What Is API 607?
API 607 is an American Petroleum Institute standard that specifies fire testing requirements for quarter-turn valves and their actuators, defining the test procedure, fire exposure conditions, leakage acceptance criteria, post-fire operability requirements, and certification documentation that demonstrate a valve design’s ability to maintain pressure boundary integrity and limited seat leakage after surviving direct fire exposure. It is the primary fire-safe qualification standard for ball valves and plug valves in oil, gas, and petrochemical service, and forms a critical specialized certification reference within the valve standards overview hub.
Key Takeaways
- API 607 defines fire testing for quarter-turn valves — the standard applies to ball valves, plug valves, and their actuators; it does not apply to gate valves (which are fire tested per API 6FA) or to multi-turn valves (globe valves, which rely on graphite packing fire resistance rather than soft seat backup sealing).
- Evaluates pressure containment and seat leakage after fire exposure — the test measures both external leakage from the body and bonnet pressure boundary and internal seat leakage past the closed closure element after the valve has been subjected to the standardized fire temperature profile, not only during the fire itself.
- Commonly applied to ball and plug valves — the soft seats of standard ball and plug valves (PTFE, PEEK, nylon inserts) are destroyed in a fire, and API 607 certification verifies that the valve’s metal backup seats provide acceptable sealing after the soft seats are gone, preventing catastrophic fluid release that would feed and spread the fire.
- Required in refinery, petrochemical, and hazardous fluid service — API 607 certification is a mandatory purchase requirement specified in project valve specifications for all quarter-turn valve positions in flammable hydrocarbon service on oil platforms, in refinery process units, in LNG facilities, and in any installation where fire survivability is a process safety requirement.
How It Works
Fire Exposure Testing Procedure
API 607 specifies a prototype type test — conducted once on a representative valve design — that subjects the valve to a standardized fire scenario replicating the thermal conditions of a pool fire or jet fire in a hydrocarbon processing facility. The test sequence begins with a pre-fire baseline pressure test: the valve is pressurized to its rated working pressure with both the body cavity and the seat leakage measurement circuit pressurized, and baseline leakage rates are recorded to confirm the valve’s pre-fire sealing performance meets the standard’s requirements. The valve is then installed in the fire test rig — an enclosure designed to subject the valve’s external surfaces uniformly to the specified fire temperature profile — with the valve in the closed position, at or near the rated working pressure, to represent the worst-case fire scenario of a pressurized valve under active fire attack. The fire is ignited and maintained for a minimum of 30 minutes at a flame temperature between 750°C and 1000°C, measured by thermocouples positioned around the valve body — this temperature range replicates the thermal environment of a sustained hydrocarbon pool fire at the valve’s external surface. During the 30-minute fire exposure period, the valve is continuously monitored for external body leakage (any visible flame at leakage points from the body pressure boundary indicates unacceptable leakage) and internal seat leakage (measured by flow from the downstream side of the closed valve). After the 30-minute fire exposure, the fuel supply is shut off and the valve is allowed to cool naturally for a specified period (typically 30 minutes minimum) before the post-fire measurements are taken.
Leakage Measurement and Pressure Integrity
The post-fire leakage measurement is the critical acceptance test in API 607 — it establishes whether the valve’s metal backup seats provide adequate sealing after the soft seat materials have been thermally destroyed by the fire exposure. The post-fire seat leakage test is conducted at the rated working pressure, and the acceptance criterion for internal seat leakage (past the closed seats) is a maximum of 1,500 milliliters per minute per inch of nominal pipe diameter — a defined allowance rather than zero leakage, recognizing that thermally distorted metal backup seats cannot achieve the zero leakage of new soft seats, but must limit leakage sufficiently to prevent the fire from being fed by flammable fluid escaping through the valve. For external leakage from the body pressure boundary (through body wall, bonnet joint, gland, or end connections), the acceptance criterion is zero visible leakage in the form of ignitable fluid — the body must remain pressure-tight even after fire distortion. The post-fire shell and seat leakage testing principles are aligned with the general production testing framework addressed in the what is API 598 reference, though the API 607 post-fire acceptance criteria differ from API 598’s ambient production test criteria. Detailed valve pressure testing procedures are addressed in the valve pressure testing procedure reference.
