ISO 15859-4:2004 specifies limits for the composition of helium and establishes the sampling and test requirements applicable for the verification of the helium composition.

ISO 15859-4:2004 is applicable to helium, used in both flight hardware and ground facilities, systems and equipment, of the following types and grades:Type I, gaseous (Grade A: purging and pressurizing helium, Grade F: purging and pressurizing helium, Grade J: purging and pressurizing helium) and Type II, liquid (Grade A: purging and pressurizing helium, Grade F: purging and pressurizing helium).

ISO 15859-4:2004 is applicable to influents only within the specified limits.

ISO 15859-4:2004 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.