den anwendbaren örtlichen Bestimmungen über die Gaszusammensetzung oder wie in ISO 13686 festgelegt. Es gilt ebenfalls für andere Gase, die diese Anforderungen erfüllen, einschließlich Biomethan, aufbereitetes Kohleflöz-Methan (CBM, en: coal-bed methane) und Gas aus der Verdampfung von LNG (vor Ort oder im Werk).
Dieses Dokument umfasst die gesamte Ausrüstung für die nachgelagerte Gasversorgungsleitung (d. h. den Trennungspunkt zwischen den Rohrleitungen der CNG-Tankstelle und dem Rohrleitungs-Netzwerk). Füllkupplungen von Tankstellen sind in diesem Dokument nicht festgelegt.
Dieses Dokument behandelt Tankstellen mit den folgenden Eigenschaften:
   langsame Betankung;
   schnelle Betankung;
   privater Zugang;
   öffentlicher Zugang (Selbstbedienung oder mit Tankwart-Service);
   Tankstellen mit fest installierter Speicherung;
   Tankstellen mit mobiler Speicherung (Tochtertankstelle);
   Multikraftstoff-Tankstellen.
Dieses Dokument gilt nicht für CNG-Betankungseinrichtungen im häuslichen Bereich ohne Zwischenspeicher.
ANMERKUNG   Dieses Dokument basiert auf der Bedingung, dass das der Tankstelle gelieferte Gas odoriert ist. Für Tankstellen mit nicht odoriertem Gas sind zusätzliche Sicherheitsanforderungen in Abschnitt 10 enthalten.

Stations-service de gaz naturel - Stations GNC pour le ravitaillement de véhicules (ISO 16923:2016)

L'ISO 16923:2016 traite de la conception, la construction, l'exploitation, l'inspection et la maintenance des stations de ravitaillement au gaz naturel comprimé (GNC) pour véhicules, dont les appareils et les dispositifs de sécurité et de contrôle.
L'ISO 16923:2016 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 (GNCL) est distribué conformément à l'ISO 16924.
L'ISO 16923:2016 s'applique aux stations-service alimentées par gaz naturel tel que défini par les règlements locaux applicables relatifs à la composition des gaz ou par l'ISO 13686. Elle s'applique également à d'autres gaz satisfaisant à ces exigences tels que le biométhane, le méthane de houille (MH) valorisé et les gaz provenant de la vaporisation de GNL (sur ou hors site).
L'ISO 16923:2016 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 ce document.
L'ISO 16923:2016 comprend les stations-service avec les caractéristiques suivantes:
- remplissage lent;
- remplissage rapide;
- accès privé;
- accès public (self-service ou avec assistance);
- stations-service avec stockage fixe;
- stations-service avec stockage mobile (station secondaire);
- stations multi-carburants.
L'ISO 16923:2016 ne s'applique pas aux dispositifs domestiques de ravitaillement de GNC sans stockage tampon.
NOTE       L'ISO 16923:2016 repose sur la condition que les gaz fournis à la station-service sont 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 (ISO 16923:2016)

Standard ISO 16923:2016 zajema projektiranje, izgradnjo, obratovanje, nadzor in vzdrževanje polnilnih postaj za oskrbo vozil s stisnjenim zemeljskim plinom (CNG), vključno z opremo ter varnostnimi in krmilnimi napravami.
Standard ISO 16923:2016 se uporablja tudi za predele polnilnih postaj, v katerih je zemeljski plin v plinastem stanju in se vozila polnijo s stisnjenim zemeljskim plinom, ki izhaja iz utekočinjenega zemeljskega plina (LCNG) v skladu s standardom ISO 16924.
Standard ISO 16923:2016 se uporablja za polnilne postaje z zemeljskim plinom, kot je določeno v lokalnih veljavnih predpisih o sestavi plina ali standardu ISO 13686. Uporablja se tudi za druge pline, ki ustrezajo tem zahtevam, vključno z biometanom, nadgrajenim premogovnim metanom (CBM) in oskrbo s plinom, pridobljenim z uparjanjem tekočega zemeljskega plina (na mestu uporabe ali drugje).
Standard ISO 16923:2016 vključuje vso opremo za plinski priključek (npr. od točke ločitve cevovoda polnilne postaje s stisnjenim zemeljskim plinom od cevovodnega omrežja). Ta dokument ne določa šob polnilnih postaj.
Standard ISO 16923:2016 vključuje polnilne postaje z naslednjimi lastnostmi:
– s počasnim dovodom goriva;
– s hitrim dovodom goriva;
– z zasebnim dostopom;
– z javnim dostopom (samopostrežne ali ne);
– polnilne postaje s fiksnim rezervoarjem;
– polnilne postaje z mobilnim rezervoarjem (hčerinska postaja);
– postaje z različnimi vrstami plina.
Standard ISO 16923:2016 se ne uporablja za hišne polnilne postaje s stisnjenim zemeljskim plinom brez rezervoarja za začasno skladiščenje.
OPOMBA: ISO 16923:2016 temelji na pogoju, da ima plin, ki vstopa v polnilno postajo, vonj. Za polnilne postaje za oskrbo s plinom brez vonja veljajo dodatne zahteve za varnost, ki so vključene v točki 10.

