A ball valve datasheet marked API 608 does not prove that the valve design has passed an API 607 fire test. API 608 sets product requirements for the metal ball valves within its scope. API 607 evaluates how a qualified valve design performs during and after a defined fire test.
The two standards therefore answer different approval questions. API 608 concerns the valve supplied: its design, construction, inspection, testing and marking requirements. API 607 concerns the fire-test evidence and the range of valve constructions covered by that evidence. A test report, certificate or listing should not be treated as automatic approval for every size, pressure class, seat material or body construction.
Projects involving hydrocarbons, fuel gas or other fire-risk services may specify both standards. The buyer should confirm that the offered valve meets the required API 608 edition and that its construction falls within the documented API 607 qualification scope. This distinction also applies when reviewing other valve standards and documents.
API 607 and API 608 Answer Different Questions
API 607 belongs against the fire-test evidence, while API 608 belongs against the supplied ball valve’s product requirements. Seeing both references on a specification is not duplication. Each standard supports a different part of technical approval.
| Comparison point | API 607 | API 608 |
|---|---|---|
| Primary purpose | Fire type testing and acceptance within the standard’s scope | Product requirements for covered metal ball valves |
| What is evaluated | A representative valve design during and after a defined fire test | The ball valve’s design, construction, inspection, testing and marking |
| Buyer approval question | Does the fire-test evidence cover the offered construction and applicable qualification range? | Does the offered ball valve meet the specified API 608 edition and product scope? |
| Typical documents reviewed | Test report and, where issued, a certificate or listing that identifies the tested design and scope | Datasheet, drawings, material records, inspection and pressure-test records, and compliance documentation |
| What it does not prove | Compliance with a separate ball valve product standard | Qualification to API 607 or another fire-test standard |
API 607 is a type test, so production valves are not individually exposed to fire as a routine acceptance test. The submitted evidence must instead be checked against the offered valve’s design and the qualification rules required by the project.
The word “metal” in the API 608 title describes the ball valve product, not a requirement that every valve use a metal seat. An API 608 claim also says nothing about fire-test qualification unless the manufacturer supplies separate, applicable evidence.
What API 607 Actually Tests in a Fire Type Test
API 607 is a fire type-test standard. It does not require every production valve to be exposed to fire. Instead, a representative valve is tested, and the result may qualify other valves only within the size, pressure rating, material, and design rules of the applicable edition.
The current API 607 Eighth Edition was published in October 2022. It covers quarter-turn valves with metallic or nonmetallic seats, as well as other operated valves with nonmetallic seating within its stated scope.
API 607 Fire-Test Conditions and Sequence
| Test Stage | Main Condition | What Is Evaluated |
|---|---|---|
| Test preparation | The assembled valve is filled with water, air is removed, and the valve is placed in the required closed position. | The test valve, sealing direction, pressure boundary, and leakage measurement system are prepared for the fire test. |
| Test pressure | Nonmetallic-seated Class 150 and Class 300 valves use a low test pressure of approximately 0.2 MPa, equal to 30 psig. Other applicable valves use a higher pressure based on 75% of the maximum permitted seat working pressure at 20°C. | The valve’s ability to contain the test fluid while its seats, seals, packing, and gaskets are exposed to fire. |
| Fire exposure | The closed and pressurised valve is fully surrounded by flames. The flame environment is maintained at approximately 750°C to 1000°C for 30 minutes. | Whether the valve receives enough heat to expose its seats, stem seals, body seals, and pressure-containing parts to the defined fire conditions. |
| Leakage during the fire | Test pressure is maintained while leakage is measured throughout the burn period. | Through-seat leakage and external leakage from the stem, body joints, gaskets, seals, and other pressure-boundary locations. |
| Cavity-pressure control | For double-seated valves, body-cavity pressure is monitored as the trapped test liquid expands during heating. | Whether the valve’s cavity-pressure relief arrangement operates without causing uncontrolled external or through-seat leakage. |
| Cool-down | After the burn, the valve is cooled while the required pressure and leakage monitoring are maintained. The external surface is cooled below 100°C within the permitted cooling period. | External leakage and pressure-boundary behaviour as damaged seals and metal parts contract during cooling. |
| Post-fire seat test | Through-seat leakage is checked again after the valve has cooled. | Whether the fire-damaged valve can still limit internal leakage within the applicable size-based acceptance value. |
| Operability and final external leakage | The valve is operated from fully closed to fully open under the required pressure. External leakage is then checked with the valve open. | Whether the valve can still be operated after the fire and whether the pressure boundary remains within the permitted external leakage limit. |
What Counts as Passing API 607?
