Air Header vs Pressure Vessel Determination

[KDKIM]

Dear, ALL !!

We have some arguments that whether or not the big air headers to supply air to the 16 reciprocating gas engines at air system in power plant are a pressure vessel.

Air header or vessel specification installed at power plant

§ have 2 headers, the length is 100foot, the diameter is 16 inches, the material is A106 B and the capacity is 140 cubic foot, also have the header relief valve set 475 psig. Each header has connected 8 pipes sized 1and ½ inches.

§ have 4 headers, the diameter is 24 inches, the material is A106 B and each header has the header relief valves set 475 psig. Each header has connected 4 pipes sized 1and ½ inches.

Those air headers look very similar pressure vessel because of the big sized pipe and pressure and capacity. But those headers have not the fuction of storage and made of seamless pipe under ASME Power Piping Code. But someone insists that those header is pressure vessel.. What do you think about that? and is there any special definition for determination?

 

[Latexman]

They sound more pipe-ular than vessel-ular to me. Were they built from pipe using a pipe spec for their components? If so, pipe.

Good luck,
Latexman

 

[BigInch]

Storage is not a requirement of a pressure vessel, so that's not the deciding factor. They could certainly fulfill the function normally attributable to pipe, so I'll agree with Latexman, its pipe, unless it was built under the pressure vessel code. If it was, there would be a pressure vessel nameplate with it's rating on it somewhere afixed to these pipes. I feel that a pressure vessel code design for that component would have been HIGHLY unlikely. Is the guy complaining a piping or a pressure vessel engineer. Have him read the title of the A106 specification. You probably won't have to go any farther than that. If he's still giving you problems, make him show you the name plate.

If it ain't broke, don't fix it. If it's not safe ... make it that way.

 

[stanweld]

While the air headers are outside the scope of ASME VIII, they can be made to it - or not. Refer to U-1(c)(2)(c), (e) & (h)(1).

 

[BigInch]

Certainly true, however unlikely it may be.

If it ain't broke, don't fix it. If it's not safe ... make it that way.

 

[bimr]

It is ultimatedly up to the regulatory agency and/or the insurer of the equipment to determine the applicable code or standard.

Check the design and fabrication drawings.

Pressure Vessels are defined in ASME Section VIII, Div 1 introduction:

"Pressure Vessels are containers for the containment of pressure either external or internal. The pressure may be obtained from an external source, or by the application of heat from a direct or indirect source, or any combination thereof"

Piping is a pressure-retaining component that conveys fluids.