EN 12266 Butterfly Valves
What EN 12266 requires for butterfly valves — applicability, key and testing requirements, the alternative standards, and compliant supply with full certification.
What does EN 12266 require for butterfly valves?
EN 12266 (Industrial Valves - Testing of Metallic Valves (Parts 1 and 2), European Committee for Standardization (CEN)) sets the design, material and testing requirements for butterfly valves in its scope. EN 12266 is the European standard for pressure testing of metallic industrial valves - the EU equivalent of API 598 and ISO 5208, commonly specified in European refinery and petrochemical projects.
Applicable Pressure Classes
Key Requirements
- Shell test (Part 1, Clause 5.1): 1.5× PS (maximum allowable pressure) at 20°C; acceptance criterion: Rate A (no visible leakage)
- Seat test (Part 1, Clause 5.2): 1.1× PS; acceptance criterion: Rate A (zero) for tight-shutoff or Rate D for standard service
- Rate definitions: Rate A = no visible leakage; Rate B/C/D = measured leakage limits per pipe size and pressure class
- Backseat test (Part 1, Clause 5.3): for valves with packing isolation feature; 1.1× PS behind the backseat
- Part 2 supplementary tests: high-temperature seat test, low-temperature seat test, fugitive emission test
- EN 12266 is mandatory for PED 2014/68/EU compliance in Europe - documented FAT required
Testing Requirements
- EN 12266-1 shell and seat test with documented FAT report
- CE marking attestation if PED-relevant
Alternative Standards for Butterfly Valves
Other standards that also govern butterfly valves — useful for spec cross-acceptance.
Connected Engineering
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