A spool is a short length of rigid pipe typically used to tie in a pipeline to a structure.

A metrology spool is a short length of rigid pipe that has been fabricated to suit measurements made subsea so that it 'closes' exactly.

The attached file shows a resonably complicated spool lift.

http://thaijournal.files.wordpress.com/2007/03/spool-piece.jpg

I suspect this does indeed mean significantly different things to different folks, and therefore what is wanted probably should be clarified with more description by the specifier [I guess it is possible the moniker originally came from a short flange by flange or hubbed end pipe piece, with outer contour that looks indeed not unlike a "spool" used to wrap thread or cable etc.]

Downstrem usage may call out for typical sizes of the pipe spools between fittings? I remember minimum length of pipe spools were called out in refinery piping.

regards

Siddharth
These are my personal views/opinions and not of my employer's.

rconnor is correct - it depends.  A spool piece is a section of pipe that is put in temporarily for some reason or another.  Maybe you need to pull out a valve and want to drop in a spool piece until you get another one or get it repaired, many reasons for spool pieces.  

Pipe spools on the other hand are generally from piping Iso's and are related to fabrication.  It is a way of taking a larger, complicated piping system and breaking it up into smaller pieces for fabrication and then putting it together, like tinker toys.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website: www.oil-gas-consulting.com

thanks guys,
The lifting photo was amazing.
I had seen spreader bars for deck lifting, but not "spreader truss"

I meant the spool piece which is used at the connection of a subsea pipeline to riser...

So in your case it is a 'short'(typically 10-50m in length although I have worked on projects where they were 80m long) length of pipe, and usually 'L' or 'Z' shape to take account of expansion.

It will fit in between the end of the pipe and the  bottom of the riser thus tying the pipeline into the riser.

cavatina

For risers, again, it depends.  If the riser is stalked on there is no spool.  Otherwise, you have some options, maybe a sub-sea flange or a spool that is hyperbarically welded. In any case it is a piece of pipe, with or without any appurtenances, that is used to complete a piping system.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website: www.oil-gas-consulting.com

I guess you are refering to the expansion/tie-in spool between the riser and the pipeline. Risers installed by stalk on method will have smaller spools mostly a tie-in spool to fit the distance between the riser bend and the pipeline laydown point. If by design a larger expansion spool then either a L or Z spool will be used between the riser and pipeline and is installed either by flanged connection or hyperbarbic welding [but rarely due to costs].

In piping, spools are generally called pup pieces which are used to do site fit ups.

Narendranath R
Pipeline engineering is made easy with state of the art computer software, visit www.narendranath.itgo.com.

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