scope:

This standard establishes minimum requirements for pressure relief devices intended for use on fuel containers that comply with ANSI/CSA NGV2, Compressed Natural Gas Vehicle (NGV) Fuel Containers, FMVSS 304, Federal Motor Vehicle Safety Standards, 49 CFR Part 571.304, Compressed Natural Gas Fuel Container Integrity, CSA B51, Part 2, High Pressure Cylinders for On-Board Storage of Natural Gas as a Fuel for Automotive Vehicles and/or ISO 11439 Gas Cylinders - High Pressure Cylinders for the Onboard Storage of Natural Gas as a Fuel for Automotive Vehicles.

Pressure relief devices may be of any design or manufacturing method that meets the requirements of this standard.

The construction of pressure relief devices, whether specifically covered in this standard or not, shall be in accordance with reasonable concepts of safety, performance and durability.

This standard does not apply to reseating or resealing devices.

Pressure relief devices designed to comply with this standard are expected to be used with natural gas fuel containing no more than two percent hydrogen by volume.

Resistance to chloride stress corrosion cracking shall be taken under consideration if selecting stainless steel materials. Resistance to stress corrosion cracking and sustained load cracking shall be taken under consideration if selecting aluminum materials. Resistance to sulfide stress cracking shall be taken under consideration if selecting steel materials.