General Information

• Status: Published
• Publication Date: 03-Apr-2018
• Withdrawal Date: 30-Oct-2018
• 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 1 - NGV filling stations
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 04-Apr-2018
• Due Date: 30-Nov-2019
• Completion Date: 04-Apr-2018
• Directive: 2014/94/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 16923:2018 - Natural gas fuelling stations - CNG stations for fuelling vehicles (ISO 16923:2016)

Relations

• Revised: FprEN ISO 16923 - Natural gas fuelling stations - Compressed natural gas (CNG) stations for fuelling vehicles (ISO/FDIS 16923:2025)
• Effective Date: 18-Jan-2023

Standards Content (Sample)

SLOVENSKI STANDARD
01-junij-2018
Polnilne postaje za oskrbo z zemeljskim plinom - Postaje za oskrbo vozil s
stisnjenim zemeljskim plinom (ISO 16923:2016)
Natural gas fuelling stations - CNG stations for fuelling vehicles (ISO 16923:2016)
Erdgastankstellen - CNG-Tankstellen zur Betankung von Fahrzeugen (ISO 16923:2016)
Stations-service de gaz naturel - Stations GNC pour le ravitaillement de véhicules (ISO
16923:2016)
Ta slovenski standard je istoveten z: EN ISO 16923:2018
ICS:
75.200 2SUHPD]DVNODGLãþHQMH Petroleum products and
QDIWHQDIWQLKSURL]YRGRYLQ natural gas handling
]HPHOMVNHJDSOLQD equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 16923
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2018
EUROPÄISCHE NORM
ICS 75.200
English Version
Natural gas fuelling stations - CNG stations for fuelling
vehicles (ISO 16923:2016)
Stations-service de gaz naturel - Stations GNC pour le Erdgastankstellen - CNG-Tankstellen zur Betankung
ravitaillement de véhicules (ISO 16923:2016) von Fahrzeugen (ISO 16923:2016)
This European Standard was approved by CEN on 26 January 2018.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey 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
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 16923:2018 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Annex A (informative) A-deviation . 5

European foreword
The text of ISO 16923:2016 has been prepared by ISO/TMBG “Technical Management Board - groups”
of the International Organization for Standardization (ISO) and has been taken over as
Operation” the secretariat of which is held by NEN.
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 October 2018, and conflicting national standards shall
be withdrawn at the latest by October 2018.
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 has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association.
This document has been prepared under the standardization request M/533 given to CEN by the
European Commission and the European Free Trade Association in the framework of
Directive 2014/94/EU on the deployment of alternative fuels infrastructure.
The standardization request M/533 focuses on interoperability aspects of the alternative fuels
infrastructure, which for CNG fuelling stations are covered in this document by the following items:
— Fuelling pressure (service pressure): This document applies a fuelling pressure of 20,0 MPa gauge
(200 bar) at 15 °C. This document allows possible higher fuelling pressures if the necessary
requirements as provided are met accordingly. When adopting the fuelling pressure of 20,0 MPa at
15 °C, the maximum fuelling pressure can be 26,0 MPa with “temperature compensation”.
— Connector profile: The harmonized connector profile is described in EN ISO 14469:2017, that
specifies CNG refuelling nozzles and receptacles constructed entirely of new and unused parts and
materials, for road vehicles powered by CNG, and which is referenced in this document as well as
included in UN/ECE Regulation N° 110. EN ISO 14469:2017 refers to fuelling pressures of 20 MPa
and 25 MPa for both "size 1" (B200 and B250) and "size 2" (C200 and C250).
In addition to interoperability aspects, the following aspects are relevant for applying this document in
Europe:
— Fuel quality: The quality of CNG for use as automotive fuel is covered in EN 16723-2:2017, that
specifies the requirements and test methods for natural gas, biomethane and blends of both.
— Fuel labelling: The fuel label for CNG at dispensers is covered by EN 16942:2016, that lays down
harmonized identifiers for marketed liquid and gaseous fuels, and which has also been developed
to support Directive 2014/94/EU.
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, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 16923:2016 has been approved by CEN as EN ISO 16923:2018 without any modification.

