In spite of their easier ignition capability compared to metals and ceramics, non-metallic materials are often used in oxygen atmospheres because of their specific properties and, consequently, miscellaneous methods have been developped to evaluate their ignition risks which depend on their service conditions.

The main test methods implemented at “L'AIR LIQUIDE — Centre de Technologie et d'Expertise” i.e., the “bomb test” (determination of autogenous ignition temperature at high oxygen pressure), the gaseous oxygen pneumatic impact test (adiabatic compression test) and the liquid oxygen mechanical impact test will be presented first.

Then, we will give our interpretation of the results which show that: for use with high-pressure oxygen gas (up to 24 MPa), it is best to use materials with spontaneous ignition temperature at 12 MPa greater than or equal to 400°C ; however, this may not be a sufficient limit if extreme ignition sources can be expected ; on the other hand, it may not be possible to respect this limit if a compromise is required between the qualities of the product for which it is used and its resistance to ignition ; the following precautions must be taken in either of these cases: the equipment must be well-designed (small quantities of organic materials, protected wherever possible from the impact of the gas stream and in integral contact with their metal support), additional tests must be made on this equipment (such as adiabatic compression tests), a precise analysis of hazards must be made and types of use for which no incidents have been reported should be considered; for use with liquid oxygen, the materials must at least successfully pass the impact drop test at an energy level of 100 Joules.