ISO/FDIS 6338-4

• 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 6338-4 - Calculations of greenhouse gas (GHG) emissions throughout the liquefied natural gas (LNG) chain - Part 4: Shipping (ISO/DIS 6338-4:2026)
• Effective Date: 12-Feb-2026
• Consolidates: ISO 15706-2:2023 - Information and documentation — International Standard Audiovisual Number (ISAN) — Part 2: Version identifier
• Effective Date: 07-Dec-2025

ISO/FDIS 6338-4 is an ISO draft in the ISO 6338 series for calculating greenhouse gas (GHG) emissions throughout the liquefied natural gas (LNG) chain. Part 4 covers shipping and sets the method for quantifying, allocating, reporting, and independently reviewing emissions from LNG shipping for ship operators and the receiving body.

What does ISO/FDIS 6338-4 specify?

ISO/FDIS 6338-4 provides the shipping part of the LNG-chain method for calculating GHG emissions. It sets the boundary, calculation approach, allocation rules, reporting, and independent review for LNG shipping, while relying on ISO 6338-1 for the general rules.

The document is organized into clauses 1 to 9. Clause 4 gives the principles, clause 5 defines the GHG inventory boundaries, clause 6 covers quantification, clauses 7 to 9 cover quality management, reporting, and independent review.

For shipping, the facility is the ship. The report covers the ballast leg, loading, laden leg, and discharge at unloading, and it is prepared for each ship before being allocated to a cargo. Table 1 separates ship emissions that are in scope from activities handled elsewhere in the LNG chain, including FLNG, FSRU, FSU, regasification-vessel cases, and loading or unloading at liquefaction or regasification plants.

What are the key requirements of ISO/FDIS 6338-4?

Boundary and inventory rules

ISO/FDIS 6338-4 requires the ship operator to report all GHG emissions and removals within the reporting boundaries. In practice, the inventory has to follow the ship’s actual operating phases and capture emissions directly related to the ship, including during loading and unloading.

Clause 5 and Table 1 also require the operator to separate ship shipping emissions from other LNG-chain activities. That matters because cargo accounting, contractual allocation, and any comparison with other parts of the chain depend on a clean boundary.

How emissions are quantified

ISO/FDIS 6338-4 uses different approaches for combustion, fuel cells, venting, and fugitive emissions in clause 6.1. Combustion and fuel-cell emissions are generally based on primary data, with generic or specific emission factors or continuous or spot measurement as supporting methods.

Clause 6.1 also requires unburned hydrocarbons, such as methane slip, to be taken into account. In practice, operators need fuel-use or gas-use data and a way to capture losses that would otherwise be missed.

For venting, Table 4 distinguishes significant venting events from smaller ones. Primary data are expected for significant events, while secondary data may be used for events contributing less than 5 % of annual emissions.

For fugitive emissions, Table 5 allows calculation from equipment counts and standard leakage factors, with adjustment from atmospheric monitoring or LDAR fugitive emissions campaigns. That means leak surveys can improve the estimate instead of relying only on generic factors.

Other inventory rules

Clause 6.1.6 covers imported energy, utilities, and consumables. ISO/FDIS 6338-4 requires data from the exporter or ship operator when applicable, and if reliable data are not available, the full supply chain of the imported commodity has to be counted using the cut-off criteria of ISO 14044.

Clause 6.2 says the calculation is done over a period, so the inventory is time-based rather than a one-off estimate. Clause 6.3 points to the preferred units in ISO 6338-1.

Allocation, carbon capture, reporting, and review

Clause 6.4 says all emissions are allocated to the LNG shipped. Maintenance-related emissions, such as gassing up or cooling down before or after dry dock, should be spread across the next cargoes delivered and identified separately.

Clause 6.4 also says the allocation between ship owner and charterer at scheduled or unscheduled maintenance should be stated in the charterer contract. Clause 6.5, and clauses 7 to 9, refer back to ISO 6338-1 for carbon capture, GHG inventory quality management, reporting, and independent review.

What terms does ISO/FDIS 6338-4 define?

