Fire-safe ball valve: API 607, ISO 10497

A flanged carbon steel ball valve with a lever handle on a yellow gas pipe at an outdoor process skid — A lever-operated ball valve on a gas line, the kind of duty where a fire-tested design is specified.

Key takeaways

Fire-safe is a type-test result for a valve design, not a material or a visible feature.
API 607 (eighth edition, 2022) and ISO 10497:2022 judge leakage against set limits, not against zero.
A fire test certificate covers the tested design and the range its qualification extends to.
API 607 and ISO 10497 leave powered actuators out of scope; protect the actuator separately.

01What does fire-safe mean on a ball valve?

A fire-safe claim on a ball valve only counts when the design has passed a fire type test. The test follows a named standard, usually API 607 or ISO 10497. Fire-safe is not a material, a coating or a component you can point to. Two ball valves can look identical on a bench. Only one may belong to a design that was burned, cooled and measured.

The reason is the seat. A standard ball valve seals on soft PTFE or similar polymer seats, and fire destroys them. The SVF Flow Controls brief on fire-safe design gives the usual answer. A metal backup seat behind the soft seat limits the flow once the soft seats are gone.

The seat is only one leak path. Stem and body seals must hold too, because a leak to atmosphere feeds the fire. SVF names graphite-based stem and body seals, since other seals fail in the heat. Habonim's HermetiX brochure shows another route: a polymer stem seal with a metal fire lip.

“Fire-safe by design” or “API 607 certified” on a datasheet is a claim; the fire test report is the evidence. Still choosing the pattern? Start with gate, globe or ball, or gate valve vs ball valve.

02What happens in an API 607 or ISO 10497 fire test?

An API 607 or ISO 10497 fire type test burns a sample valve of one design. The valve is shut and under pressure, then cooled. Seat leakage and leakage to atmosphere are measured during the burn and after cooling. Each leak path must stay inside the limit the standard sets.

Valve Magazine (2018) notes that the API valve fire tests specify a 30-minute burn. Its author, Matt Wasielewski, PE, gives flame temperatures of 760 to 982 °C. SVF's 2025 certification guide gives about 30 minutes at around 760 °C. Confirm the burn, pressures and leak limits against the current edition and your purchase order.

ISO's summary of ISO 10497 lists four assessment criteria. They are seat leakage, external leakage, cavity pressure relief on double-seated valves, and operability. The pass mark is controlled leakage, not zero leakage. Swagelok's Fire Series catalogue (revision G, November 2021) tabulates maximum leak rates under API 607's sixth edition.

Low line pressure is the hard case for a soft-seated ball valve. In a real plant fire, pumps stop and line pressure can fall. Less pressure presses the ball less firmly onto what is left of the seat. Valve Magazine dates the low-pressure test for soft-seated valves to API 607 in 1994.

Valve Magazine reports that ball valves of 3 to 4 inch often struggle most. Valves of 2 inch and under tend to lose their seats completely. Valves of 6 inch and larger keep enough seat to seal. In between, the seat burns only partly, and fragments can lodge between ball and body. Swagelok developed its own uneven-heating test for that condition.

In their words
“Industry standards do not address situations in which a valve seat is only partially destroyed.”
Swagelok, Fire Series Ball Valves catalogue (revision G, November 2021)

03API 607, ISO 10497 or API 6FA: which standard applies?

API 607, ISO 10497 and API 6FA are all fire tests, written for different valve families. API 607 covers quarter-turn valves, plus other valves with non-metallic seats. ISO 10497 covers soft- and metal-seated isolation valves. API 6FA covers valves built to API 6A, the wellhead and tree specification, or to API 6D.

The API 2025 publications catalogue lists API 607 in its eighth edition, October 2022. Its exploration and production section lists API 6FA in its fifth edition, May 2020. ISO lists ISO 10497:2022, edition 4, as published. Confirm the edition against the publisher's current listing and your purchase order.

Three fire tests, and one pressure test that is not a fire test
Standard	Edition the publisher lists	What it covers, in short	Where it usually appears
API 607	Eighth edition, October 2022	Pressure containment during and after a fire, for quarter-turn valves and valves with non-metallic seats	The usual call-up for soft-seated ball valves
ISO 10497	Edition 4, 2022	Fire type-test of soft- and metal-seated isolation valves. Sets rules for extending a pass to untested sizes, ratings and materials	Where the specification names it; confirm it may stand in for API 607
API 6FA	Fifth edition, May 2020	Pressure containment in a fire for valves built to API 6A and API 6D	Wellhead and oil and gas valves, mostly metal-seated
API 598	Eleventh edition, February 2023	Inspection and pressure testing of ball, butterfly, gate, globe, plug and check valves	Normal-service tightness. Not a fire test.

API 6FA is most often used for metal-seated ball, gate and globe valves, says Valve Magazine. Metal-seated does not mean fire-safe by default. Some engineers treat metal-seated gate and globe valves as inherently fire-safe. Writing in 2018, Matt Wasielewski, PE, had run fire and fugitive emission tests since 1992 and sat on API standards committees. He answers that plainly: “While the majority of these valves do pass this test, some designs fail miserably.”

