Valves containing polymeric or elastomeric materials and to be operated for flammable products (should there be a leakage and its ignition point is relatively low / sparks might be occurred) should be fire tested design and certified to ISO 10497/ API 607 3rd and 5th ed., API 6FA.
API 607 4th ed. is not generally accepted for soft seated valves up to class 600 since both the operational and external leakage tests are carried out at only 2 bar compared to other procedures.
In addition to that, local (Plant / country) best practice might also be applied. For instance during the first XX minutes, shall there is leakage through (damaged) seal or joints it Should not provide significant contribution to the pool of fire or Blast in the pipeline. Or better, NO leak at all.
Period for offshore platform normally 15 minutes (zero leakage or acceptable external leakage as per ISO 10497). This period is considered as a maximum time required for all personnel to evacuate from platform (into that small ship and launched).
For refinery or Onshore normally 60 minutes (acceptable external leakage as per standard). This is the time required for Fire fighter to extinguish small fire (starting from the alarm ringing) and not the pool of fire.
I am not quite sure whether the material selection for this type of valve is also governed by such standards. Other constructive inputs are highly appreciated.
ISO 10497/API 607 and API 6FA is generally acceptable as fire safe certification alternatives to one another.
Biggest issue with API 6FA is the valve size qualification range. ISO 10497 allows vendor to fire test an 8" valve to qualify all sizes larger while API 6FA does not allow vendor to do so.
