prEN 17921

Natural gas vehicles - Fuelling and operation - Natural gas fuelling stations - LNG unloading connector

This document provides the design for an LNG (un)loading connector between LNG road tanker and LNG fuelling stations. This document can be also used for LNG rail tenders. This document includes requirements for (at least):
-   functional description of the LNG Unloading Receptacle and LNG Unloading Nozzle;
-   technical layout description of the LNG Unloading Receptacle.
The technical layout description of the LNG Unloading Nozzle is not part of this document.
The basic functional requirement of the LNG unloading connector are as follows:
-   to prevent leakage of methane during operation and in particular during disconnecting;
-   easy handling, no spillage and purging with nitrogen during disconnecting.
The loading connector between the LNG road tanker and the LNG terminal is not covered by this document.
See Figure 1.
[Figure not represented]
Figure 1 - Scope of the document

Gasfahrzeuge - Betankung und Betrieb - Gasfüllanlagen - LNG-Entladeanschluss

Dieses Dokument enthält die Auslegung für einen LNG-(Ent-)Ladeanschluss zwischen LNG-Straßentankwagen und LNG-Füllanlagen. Dieses Dokument kann auch für LNG-Schlepptender angewendet werden. Dieses Dokument enthält Anforderungen für (mindestens):
-   die Funktionsbeschreibung des LNG-Entladeempfängerstutzens und des LNG-Entladestutzens;
-   die Beschreibung der technischen Gestaltung des LNG-Entladeempfängerstutzens.
Die Beschreibung der technischen Gestaltung des LNG-Entladestutzens ist nicht Teil dieses Dokuments.
Die grundlegenden Funktionsanforderungen an den LNG-Entladeanschluss sind wie folgt:
-   Verhinderung der Leckage von Methan während des Betriebs und insbesondere beim Trennen der Verbindung;
-   einfache Handhabung, kein Auslaufen und Spülen mit Stickstoff beim Trennen der Verbindung.
Der Ladeverbinder zwischen dem LNG-Straßentankwagen und dem LNG-Terminal wird in diesem Dokument nicht behandelt.
Siehe Bild 1.
[figure not represented]
Bild 1 - Anwendungsbereich des Dokuments

Véhicules au gaz naturel - Remplissage et utilisation - Stations-service de gaz naturel - Connecteur de déchargement de GNL

Le présent document fournit la conception d'un connecteur de (dé)chargement entre un camion-citerne GNL et les stations-service GNL. Le présent document peut également être utilisé pour les tenders ferroviaires GNL. Le présent document inclut les exigences pour (au moins) :
-   la description fonctionnelle de l'about de déchargement de GNL et du pistolet de déchargement de GNL ;
-   la description de la disposition technique de l'about de déchargement de GNL.
La description de la disposition technique du pistolet de déchargement de GNL n'est pas incluse dans le présent document.
Les exigences fonctionnelles de base concernant le connecteur de déchargement de GNL sont les suivantes :
-   empêcher la fuite de méthane pendant le fonctionnement, en particulier lors de la déconnexion ;
-   manipulation facile, aucun déversement et purge à l'azote lors de la déconnexion.
Le connecteur de chargement entre le camion-citerne GNL et le terminal GNL n'est pas couvert par le présent document.
Voir Figure 1.

Vozila na zemeljski plin - Polnjenje in delovanje - Polnilne postaje za oskrbo z utekočinjenim zemeljskim plinom - Priključki za raztovarjanje

General Information

• Status: Not Published
• Publication Date: 19-Jan-2025
• ICS: 43.080.10 - Trucks and trailers
• 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: 4060 - Closure of enquiry - Enquiry
• Start Date: 16-Mar-2023
• Due Date: 23-Aug-2022
• Completion Date: 16-Mar-2023
• 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
• Ref Project: oSIST prEN 17921:2023 - Natural gas vehicles - Fuelling and operation - Natural gas fuelling stations - LNG unloading connector

Standards Content (Sample)

SLOVENSKI STANDARD
oSIST prEN 17921:2023
01-januar-2023
Vozila na zemeljski plin - Polnjenje in delovanje - Polnilne postaje za oskrbo z
utekočinjenim zemeljskim plinom - Priključki za raztovarjanje

Natural gas vehicles - Fuelling and operation - Natural gas fuelling stations - LNG

unloading connector
Gasfüllanlagen - LNG-(Ent-)Ladekupplung für mobile LNG-Lagerung
Ta slovenski standard je istoveten z: prEN 17921
ICS:
43.040.01 Sistemi za cestna vozila na Road vehicle systems in
splošno general
75.200 Oprema za skladiščenje Petroleum products and
nafte, naftnih proizvodov in natural gas handling
zemeljskega plina equipment
oSIST prEN 17921:2023 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 17921:2023
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oSIST prEN 17921:2023
DRAFT
EUROPEAN STANDARD
prEN 17921
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2022
ICS 75.200
English Version
Natural gas vehicles - Fuelling and operation - Natural gas
fuelling stations - LNG unloading connector
Gasfüllanlagen - LNG-(Ent-)Ladekupplung für mobile
LNG-Lagerung

This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee

CEN/TC 326.

