SIST EN ISO 5124:2025

SLOVENSKI STANDARD
01-februar-2025
Natovarjanje in raztovarjanje cistern in kontejnerjev z utekočinjenim zemeljskim
plinom (ISO 5124:2024)
Loading and unloading of liquefied natural gas (LNG) tank wagons and containers (ISO
5124:2024)
LNG-Kesselwagen/Container Be- und Entladen (ISO 5124:2024)
Chargement et déchargement de wagons-citernes et conteneurs de gaz naturel liquéfié
(GNL) (ISO 5124:2024)
Ta slovenski standard je istoveten z: EN ISO 5124:2024
ICS:
23.020.10 Nepremične posode in Stationary containers and
rezervoarji tanks
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 5124
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2024
EUROPÄISCHE NORM
ICS 75.200
English Version
Loading and unloading of liquefied natural gas (LNG) tank
wagons and containers (ISO 5124:2024)
Chargement et déchargement de wagons-citernes et LNG-Kesselwagen/Container Be- und Entladen (ISO
conteneurs de gaz naturel liquéfié (GNL) (ISO 5124:2024)
5124:2024)
This European Standard was approved by CEN on 27 September 2024.

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 NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 5124:2024 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 5124:2024) has been prepared by Technical Committee ISO/TC 67/SC 9
"Production, transport and storage facilities for cryogenic liquefied gases" 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 April 2025, and conflicting national standards shall be
withdrawn at the latest by April 2025.
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.
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 5124:2024 has been approved by CEN as EN ISO 5124:2024 without any modification.

International
Standard
ISO 5124
First edition
Loading and unloading of liquefied
2024-10
natural gas (LNG) tank wagons and
containers
Chargement et déchargement de wagons-citernes et conteneurs
de gaz naturel liquéfié (GNL)
Reference number
ISO 5124:2024(en) © ISO 2024
ISO 5124:2024(en)
© ISO 2024
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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 5124:2024(en)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Equipment design . 3
4.1 LNG tank wagon .3
4.2 LNG tank container .3
4.3 Tanks for LNG tank wagons and tank containers .3
4.4 Loading or unloading bay configuration .6
4.5 Connection couplings .8
4.5.1 Type and size of connections .8
4.5.2 Quick connect disconnect coupler (QCDC) .8
4.5.3 Emergency release coupling (ERC) .8
4.6 LNG transfer hoses or arms .8
4.7 General process design requirements .9
4.7.1 General .9
4.7.2 Overfill detection and overpressurization .9
4.7.3 Loading and unloading process .10
4.7.4 Quantity and quality measurement .10
4.7.5 Sampling .11
4.7.6 Predicting LNG quality change due to ageing .11
5 Leak and fire management .11
5.1 Leak avoidance, detection and management .11
5.1.1 General .11
5.1.2 Avoidance .11
5.1.3 Gas detection . 12
5.1.4 Management . 12
5.2 Fire avoidance, detection and management strategies . 13
5.2.1 Fire avoidance . 13
5.2.2 Fire detection . 13
5.2.3 Fire management . 13
6 Layout considerations .13
6.1 Safety separation distances . 13
6.2 Typical equipment layout . 13
6.3 Buildings . 13
7 Commissioning and start-up . 14
8 Operations .15
8.1 Initial checks . 15
8.2 Weighing before loading or unloading operation . 15
8.3 Loading terminal .16
9 Stakeholder analysis. 16
Bibliography .18

