This International Standard specifies gas/materials compatibility requirements (such as chemical resistance) for cryogenic vessels, but it does not cover mechanical properties (e.g. for low temperature applications). It gives general guidance for compatibility with gases and detailed compatibility requirements for oxygen and oxygen-enriched atmospheres. This International Standard also defines the testing methods for establishing oxygen compatibility of materials (metallic and non-metallic) to be used for cryogenic vessels and associated equipment. This International Standard focuses on materials that are normally with or could be in contact with cryogenic fluids.