Fire-Safe API 6FB Valve
The API Specification 6FB
describes the testing procedure and evaluation of the performance of API end connections
when exposed to fire.
The fire safe testing device is used to cease a fire for a period of 30 minutes.
Depending on the type of test, different flanges and valves can be tested.
The water pressure is measured by a pressure transducer; the water volume is measured with a scale. The temperature of the fire is measured with 6 different thermocouples and with 5 calorimeters which are shared around the flange or valve
. The control of the fire is done manually. Software is used for data logging and online evaluation.
The Fire Test according to API 6FB (dated December 2008) requires that any sealing end connection hold for 30 minutes in a flame condition and hold for a cool down period. After the assembly is cooled down to room temperature the line is depressurized and then re-pressurized. During all facets of the test the gasket must not exceed an API proscribed leak rate.
In the fire test a 6" Class 300 flange is pressurized with a test pressure of 75% of the API rated working pressure. The test pressure is maintained during the burn and cool-down period. After 5 minutes a fire is established and the flame temperature is monitored. The average of the thermocouples must reach 760 °C within 2 minutes and the average of the calorimeter shall reach 650 °C within 15 minutes. The burn period shall last for 30 minutes. After the burn period the connection is air-cooled down to 100 °C or less. After cooling down the flange is depressurized and the pressure is increased again to the test pressure and held for 5 minutes.
The maximum leak rate is 1 ml/inch/min of mean gasket circumference.