04What does a fire test certificate cover?

A fire test certificate covers the design that was burned. The pass also extends to the sizes, ratings and materials the standard allows. ISO 10497 sets rules for extending a pass within the same basic design type. Check that the quoted valve falls inside that range, body material included; see valve body materials compared.

A one-page certificate tells you a test happened; the test report tells you what was tested. ISO's summary says reports under earlier editions are acceptable with the full, compliant report. Data missing from that report is accepted or rejected at the purchaser's discretion.

A design change can take a valve outside its qualification. The same applies after repair: rebuild with the manufacturer's specified parts. Our valve testing, maintenance and repair services are no substitute for a fire type test.

05What does fire-safe not prove?

Fire-safe does not prove that a ball valve is fireproof. Fire-safe says nothing about the actuator, or about seat tightness in normal service. Fire-safe proves limited leakage from one design, under one test, during and after a burn. Each of these gaps needs its own line in the specification, because the certificate will not fill it.

Not the actuator. API 607 and ISO 10497 both leave electric, pneumatic and hydraulic actuators out of scope. Swagelok's catalogue states that its actuator accessories are not fire-test rated.
Not normal-service tightness. Seat tightness in normal service is checked by a separate factory pressure test, such as API 598.
Not every port arrangement. SVF warns that a multi-port fire-safe valve cannot ensure flow control. The extra flow path is the reason.

If an actuated shutdown valve must close in a fire, its actuator needs its own fire protection. Valve Magazine adds that a mounted actuator is still engulfed in flames during the burn. Settle that in the actuator specification; see our actuators and automation page.

Anti-static protection often travels with fire-safe designs, but it answers a different question. Fire-safe limits the damage from a fire; anti-static helps stop the valve starting one. SVF's technical brief explains why: stem seals can isolate the stem from the body. The device discharges the static that builds up in flow.

06Where should plants specify fire-safe ball valves?

Plants should specify fire-safe ball valves wherever a leaking valve would feed a fire. That means hydrocarbon lines in oil, gas and petrochemical units. It also covers natural gas, fuel gas, LPG, flammable solvents, and diesel or fuel oil to boilers. On chilled water or clean utility water, a fire-tested design adds cost and buys nothing. The plant or project specification sets the requirement.

The SVF guide to fire-safe certification says API 607 valves are often required where flammable fluids are present. Its examples are refineries, petrochemical processing, tank farms and loading stations. Our oil, gas and petrochemical page covers those duties. Hot oil and fuel lines in a palm oil refinery or oleochemical plant can qualify too.

A fire-tested design adds backup seats, fire-resistant seals and the cost of qualification. In our experience, buyers either go too cheap and face costly downtime, or over-engineer beyond what the project needs. Graphite can also be unwelcome in clean service. Habonim lists “Prevents media contamination from graphite particles” as a benefit of its graphite-free stem seal.

Before the enquiry goes out, run this checklist; each line closes a gap the certificate leaves open.

Name the standard and edition exactly as your specification states it.
Ask for the full fire test report for the design being quoted, and who witnessed the test.
Check the qualified range against the quoted size, class, body material and seat.
Confirm the stem and body seals match the tested design.
Specify actuator fire protection separately if the valve must work in a fire.
Add anti-static as its own line if the fluid can build up static.
Keep normal-service seat testing, such as API 598, as a separate requirement.

Quoting a KITZ ball valve? Ask whether a fire test report covers that figure number before the order goes out. Our KITZ valves page covers the line. Paste the seven lines into your enquiry.

For the wider selection, read choosing the right industrial valve: duty first, budget second. We don't just sell parts; we sit down with your engineers to make sure they get the right solution.

07Questions buyers ask about fire-safe ball valves

Is a fire-safe ball valve the same as a fireproof valve?

No. A fire-safe ball valve comes from a design that kept leakage inside set limits in a fire test. The valve can still leak in a real fire, and a soft-seated design's seats will burn. Fire-safe means limited leakage, not immunity.

Is a fire-safe design the same as a fire-tested valve?

No. A fire-safe design lists features such as a metal backup seat and graphite seals. A fire-tested valve belongs to a design that passed API 607, ISO 10497 or API 6FA. Ask for the fire test report; a datasheet feature list proves nothing alone.

Is ISO 10497 the same as API 607?

Not any more. API 607 and ISO 10497 were co-branded at API 607's fifth edition, says Valve Magazine. The co-branding ended with the sixth, and the two now differ in scope. Accept one in place of the other only if your specification allows it.

What is the difference between API 607 and API 6FA?

API 607 and API 6FA cover different valve families. API's catalogue files API 607 under refining, for quarter-turn valves and valves with non-metallic seats. API 6FA sits under exploration and production, for API 6A and API 6D valves. Name the one your specification calls for.

Do metal-seated ball valves need a fire test?

Yes, wherever the duty needs a fire-safe valve. A metal seat removes the polymer that burns. The body joints and stem seals still face the fire. Valve Magazine reports most metal-seated gate and globe valves pass, but some designs fail badly. Only a test shows which.

Fire-safe ball valves: what API 607 and ISO 10497 actually prove