EN ISO 20257-2:2021
(Main)Installation and equipment for liquefied natural gas - Design of floating LNG installations - Part 2: Specific FSRU issues (ISO 20257-2:2021)
Installation and equipment for liquefied natural gas - Design of floating LNG installations - Part 2: Specific FSRU issues (ISO 20257-2:2021)
This document provides specific requirements and guidance for the design and operation of floating LNG storage and regasification units (FSRU) described in ISO 20257-1.
This document is applicable to offshore, near-shore or docked FSRUs and to both new-built and converted FSRUs.
This document includes requirements to the jetty when an FSRU is moored to a jetty.
Anlagen und Ausrüstung für Flüssigerdgas - Auslegung von schwimmenden Flüssigerdgas-Anlagen - Teil 2: Spezifische Anmerkungen zu FSRU (ISO 20257-2:2021)
Dieses Dokument enthält spezifische Anforderungen und Anleitungen in Bezug auf die Auslegung und den Betrieb von schwimmenden Einheiten für die Speicherung und Wiederverdampfung (FSRU, en: floating storage regasification unit) von Flüssigerdgas (LNG, en: liquefied natural gas), wie in ISO 20257 1 beschrieben.
Dieses Dokument ist auf Offshore-Anlagen, Anlagen in Küstennähe oder angedockte FSRU anwendbar und gilt sowohl für neu gebaute als auch für umgebaute FSRU.
Dieses Dokument enthält Anforderungen an den Pier, wenn eine FSRU an einen Pier vertäut ist.
Installations et équipements de gaz naturel liquéfié - Conception des installations flottantes de GNL - Partie 2: Questions spécifiques aux FSRU (ISO 20257-2:2021)
Le présent document fournit des recommandations et exigences spécifiques pour la conception et l'exploitation des unités flottantes de stockage et de regazéification de GNL (FSRU) tel que décrites dans l'ISO 20257-1.
Le présent document s’applique aux FSRU en mer, côtiers ou à quai et tant aux FSRU construits à neuf qu'à ceux convertis.
Le présent document inclut l'appontement dans le cas de l'amarrage d'un FSRU.
Napeljave in oprema za utekočinjeni zemeljski plin - Načrtovanje plavajočih napeljav za utekočinjeni zemeljski plin - 2. del: Posebne zahteve za plavajoča skladišča z enotami za uplinjanje (FSRU) (ISO 20257-2:2021)
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-oktober-2021
Napeljave in oprema za utekočinjeni zemeljski plin - Načrtovanje plavajočih
napeljav za utekočinjeni zemeljski plin - 2. del: Posebne zahteve za plavajoča
skladišča z enotami za uplinjanje (FSRU) (ISO 20257-2:2021)
Installation and equipment for liquefied natural gas - Design of floating LNG installations
- Part 2: Specific FSRU issues (ISO 20257-2:2021)
Anlagen und Ausrüstung für Flüssigerdgas - Auslegung von schwimmenden
Flüssigerdgas-Anlagen - Teil 2: Besondere Anmerkungen zu FSRU (ISO 20257-2:2021)
Installations et équipements de gaz naturel liquéfié - Conception des installations
flottantes de GNL - Partie 2: Questions spécifiques aux FSRU (ISO 20257-2:2021)
Ta slovenski standard je istoveten z: EN ISO 20257-2:2021
ICS:
75.200 Oprema za skladiščenje Petroleum products and
nafte, naftnih proizvodov in natural gas handling
zemeljskega plina equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 20257-2
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2021
EUROPÄISCHE NORM
ICS 75.200
English Version
Installation and equipment for liquefied natural gas -
Design of floating LNG installations - Part 2: Specific FSRU
issues (ISO 20257-2:2021)
Installations et équipements de gaz naturel liquéfié - Anlagen und Ausrüstung für Flüssigerdgas - Auslegung
Conception des installations flottantes de GNL - Partie von schwimmenden Flüssigerdgas-Anlagen - Teil 2:
2: Questions spécifiques aux FSRU (ISO 20257-2:2021) Besondere Anmerkungen zu FSRU (ISO 20257-2:2021)
This European Standard was approved by CEN on 28 May 2021.
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
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 20257-2:2021 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (EN ISO 20257-2:2021) has been prepared by Technical Committee ISO/TC 67
"Materials, equipment and offshore structures for petroleum, petrochemical and natural gas industries"
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 December 2021, and conflicting national standards
shall be withdrawn at the latest by December 2021.
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.
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 20257-2:2021 has been approved by CEN as EN ISO 20257-2:2021 without any
modification.