If this draft becomes a European Standard, 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.

This draft European Standard was established by CEN 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.

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.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without

notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 17921:2022 E

worldwide for CEN national Members.
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oSIST prEN 17921:2023
prEN 17921:2022 (E)
Contents Page

European foreword .................................................................................................................................................... 4

Introduction .................................................................................................................................................................. 5

1 Scope .................................................................................................................................................................. 6

2 Normative references .................................................................................................................................. 7

3 Terms and definitions ................................................................................................................................. 7

4 Functional requirements ........................................................................................................................... 9

4.1 General requirement ................................................................................................................................... 9

4.2 Functional description of the LNG unloading connector ................................................................ 9

4.2.1 General.............................................................................................................................................................. 9

4.2.2 Dry connector ................................................................................................................................................. 9

4.2.3 Protective cap ................................................................................................................................................. 9

4.2.4 Type of mounting .......................................................................................................................................... 9

4.2.5 Positive locking ............................................................................................................................................. 9

4.2.6 safe disconnect ............................................................................................................................................ 10

4.2.7 (Internal) Check valve .............................................................................................................................. 10

4.2.8 Venting and depressurization ............................................................................................................... 10

4.2.9 Electrical conductivity ............................................................................................................................. 10

4.2.10 Spillage volume ........................................................................................................................................... 10

5 Technical description of LNG unloading connector ...................................................................... 10

5.1 Materials ....................................................................................................................................................... 10

5.1.1 General........................................................................................................................................................... 10

5.1.2 LNG unloading connector ........................................................................................................................ 11

5.1.3 Corrosion protection ................................................................................................................................ 11

5.2 Pressure rating ........................................................................................................................................... 11

5.2.1 Maximum allowable working pressure (MAWP) ........................................................................... 11

5.2.2 Maximum working pressure .................................................................................................................. 11

5.2.3 Design cycle life; ......................................................................................................................................... 11

5.3 LNG unloading connector mounting ................................................................................................... 11

5.4 LNG unloading connector working temperature range ............................................................... 11

5.4.1 General........................................................................................................................................................... 11

5.4.2 Material of the bodies of the LNG Unloading Receptacle and of the LNG unloading

nozzle ............................................................................................................................................................. 11

6 Design of the LNG unloading connector ............................................................................................. 11

7 Tests requirements ................................................................................................................................... 13

7.1 General requirements .............................................................................................................................. 13

7.1.1 General........................................................................................................................................................... 13

7.1.2 Ambient test conditions .......................................................................................................................... 13

7.1.3 Cryogenic test conditions ........................................................................................................................ 14

7.2 Shell tightness at ambient temperature ............................................................................................ 14

7.3 Shell strength at ambient temperature ............................................................................................. 14

7.4 Seat tightness at ambient temperature ............................................................................................. 14

7.5 Obturator strength at ambient temperature against atmosphere .......................................... 14

7.6 Shell tightness at minimum working temperature ....................................................................... 15

7.7 Seat tightness at minimum working temperature ......................................................................... 15

7.7.1 General........................................................................................................................................................... 15

7.7.2 Test arrangement for LNG unloading nozzle (Figure 3) .............................................................. 15

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7.7.3 Test arrangement for LNG unloading receptacle ............................................................................ 16

7.8 Burst test ........................................................................................................................................................ 16

7.9 Operation test at minimum working temperature ........................................................................ 16

7.10 Endurance test ............................................................................................................................................. 16

7.11 Bending test .................................................................................................................................................. 16

7.12 Drop test ........................................................................................................................................................ 17

7.13 Cycle testing .................................................................................................................................................. 18

7.14 Tensile force ................................................................................................................................................. 18

7.14.1 Manual force in warm conditions ......................................................................................................... 18

7.14.2 Manual force at cold conditions under frost ..................................................................................... 18

7.15 Corrosion resistance ................................................................................................................................. 18

8 Safety requirements .................................................................................................................................. 18

9 Operational aspects ................................................................................................................................... 18

10 Maintenance ................................................................................................................................................. 19

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oSIST prEN 17921:2023
prEN 17921:2022 (E)
European foreword

This document (prEN 17921:2022) has been prepared by Technical Committee CEN/TC 326 “Natural gas

vehicles - Fuelling and operation”, the secretariat of which is held by TSE.
This document is currently submitted to the CEN Enquiry.
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oSIST prEN 17921:2023
prEN 17921:2022 (E)
Introduction

The transport of LNG over the road in Europa is organized through ADR regulations. This European

Agreement concerning the International Carriage of Dangerous Goods by Road specifies the safety

procedures of the road tanker and driver. The design, construction, operation, maintenance and

inspection including equipment safety and control devices for LNG fuelling stations are described in

EN ISO 16924:2016 “Natural gas fuelling stations — LNG stations for fuelling vehicles”.

