External fire on equipment: standard practice re: associated pipe
External fire on equipment: standard practice re: associated pipe
(OP)
API 521, §5.15.1.1 is not definitive as to whether or not associated piping is included in the calculation of the area for impingement of a pool fire. In fact, it essentially says that it's at the discretion of the user.
I'm trying to find out what standard / common practice is; that is, does such practice include or exclude the piping? My sense is that such piping is EXCLUDED, since including it would open subjective questions as to where to draw the envelope. I'd like opinions/experience, please. Thanks.
I'm trying to find out what standard / common practice is; that is, does such practice include or exclude the piping? My sense is that such piping is EXCLUDED, since including it would open subjective questions as to where to draw the envelope. I'd like opinions/experience, please. Thanks.





RE: External fire on equipment: standard practice re: associated pipe
RE: External fire on equipment: standard practice re: associated pipe
I have not seen pipe wetted surface commonly used for other applications.
It is part of engineering judgement.
RE: External fire on equipment: standard practice re: associated pipe
That said, it also seems to me that it's reasonable to exclude piping that clearly exits the equipment envelope since that provides a consistent criterion as to where to draw that envelope (e.g., at the flanges where such piping connects to the equipment in question).
I'm still interested, by the way, in other opinions.
RE: External fire on equipment: standard practice re: associated pipe
If the line is from the top of a tall tower or in a pipe rack, than it might not be necfessary to include that surface area since it will not really be affected by the fire;
however the bottoms line from the column (going to the reboiler) would surely be in the middle of the fire and therefore should be added.
One might also include the other vessel trims (drains, purge, level gauges and stand-pipes...) - and to simplify we usually lump all that in the 10%...
it all depends on the piping arrangement you are looking at.
RE: External fire on equipment: standard practice re: associated pipe
Best regards
Morten
RE: External fire on equipment: standard practice re: associated pipe
RE: External fire on equipment: standard practice re: associated pipe
Regards
RE: External fire on equipment: standard practice re: associated pipe
That said: In may apps. your assumption is OK with me.
Best regards
Morten