Annex A
(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 national 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 –
th
Ministerial Decree of 24 May 2002 (published on the
Internal separation
Official Journal of the Italian Republic n. 131 of
distances
th
6 June 2002), as amended by Ministerial Decree of
28th June 2002 (published on the Official Journal of
th
the Italian Republic n. 161 of 11 July 2002)

INTERNATIONAL ISO
STANDARD 16923
First edition
2016-12-15
Natural gas fuelling stations — CNG
stations for fuelling vehicles
Stations-service de gaz naturel — Stations GNC pour le ravitaillement
de véhicules
Reference number
ISO 16923:2016(E)
©
ISO 2016
ISO 16923:2016(E)
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2016 – All rights reserved

ISO 16923:2016(E)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols and abbreviated terms . 8
4.1 Symbols . 8
4.2 Abbreviated terms . 8
5 Risk management . 8
6 General design requirements . 9
6.1 General . 9
6.2 Site layout .10
6.3 Pressure safety relief valves and venting .10
7 Fuel supply to the fuelling station .11
7.1 Supply by pipeline .11
7.2 Supply by mobile storage .11
8 Dryer .12
9 Compressors .12
9.1 General .12
9.2 Instrumentation and control .13
9.3 Crankcase design .13
9.4 Compressor enclosures, buildings and canopies .14
9.5 Underground compressor installations .16
9.6 Hazardous area classification.16
10 Buffer storage .16
11 Dispensers .17
11.1 General requirements .17
11.2 Breakaway devices .17
11.3 Fuelling hose assemblies .18
11.4 Fuelling hoses .19
11.5 Enclosure .19
11.6 Fuelling controls and instrumentation .20
11.7 Electrical systems and interconnections .22
11.8 Documentation .22
12 Gas odorization .22
13 Pipework .23
13.1 General .23
13.2 Buried piping .23
14 Electrical .24
14.1 Labelling .24
14.2 Contact with live parts.24
14.3 Cables .24
14.4 Performance after power fail and restoration .24
14.5 Electrical bonding and grounding .25
15 Instrumentation and control system .25
15.1 Gas detection .25
15.2 Emergency shutdown devices .25
16 Emergency shutdown .26
16.1 Emergency shutdown procedure .26
ISO 16923:2016(E)
16.2 Restoration after emergency shutdown .26
17 Indoor fuelling .26
17.1 General .26
17.2 Ventilation .26
17.3 Additional requirements .27
18 Testing and commissioning .27
19 Operation .28
19.1 Fuelling procedures .28
19.2 Safety signs .28
19.3 Training .28
19.4 Emergency response plan .29
19.5 Operations manual .29
20 Inspection and maintenance .29
20.1 Inspection and maintenance program.29
20.2 Maintenance and testing frequency of gas detection .30
Annex A (informative) Examples of hazardous zone classification .31
Annex B (normative) Separation distances .38
Annex C (informative) Fuelling procedures .39
Annex D (informative) Emergency instructions example .40
Annex E (informative) Example of fuelling station periodic inspection and maintenance .41
Bibliography .43
iv © ISO 2016 – All rights reserved

ISO 16923:2016(E)
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 (see 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 (see 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 World Trade Organization (WTO) principles in the
Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.
The committee responsible for this document is ISO/PC 252, Natural gas fuelling stations for vehicles.
INTERNATIONAL STANDARD ISO 16923:2016(E)
Natural gas fuelling stations — CNG stations for fuelling
vehicles
1 Scope
This document covers the design, construction, operation, inspection and maintenance of stations for
fuelling compressed natural gas (CNG) to vehicles, including equipment, safety and control devices.
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 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
including biomethane, upgraded coal-bed methane (CBM) and gas supplies coming from LNG
vaporization (on-site or off-site).
This document includes all equipment for downstream gas supply connection (i.e. point of separation
between the CNG fuelling station piping and the pipeline network). Fuelling station nozzles 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 domestic CNG fuelling devices without buffer storage.
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 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 7-1, Pipe threads where pressure-tight joints are made on the threads — Part 1: Dimensions, tolerances
and designation
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 8580, Rubber and plastics hoses — Determination of ultra-violet resistance under static conditions
ISO 16923:2016(E)
ISO 9809-1, Gas cylinders — Refillable seamless steel gas cylinders — Design, construction and testing —
Part 1: Quenched and tempered steel cylinders with tensile strength less than 1 100 MPa
ISO 9809-2, Gas cylinders — Refillable seamless steel gas cylinders — Design, construction and testing —
Part 2: Quenched and tempered steel cylinders with tensile strength greater than or equal to 1 100 MPa
ISO 11119-1, Gas cylinders — Refillable composite gas cylinders and tubes — Design, construction and
testing —Part 1: Hoop wrapped fibre reinforced composite gas cylinders and tubes up to 450 l
ISO 11119-2, Gas cylinders — Refillable composite gas cylinders and tubes — Design, construction and
testing — 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 — Refillable composite gas cylinders and tubes — Design, construction and
testing — Part 3: Fully wrapped fibre reinforced composite gas cylinders and tubes up to 450L with non-
load-sharing metallic or non-metallic 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
IEC 31010, Risk management — Risk assessment techniques
IEC 60079-0, Electrical apparatus for explosive gas atmospheres — Part 0: General requirements
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)
IEC 60079-25, Explosive atmospheres — Part 25: Intrinsically safe electrical systems
IEC 60204-1, Safety of machinery — Electrical equipment of machines — Part 1: General requirements
IEC 60529, Degrees of protection provided by enclosures (IP Code)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2 © ISO 2016 – All rights reserved