API 607 does not require the valve to remain undamaged or provide zero leakage. The tested valve passes when the measured results stay within the applicable limits for:
- Through-seat leakage during the fire.
- External leakage during the fire and cool-down periods.
- Post-fire seat leakage after cooling.
- Operability under the specified differential pressure.
- External leakage after operation with the valve in the open position.
The permitted leakage values depend on the valve size and test condition. For this reason, a general statement such as “API 607 means zero leakage” is not technically correct.
Video source: Union Tech on YouTube.
What API 608 Defines for the Supplied Ball Valve
API 608 is a product standard for the metal ball valves covered by its scope. Its official title is Metal Ball Valves-Flanged, Threaded, and Welding Ends. API published the seventh edition in April 2025, and the API Monogram Program effective date was 2 October 2025, as stated in the API Standard 608 update.
What Is Actually Pressure-Tested on an API 608 Ball Valve?
API 608 is the ball valve product standard. The detailed production pressure-test pressures, durations, test media, and leakage limits are applied through API 598 valve inspection and testing. API 598 supports API 608; it is not a third competing product standard.
| Test | API 598 Applicability to Ball Valves | Test Parameter | What It Verifies |
|---|---|---|---|
| Shell test | Required for every floating and trunnion-mounted ball valve. | For steel and nonferrous alloy valves, the minimum hydrostatic pressure is generally 1.5 times the applicable pressure rating at 38°C. A lower-rated end connection may limit the test pressure. | Integrity of the pressure boundary, including the body and fixed body joints. Visually detectable leakage is not permitted. |
| Low-pressure closure test | Required for floating ball valves. For trunnion-mounted ball valves, it is required within the lower size-and-class ranges shown below and optional for the higher ranges. | Air, nitrogen, or another inert gas at 5.5 ± 1.5 bar gauge, equal to 80 ± 20 psig. | Seat sealing at low differential pressure. Resilient-seated valves have a zero visible leakage requirement for the minimum test duration. |
| High-pressure closure test | Normally optional for floating ball valves. For trunnion-mounted ball valves, it is required in the higher size-and-class ranges shown below and optional in the lower ranges. | 110% of the maximum allowable pressure at 38°C under the applicable purchase specification. | Seat sealing under higher differential pressure. Leakage acceptance depends on whether the valve is resilient-seated or metal-seated. |
| DBB high-pressure closure test | For a valve specified as double block and bleed, the successive DBB high-pressure closure test is required unless the purchaser states otherwise. | Pressure is applied to each side in sequence, while leakage into the body cavity is checked through the drain or bleed connection. | Independent seat isolation and leakage into the valve body cavity. |
| High-pressure pneumatic shell test | Optional and performed only when specified in the purchase order. | 110% of the maximum allowable pressure at 38°C, or another pressure stated in the purchase order. It follows the hydrostatic shell test. | Gas-tight pressure-boundary integrity. Visible leakage is not permitted. |
Minimum Pressure-Test Duration
| Valve Size | Shell Test | Closure Test per Seat-Sealing Direction |
|---|---|---|
| Up to DN 50 / NPS 2 | 15 seconds | 15 seconds |
| DN 65 to DN 150 / NPS 2 1/2 to NPS 6 | 60 seconds | 60 seconds |
| DN 200 to DN 300 / NPS 8 to NPS 12 | 120 seconds | 120 seconds |
| DN 350 to DN 600 / NPS 14 to NPS 24 | 300 seconds | 120 seconds |
The duration starts after the valve is fully prepared and has reached the full test pressure. The closure time applies to each required seat-sealing direction.
Test Medium and Leakage Acceptance
- Shell and high-pressure closure tests: The test fluid may be air, nitrogen, another inert gas, kerosene, water, or a suitable non-corrosive liquid with viscosity no higher than water.
- Low-pressure closure test: The permitted test media are air, nitrogen, or another inert gas.
- Test temperature: Unless the purchase order states otherwise, the test fluid must be between 5°C and 38°C.
- Austenitic stainless steel: Water used for testing must have a chloride content no higher than 50 ppm, and the manufacturer must be able to document it.
- Resilient seats: API 598 permits zero visible seat leakage during the minimum test duration.
- Metal seats: A limited size-based leakage rate is permitted under API 598 rather than applying a universal zero-leakage claim.
The test procedure must not use excessive handle, gearbox, or actuator force to obtain a passing seat-leakage result. Any added closing force must remain within the manufacturer’s documented limit.