This document describes a harmonized (un)loading connector for LNG road tanker at LNG fuelling

stations.

While LNG is also transported by rail, European regulations are organized through the International

Carriage of Dangerous Goods by Rail (RID). The same configuration as defined by this document, can be

utilized for LNG RID applications.
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oSIST prEN 17921:2023
prEN 17921:2022 (E)
1 Scope

This document provides the design for an LNG (un)loading connector between LNG road tanker and LNG

fuelling stations. This document can be also used for LNG rail tenders. This document includes

requirements for (at least):

— functional description of the LNG Unloading Receptacle and LNG Unloading Nozzle;

— technical layout description of the LNG Unloading Receptacle.

The technical layout description of the LNG Unloading Nozzle is not part of this document.

The basic functional requirement of the LNG unloading connector are as follows:

— to prevent leakage of methane during operation and in particular during disconnecting;

— easy handling, no spillage and purging with nitrogen during disconnecting.

The loading connector between the LNG road tanker and the LNG terminal is not covered by this

document.
See Figure 1.
Figure 1 — Scope of the document
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oSIST prEN 17921:2023
prEN 17921:2022 (E)
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 16903:2015, Petroleum and natural gas industries — Characteristics of LNG, influencing the design,

and material selection

ISO 16924:2016, Natural gas fuelling stations — LNG stations for fuelling vehicles

ISO 2768-1:1989, General tolerances — Part 1: Tolerances for linear and angular dimensions without

individual tolerance indications
ISO 5208:2015, Industrial valves — Pressure testing of valves
EN 10272:2016, Stainless steel bars for pressure purposes

EN 12266-1:2012, Industrial valves — Testing of metallic valves — Part 1: Pressure tests, test procedures

and acceptance criteria — Mandatory requirements

EN 12516-1:2014+A1:2018, Industrial valves — Shell design strength — Part 1: Tabulation method for

steel valve shells

EN 12516-2:2014+A1:2021, Industrial valves — Shell design strength — Part 2: Calculation method for

steel valve shells

ISO 6708:1995, Pipework components — Definition and selection of DN (nominal size)

EN 13480-1:2017, Metallic industrial piping: General

EN ISO 9227:2017, Corrosion tests in artificial atmospheres — Salt spray tests ISO 9227:2017)

3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
offloading

process of transferring LNG from the LNG road tanker to the LNG storage of the fuelling station

3.2
LNG offloading area

area where the LNG road tanker connects to the LNG fuelling station for offloading LNG into the LNG

storage tank
3.3
LNG transfer point

connection point between the hose of the LNG tanker and the fixed pipeline to the LNG storage tank

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3.4
LNG road tanker
vehicle to carry bulk LNG on the road

Note 1 to entry: For example, a cryogenic vacuum insulated tank mounted on a truck or semi-trailer or an ISO

container, fixed on a truck or trailer.
3.5
LNG unloading connector
joined assembly of LNG unloading nozzle (3.7) and LNG unloading receptacle (3.6)
3.6
LNG unloading receptacle

device (3.8) connected to the unloading point of an LNG fuelling station which permits quick connection

and disconnection of the unloading hose between LNG road tanker and LNG fuelling station storage

3.7
LNG unloading nozzle

device (3.8) connected to the unloading hose of the LNG road tanker which permits a quick connection

and disconnection with the LNG Unloading Receptacle to safely transfers LNG to the LNG storage of a

fuelling station
3.8
device
LNG unloading nozzle or receptacle
3.9
maximum allowable working pressure MAWP

maximum pressure to which the LNG unloading connector is designed to be subjected and which is the

basis of determining the strength of the connector
3.10
working pressure

pressure to which the LNG unloading connector is designed to be subjected to during normal operation

3.11
working temperature

temperature to which the LNG unloading connector is designed to be subjected to during normal

operation
3.12
check valve

part of the LNG unloading receptacle and of the LNG unloading nozzle mounted inside, preventing return

flow or venting of fuel after the LNG unloading nozzle was disconnected from the LNG unloading

receptacle
3.13
cycle life

number of unloading cycles, as specified in this document, which the component can withstand without

leak or without another fail of function
3.14
obturator
closing part of the check valve
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4 Functional requirements
4.1 General requirement

A dry LNG unloading connector is required for the LNG transfer between LNG road tanker and LNG

storage.

a) The LNG unloading receptacle certified to this document shall be functionally compatible from a

safety and performance perspective with all types of LNG unloading nozzles of compatible profile

and system pressure.

The LNG unloading receptacle profile is specified in this document. An LNG unloading nozzle shall mate

with this LNG unloading receptacle profile.
4.2 Functional description of the LNG unloading connector
4.2.1 General

The LNG unloading receptacle manufactured in accordance with this document shall be designed with

reasonable concepts of safety, durability, and maintainability.
LNG unloa
...