ISO 16923:2016(E)
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
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 ground/earth
3.5
breakaway device
coupling which separates at a predetermined section when required and each separated section
contains a self-closing shut-off valve which seals automatically
[SOURCE: ISO/TS 18683:2015, 3.1.3]
3.6
buffer storage
one or more suitable pressure vessels designed for the purpose of storing compressed natural gas
3.7
building
structures, usually enclosed by walls and a roof, constructed to provide support or shelter for an
intended occupancy
3.8
burst pressure
p
b
pressure that causes failure and consequential fluid loss through the component envelope
3.9
canopy
roof, overhead shelter, or hood, that affords a degree of weather protection
3.10
CNG fuelling station
facility at which compressed natural gas is dispensed to vehicles
3.11
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
ISO 16923:2016(E)
3.12
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]
3.13
compressor
machine that increases the pressure of gas
3.14
conduit
casing, tubing or liner, either metallic or non-metallic
[SOURCE: ISO 14310:2008, 3.6]
3.15
cylinder
pressure vessel used for the storage of compressed natural gas
3.16
cylinder working pressure
settled pressure of a fully filled cylinder at a uniform temperature of 15 °C
3.17
dispenser
equipment through which the fuel is supplied to the vehicle
Note 1 to entry: This equipment can include metering.
3.18
dryer
equipment which decreases the water vapour content (moisture) of natural gas
3.19
enclosure
structure, not being a building or canopy, that encloses a component of the fuelling station
EXAMPLE Housing, container and machine cabinet.
3.20
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]
3.21
fail-safe
design feature that ensures that safe conditions are maintained in the event of a malfunction of a
control device or an interruption of a supply source
3.22
fast fill
fuelling operation which has a designed flow rate greater than 100 m (N)/h per nozzle
3.23
field piping
piping installed for interconnection between equipment at the site
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ISO 16923:2016(E)
3.24
fire resistant
property that prevents or retards the passage of excessive heat, hot gases or flames under specified
conditions
3.25
fire wall
wall, or separating partition erected to reduce the effects of radiated heat
3.26
fuelling
transfer of fuel from dispenser to the vehicle
3.27
fuelling pressure
pressure at which the fuel is delivered to the vehicle
3.28
fuelling station
facility at which vehicles fuels are dispensed
3.29
grounding
electrical connection of potentially live exposed metallic parts to earth
3.30
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]
3.31
hose
pipeline of flexible material with end fittings attached
3.31.1
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
3.32
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
3.33
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”.]
ISO 16923:2016(E)
3.34
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.
3.35
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
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
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
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]
6 © ISO 2016 – All rights reserved

