Shop fab, bending, socket weld vs butt weld are producability and cost savings
measures which will apply to any piping system as long as they are done within
the requirements.
I never claimed it was complicated, but water (of some form from super heated
steam to sewage) and fuel/lube/hyd oils are the typically normal fluids.
Aaron Taylor wrote:
> I work in the Marine industry and bending small bore pipe is very common. US
Navy standards allow 5D bends without question. Any radius less than that has to
go through a qualified procedure and rigid QA inspection. If you utilize 5D
bends, I would not worry about wall thinning and deformation of pipe (piping can
become oval or the inside of the bend can develop ripples). It saves the
material cost of fittings, the welding and fitting of additional joints, and
reduces the number of joints that can fail. It also reduces the possibility of
crevice corrosion and the chance of having a bad fit up of a socket weld fitting
(too deep can cause high stress in the joint once welded). It has been my
experience that piping fabbed in a shop costs 10 times less than piping stick
built on site. Typically this is due to proximity of material and tools in the
shop. We always had welding lines and torches within 20 feet in a shop, but you
may have to search for one in
> the field. Material was stored in the shop, where on site there is typically a
material lay down area that is centralized, so no doubt when you get further
away from it, it takes longer to retrieve material.
But with sub/ship work the process fluid is likely to be water only, no?
I always find it a bit amusing when the marine/offshore gang describes their work as "complicated" when they only have 10-15 process fluids to deal with.
Paul
[Non-text portions of this message have been removed] Received on Fri May 16 12:19:00 2008
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