INTERNATIONAL ISO
STANDARD 20257-2
First edition
2021-06
Installation and equipment for
liquefied natural gas — Design of
floating LNG installations —
Part 2:
Specific FSRU issues
Installations et équipements de gaz naturel liquéfié — Conception des
installations flottantes de GNL —
Partie 2: Questions spécifiques aux FSRU
Reference number
ISO 20257-2:2021(E)
©
ISO 2021
ISO 20257-2:2021(E)
© ISO 2021
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
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Published in Switzerland
ii © ISO 2021 – All rights reserved
ISO 20257-2:2021(E)
Contents Page
Foreword .vi
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 2
3.1 Terms and definitions . 2
3.2 Abbreviated terms . 2
4 Basis of design . 3
4.1 General description of FSRU. 3
4.2 Main design criteria for process facilities . 5
4.3 Reliability, availability and maintainability of LNG floating installation . 6
4.4 Specific requirements for FSRU operating as LNG carrier . 6
4.5 Specific FSRU studies . 6
4.5.1 General. 6
4.5.2 Environmental impact of seawater intake and discharge study. 6
4.5.3 Recirculation study . 7
4.5.4 Scour protection study . 7
5 Specific health, safety and environmental issues . 7
5.1 General . 7
5.2 Environmental considerations related to water heating and cooling issues . 7
5.3 Safety considerations . 8
5.3.1 General requirements . 8
5.3.2 Layout constrains . 8
5.3.3 Layout constraints with respect to surroundings . 9
5.3.4 Layout constraints with respect to facility arrangement .10
5.3.5 Risk prevention measures .11
6 Mooring and stationkeeping .16
7 Hull design .16
8 LNG storage .17
8.1 Specific requirements for cargo tank pressure management .17
8.2 Specific requirements for LNGC overpressure protection .17
8.3 Rollover risk .17
9 Transfer systems .17
9.1 General .17
9.2 Send-out natural gas: NG gas transfer requirements .17
9.2.1 Functional requirements .17
9.2.2 Transfer systems design .18
9.2.3 Emergency disconnection .19
9.2.4 Operating envelope . .19
9.3 LNG sampling .20
10 BOG handling and recovery .21
10.1 General .21
10.2 LNG tank design pressure flexibility .21
10.3 Specific requirements for recondenser .21
10.4 Specific requirements for gas compressors .22
10.4.1 General.22
10.4.2 Specific functional requirements for LD compressors .22
10.4.3 Specific functional requirements for HD compressors .22
10.4.4 Specific functional requirements for HP or MSO compressors .22
11 Regasification equipment requirements .23
11.1 LNG pumps .23
ISO 20257-2:2021(E)
11.1.1 General.23
11.1.2 Functional requirements .23
11.1.3 Materials selection .23
11.1.4 In-tank LNG pump .23
11.1.5 HP LNG pump .23
11.2 LNG vaporization system .24
11.2.1 Functional requirements .24
11.2.2 Vaporization type .24
11.2.3 Materials selection .25
11.2.4 Protective coating .25
11.2.5 Marine growth .25
11.2.6 Stability/vibration .25
11.2.7 Safety relief valves .26
11.3 Trim heater.26
11.4 Venting from regasification systems .26
12 Gas send out.26
12.1 High integrity pressure protection system .26
12.1.1 Send-out pressure control .26
12.1.2 Typical description of HIPPS .27
12.1.3 Design requirements for HIPPS .28
12.2 Send-out gas metering .29
12.2.1 Uses of send-out gas metering .29
12.2.2 Measurement devices type .29
12.2.3 Accuracy .29
12.2.4 External influences .29
12.2.5 Gas chromatograph – Gas analyser .30
12.2.6 Sparing philosophy .30
12.2.7 Z-configuration .30
12.3 Odorization systems .30
13 Utilities .30
13.1 General .30
13.2 Cooling and heating medium .30
13.2.1 Cooling medium . .30
13.2.2 Heating medium .31
13.2.3 Nitrogen system . .31
13.2.4 Fuel gas . .31
14 Process and safety control systems .32
14.1 General requirements .32
14.2 Interfaces between FSRU and gas export connection .32
14.3 Communication onshore/offshore .32
15 Security management .32
16 Commissioning .32
17 Inspection and maintenance .33
17.1 General requirements .33
17.2 Cargo tank .33
17.3 In-tank LNG pump .33
17.4 Regasification equipment .33
17.4.1 HP LNG pump .33
17.4.2 LNG vaporizer.33
17.5 Recondenser .33
17.6 Handling/Crane equipment .33
18 Preservation and corrosion protection .34
19 Conversion of existing unit to floating LNG installations .34
Annex A (informative) Regasification system description.35
iv © ISO 2021 – All rights reserved
ISO 20257-2:2021(E)
Bibliography .40
ISO 20257-2:2021(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 67, Materials, equipment and offshore
structures for petroleum, petrochemical and natural gas industries, Subcommittee SC 9, Liquefied natural
gas installations and equipment, 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).
