This part of ISO 14951 specifies limits for the composition of nitrogen and test methods for verification of nitrogen composition. This part of ISO 14951 is applicable to nitrogen of the following types and grades, intended for purging and pressurization of propellant systems of space systems and for preparing oxygen-nitrogen mixtures for breathing purposes on board space vehicles:

• type I: gaseous
  • grade A: 99,5 % pure, purging/pressurizing;
  • grade B: 99,99 % pure, crew breathing;
  • grade C: 99,995 % pure;
  • grade F: 99,99 % pure;
• type II: liquid
  • grade A: 99,5 % pure, purging/pressurizing;
  • grade B: 99,99 % pure, crew breathing;
  • grade C: 99,995 % pure;
  • grade F: 99,99 % pure.

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