ISO/FDIS 6338-5

• Status: Not Published
• ICS: 13.020.40 - Pollution, pollution control and conservation
• ICS: 75.020 - Extraction and processing of petroleum and natural gas
• Technical Committee: ISO/TC 67/SC 9 - Liquefied natural gas installations and equipment
• Drafting Committee: ISO/TC 67/SC 9/WG 10 - GHG emissions at LNG plant
• Current Stage: 5000 - FDIS registered for formal approval
• Start Date: 21-Jul-2026
• Completion Date: 24-Aug-2026

• Consolidates: prEN ISO 6338-5 - Calculations of greenhouse gas (GHG) emissions throughout the liquefied natural gas (LNG) chain - Part 5: Regasification (ISO/DIS 6338-5:2026)
• Effective Date: 12-Feb-2026
• Consolidates: ISO 15706-1:2023 - Information and documentation — International Standard Audiovisual Number (ISAN) — Part 1: Audiovisual work identifier
• Effective Date: 07-Dec-2025

ISO/FDIS 6338-5 is an ISO document for calculating greenhouse gas (GHG) emissions throughout the liquefied natural gas (LNG) chain, specifically for regasification. It covers the regasification plant from inlet to outlet and is meant to be used together with the general requirements in ISO 6338-1. For operators, owners, and reviewers, it sets out what to include in the GHG inventory and how to quantify the main emission sources in practice.

What does ISO/FDIS 6338-5 specify?

ISO/FDIS 6338-5 specifies the part of the LNG-chain GHG calculation method that applies to regasification. It defines the reporting boundary for a regasification plant, identifies the main source categories, and points readers to ISO 6338-1 for the general method, principles, reporting, and review.

Clause 5 and Table 1 show the facilities associated with regasification that fall in or out of scope.

Facility or activity	Scope in this part
Marine facilities, LNG storage, regasification unit, utilities, onsite power generation, imported utilities, FSRU, injection in gas grid	In scope
LNG carrier	Out of scope - covered by ISO 6338-4
Loading of road/rail/ship tankers, distribution of LNG by road/rail, gas transmission grid	Out of scope

What are the key requirements of ISO/FDIS 6338-5?

ISO/FDIS 6338-5 focuses on boundary setting, source identification, and source-specific quantification methods. In practice, it tells an organization what data to gather, when primary measurements are expected, and when secondary data or calculation methods may be used.

Inventory boundaries and reporting

Clause 5 requires the GHG report for LNG regasification to cover all associated facilities within the reporting boundaries. The organization with financial and/or operational control over those facilities shall report emissions and removals at least on an annual average basis. That matters because it fixes who reports what, and prevents parts of the regasification chain from being left out.

Fuel combustion

Clause 6.2.2 describes how to treat emissions from gas turbines, diesel drivers, boilers, fired heaters, incinerators, and thermal or catalytic oxidizers. The document expects primary data where possible, such as measured fuel quantities, and allows calculation from operating duty and efficiency when direct fuel measurement is not available. It also says unburned hydrocarbons, such as methane slip, shall be taken into account.

Flaring and venting

Clause 6.2.3 separates atmospheric releases from flares and gives different treatment to significant and minor venting events. Primary data are expected for major events, while secondary data may be used when venting contributes less than 5 % of total annual emissions. This helps operators focus measurement effort on the sources that drive the inventory.

Fugitive emissions

Clause 6.2.4 covers permeation and gas leaks from pipes, fittings, storage tank seals, and related equipment. Permeation may be calculated with emission factors for the materials used, while leaks are typically estimated from equipment counts and generic leakage factors, adjusted where atmospheric monitoring data are available. That is the practical basis for leak inventory work and emissions reduction tracking.

Imported energy, utilities, consumables, and allocation

Clause 6.2.5 requires supplier emissions data for imported electricity, heat, steam, utilities, and consumables such as refrigerant. If reliable data are not available, the calculation shall account for the full supply chain of the imported commodity, with cut-off criteria set according to ISO 14044. Clause 6.5 also requires emissions from regasification to be allocated to the types and quantities of energy used and produced in the process, such as heat, cold, and electricity.

What terms does ISO/FDIS 6338-5 define?

ISO/FDIS 6338-5 uses the definitions from ISO 6338-1 and ISO 14064-1. The following terms are central to reading the document:

• Greenhouse gas (GHG) - the emissions and removals being quantified for the regasification inventory.
• Liquefied natural gas (LNG) - natural gas in liquefied form, which is the product handled through the chain.
• Regasification - the process covered here, from LNG entering the plant to gas leaving it.
• Floating Storage and Regasification Unit (FSRU) - a floating facility that stores LNG and performs regasification.
• Boil-off gas (BOG) - gas released from LNG handling that the document treats as part of emissions control and flaring/venting considerations.
• Allocation - the method of assigning emissions to the heat, cold, and electricity produced or used in the process.

Who uses ISO/FDIS 6338-5?