A list of all parts in the ISO 20257 series can be found on the ISO website.
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.
vi © ISO 2021 – All rights reserved
INTERNATIONAL STANDARD ISO 20257-2:2021(E)
Installation and equipment for liquefied natural gas —
Design of floating LNG installations —
Part 2:
Specific FSRU issues
1 Scope
This document provides specific requirements and guidance for the design and operation of floating
LNG storage and regasification units (FSRU) described in ISO 20257-1.
This document is applicable to offshore, near-shore or docked FSRUs and to both new-built and
converted FSRUs.
This document includes requirements to the jetty when an FSRU is moored to a jetty.
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 20257-1:2020, Installation and equipment for liquefied natural gas — Design of floating LNG
installations — Part 1: General requirements
AGA 9, Measurement of Gas by Multipath Ultrasonic Meters
AGA 10, Speed of Sound in Natural Gas and Other Related Hydrocarbon Gases
EN 1776, Gas infrastructure — Gas measuring systems — Functional requirements
EN 12186, Gas infrastructure — Gas pressure regulating stations for transmission and distribution -
Functional requirements
ISO 13734, Natural gas — Organic components used as odorants — Requirements and test methods
EN 14382, Safety devices for gas pressure regulating stations and installations — Gas safety shut-off
devices for inlet pressures up to 100 bar
IEC 61508 (all parts), Functional safety of electrical/electronic/programmable electronic safety-related
systems
IEC 61511 (all parts), Functional safety — Safety instrumented systems for the process industry sector
ISO 5168, Measurement of fluid flow — Procedures for the evaluation of uncertainties
ISO 6976, Natural gas — Calculation of calorific values, density, relative density and Wobbe indices from
composition
ISO 8943, Refrigerated light hydrocarbon fluids — Sampling of liquefied natural gas — Continuous and
intermittent methods
ISO 12213-1, Natural gas — Calculation of compression factor — Part 1: Introduction and guidelines
ISO 20257-2:2021(E)
ISO 12213-2, Natural gas — Calculation of compression factor — Part 2: Calculation using molar-
composition analysis
ISO 13709, Centrifugal pumps for petroleum, petrochemical and natural gas industries
ISO 16903, Petroleum and natural gas industries — Characteristics of LNG, influencing the design, and
material selection
ISO 17089-1, Measurement of fluid flow in closed conduits — Ultrasonic meters for gas — Part 1: Meters for
custody transfer and allocation measurement
Code IGC International Code of the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk,
International Maritime Organization (IMO)
OIML R 137-1, Gas meters — Part 1: Metrological and technical requirements
OIML R 137-2, Gas meters — Part 2: Metrological controls and performance tests
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 20257-1:2020 and the
following 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/
3.1.1
fiscal metering
metering aimed to define the quantity and financial value of hydrocarbon product transaction
3.1.2
custody transfer
physical transfer of hydrocarbon product that results in change in ownership and/or a change in
responsibility
3.2 Abbreviated terms
ALARP as low as reasonably practicable
BOG boil-off gas
CLV closed loop vaporizer
EDS emergency disconnection system
ERC emergency release coupling
ESD emergency shut down
FSRU floating storage and regasification unit
GCU gas combustion unit
HAZOP hazard and operability (study)
2 © ISO 2021 – All rights reserved
ISO 20257-2:2021(E)
HD high duty
HIPPS high integrity pressure protection system
HP high pressure
HVAC heating, ventilation and air conditioning
HW hot water
IFV intermediate fluid vaporizer
IR infrared
LD low duty
LNG liquefied natural gas
LP low pressure
MAC manual alarm call
MOP maximum operating pressure
MSO minimum send out
NG natural gas
NPSH net positive suction head
OEM original equipment manufacturer
OESD Offloading Emergency Shut Down
OLV open loop (direct contact) vaporizer
ORV open rack vaporizer
QRA quantitative risk analysis
RAM reliability, availability, maintainability
SCV submerged combustion vaporizer
SIL safety integrity level
SIS safety instrumented system
UV ultraviolet
4 Basis of design
4.1 General description of FSRU
Figure 1 illustrates a typical arrangement of FSRU facilities, showing an FSRU berthed to a single jetty.
