BS 6364 Butterfly Valves
What BS 6364 requires for butterfly valves — applicability, key and testing requirements, the alternative standards, and compliant supply with full certification.
What does BS 6364 require for butterfly valves?
BS 6364 (BS 6364 - Specification for Valves for Cryogenic Service, British Standards Institution (BSI)) sets the design, material and testing requirements for butterfly valves in its scope. BS 6364 is the primary cryogenic valve standard, specifying design and testing requirements for valves used in LNG, liquid nitrogen, liquid oxygen, and other cryogenic services below -46°C.
Applicable Pressure Classes
Key Requirements
- Extended bonnet design mandatory - bonnet length to maintain packing at ambient temperature
- Body and bonnet materials: A352 LCC (-101°C min), SS316/CF8M (-196°C min)
- Cold-shock test: valve filled with liquid nitrogen, cycled 10 times, then seat leak tested at cryogenic temperature
- Low-temperature impact testing per ASTM A370 - minimum 27J Charpy at -196°C for austenitic SS
- Seat leakage not to exceed Class VI (API 598) when cold-tested
- Venting provision in body to prevent hydraulic lock from vaporising liquid
Testing Requirements
- Cold-shock test at -196°C
- Seat leakage test at cryogenic temperature
- Low-temperature Charpy impact test
Alternative Standards for Butterfly Valves
Other standards that also govern butterfly valves — useful for spec cross-acceptance.
Connected Engineering
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