Fisher 399A-6365 pilot PSV or backpressure regulator on Natural Gas fuel line to Steam Boiler 1

[carol2005]

I was asked to check the adequacy of a relief valve on some pipelines of supplying natural gas fuel to steam boilers (the steam boilers are to generate 270 pounds of steam for a chemical plant which is located in a place where ASME codes apply).

Thesse relief valves all located downstream of pressure regulators which reduce the Natural Gas pressure to about 15 to 20 PSIG. These relief valves have set pressure of 30 PSIG for regulator failure scenario.

Although I haven't talk to the relief valve suppliers yet, I pretty sure these relief valves are not compliant with ASME Section I because these valves:
One of them has model as Fisher Easy Joe Type 399A-6365 pilot-operated pressure relief valve. This type of valve requires buidup of 5 PSI over Set pressure 30 PSIG to fully open
Another model is Fisher 399A-6358 backpressure regulator which is not even a pressure relief valve.

My question: are these relief valve adequate for this application (on natural gas line to high pressure steam boilers)? Don't they have to be ASME Section I stamped? Thank you very much for your advice.

 

[don1980]

Refer to the ASME Sec I document. You'll see a diagram showing the scope boundaries for Sec-I. The fuel gas line isn't within that scope. Sec-I is for the steam (and some boiler water) services only.

 

[carol2005]

You are correct. My further research reveals these pipelines are under ASME B31.8 Gas Transportation and Distribution Piping Systems.

 

[TD2K]

Interesting, I haven't looked at the scope sketch for B31.8 but if it's in a chemical plant, I would normally expect to see this piping covered under B31.3.