Main Components
Fire Curve and Temperature Requirements
The standardized fire temperature curve in API 607 specifies that the flame temperature at the valve surface shall reach and maintain 750°C to 1000°C throughout the 30-minute fire exposure period — a temperature range calibrated to replicate the thermal conditions that valves in hydrocarbon facilities experience during sustained pool fires fed by spilled liquid hydrocarbons. At these temperatures, all thermoplastic seat materials (PTFE melts at 327°C, PEEK begins to degrade above 450°C, nylon decomposes above 300°C) are completely destroyed within the first few minutes of fire exposure, leaving only the metal backup seats, graphite packing, and fire-resistant metallic gaskets to maintain sealing. The test rig design must ensure uniform temperature distribution around the entire valve surface — localized hot or cool spots that would not represent actual fire conditions are not permitted, as they could produce misleading test results by either over-stressing or under-stressing specific valve components. The valve pressure class and body material affect the structural response to the fire temperature — at 750°C to 1000°C, carbon steel body and bonnet components soften toward their hot yield strength, and the pressure-temperature ratings per what is ASME B16.34 at these temperatures are far below the ambient rated pressure, meaning the test pressure during fire exposure represents a significant fraction of the material’s residual hot strength.
Secondary Sealing and Design Requirements
The fire-safe design features that enable a valve to pass API 607 are built into the valve design at the manufacturing stage — they cannot be retrofitted to a standard soft-seated valve. The primary fire-safe design element is the metal backup seat: a secondary sealing surface, typically a ring of stainless steel or stellite hard-faced metal, positioned behind the primary soft seat insert so that when the soft seat is destroyed by fire, the metal backup seat contacts the ball or plug surface and provides the residual sealing that limits post-fire leakage to the API 607 acceptance criterion. The effectiveness of the metal backup seat depends on the seating contact stress between the backup seat ring and the ball or plug surface at the elevated temperature after fire — trunnion-mounted ball valve designs with spring-loaded seats maintain positive seat contact force independently of line pressure, making them inherently better suited to fire-safe service than floating ball designs where seat contact force depends on line pressure. Graphite-filled packing and graphite spiral wound gaskets are mandatory in fire-safe valve designs — PTFE packing and asbestos-free fiber gaskets burn away in a fire, while flexible graphite retains its sealing capability at temperatures above 1000°C. The complete fire-safe valve design framework and certification qualification process is addressed in the fire-safe certification reference.
Emission and Certification Documentation
API 607 fire testing is a prototype type test — the test is conducted on a single valve representative of a design family, and the test certificate applies to the full range of nominal sizes and pressure classes covered by that design family per the standard’s qualification range rules. This distinguishes API 607 fire certification from API 598 production testing, which is conducted on every individual valve before shipment. A manufacturer holding an API 607 test certificate for a ball valve design at Class 300 in NPS 3 can extend that qualification to other sizes and pressure classes within the ranges defined by API 607’s qualification extension rules — typically ±two nominal sizes and one pressure class step, subject to confirmation that the extended design uses the same materials and sealing geometry as the tested prototype. Fire testing is explicitly distinct from fugitive emission testing — fugitive emission testing per what is ISO 15848 measures stem seal leakage under ambient temperature thermal and pressure cycling, while API 607 measures body and seat leakage after fire destruction of soft sealing materials. A valve may hold both API 607 fire certification and ISO 15848 fugitive emission classification simultaneously — both are prototype qualifications that apply to the design family rather than individual production valves. The complete certification documentation package framework is addressed in the valve certification documents reference, and verification procedures are addressed in the how to verify valve compliance reference.
Advantages
Fire Safety and Industry Acceptance
API 607 certification provides documented, prototype-test-validated assurance that a valve design’s metal backup seating system will function as intended in an actual fire scenario — preventing catastrophic pressure release of flammable process fluid that would convert a contained fire incident into a major uncontrolled fire. This assurance cannot be obtained from the valve’s production test certificates alone, since API 598 production testing verifies soft seat performance at ambient conditions but provides no information about metal seat performance after fire. The standardized test conditions and acceptance criteria of API 607 make fire-safe certifications from different manufacturers directly comparable — a purchasing engineer reviewing two API 607 certificates from different manufacturers knows that both designs were subjected to the same 750°C to 1000°C temperature profile for 30 minutes and evaluated against the same 1,500 ml/min/inch post-fire leakage criterion. API 607 certification may be combined with design standards including what is API 6D for pipeline ball valves where fire-safe construction is a mandatory API 6D requirement, with what is API 600 for refinery gate valves where fire-safe certification is a supplementary project requirement, and with what is API 602 for compact forged steel valves at instrument and auxiliary positions in flammable service.
