1.1 This specification defines the minimum fuel quality requirements for gaseous fuels consisting primarily of methane blended with volume fraction of up to 10 % hydrogen (H₂) when used as an internal combustion engine fuel.

1.2 This specification defines the criteria for blending hydrogen with natural gas, biogas, or renewable natural gas (RNG) and then compressed into compressed natural gas (CNG) for use as a fuel for internal combustion engines in motor vehicles.

1.3 The total volume fraction of hydrogen within the fuel shall consist of hydrogen contained in the natural gas, biogas, or renewable gas and any additional hydrogen blended into the fuel mixture.

1.4 This specification covers the needs of internal combustion engines designed for use in motor vehicles.

1.5 This specification applies to the fuel as delivered into the on-board fuel tanks of a motor vehicle as a compressed gas.

1.6 This specification is not a natural gas pipeline standard; those requirements are determined by national and regional tariffs.

1.7 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.

1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.9 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.