ISO/FDIS 6338-5 is used by LNG terminal operators, asset owners, and organizations with financial or operational control of regasification facilities. It is also relevant to GHG inventory teams, sustainability and environmental managers, process engineers, and independent reviewers who need a consistent way to quantify regasification emissions. Buyers and regulators can use it to compare inventories prepared on the same basis.

Which standards are used with ISO/FDIS 6338-5?

ISO/FDIS 6338-5 is used with these named standards and parts:

• ISO 6338-1 - provides the general principles, calculation approach, preferred units, allocation principles, quality management, reporting, and independent review.
• ISO 14044 - provides the life cycle assessment guidance used for cut-off criteria when imported emissions data are not reliable.
• ISO 14064-1 - provides organization-level GHG terminology and reporting guidance used in the terms and definitions.
• ISO 6338-4 - covers the LNG carrier, which Table 1 places outside the scope of this part.
• ISO 20257-1 and ISO 20257-2 - provide information on FSRU design issues mentioned in the regasification plant description.
• ISO 25624 series - is cited for validating combustion efficiency with measured emission data.

What does the ISO/FDIS 6338-5 document contain?

ISO/FDIS 6338-5 contains a short, method-focused structure: scope, normative references, terms and definitions, principles, boundaries, quantification, quality management, reporting, and independent review. It uses Table 1 to define the regasification boundary and Tables 2 to 6 to set out source-specific quantification approaches for combustion, flaring and venting, fugitive emissions, and imported energy and consumables.

The document also includes Figure 1, which shows a typical regasification plant layout and the main equipment and emission points. The result is a working framework for building a regasification GHG inventory without reproducing the detailed calculations in this overview.

FINAL DRAFT
International
Standard
ISO/TC 67/SC 9
Calculations of greenhouse gas
Secretariat: AFNOR
(GHG) emissions throughout the
Voting begins on:
liquefied natural gas (LNG) chain —
2026-10-12
Part 5:
Voting terminates on:
2026-12-07
Regasification
Calcul des émissions de gaz à effet de serre (GES) dans la chaîne
gaz naturel liquéfié (GNL) —
Partie 5: Regazéification
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 SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/CEN PARALLEL PROCESSING LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
FINAL DRAFT
International
Standard
ISO/TC 67/SC 9
Calculations of greenhouse gas
Secretariat: AFNOR
(GHG) emissions throughout the
Voting begins on:
liquefied natural gas (LNG) chain —
Part 5:
Voting terminates on:
Regasification
Calcul des émissions de gaz à effet de serre (GES) dans la chaîne
gaz naturel liquéfié (GNL) —
Partie 5: Regazéification
© ISO 2026
All rights reserved.
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
This ISO publication is protected by copyright and is owned by ISO and/or its licensors.
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
The content of this ISO publication is provided under licence, not sold. Use is subject to the applicable licence terms issued by ISO,
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
an ISO member body, or an authorized third-party distributor.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
Except as required for implementation or expressly permitted by a separate licence, no part of this ISO publication may be
ISO/CEN PARALLEL PROCESSING
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
reproduced, distributed, modified, used, or made available in any form or by any means – electronic or mechanical, including
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
photocopying, scanning, recording, or posting on internal or external digital platforms. TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
Any use beyond the scope of the granted rights is prohibited and may result in legal action.
MADE IN NATIONAL REGULATIONS.
ISO copyright office
CP 401 • CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
Reference number
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principles . 1
5 GHG inventory boundaries . 1
6 Quantification of GHG emissions . 2
6.1 General .2
6.2 Identification of GHG sources and quantification approach .3
6.2.1 General .3
6.2.2 Emissions from fuel combustion . .3
6.2.3 Emissions from flaring and venting .4
6.2.4 Fugitive emissions .4
6.2.5 Emissions associated with imported energy, utilities, and consumables .5
6.3 Calculation of GHG emissions .5
6.4 Preferred units .5
6.5 Allocation .6
6.6 Carbon capture .6
7 GHG inventory quality management . 6
8 GHG reporting . 6
9 Independent review . . 6
Bibliography . 7

iii
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, Refrigerated Liquefied Gases (RLG) SEVESO infrastructure design and operation, in accordance with the
Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
A list of all parts in the ISO 6338 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.

iv
Introduction
Natural gas is playing a key role in the energy transition (e.g. by replacing coal to produce electricity) and the
use of liquefied natural gas (LNG) to transport natural gas is expected to increase. The process of liquefying
natural gas is energy-intensive. Gas producers are increasingly accountable for their greenhouse gas (GHG)
emissions and the ambition to reduce them. Furthermore, there is an emerging marketing demand for GHG
data to enable commercial mechanisms such as offsetting to be utilized.
There is no standardized and auditable methodology to calculate the carbon footprint of the whole LNG
chain (including but not limited to the well, upstream treatment, transportation, liquefaction, shipping,
regasification and end user distribution). Various standards indicate possible approaches but are
inconsistent in their results or not easily applicable.
The ISO 6338 series covers each part of the LNG chain and enables a consistent GHG inventory.
The KPIs and related requirements to access to key international initiatives, agreements and reporting/
accounting standards on climate ambitions and zero carbon emission strategies are given in ISO 6338-1:2024,
Annex B.
Attention is paid to activities that can occur in different parts (e.g. gas treatment and distribution upstream
of the liquefaction plant).
NOTE It is not possible to make like-for-like comparisons, or define a certification scheme, for one block only.