iii
ISO 5124:2024(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 67, Oil and gas industries including lower
carbon energy, Subcommittee SC 9, Production, transport and storage facilities for cryogenic liquefied gases, in
collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/TC 282,
Installation and equipment for LNG, in accordance with the Agreement on technical cooperation between ISO
and CEN (Vienna Agreement).
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
International Standard ISO 5124:2024(en)
Loading and unloading of liquefied natural gas (LNG) tank
wagons and containers
1 Scope
This document provides requirements and recommendations for the design, construction and operation of
newly installed liquefied natural gas (LNG) railway loading and unloading facilities for use on onshore LNG
terminals, LNG satellite plants, handling LNG tank wagons or tank containers engaged in international trade.
The designated boundary limits of this document are between the LNG terminal’s inlet/outlet piping headers
at the beginning of the rail loading or unloading area and the rail track area used for LNG tank wagons and
containers. It is applicable to all rail loading bays, weighbridge(s) and related subsystems.
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, Petroleum and natural gas industries — Characteristics of LNG, influencing the design, and material
selection
EN 1473:2021, Installation and equipment for liquefied natural gas — Design of onshore installations
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
ageing
gradual change in the molecular composition of LNG (3.8) throughout the supply chain caused by differential
evaporation because LNG has components with different boiling points
3.2
boil-off gas
BOG
natural gas (3.11) resulting from slow evaporation of LNG (3.8) at its equilibrium state or rapid evaporation
of LNG, also called flashing, inside equipment
3.3
control room
core functional entity, and its associated physical structure, where operators are stationed to carry out
centralized control, monitoring and administrative responsibilities
[SOURCE: ISO 11064-1:2000, 3.2]

ISO 5124:2024(en)
3.4
emergency release coupling
ERC
device to provide a means of quick release of LNG transfer system when such action is required only as an
emergency measure
[SOURCE: ISO/TR 17177:2015, 2.1.4]
3.5
ESD
emergency shutdown
system that safely and effectively stops the whole plant or individual units to minimize incident escalation
[SOURCE: ISO 20257-1:2020, 3.1.15, modified — "emergency shutdown" has been changed from a preferred
term to an admitted term.]
3.6
flare
system to ignite the vapour on a safe location in a controlled manner
3.7
impounding basin
area defined at the site for collecting any accidental spill of hydrocarbons
3.8
LNG
liquefied natural gas
colourless and odourless cryogenic fluid in the liquid state at normal pressure composed predominantly
of methane which can contain minor quantities of ethane, propane, butane, nitrogen, or other components
normally found in natural gas (3.11)
Note 1 to entry: LNG is designated as “UN 1972” by United Nations.
[SOURCE: ISO 16903:2015, 3.3, modified — Note 1 to entry has been added.]
3.9
LNG tank wagon
railway goods wagon with a tank and loading or discharge arrangement for the transport of permanently
mounted LNG (3.8)
3.10
LNG tank container
mobile tank for the transport of LNG (3.8) that may be mounted on railway wagons and may also be loaded
or unloaded while mounted
3.11
natural gas
NG
complex gaseous mixture of hydrocarbons, primarily methane, but generally including ethane, propane and
higher hydrocarbons, and some non-combustible gases such as nitrogen and carbon dioxide
[SOURCE: ISO 14532:2014, 2.1.1.1, modified — "includes" has been changed to "including"; note 1 to entry
has been removed.]
3.12
quick connect disconnect coupler
QCDC
manual or hydraulic mechanical device used to connect the transfer system (3.14) to the LNG tank wagon
(3.9) or container (3.10)
[SOURCE: ISO 16904:2016, 3.39, modified — "cargo manifold" has been changed to "LNG tank wagon or
container"; "without employing bolts" at the end of the definition has been removed.]

ISO 5124:2024(en)
3.13
transfer
loading or unloading operation
3.14
transfer system
flexible (hose) or rigid (articulated arm) system used for transferring LNG (3.8) between the terminal and
LNG tank wagon (3.9) or container (3.10)
Note 1 to entry: It can be referred to as a “loading arm or loading hose” or “unloading arm or unloading hose”.
4 Equipment design
4.1 LNG tank wagon
It is presupposed that the LNG tank wagon is designed, homologated, tested and equipped according to the
requirements of dangerous goods transport of the national regulatory body following the UN transport
recommendations (orange book, e.g. RID for Europe and MED) and that regular inspections and maintenance
are performed according to the applicable laws and regulations for dangerous goods applicable for LNG UN1972.
The dimensions of an LNG tank wagon shall be chosen in a way that payload and tank volume are
corresponding when loaded with LNG.
LNG tank wagons shall be equipped with cabinets on both sides of the wagon which contain the operating
valves and connections. These cabinets should be executed to work as drip trays.
4.2 LNG tank container
It is presupposed that the LNG tank container is designed, tested and equipped according to the requirements of
IMO-IMDG or requirements of the valid national regulatory body following the UN transport recommendations
(orange book, e.g. RID for Europe and MED) and that regular inspections and maintenance shall be performed
according to the applicable laws and regulations for dangerous goods mandatory for LNG UN1972.
The dimensions of a tank container shall be chosen in a way that payload and tank volume are corresponding
when loaded with LNG.
Tank containers shall be equipped with cabinets which contain the operating valves and connections. These
shall be provided on the side or at the face of the tank container. These cabinets should be executed to work
as drip trays.
4.3 Tanks for LNG tank wagons and tank containers
Tanks for the transport of LNG shall provide the following connections:
— product connection liquid phase;
— product connection vapour phase;
— drive away protection;
— electric earthing connecting point;
— air connection, if pneumatic valves are used for the LNG tank wagon.
Tanks shall provide the following equipment:
— overpressure protection valve;
— thermal relief valves on lines between block valves;
— closing installation for first closure valves in case the wagon moves.

