Pig Launcher and Receiver

[mucour]

Guys,

I am aware that pig traps are designed based on ANSI B31.4 for pure liquid service and ANSI B31.8 for gas service. But I came across a vendor manual that informs that the pig trap was constructed according to ASME VIII, Vessel code. Has anyone encountered this? If yes, what are the differences between using the ANSI-31.4/31.8 compared to using the ASME VIII code.

I am particularly interested in knowing why would ASME VII code be used for the pig trap design/construction.

 

[1969grad]

The ASME BPV Code results in a thicker vessel wall and is not used by experienced engineers for trap fabrication. Bottom line is that the trap is more expensive to fabricate using the BPV code rules.

In ASME B31.4 and B31.8 (it is ASME and not ANSI)the trap is considered to be a fabricated piping assembly.