ISO 23306-2020 PDF

Full title and description

ISO 23306:2020 — Specification of liquefied natural gas as a fuel for marine applications. This International Standard defines quality requirements for liquefied natural gas (LNG) when used as a ship fuel, describing the measurable fuel parameters, the required values (where specified) and the reference test methods to be used at delivery/custody transfer.

Abstract

This document specifies the quality requirements for LNG used as a fuel for marine applications. It defines relevant parameters to measure (composition, physical properties and performance-related indices), the values or limits to be reported or agreed between supplier and user, and the test reference methods for those parameters. The standard applies to LNG from any source (conventional reservoirs, shale gas, coalbed methane, biomethane, synthetic methane and renewable routes) and covers fuel delivered at the time and place of custody transfer (the delivery/bunkering point).

General information

• Status: Published
• Publication date: 23 October 2020
• Publisher: International Organization for Standardization (ISO)
• ICS / categories: 75.160.30 (Gaseous fuels)
• Edition / version: 1 (First edition, 2020)
• Number of pages: 21

Scope

ISO 23306:2020 applies to liquefied natural gas intended for use as a marine fuel and specifies which properties must be measured and reported at custody transfer. It covers LNG irrespective of origin (fossil or renewable) and addresses sampling, analytical test methods, reporting requirements and quality assurance considerations to support safe bunkering, engine performance and interoperability across the supply chain.

Key topics and requirements

• Definition of mandatory and recommended fuel parameters to be measured and reported (composition by component, density of the liquid phase, calorific value, Wobbe index, methane number / knock resistance and key impurities or contaminants).
• Reference test and analysis methods for composition and properties (references to established methods such as ISO 6974, ISO 6976 for composition/calorific calculations and ISO 8943 for LNG sampling).
• Requirements and provisions for representative sampling at the delivery/bunkering point and for handling liquid-to-gas sample preparation to avoid fractionation.
• Guidance on acceptable limits or reporting practices for constituents and contaminants that may affect personnel safety, ship systems or engine/machinery performance.
• Reporting, documentation and custody-transfer information to be supplied by the fuel provider to the ship (composition, calculated properties, methane number or equivalent knock metric, date/time of sampling, sampling method, analytical methods used).
• Informative annexes providing calculation methods and examples (e.g., methane number calculation approaches, example LNG compositions, discussion of ageing along the bunkering chain and considerations for particles and trace components).

Typical use and users

Used to specify and verify LNG quality for bunkering and shipboard consumption, ISO 23306:2020 is primarily relevant to shipowners and operators, LNG suppliers and terminals, engine and fuel-system manufacturers, testing laboratories, bunker surveyors, port authorities and regulators. Typical use cases include contract specifications for bunkering, acceptance testing at delivery, engine warranty and tuning agreements, and design input for fuel-system and tank design.

Related standards

ISO 23306 references and is used alongside other standards for sampling, analysis and property calculations — notably ISO 8943 (LNG sampling), ISO 6974 (gas composition by GC), ISO 6976 (calculation of calorific values and Wobbe index) and complementary national / regional guidance such as EN 16726 for gas quality. It also cross-references other ISO methods for density, sulfur and related measurements used in custody transfer and quality control.

Keywords

LNG, liquefied natural gas, marine fuel, bunkering, methane number, Wobbe index, gas composition, sampling, custody transfer, ISO 6974, ISO 6976, ISO 8943, fuel quality, contaminants.

FAQ

Q: What is this standard?

A: ISO 23306:2020 is an International Standard that specifies quality requirements and test/reporting methods for liquefied natural gas when used as a fuel for marine applications.

Q: What does it cover?

A: It covers which LNG properties must be measured and reported at the delivery (custody-transfer) point, the reference analytical and sampling methods to be used, documentation and quality-assurance considerations, and informative guidance (annexes) on calculations and practical issues such as ageing and sampling representativity.

Q: Who typically uses it?

A: Shipowners/operators, LNG suppliers and terminals, engine and equipment OEMs, testing laboratories, bunker surveyors, port authorities and regulators use the standard to specify, supply, test and accept LNG for marine use.

Q: Is it current or superseded?

A: ISO 23306:2020 was published in October 2020. As an ISO standard it is subject to periodic review (typically every five years); users should check the issuing body or national standards organization for any amendments, confirmations or subsequent revisions after 2020.

Q: Is it part of a series?

A: It is a stand‑alone ISO International Standard focused on LNG as marine fuel but is intended to be used together with other ISO standards for sampling and analysis (for example ISO 8943, ISO 6974 and ISO 6976) and with regional/national bunkering or fuel-quality guidance.

Q: What are the key keywords?

A: LNG, marine fuel, bunkering, methane number, Wobbe index, gas composition, sampling, custody transfer, fuel quality.