I currently designing a gas receiving facility that have all reliefing gas directed to an existing flare header.
The existing flare header has 8 meters elevation. If I want all the inlet line and outlet line of the PSVs have no pocket, I should locate my PSVs at higher than 8 meters elevation and therefore this would be costly for the pipe support.
My question is, is it absolutely impermissible to have any pocket in my PSV line (both inlet & outlet)? Or is there any special case that permit the PSV lines to have pocket?