A statement that a valve is manufactured to API 608 is also different from permission to apply the API Monogram. If monogrammed equipment is required, confirm the manufacturer’s current licence scope and the marking allowed for the supplied product. Neither statement proves API 607 fire-test qualification.
When a Ball Valve Specification Should Require Both
A project should specify API 608 and API 607 together when it needs a ball valve within the API 608 product scope and separate evidence of fire-test qualification. This combination is often considered for refinery, petrochemical, fuel-gas and hydrocarbon duties where loss of seat or stem sealing during a fire could release more flammable fluid.
API 608 establishes the ball valve product requirements. API 607 adds fire type-test evidence for a representative design. Specifying only API 608 does not prove fire performance, while specifying only API 607 leaves the product requirements to other standards and project documents.
The presence of a flammable medium does not automatically make API 607 mandatory for every valve. The owner or engineering contractor must consider the fire-risk assessment, valve location, isolation duty, regulations and contract requirements. The specified editions should also be named when bids or technical approvals may span an edition change.
Example specification wording:
Ball valve to API 608, 7th Edition, with API 607 fire type-test evidence to the project-specified edition. The submitted evidence shall cover the offered valve construction and applicable qualification range.
This wording is a starting point, not a universal project clause. The final datasheet still controls details such as ball valve construction, bore, nominal size, pressure class, materials, end connection, seat and seal arrangement, operation method and leakage requirement.
Does API 607 add a fixed cost premium?
There is no standard percentage that can be applied to every API 607 valve. The effect on price and delivery depends on the evidence already available and whether it covers the offered construction.
Common cost drivers include:
- Existing qualification: a suitable report may already cover the offered size, class and construction.
- New testing: a different construction may require a new test programme, laboratory time and third-party involvement.
- Design changes: fire-safe seating, packing, body seals or other construction changes can affect the valve and its documentation.
- Project review: added document approval, inspection and traceability requirements can increase engineering work and lead time.
Cost claims such as a fixed 30% or 50% increase are therefore unreliable without a defined valve and qualification scope.
How to Check the Datasheet and Fire-Test Evidence
A valid-looking API 607 certificate is not enough for technical approval. Every item below must connect the submitted evidence to the valve that will be manufactured and supplied:
- Confirm the standards and editions: compare the purchase specification, datasheet, test report and certificate. Do not assume that an undated reference means the edition required by the project.
- Identify the offered construction: check floating or trunnion-mounted design, full or reduced bore, body style and flanged, threaded or welded ends.
- Check size and class coverage: confirm that the nominal size and pressure class fall within the documented qualification range. Do not create an extrapolation range without the governing rules.
- Compare sealing and pressure-boundary materials: review seats, packing, stem seals, body seals and other nonmetallic parts that affect fire-test performance.
- Verify the document identity: check the report number, test date, standard edition, tested valve description, manufacturer and issuing organisation.
- Match the final production documents: confirm that the approved drawing, bill of materials, nameplate and supplied valve retain the construction represented by the qualification evidence.
Common document mismatches
The following findings should stop automatic approval:
- The certificate names API 607 but does not show a clear edition or qualification scope.
- The tested valve construction differs from the offered body, bore, end connection or ball support design.
- The seat, packing, stem seal or body seal materials do not match the approved test configuration.
- The supplier changed the drawing or bill of materials after the fire-test evidence was reviewed.
Where the scope is unclear, obtain the full report or a traceable qualification statement before the valve is released for manufacture, final inspection or shipment.
API 607 vs API 6FA and API 608 vs API 6D
Related API numbers may appear on the same datasheet, but similar subjects do not make the standards interchangeable. Each reference must match the valve type, service and approval basis.
API 607 vs API 6FA
API 607 and API 6FA both address valve fire testing, but their scopes and qualification rules differ. A report to one standard should not be accepted as evidence for the other unless the project permits it and the technical scope has been reviewed.
The required fire-test standard and edition should be stated in the datasheet. The wider API valve standards guide explains how fire testing fits beside product and inspection standards.
API 608 vs API 6D
API 608 applies to metal ball valves within its product scope. API 6D covers pipeline and piping valves within its scope and is not limited to ball valves. The intended system and owner specification should decide which standard controls the valve.
Do not choose between them by pressure class or end connection alone. Pipeline duty, bore, pigging, isolation function, operation, testing, marking and document requirements can change the approval route. See the dedicated API 608 vs API 6D comparison for that decision.
Conclusion
API 608 and API 607 are complementary when a project needs both a covered metal ball valve product and applicable fire-test evidence. Review them as separate approval items: confirm the API 608 edition and product documents, then verify that the API 607 report covers the offered construction, materials and qualification range.