Polyethylene Pipe Supports
Polyethylene Pipe Supports
(OP)
The company that I work for uses HDPE pipe on trestles to trasport slurries. The trestles were originally designed for steel pipes. Because of the large coefficients of expansion with HDPE we at times have problems with pipe support details. Is anyone on the forum familiar with pipe support details that work or other companies supporting polyethylene pipes in this fashion. The pipes we are using are 14", 16" and 20" diameters. The manufacturer of the pipes says most people do not support their pipes on trestles. Where we are located it can get to -40 deg F in the winter and 90 deg f in the summer.





RE: Polyethylene Pipe Supports
Mike Halloran
Pembroke Pines, FL, USA
RE: Polyethylene Pipe Supports
RE: Polyethylene Pipe Supports
BigInch
-born in the trenches.
http://virtualpipeline.spaces.msn.com
RE: Polyethylene Pipe Supports
RE: Polyethylene Pipe Supports
The HDPE pipework will snake, one just has to calculated the amount of snaking, and position guides and anchor block to accomodate the amount of load and movement that one requies. I have designed Copper refinery HDPE like this (1.2M Dia) and have verified the calculation with CAESAR II in doing a "shrinkage" calculation, i.e. control the snaking effect and contract the pipework to get inverse sign loads and stresses, they are about 25% conservative in comparison to the strain gauge method.
HDPE also experiences visco-elastic creep and does not return to it's original state if the pressures/loads etc are to high for the required design life of the pipe/fitting. A PE 80B material for instance may be rated to 10bar at 21 deg C, but at 55 deg C will only be able to handle 5 bar for a life span around 12-15 years, sorry, do not have the info handy and am just approximating the life span.
Hope this helps.
Cheers
Rob
RE: Polyethylene Pipe Supports
Mark Hutton