Soft seats and seals burn away in a fire, so fire-safe valves add metal-to-metal secondary seats and graphite stem and body seals that take over. The design is proven by a type test such as API 607 or ISO 10497, in which a pressurized, closed valve is engulfed in flame for about 30 minutes and through-leakage and external leakage are measured, followed by an operational check.
Hydrocarbon service means the ball valves have to be fire-safe certified, check the cert, not just the catalog.
Fire-safe describes the design, not a promise of tight shutoff after a fire; the tests allow measured leakage.
Also heard as
- fire-tested
- fire safe
Related terms
Ball valve
A quarter-turn valve that opens and closes by rotating a ball with a bore through it.
Seat
The surface inside a valve that the closure member presses against to stop flow.
Triple-offset butterfly valve
A metal-seated butterfly valve whose geometry lets the seal touch the seat only at the end of closure, for tight, rub-free shutoff.
Packing
Compressible rings packed around a valve stem to stop process fluid leaking out to atmosphere.