FprEN ISO 6338-4

• Abstract:

  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.

• Status: Not Published
• Publication Date: 07-Mar-2027
• ICS: 13.020.40 - Pollution, pollution control and conservation
• ICS: 75.020 - Extraction and processing of petroleum and natural gas
• Technical Committee: CEN/TC 282 - Installation and equipment for LNG
• Drafting Committee: CEN/TC 282 - Installation and equipment for LNG
• Current Stage: 4599 - Dispatch of FV draft to CMC - Finalization for Vote
• Start Date: 30-Sep-2026
• Due Date: 14-Jan-2028
• Completion Date: 30-Sep-2026
• Ref Project: oSIST prEN ISO 6338-4:2026 - Calculations of greenhouse gas (GHG) emissions throughout the liquefied natural gas (LNG) chain - Part 4: Shipping (ISO/DIS 6338-4:2026)

• Consolidated By: ISO/FDIS 6338-4 - Calculations of greenhouse gas (GHG) emissions throughout the liquefied natural gas (LNG) chain — Part 4: Shipping
• Effective Date: 12-Feb-2026

FprEN ISO 6338-4 is a CEN/ISO draft standard for calculating greenhouse gas (GHG) emissions throughout the liquefied natural gas (LNG) chain, limited to shipping. It tells LNG ship operators and GHG inventory teams how to identify, quantify, allocate and report emissions from ship operations, using the general rules in ISO 6338-1.

What does FprEN ISO 6338-4 specify?

FprEN ISO 6338-4 specifies the shipping part of the method for calculating GHG emissions throughout the LNG chain. It is written to be used with ISO 6338-1, which carries the general requirements.

The document is organized into clauses 1 to 9:

• scope
• normative references
• terms and definitions
• principles
• GHG inventory boundaries
• quantification of GHG emissions
• GHG inventory quality management
• GHG reporting
• independent review

Clause 5 sets the shipping boundary around the ship and its associated activities. The activity list is not exhaustive, and the standard separates in-scope shipping emissions from activities that belong to other parts of the LNG chain, such as FLNG or regasification vessels.

What are the key requirements of FprEN ISO 6338-4?

FprEN ISO 6338-4 requires a ship-based GHG report that covers all associated activities within the reporting boundary. In practice, the organization that has operational control over the ship is the one that reports the emissions and removals.

Reporting boundaries and allocation

Clause 5 requires reporting over a period, for each ship, and then allocation to a cargo, including the ballast leg. That matters because shipping emissions are not tied only to loaded voyages - the return voyage and other ship activities also affect the cargo footprint.

Clause 6.4 says all emissions are allocated to the LNG shipped. It also says emissions from planned or unplanned maintenance activities, such as gassing up or cooling down before or after dry dock, should be spread across the next cargoes delivered. In practice, this means the operator needs a consistent allocation rule and must keep the supporting records.

What has to be quantified

Clause 6.1 groups shipping emissions into combustion, fuel cells, venting, fugitive emissions, and emissions associated with imported energy, utilities and consumables. For shipping, the document notes that there are no such imported-energy emissions in this part.

The combustion guidance is practical and source-based: gas combustion units, internal combustion engines, inert gas generators, gas turbine drivers, boilers and incinerators are all covered through measured gas or liquid quantities, emission factors, or emissions measurements. The document also says unburned hydrocarbons, including methane slip, have to be taken into account across the sections.

Measurement approach

Clause 6.1 emphasizes primary data where possible. For venting, significant events should be recorded, and for fugitive emissions the document allows calculation from equipment counts and standard leakage factors, with measured leakage data used to adjust those factors. In practice, this gives operators a route from engineering estimates toward measured data as their monitoring improves.

Other linked requirements

Clause 6.2 points back to ISO 6338-1 for the calculation method. Clause 6.3 points back to ISO 6338-1 for preferred units. Clause 6.5 points back to ISO 6338-1 for carbon capture, and clauses 7 to 9 also rely on ISO 6338-1 for quality management, reporting and independent review.

What terms does FprEN ISO 6338-4 define?

FprEN ISO 6338-4 uses the terms and definitions from ISO 14064-1 and ISO 6338-1.

