pup piece on piping fittings and items
pup piece on piping fittings and items
(OP)
what are the criteria that qualify the inclusion of a pup piece on various piping items like barred tee, valves that is to be installed on a line.
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pup piece on piping fittings and items
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RE: pup piece on piping fittings and items
- "Need" - The distance from the butt weld end of one object to the butt weld end of another adjoining object exceeds the normal weld gap. Example: a 10" NPS line is in a pipe rack and reaches the point where it needs to leave the pipe rack to go to a piece of equipment. The center to end of a 10" long radius Elbow is 15" (10"D x 1.5). Two elbows welded together would be 30" (15" + 15"). The distance between the perpendicular levels of travel is 36". This leaves a distance (or Gap) of 6" to be filled with a short length of pipe. This short length of pipe is called a "Pup".
You will get a lot of advice about the minimum length of a "Pup". I believe a pup piece can be as short as four times the pipe wall thickness when the circumstances require it. Others will tell you there are minimum lengths rules such as "One Pipe Diameter" or 4" minimum. The bottom line is simply, every situation needs to be evaluated on it's own merits.
prognosis: Lead or Lag
RE: pup piece on piping fittings and items
I hate Windowz 8!!!!
RE: pup piece on piping fittings and items
Other fittings are less sensitive to testing issues, but not the welding one so if you can weld line pipe to a fitting made from perhaps lower strength material in a shop where they already have suitable weld procedures then it's worth it.
Otherwise Penn piper has it nailed for piping pp's. Thin ones just don't look good, but if you need one then insert it. You should always have some"green" length if going fitting to fitting, just try and make it 1D if you can, but if you can't go for the longest you can.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: pup piece on piping fittings and items