A.2.2.2 Test environment Tests shall be carried out at the pressure not less than the MAWP and results are valid for all pressures equal to or less than the pressure used in the tests. The hydrogen used for testing shall comply with the requirement listed in EN ISO 11114-4. Temperature shall be such that the occurrence of hydrogen embrittlement is maximum. NOTE For carbon and low alloy steel and aluminium alloys maximum hydrogen embrittlement occurs at room temperature. Other steels (e.g. stainless steels) and metallic materials can require different temperatures to be determined.

Given the above clause answer the following question.

Whats the temperature that maximum hydrogen embrittlement occurs in stainless steel ?