Standard Specification

BS 5351 Ball Valves

What BS 5351 requires for ball valves — applicability, key and testing requirements, the alternative standards, and compliant supply with full certification.

What does BS 5351 require for ball valves?

BS 5351 (Steel Ball Valves for Petroleum, Petrochemical and Allied Industries, British Standards Institution (BSI)) sets the design, material and testing requirements for ball valves in its scope. BS 5351 is the British Standard covering steel ball valves for the petroleum, petrochemical, and allied industries, serving a similar purpose to API 6D and API 608 but tailored for the UK and European market requirements. It specifies design, materials, dimensions, inspection, and testing requirements for full-bore and reduced-bore floating and trunnion-mounted ball valves in flanged and butt-welding end configurations. BS 5351 is commonly specified by UK refineries, North Sea offshore operators, and European EPC contractors alongside or in lieu of API 6D on process piping systems.

Applicable Pressure Classes

Class 150Class 300Class 600Class 900Class 1500Class 2500PN 16 to PN 420

Key Requirements

Full-bore (full-port) bore diameter shall equal nominal pipe bore
Reduced-bore minimum port area: not less than 70% of full-bore area
Anti-static device between ball and body earthing provision
Blow-out-proof stem design mandatory for all sizes
Seat design: PTFE, reinforced PTFE, or metal seat per service temperature
Fire-tested design per BS 6755 Part 2 when fire-safe service is specified
Body cavity pressure relief (self-venting seat) for liquid service
Positive material identification (PMI) of all pressure-containing parts

Testing Requirements

Shell test: 1.5× rated pressure, 15 minutes minimum, zero leakage
Seat leakage test: 1.1× rated pressure per API 598 or ISO 5208 acceptance criteria
Anti-static continuity test: electrical resistance ≤10 ohms across stem-ball-body
Fire-safe test per BS 6755 Part 2 / ISO 10497 when specified