What Is API 6FA?

Quick Answer

API 6FA (now withdrawn and replaced by the fire test requirements within API 6D Annex F and API 6A) was the fire test standard for pipeline and wellhead valves. It qualified valve designs to maintain structural integrity and acceptable leakage after exposure to a hydrocarbon pool fire at 760-980 degC (1400-1800 degF) for 30 minutes. While API 6FA has been formally withdrawn, many specifications still reference it, and its test methodology has been absorbed into the current editions of API 6D and API 6A.

API 6FA Test Procedure

Step	Description	Duration
1. Pre-fire seat test	Verify zero or minimal seat leakage before fire	Per API 598
2. Fire exposure	Engulf valve in hydrocarbon pool fire (jet fuel)	30 minutes
3. Fire temperature	760-980 degC (1400-1800 degF) measured by thermocouples	Continuous monitoring
4. During-fire leakage	Measure external (body) and through-seat leakage during fire	Continuous
5. Burn-down / cool-down	Quench fire and allow valve to cool	Per procedure
6. Post-fire seat test	Pressurize and measure leakage after fire damage	Per procedure
7. Post-fire operability	Verify valve can be operated (opened and closed) after fire	Functional test

Acceptance Criteria

Criterion	Requirement
External leakage (during fire)	No burn-through of body, bonnet, or end connections
Through-seat leakage (during fire)	Limited leakage rate (liquid and gas) per valve size
Post-fire seat leakage	Must seal within specified limits
Post-fire operability	Valve must open and close (may require reasonable force)
Structural integrity	No body deformation that prevents operation

API 6FA vs API 607

Parameter	API 6FA	API 607
Scope	Pipeline and wellhead valves (API 6D, API 6A)	Quarter-turn valves (ball, butterfly, plug)
Fire duration	30 minutes	30 minutes
Fire temperature	760-980 degC	760-980 degC
Test medium	Water and air/nitrogen	Water and air/nitrogen
Post-fire operability	Required	Required
Valve cycling during fire	Not required	Three open-close cycles during fire
Current status	Withdrawn (absorbed into API 6D/6A)	Active (7th edition)
Typical valve types	Gate, ball, plug (pipeline)	Ball, butterfly, plug

The key difference: API 607 requires the valve to be cycled (opened and closed) during the fire to verify that the mechanism still functions while engulfed in flames. API 6FA tested the valve in the closed position throughout the fire without cycling.

Current Standards (Post-Withdrawal)

Since API 6FA was withdrawn, fire test requirements are now specified within:

Standard	Section	Scope
API 6D (2021)	Annex F	Pipeline valves fire test
API 6A (2018)	Annex F	Wellhead and Christmas tree valves
API 607 (2016)	Full standard	Quarter-turn valves (general process)
ISO 10497	Full standard	International fire test for industrial valves

Why Fire Testing Matters

Soft-seated valves (ball, butterfly, plug) use elastomeric or PTFE seats that melt or burn at fire temperatures. Without fire-safe design, the primary seat is destroyed and the valve leaks catastrophically, feeding the fire with additional fuel.

Fire-safe valves incorporate a secondary metal-to-metal seal (graphite packing backup, metal seat ring behind soft seat) that engages when the primary soft seat is destroyed. Fire testing per API 6FA/607 verifies that this secondary seal functions as designed.

Pro Tip

Even though API 6FA is officially withdrawn, many project specifications written before the withdrawal still reference it. When encountered, confirm whether the client will accept compliance with the current API 6D Annex F or API 607 instead. Most will accept the equivalent current standard.

Read the full guide to valve types