v
FINAL DRAFT International Standard ISO/FDIS 6338-5:2026(en)
Calculations of greenhouse gas (GHG) emissions throughout
the liquefied natural gas (LNG) chain —
Part 5:
Regasification
1 Scope
This document provides the part of the method to calculate the GHG emissions throughout the LNG chain
specific to regasification. It covers activities from the inlet to
...

ISO/TC 67/SC 9
Secretariat: AFNOR
Date: 2026-07-1609-25
Calculations of greenhouse gas (GHG) emissions throughout the
liquefied natural gas (LNG) chain —
Part 5:
Regasification
Calcul des émissions de gaz à effet de serre (GES) dans la chaîne gaz naturel liquéfié (GNL) —
Partie 5: Regazéification
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© FDIS stage
All rights reserved. Unless otherwise specified,
This ISO publication is protected by copyright and is owned by ISO and/or its licensors.
The content of this ISO publication is provided under licence, not sold. Use is subject to the applicable licence terms issued
by ISO, an ISO member body, or an authorized third-party distributor.
Except as required in the context of its for implementation or expressly permitted by a separate licence, no part of this
ISO publication may be reproduced or utilized otherwise, distributed, modified, used, or made available in any form or
by any means, – electronic or mechanical, including photocopying, scanning, recording, or posting on internal or external
digital platforms.
Any use beyond 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 countryscope of the requestergranted rights is prohibited and may
result in legal action.
ISO copyright office
CP 401 • CH. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
E-mailEmail: [e-mail]
Website: www.iso.org
Published in Switzerland
iii
Contents
Foreword . v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principles . 1
5 GHG inventory boundaries . 1
6 Quantification of GHG emissions . 2
6.1 General. 2
6.2 Identification of GHG sources and quantification approach . 4
6.3 Calculation of GHG emissions . 6
6.4 Preferred units . 6
6.5 Allocation . 6
6.6 Carbon capture . 6
7 GHG inventory quality management . 6
8 GHG reporting . 6
9 Independent review . 6
Bibliography . 7

iv
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,
Refrigerated Liquefied Gases (RLG) SEVESO infrastructure design and operation, in accordance with the
Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
A list of all parts in the ISO 6338 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.
v
Introduction
Natural gas is playing a key role in the energy transition (e.g. by replacing coal to produce electricity) and the
use of liquefied natural gas (LNG) to transport natural gas is expected to increase. The process of liquefying
natural gas is energy-intensive. Gas producers are increasingly accountable for their greenhouse gas (GHG)
emissions and the ambition to reduce them. Furthermore, there is an emerging marketing demand for GHG
data to enable commercial mechanisms such as offsetting to be utilized.
There is no standardized and auditable methodology to calculate the carbon footprint of the whole LNG chain
(including but not limited to the well, upstream treatment, transportation, liquefaction, shipping,
regasification and end user distribution). Various standards indicate possible approaches but are inconsistent
in their results or not easily applicable.
The ISO 6338 series covers each part of the LNG chain and enables a consistent GHG inventory.
The KPIs and related requirements to access to key international initiatives, agreements and
reporting/accounting standards on climate ambitions and zero carbon emission strategies are given in ISO
6338-1:2024, Annex B.
Attention is paid to activities that can occur in different parts (e.g. gas treatment and distribution upstream of
the liquefaction plant).
NOTE It is not possible to make like-for-like comparisons, or define a certification scheme, for one block only.
vi
Calculations of greenhouse gas (GHG) emissions throughout the
liquefied natural gas (LNG) chain —
Part 5:
Regasification
1 Scope
This document provides the part of the method to calculate the GHG emissions throughout the LNG chain
specific to regasification. It covers activities from the inlet to the outlet of the regasification plant.
The general requirements are covered in ISO 6338-1.
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 6338--1, Calculations of greenhouse gas (GHG) emissions throughout the liquefied natural gas (LNG) chain
— Part 1: General
ISO 14044, Environmental management — Life cycle assessment — Requirements and guidelines
ISO 14064--1, Greenhouse gases — Part 1: Specification with guidance at the organization level for
quantification and reporting of greenhouse gas emissions and removals
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 6338-1 and ISO 14064-1 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/
4 Principles
The principles given in ISO 6338-1 shall be followed.
5 GHG inventory boundaries
The GHG report for regasification of LNG shall cover all associated facilities. The list in Table 1Table 1 is not
exhaustive.
Table 1 — List of facilities within the scope of this document
LNG Regasification Faci
...