EN ISO 21593:2019

SLOVENSKI STANDARD
01-januar-2020
Ladijska in pristaniška tehnologija - Tehnične zahteve za suhe spoje za priklop in
odklop pri polnjenju plovil na utekočinjeni zemeljski plin (ISO 21593:2019)
Ship and marine technology - Technical requirements for dry-disconnect/connect
couplings for bunkering liquefied natural gas (ISO 21593:2019)
Schiff- und Meerestechnik- Trockene Anschluss- und Trennkupplung(en) für das
Bunkern flüssigerdgasbetriebener Schiffe (ISO 21593:2019)
Navires et technologie maritime - Exigences techniques relatives au couplage de
connexion et de déconnexion à sec pour le soutage de gaz naturel liquéfié (ISO
21593:2019)
Ta slovenski standard je istoveten z: EN ISO 21593:2019
ICS:
47.020.99 Drugi standardi v zvezi z Other standards related to
ladjedelništvom in shipbuilding and marine
konstrukcijami na morju structures
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 21593
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2019
EUROPÄISCHE NORM
ICS 47.020.99
English Version
Ship and marine technology - Technical requirements for
dry-disconnect/connect couplings for bunkering liquefied
natural gas (ISO 21593:2019)
Navires et technologie maritime - Exigences techniques Schiff- und Meerestechnik- Trockene Anschluss- und
relatives au couplage de connexion et de déconnexion à Trennkupplung(en) für das Bunkern
sec pour le soutage de gaz naturel liquéfié (ISO flüssigerdgasbetriebener Schiffe (ISO 21593:2019)
21593:2019)
This European Standard was approved by CEN on 19 January 2019.

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, 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
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21593:2019 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 21593:2019) has been prepared by Technical Committee ISO/TC 8 "Ships and
marine technology" in collaboration with Technical Committee CEN/TC 282 “Installation and
equipment for LNG” the secretariat of which is held by AFNOR.
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 March 2020, and conflicting national standards shall
be withdrawn at the latest by March 2020.
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.
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, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 21593:2019 has been approved by CEN as EN ISO 21593:2019 without any modification.

INTERNATIONAL ISO
STANDARD 21593
First edition
2019-07
Ships and marine technology —
Technical requirements for dry-
disconnect/connect couplings for
bunkering liquefied natural gas
Navires et technologie maritime — Exigences techniques relatives au
couplage de connexion et de déconnexion à sec pour le soutage de gaz
naturel liquéfié
Reference number
ISO 21593:2019(E)
©
ISO 2019
ISO 21593:2019(E)
© ISO 2019
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: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved

ISO 21593:2019(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General requirements . 3
4.1 General . 3
4.2 Basic design principle . 3
4.3 Design parameters . 4
4.4 Functional requirements . 5
4.5 Internal valve . 5
4.6 Protective cap/plug . 6
4.7 Handle. 6
5 Materials . 6
5.1 General . 6
5.2 Body of coupling . 6
5.3 Bolting . 6
5.4 Spring . 6
5.5 Seals . 6
5.6 Welding . 6
6 Interface types and dimensions . 6
7 Marking . 9
8 Testing . 9
8.1 General . 9
8.2 Ambient test conditions .10
8.3 Cryogenic test conditions .10
8.4 Test arrangement .11
8.5 Shell tightness at ambient temperature .12
8.6 Shell strength at ambient temperature .12
8.7 Internal valve tightness at ambient temperature .12
8.8 Internal valve strength at ambient temperature .13
8.9 Shell tightness at minimum working temperature .13
8.10 Internal valve tightness at minimum working temperature .13
8.11 Operation test at minimum working temperature .14
8.12 Electrical conductivity .14
8.13 Manual force at cold conditions under frost .14
8.14 Bending test .14
8.15 Drop test .15
8.16 Endurance test .15
8.17 High-pressure test .16
Bibliography .17
ISO 21593:2019(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 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 8, Ships and marine technology.
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.
iv © ISO 2019 – All rights reserved

