This part of ISO 14951 specifies limits for the chemical composition and physical properties of hydrazine (N₂H₄) propellant and test methods for verification of propellant composition. This part of ISO 14951 is applicable to hydrazine propellant of the following grades, intended for use as a fuel in propellant systems of space systems:

• standard: normal production and quality control (suitable for most uses);
• monopropellant: normal product with strict control of specified impurities (to be specified only for monopropellant catalytic engines where extended life of the catalyst is desired);
• high purity: special production with strict control of specified impurities.

This part of ISO 14951 is applicable to propellant used in both flight hardware and ground facilities, systems, and equipment. It is applicable to influents only to the extent specified herein.