FM Approved Gas Valve Question

[dbrune]

Can anyone tell me what is required for a shutdown valve on a fuel train for an indirect line heater to obtain FM approval? The reason I ask is we are bidding a job to a client that wants FM approved valves on the fuel train but they want the bare minimum for cost reasons. I have always used a limit switch for proof of closure back to the DCS or PLC but do not know if this is a requirement for the valve to be FM approved.

Thanks,

Darren