What are pipe "loops"?

[skuntz]

While looking at photographs of a chemical plant, I had noticed that in several places the piping takes a right angle jog, turns back to the original direction, then takes two more turns to be back in line with the pipe. On the photos these were referred to as "loops." What is the purpose? It did not appear that these were put in to avoid obstructions.

 

[pennpiper]

Skuntz,
Not having the benefit of the photographs you saw I would guess that the "Loops" were for the adsorption of thermal expansion due to high temperature of the pipe lines.

 

[zdas04]

The sort of "loop" you described is normally called an "expansion loop" and works as penpiper described.

The term "line loop" is usually reserved for a second (or third or fourth) line laid alongside a primary line to alleviate bottlenecks in the system flow. I've never heard why this kind of expansion is called a "loop".

David

 

[MJCronin]

This is pretty good explanation.....

Scroll to bottom of the page

http://www.spiraxsarco.com/resource...m-distribution/pipe-expansion-and-support.asp

 

[europipe]

The plant I work for now uses the term loop for a circulationline through the plant from discharge of a pump with users along the line to the suction of that pump.

 

[dtlb26]

Loops are typically used to create a pressure drop to minimize water/condensate hammer through long pipe runs. Have seen on steam, condensate and cooling tower applications.

 

[TBP]

dtlb - Loops won't prevent water hammer. The only way to prevent water hammer in a steam system is to have it designed correctly - properly sloped and trapped.

 

[rmw]

I'm learning stuff here. I've never heard of 'creating' pressure drop with piping, etc. Seen a lot of piping designed to minimize pressure drop, however.

rmw

 

[chicopee]

Those that I have seen in our local chemical plant was for expansion and contraction eventho the piping was insulated.

 

[jistre]

I used to work in the petrochem process industry. Those loops are definitely to allow the pipe to expand and contract thermally. By adding the loops at strategic locations, you can reduce the stress on the pipe and its supports/structure/etc. to prevent breakage.

 

[bimr]

Another type of loop is the liquid seal loop that is sometimes used. The liquid in the seal loop is there to prevent the escape of gas when no liquids enters.