INTERNATIONAL STANDARD ISO 21593:2019(E)
Ships and marine technology — Technical requirements
for dry-disconnect/connect couplings for bunkering
liquefied natural gas
1 Scope
This document specifies the design, minimum safety, functional and marking requirements, as well as
the interface types and dimensions and testing procedures for dry-disconnect/connect couplings for
LNG hose bunkering systems intended for use on LNG bunkering ships, tank trucks and shore-based
facilities and other bunkering infrastructures. It is not applicable to hydraulically operated quick
connect/disconnect couplers (QCDC) used for hard loading arms, which is covered in ISO 16904.
Based on the technology used in industrial manufacturing at the time of development of this document,
it is applicable to sizes of couplings ranging from DN 25 to DN 200.
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 amendment) applies.
ISO 3834 (all parts), Quality requirements for fusion welding of metallic materials
ISO 5208:2015, Industrial valves — Pressure testing of metallic valves
EN 1092-1, Flanges and their joints
EN 12266-1:2012, Industrial valves — Testing of metallic valves — Part 1: Pressure tests, test procedures
and acceptance criteria — Mandatory requirements
ASME B16.5-2009, Pipe flanges and flanged fittings
ASME B31.3-2018, Process piping
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:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
bunkering
operation of transferring LNG fuel to a vessel
[SOURCE: ISO 20519:2017, 3.1, modified — Note 1 to entry has been deleted.]
ISO 21593:2019(E)
3.2
dry-disconnect
method that reduces LNG or natural gas releases into the atmosphere under normal operation to a
negligible amount consistent with safety, either by equipment design or procedural practice
[SOURCE: ISO 20519:2017, 3.6]
3.3
dry-disconnect/connect coupling
coupling
dry disconnect coupling
dry break coupling
mechanical device, consisting of a nozzle (3.4) and a receptacle (3.5), which permits quick connection
and disconnection of a hose bunkering system of the bunker facility to the manifold of the receiving
vessel, in a safe manner, without employing bolts
3.4
nozzle
half part of the dry-disconnect/connect coupling (3.3) typically mounted on the hose bunkering system
of the bunker facility, which permits a quick connection and disconnection to the receiving vessel in a
safe manner
Note 1 to entry: It includes an internal valve to seal the nozzle/bunkering system when disconnected and is
opened after connection by manual operation.
Note 2 to entry: See 4.2.4.
3.5
receptacle
half part of the dry-disconnect/connect coupling (3.3), which is typically mounted to the manifold flange
of the receiving vessel, which permits a quick connection and disconnection of the hose bunkering
system in a safe manner
Note 1 to entry: It includes an internal valve to seal the receptacle/manifold (3.7) system when disconnected and
is opened after connection by manual operation of the nozzle (3.4).
Note 2 to entry: The receptacle shall always be equipped with a seal, as shown in Figure 3.
Note 3 to entry: See 4.2.4.
3.6
dry gas
gas with moisture content such that the dew point of the gas at the required test pressure is at least
11 °C below the ambient test temperature
3.7
manifold
pipe assembly mounted on board LNG-fuelled vessel to which the flange of the receptacle (3.5) is
connected
3.8
verification testing
series of tests to assure that each coupling (3.3) part (including nozzle (3.4) and receptacle (3.5)) meets
all of its design specifications and requirements and that it fulfils its intended purposes
3.9
production testing
process of measuring the properties or performance of the coupling (3.3) and checking it and obtaining
an indication of well productivity before being delivered from factory to customer
2 © ISO 2019 – All rights reserved

ISO 21593:2019(E)
4 General requirements
4.1 General
The dry-disconnect/connect coupling shall be functionally compatible with the LNG bunkering system;
the nozzle shall be functionally compatible with the corresponding receptacles, and vice versa.
4.2 Basic design principle
4.2.1 The coupling consists of a nozzle and a receptacle. The nozzle allows a quick connection and
disconnection of the LNG bunkering system to the receptacle.
4.2.2 The poppet faces of the internal valve from the nozzle interacts and pushes the receptacle poppet
toward the open position in order to allow a medium flow.
4.2.3 The nozzle and receptacle shall remain in the final position when the coupling is connected and
is in fully open condition.
4.2.4 The typical structure of the two-part coupling is shown in Figure 1 and Figure 2:
Key
1 internal valve
2 poppet
3 flange
4 manifold of LNG receiving vessel
5 receptacle
6 nozzle
7 hose of LNG bunkering facility
8 handle
Figure 1 — Sketch structure of a dry-disconnect/connect coupling — Disconnected condition
ISO 21593:2019(E)
Key
1 internal valve
2 poppet
3 flange
4 manifold of LNG receiving vessel
5 receptacle
6 nozzle
7 hose of LNG bunkering facility
8 handle
9 coupling
Figure 2 — Sketch structure of a dry-disconnect/connect coupling — Connected condition
4.2.5 The dry disconnect/connect coupling shall be designed according to a design standard for
pressure-containing equipment. Accepted design codes are:
— ASTM Boiler and Pressure Vessel Code;
— European Pressure Equipment Directive 2014/68/EU;
— EN 12516 Industrial Valves – Shell design strength;
— ISO 16904:2016, 7.2 Design of QCDC; Section 7.3 QCDC system; 9.3.8 QCDC (Testing requirements).
Other design codes can be accepted if they provide the same level of safety with respect to pressure
containment.
The wall thickness of the coupling shall take into account, as a minimum but not limited to, the internal
pressure, the external loads and the moments.
4.2.6 The receptacle shall always be equipped with a seal, as shown in Figure 3.
4.3 Design parameters
The design pressure and temperature of the dry-disconnect/connect coupling shall comply with:
a) Minimum design pressure:
1,6 MPa.
4 © ISO 2019 –
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