Typical Applications
Refinery, Petrochemical, and Offshore Service
API 607 certification is a mandatory purchase requirement at every quarter-turn valve position in flammable hydrocarbon service in refineries, petrochemical plants, LNG facilities, and offshore installations where fire risk assessment identifies valve positions whose fire failure could escalate an incident. In refinery crude distillation units, API 607 certified ball valves provide fire-safe isolation at all flanged block valve positions on crude, vacuum residue, naphtha, and kerosene service lines — the large number of API 607 positions in a single process unit reflects the thoroughness with which refinery fire risk assessments identify fire-critical valve positions. In LNG liquefaction plants and regasification terminals, all quarter-turn isolation valves in LNG service are specified with API 607 fire-safe certification — LNG fires are particularly hazardous because liquid natural gas at −162°C vaporizes rapidly to form a large flammable vapor cloud, and fire-safe valve performance is a critical line of defense against escalation. On offshore oil and gas platforms, API 607 certification for all hydrocarbon service quarter-turn valves is typically a mandatory requirement of the offshore safety case and insurance policy — the confined nature of platform topside areas and the difficulty of fire suppression in offshore environments make fire-safe valve performance a fundamental platform safety requirement. In European refinery and petrochemical installations where both API 607 fire-safe qualification and PED CE marking are required for regulatory compliance, the integration of fire-safe prototype testing with EU conformity assessment is addressed in the what is PED 2014/68/EU reference.
Frequently Asked Questions
What valves are covered by API 607?
API 607 applies to quarter-turn valves — primarily ball valves and plug valves — and their actuators. It covers all nominal sizes and pressure classes of quarter-turn valve designs used in oil, gas, and petrochemical service where fire-safe certification is required. Gate valves are tested for fire safety under API 6FA rather than API 607, because the gate valve’s wedge or parallel slide closure mechanism and rising stem design require a different fire test configuration than the quarter-turn rotary mechanism of ball and plug valves. Multi-turn globe valves rely on graphite packing integrity for fire safety and are not typically subject to the same fire-safe prototype testing requirements as soft-seated quarter-turn valves.
Is API 607 the same as fire-safe certification?
API 607 is one of the standards used to demonstrate fire-safe performance — it is the primary fire test standard for quarter-turn valves in North American and global oil and gas industry practice. Other fire test standards include API 6FA (pipeline valves, including gate valves), BS 6755 Part 2 (UK and some European specifications), and ISO 10497 (an international standard harmonized with API 607 requirements). A valve described as “fire-safe” or “fire-tested” may have been tested to any of these standards — confirming which specific standard was used and that the test conditions and acceptance criteria are appropriate for the project’s requirements is part of compliance verification.
Does API 607 replace API 598 testing?
No — API 607 and API 598 address entirely different aspects of valve qualification. API 598 is a production test conducted on every individual valve before shipment, verifying ambient-temperature pressure boundary integrity and soft seat sealing performance. API 607 is a prototype type test conducted once on a representative design, verifying post-fire metal seat sealing performance and body integrity after fire exposure. Both certifications are required simultaneously for fire-safe valves in critical service — the API 598 production test certificate confirms the individual valve’s quality, while the API 607 prototype test certificate confirms the design family’s fire survival capability.
Is API 607 mandatory?
API 607 has no inherent legal mandatory status as a voluntary industry standard. It becomes effectively mandatory when specified in project valve purchase specifications for valve positions identified as requiring fire-safe certification by the project’s fire and explosion risk assessment, or when required by insurance policy conditions, regulatory authority operating permits, or platform/facility safety cases. In practice, API 607 fire-safe certification is specified as mandatory for all quarter-turn valve positions in flammable hydrocarbon service in virtually all refinery, petrochemical, LNG, and offshore oil and gas projects, making non-compliance commercially unacceptable for valve supply to these sectors.
Conclusion
API 607 is the governing fire test qualification standard for quarter-turn valves in oil and gas service — its standardized 30-minute fire exposure at 750°C to 1000°C, mandatory post-fire leakage measurement at rated pressure, post-fire operability verification, and prototype qualification documentation provide the fire safety assurance that cannot be obtained from ambient production testing alone. Correct specification requires confirming that the API 607 test certificate covers the specific valve design, nominal size, pressure class, and body material being purchased, and that the test was conducted by an accredited third-party test facility using the current edition of the standard. Engineers requiring a comprehensive framework that integrates API 607 fire-safe certification within the full landscape of valve design, testing, dimensional, and documentation standards should consult the valve standards overview hub as the governing reference for all fire-safe valve qualification standards navigation.