The arrangement can differ in case of use of other mooring designs.
ISO 20257-2:2021(E)
Key
1 hull (see Clause 7) 7 cargo containment system (see Clause 8)
2 LNG transfer (see ISO 20257-1:2020, Clause 10) 8 cargo handling system – BOG handling system (see
Clause 10)
3 regasification vent mast 9 regasification system (see Clause 11)
a
4 mooring (see Clause 4) Gas send out (see Clause 12).
5 HP manifold and FSRU ESD valve (see Clause 9)
6 living quarters
Figure 1 — Example of FSRU arrangement (berthed to a jetty)
For safe loading, storage and regasification of LNG and discharging NG through HP manifolds to the
shore, an FSRU is typically equipped with integrated systems for:
a) cargo handling;
b) cargo containment;
c) regasification.
Associated systems and equipment for cargo, such as BOG management systems, cargo tank spray
systems, inert gas system, nitrogen system, venting system, auxiliary system., are provided in
accordance with applicable (project, class, …) requirements.
Figure 2 illustrates the terminology typically used in descriptions of the regasification system.
4 © ISO 2021 – All rights reserved
ISO 20257-2:2021(E)
Figure 2 — Description of the regasification system
4.2 Main design criteria for process facilities
The process facilities of FSRU shall be designed considering the following conditions:
a) NG send-out capacity, which can be minimum, nominal, peak and zero;
b) redundancy, holding period and turn-down requirements of process facilities;
ISO 20257-2:2021(E)
c) regasification type (e.g. open loop, combined or closed loop);
d) regasification operation (e.g. metocean and site conditions during regasification operation);
e) maximum operating and design send-out pressure at HP manifold;
f) minimum and maximum send-out temperature at HP manifold;
g) design range of seawater temperature and flowrate for regasification;
h) LNG loading rate concurrent with regasification (minimum send-out capacity to be considered);
i) LNG quality and chemical composition;
j) odorization, if required;
k) discharge seawater conditions (i.e. seawater used for regasification process);
l) BOG management (e.g. venting and flaring philosophy required);
m) dual operation FSRU and LNG carrier requirements.
4.3 Reliability, availability and maintainability of LNG floating installation
A RAM analysis should be performed to determine the availability of gas export from FSRU given a
certain demand profile. Availability curves should be prepared for various demand scenarios.
Metocean conditions shall be considered while operating regasification facilities to define availability.
The design should consider N+1 configurations for all key equipment to ensure a high availability of gas
export. Typically based on operational experience, the HD compressor and HP compressors would not
be subject to the N+1 philosophy.
4.4 Specific requirements for FSRU operating as LNG carrier
When an FSRU is operating as LNG carrier (part time or after extended stay on location), provisions
shall be taken to
a) shutdown and isolate the regasification facilities, and
b) fasten potential transfer systems.
After extended stay on location, additional requirements such as revision of drydock plan before
starting operating as LNG carrier can be required by flag and/or class requirements.
4.5 Specific FSRU studies
4.5.1 General
The relevant studies mentioned in ISO 20257-1:2020, Clause 4 shall be performed. In addition, the
process and environmental aspects described in 4.5.2 to 4.5.4 shall be addressed.
4.5.2 Environmental impact of seawater intake and discharge study
Specific studies related to environmental impact of seawater intake and discharge shall be performed
in accordance with 5.2. Local requirements can have an impact on the regasification type selection.
6 © ISO 2021 – All rights reserved
ISO 20257-2:2021(E)
4.5.3 Recirculation study
During the regasification process, an FSRU takes in seawater, extracts heat from it for regasification of
LNG, and discharges the seawater at a lower temperature. The recirculation pattern of the discharged
effluent towards the intake point can lead to lower intake temperature and reduce the unit’s efficiency.
The aim of a recirculation study is to assess the risk of recirculating the cold water effluent based on
the discharge characteristics during FSRU operations and the ambient characteristics of the receiving
water body. A recirculation study can also assist the FSRU owner and builder by optimizing the intake
and outlet locations in the design.
To assess the recirculation risk, the behaviour of the cold water plume in a mid-field, far-field and near-
field model shall be analysed. A 3D far-field model can be used to analyse the large-scale circulation
patterns and their influence on the recirculation risk and to generate the boundary conditions for a 3D
near-field model. In a detailed near-field model, different scenarios are assessed on their potential for
recirculation.