ISO 16923:2016(E)
3.43
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
odor so gas leaks can be detected at concentrations below their lower flammability limit
Note 1 to entry: ISO/TR 16922 gives the specifications and guidelines for the methods to be 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.]
3.44
odorization
process of introducing odorant(s) into natural gas
3.45
overpressure
condition under which the pressure exceeds the maximum allowable working pressure
3.46
power failure
reduction in power such that any electrical component or sub system (such as flow control) are
operating outside manufacturers specification
3.47
refuelling receptacle
device connected to a vehicle or storage system which receives the CNG refuelling nozzle and
permits safe transfer of fuel
[SOURCE: ISO 14469-1:2004, 3.7]
3.48
separation distance
minimum separation between a hazard source and an object, which is required to mitigate the effect of
a likely foreseeable incident and prevent a minor incident escalating into a larger incident
3.48.1
external separation distance
separation distance between a hazard source and an object situated outside the boundaries of the
fuelling station
3.48.2
internal separation distance
separation distance between a hazard source and an object situated within the boundaries of the
fuelling station
3.49
service duct
enclosed conduit through which gas piping, utility piping, electrical cabling, etc. is routed
3.50
settled pressure
gas pressure when a given settled temperature is reached and there is no gas flow
3.51
settled temperature
uniform gas temperature in the cylinder after the dissipation of any heat caused by fuelling
3.52
slow fill
fuelling operation which has a designed flow rate equal or less than 100 m (N)/h per nozzle
ISO 16923:2016(E)
3.53
vault
room or space, typically situated underground
3.54
ventilation
movement of air and its replacement with fresh air due to the effects of wind, temperature gradients, or
artificial means (for example fans or extractors)
3.55
venting
controlled release of natural gas to the atmosphere
3.56
zone
hazardous area classified based upon the frequency of the occurrence and duration of an explosive gas
atmosphere
[SOURCE: IEC 60079-10-1:2015, 3.3.3, modified — “gas” has been added.]
4 Symbols and abbreviated terms
4.1 Symbols
p burst pressure
b
p maximum allowable working pressure
MAWP
4.2 Abbreviated terms
CNG compressed natural gas
IS intrinsically safe
ERP emergency response plan
LEL lower explosive limit
MAOP maximum allowable operating pressure
MAWP maximum allowable working pressure
NGV natural gas vehicle
P&I process and instruments
5 Risk management
5.1 Risk assessment shall follow the techniques described in ISO 12100 for assessment of machinery
safety and IEC 31010 for general site risk management, or local applicable standards.
5.2 The CNG fuelling station installation shall be sited to minimize risk to users, operating personnel,
properties, and environment.
5.3 Risk assessment shall include design, construction, operation and maintenance of the CNG fuelling
station. The risk assessment process shall be used to evaluate the consequences of hazardous events and
to determine appropriate means of risk reduction and/or mitigation of consequences.
5.4 Measures to reduce fire and explosion risks shall be applied, including but not limited to:
— prevention of the formation of a flammable or explosive mixture;
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ISO 16923:2016(E)
— prevention of static charge build-up;
— avoidance of ignition sources;
— mitigation of the effects of a fire or explosion.
5.5 Protection from ignition in explosive atmospheres shall be by the use of protection systems defined
in the IEC 60079 series where the applicable hazard zones are defined in IEC 60079-10-1.
NOTE Examples of hazardous area classifications are given in Annex A.
6 General design requirements
6.1 General
6.1.1 Installation and equipment design shall minimize the number of connections and other possible
points of leakage or release to atmosphere.
6.1.2 Configurations generating the possibility of a confined explosive atmosphere should be avoided.
Fire and explosion risk prevention shall take into account foreseeable malfunctions and misuse.
6.1.3 Underground service ducts routing natural gas pipeline shall not be shared with other services
(e.g. water piping, fuel piping, electrical cabling).
6.1.4 Pressure indication shall be provided such that the pressure on any piping segment can be
determined.
6.1.5 Pressure piping system shall have provision for safe manual depressurization. Depressurization
shall not be performed by opening pipe joints.
6.1.6 The mounting of equipment and supporting foundations shall be designed and constructed to be
suitable for local seismic and geological conditions.
6.1.7 All CNG equipment exposed to the risk of vehicle collision shall be provided with barriers or
other mechanisms to protect the gas equipment from collision damage.
6.1.8 The CNG fuelling station shall be designed to shut down safely in the event of a loss of power.
Restoration of power shall be in accordance with 16.2.
6.1.9 The CNG fuelling station shall include firefighting equipment in accordance with local applicable
regulations.
6.1.10 The CNG fuelling station shall have means of ensuring that oil carryover from the compressor,
dust, water and other contaminants in the gas stream meet the local applicable gas quality standards or
regulations.
6.1.11 All equipment shall be operated within temperature and pressure limits specified by the
manufacturer.
6.1.12 The CNG fuelling station shall be designed while taking into account the specific climatic
conditions of the site location and expected minimum and maximum temperatures.
ISO 16923:2016(E)
6.2 Site layout
6.2.1 The CNG fuelling station separation distances shall follow the requirements listed in Annex B.
6.2.2 The CNG fuelling installation shall be designed so that authorized personnel shall have easy
access to and exit from the operating area of the installation at all times.
6.2.3 Adequate means of escape in the case of emergency shall be provided. I
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