ISO 5124:2024(en)
It can be useful to provide a regasification or pressurizing circuit to speed up the discharge in case no
external source of pressure is available.
The tank of the wagon or container shall be insulated to minimize boil-off gas during possible transportation
time as it reduces the thermal ingress from the environment and thus significantly reduces the associated
safety risks.
NOTE Information on the design of vacuum insulated tanks is given in the ISO 20421 series.
The tank shall be designed in order to withstand liquid nitrogen (for commissioning) temperatures on the
low range and up to +50 °C on the high range.
The manufacturer of the tank shall provide for its appropriate operation:
— approval of the tank by a surveying institute including calculation of the shell;
— operating manual including a description of the tank;
— loading data sheet of initial filling, holding time and payload;
— loading data sheet of initial pressure and holding time;
— flow schemes;
— information about spare parts.
Loading of an LNG tank wagon or container can be controlled by scales or by using level-check valves (if
level-loading) to prevent overloading.
The basic layout of tanks for LNG tank wagons or tank containers is shown in Figure 1 and Figure 2. Examples
of an LNG tank wagon and an LNG tank container are given in Figure 3 and Figure 4.
Key
closure, flange or coupler
product line or operational line
valve
return line for thermal expansion
1 tank shell
ISO 5124:2024(en)
2 insulation
3 outer shell
4 test valve for vacuum (if applicable)
5 foot valve
6 gas return valve
7 side valves
8 connecting coupler (if applicable) or connecting flange
9 test lines for level loading
10 safety valves
11 pneumatic control of foot valve and gas-exchange valve
12 thermal expansion safety valve
13 connection to connect boil-off
14 evaporator/heat exchanger (if applicable)
Figure 1 — LNG tank wagon/container with connections on the side
Key
closure, flange or coupler
product line or operational line
valve
return line for thermal expansion
1 tank shell
2 insulation
3 outer shell
4 test valve for vacuum (if applicable)
5 foot valve
6 gas return valve
7 side valves
8 connecting coupler (if applicable) or connecting flange

ISO 5124:2024(en)
9 test lines for level loading
10 safety valves
11 pneumatic control of foot valve and gas-exchange valve
12 thermal expansion safety valve
13 connection to connect boil-off
14 evaporator/heat exchanger (if applicable)
Figure 2 — Tank container with connections on the end
Figure 3 — Example of an LNG tank wagon
Figure 4 — Example of an LNG tank container
4.4 Loading or unloading bay configuration
The loading or unloading bay:
a) shall be equipped with a flexible hose or loading arm, which may be equipped with a cryogenic QCDC,
dry break coupler, or similar;
b) shall have means of preventing leaks at hose or arm rupture such as an ERC, cryogenic break away
coupling or other measures;
c) shall be equipped with shut-off valves or ESD valves;

ISO 5124:2024(en)
d) shall allow for complete purging of the loading arm or hose after loading or unloading back to the header
with nitrogen to avoid emissions;
e) shall allow for accurate loading or unloading, via flowmeters (e.g. Coriolis), both on liquid and vapour
return line and/or (dynamic) weighbridge; another custody transfer flow meter may be considered;
f) shall be equipped with liquid, vapour, nitrogen and ground earthing connections;
g) shall be equipped with instrument air connection if the LNG tank wagon or container is equipped with
pneumatic foot valves;
h) shall be equipped with an instrument air connection hose with suitable coupling to connect to the
pneumatically actuated foot valve of the LNG tank wagon or container, if the
...