The following scenarios shall be considered:
a) For the far-field model: evaluation of the far-field transitional phase behaviour under varying
hydrodynamic conditions.
b) For the near-field model:
1) sensitivity analysis to evaluate near-field model performance and variation of ambient water
characteristics and flow conditions;
2) analysis of recirculation risk for varying water level conditions and draughts of FSRU, for flood
conditions;
3) analysis of recirculation risk with alternative outlet configurations, for varying water levels
and draughts of FSRU, for both flood and ebb flow conditions;
4) similar setup of conditions as in 2) and 3) adding an LNG carrier berthed alongside the FSRU, if
this is a realistic scenario.
4.5.4 Scour protection study
Additional investigation concerning scour protection, where relevant, shall be performed due to water
intake/outfall of regasification system.
5 Specific health, safety and environmental issues
5.1 General
This clause describes the specificities of FSRU application and shall be applied in addition to
ISO 20257-1:2020, Clause 5.
5.2 Environmental considerations related to water heating and cooling issues
Systems used for seawater heating/cooling should follow the environmental recommendations of the
[15]
World Bank Group . Where chemicals are used to prevent marine fouling in the shipboard facilities,
these should be minimized and alternate measures should be considered. This can involve taking water
from depth where this is possible. For a near-shore FSRU, the limited water depth and limited potential
for marine growth should be considered. Providing screens on water intakes to avoid entrainment of
marine organisms should also be considered.
Change in ambient seawater temperature due to discharge of seawater should be limited to less than
3 °C at the edge of a defined mixing zone. In case of use of a chlorination system, free chlorine (total
ISO 20257-2:2021(E)
residual oxidant in seawater) concentration in seawater water discharges at water disposal outlets
should be maintained below 0,2 ppm (see Reference [13]).
5.3 Safety considerations
5.3.1 General requirements
The project development team shall establish early in the design (conceptual stage) a high-level safety
strategy (hazard prevention and hazard minimization) that outlines the measures to be considered to
eliminate/manage hazard introduced by the design. These measures shall then be further matured into
a set of safety philosophies, which will provide clear guidance and define design requirements to the
design team, and further realized in detailed engineering as the design evolves.
The philosophies shall include but are not limited to the following:
a) layout safety, including explosion protection;
b) fire and gas detection;
c) emergency shutdown;
d) emergency depressurizing;
e) fire protection, covering both active and passive protection;
f) cold spill protection;
g) ignition source management, including hazardous area classification;
h) drainage;
i) escape, evacuation and rescue.
NOTE Most principles specified in ISO 20257-1:2020 also apply to this document.
The regasification system of the FSRU shall be verified as part of the overall risk studies as described in
ISO 20257-1:2020.
5.3.2 Layout constrains
A risk analysis including the whole facilities and surroundings (and not only the FSRU itself) shall be
performed to maximize the safety of installation with respect to ignition sources through a layout
review (see also ISO 20257-1:2020, 5.4.4). The risk analysis shall focus on
a) the wind rose,
b) the location of significant ignition sources (e.g. flare, combustion equipment),
c) the location of vulnerable areas (e.g. accommodations, administrative areas),
d) the location of fences and public in case of docked floating LNG installations, and
e) the influence of other shipping passing nearby.
The acceptance criteria for risk can differ depending whether the LNG floating installation is at shore/
docked or offshore considering the risk to public.
8 © ISO 2021 – All rights reserved
ISO 20257-2:2021(E)
5.3.3 Layout constraints with respect to surroundings
5.3.3.1 Applicability
Subclause 5.3.3 is applicable in the case the facility is docked at or close to shore (either in an existing
harbour or at a new location).
5.3.3.2 Qualitative analysis
Whatever the exact configuration of the facility, the choice of the location shall be based on a thorough
review of the surroundings. The following areas shall be identified in this review:
a) industrial areas;
b) commercial areas;
c) dense areas with high population;
d) rural areas.
5.3.3.3 Confirmation by calculation
The identification of areas will help to find the most suitable site location with respect to the risks
inherent to the kind of facility. In addition, prior to the development of any detailed safety study as
required by this document or local regulation, it is recommended to perform a set of safety distances
calculations due to jet fires, explosions, pool fires, etc. These calculations can include the following:
a) Large leak release: The objective of these calculations is to define the area where control of the
surroundings is required. This will help defining the location of the potential onshore fence.
b) Worst case scenarios (e.g. full bore rupture): The objective of these calculations is to provide the
local authorities with a clea
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