• GHG - Greenhouse gas, the emissions being quantified throughout the LNG shipping activity.
• LNG - Liquefied natural gas, the cargo whose shipping emissions are covered.
• FLNG - Floating liquefied natural gas, a separate LNG-chain case referenced in the activity table.
• FSRU - Floating storage regasification unit, a separate case handled outside this part.
• FSU - Floating storage unit, another separate case listed outside the shipping scope.
• LDAR - Leak detection and repair, a monitoring campaign used to refine fugitive-emission estimates.

Who uses ISO/FDIS 6338-4?

ISO/FDIS 6338-4 is used by ship operators with operational control over LNG carriers, because they have to compile the shipping inventory and allocate it to cargoes. It is also used by ship owners and charterers, since maintenance allocation and contract wording are part of the method.

The document is also relevant to receiving bodies that ask for emissions reports, and to independent reviewers who check the quantification. In practice, it supports LNG-chain GHG accounting, reporting, and verification work.

Which standards are used with ISO/FDIS 6338-4?

• ISO 6338-1 - gives the general LNG-chain method, including principles, boundaries, quantification, units, allocation, carbon capture, quality management, reporting, and independent review.
• ISO 14044 - provides life cycle assessment requirements and the cut-off criteria used when imported commodities must be accounted for across their full supply chain.
• ISO 14064-1 - provides terms and definitions and organization-level GHG quantification and reporting guidance.
• ISO 6338-5 - covers regasification-side ship cases, including FSRU, FSU, regasification vessels, and related loading and unloading.
• ISO 6338 - is cited for LNG plant calculations in the wider series.
• ISO 25624 series - is cited as a source for validating combustion efficiency measurements.

What does the ISO/FDIS 6338-4 document contain?

ISO/FDIS 6338-4 contains one activity table for the shipping boundary and four method tables for combustion, fuel cells, venting, and fugitive emissions. Those tables guide primary data use, emission factors, continuous or spot measurement, leakage factors, and the treatment of methane slip.

The document also sets out the reporting boundary for the ship, the treatment of ballast and cargo legs, and the allocation of emissions to LNG shipped. It includes guidance for imported energy, utilities, consumables, maintenance emissions, carbon capture, reporting, and independent review, so it can be used for inventory preparation, reporting, and verification work.

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 4:
Voting terminates on:
2026-12-07
Shipping
Calcul des émissions de gaz à effet de serre (GES) dans la chaîne
gaz naturel liquéfié (GNL) —
Partie 4: Transport maritime
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 4:
Voting terminates on:
Shipping
Calcul des émissions de gaz à effet de serre (GES) dans la chaîne
gaz naturel liquéfié (GNL) —
Partie 4: Transport maritime
© 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 Identification of GHG sources and quantification approach .2
6.1.1 General .2
6.1.2 Emissions from combustion .2
6.1.3 Emissions from fuel cells .3
6.1.4 Emissions from venting.3
6.1.5 Fugitive emissions .4
6.1.6 Emissions associated with imported energy, utilities, and consumables .4
6.2 Calculation of GHG emissions .4
6.3 Preferred units .4
6.4 Allocation .4
6.5 Carbon capture .4
7 GHG inventory quality management . 4
8 GHG reporting . 4
9 Independent review . . 5
Bibliography . 6

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 certificat
...

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 4:
Shipping
Calcul des émissions de gaz à effet de serre (GES) dans la chaîne gaz naturel liquéfié (GNL) —
Partie 4: Transport maritime
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©
FDIS stage
This draft is submitted to a parallel vote in ISO, CEN.

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 Identification of GHG sources and quantification approach . 2
6.2 Calculation of GHG emissions . 4
6.3 Preferred units . 4
6.4 Allocation . 4
6.5 Carbon capture . 4
7 GHG inventory quality management . 4
8 GHG reporting . 5
9 Independent review . 5
Bibliography . 6

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 4:
Shipping
1 Scope
This document provides the part of the method to calculate the GHG emissions throughout the LNG chain
specific to shipping.
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
...