• LNG - liquefied natural gas, the cargo and energy carrier whose shipping emissions are being calculated.
• GHG - greenhouse gas, the emission category that the whole series quantifies and reports.
• ballast leg - the ship’s return leg without cargo, which can still be part of the allocated footprint.
• venting - release of gas to the atmosphere during purging, pressure protection or similar activities.
• fugitive emissions - unintended leaks from pipes, fittings, seals, valves and related equipment.
• FSRU - floating storage and regasification unit, a vessel type linked to regasification rather than shipping in this part.
• FLNG - floating liquefied natural gas, a separate chain part handled by another standard in the series.

Who uses FprEN ISO 6338-4?

FprEN ISO 6338-4 is used by LNG ship operators, GHG inventory specialists, sustainability and reporting teams, and organizations that need auditable GHG data for LNG shipping. It is relevant in the oil and gas industries, especially where LNG is transported as part of a wider value chain.

It also supports reviewers and verification teams that check how emissions were calculated and allocated. The introduction notes that consistent GHG data is increasingly needed for accountability, commercial mechanisms and reporting.

Which standards are used with FprEN ISO 6338-4?

• ISO 6338-1 - provides the general requirements, principles, calculation approach, preferred units, allocation rules, quality management, reporting and independent review used throughout this part.
• ISO 14044 - provides life cycle assessment requirements and the cut-off criteria mentioned for imported energy, utilities and consumables.
• ISO 14064-1 - provides the terms and definitions used for organizational GHG quantification and reporting.
• ISO 6338-3 - covers FLNG, which the shipping boundary table points to as a different part of the LNG chain.
• ISO 6338-5 - covers regasification vessels and ship unloading at the regasification plant, which are excluded from this part.

What does the FprEN ISO 6338-4 document contain?

FprEN ISO 6338-4 contains boundary rules, source-by-source quantification guidance and allocation rules for LNG shipping emissions. Its tables distinguish combustion, fuel cells, venting and fugitive emissions and show the practical quantification approach for each source.

The document also gives the reporting structure for each ship and cargo, plus guidance on how to treat methane slip and maintenance-related emissions. Clause 6.1.2 is especially useful for operators because it ties each shipboard source to a measurement or estimation method.

In addition, the document points readers to ISO 6338-1 for the common calculation framework and to ISO 14044 for cut-off criteria where upstream imported inputs matter.

SLOVENSKI STANDARD
01-april-2026
Izračuni emisij toplogrednih plinov v oskrbovalni verigi z utekočinjenim
zemeljskim plinom (LNG) - 4. del: Transport (ISO/DIS 6338-4:2026)
Calculations of greenhouse gas (GHG) emissions throughout the liquefied natural gas
(LNG) chain - Part 4: Shipping (ISO/DIS 6338-4:2026)
Berechnungsverfahren der Treibhausgasemissionen (THG) in der gesamten
Flüssigerdgas-(LNG-)Kette - Teil 4: Transport (ISO/DIS 6338-4:2026)
Calcul des émissions de gaz à effet de serre (GES) dans la chaîne gaz naturel liquéfié
(GNL) - Partie 4: Transport maritime (ISO/DIS 6338-4:2026)
Ta slovenski standard je istoveten z: prEN ISO 6338-4
ICS:
13.020.40 Onesnaževanje, nadzor nad Pollution, pollution control
onesnaževanjem in and conservation
ohranjanje
75.020 Pridobivanje in predelava Extraction and processing of
nafte in zemeljskega plina petroleum and natural gas
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/DIS 6338-4
ISO/TC 67/SC 9
Calculations of greenhouse gas
Secretariat: AFNOR
(GHG) emissions throughout the
Voting begins on:
liquefied natural gas (LNG) chain —
2026-02-09
Part 4:
Voting terminates on:
2026-05-04
Shipping
ICS: 13.020.40; 75.020
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
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PROVIDE SUPPORTING DOCUMENTATION.
Reference number
ISO/DIS 6338-4:2026(en)
DRAFT
ISO/DIS 6338-4:2026(en)
International
Standard
ISO/DIS 6338-4
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
ICS: 13.020.40; 75.020
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2026
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
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BE CONSIDERED IN THE LIGHT OF THEIR
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Website: www.iso.org
Published in Switzerland Reference number
ISO/DIS 6338-4:2026(en)
ii
ISO/DIS 6338-4:2026(en)
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
ISO/DIS 6338-4:2026(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
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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
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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.
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
ISO/DIS 6338-4:2026(en)
Introduction
Natural gas will play 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
...