ISO 15859-3:2004 specifies limits for the composition of nitrogen and establishes the sampling and test requirements applicable for the verification of nitrogen composition.

ISO 15859-3:2004 is applicable to nitrogen, used in both flight hardware and ground facilities, systems and equipment, of the following types and grades of nitrogen: Type I, gaseous (Grade A: purging/pressurizing, Grade B: crew breathing, Grade C, Grade F, Grade J) and Type II, liquid (Grade A: purging/pressurizing, Grade B: crew breathing, Grade C, Grade F).

ISO 15859-3:2004 is applicable to influents only within the specified limits.

ISO 15859-3:2004 is applicable to any sampling operation required to ensure that, when the fluid enters the launch vehicle or spacecraft, the fluid composition complies with the limits provided hereafter or with any technical specification agreed to for a particular use.