Polyethilene

A double-walled pipe is a secondary contained piping system. It is a pipe within a pipe, or encased in an outer covering, with an annulus (interstitial space) between the two diameters. The inner pipe is the  primry or carrier pipe and the outer pipe is called the secondry or containment pipe. The great majority of double-walled piping applications involve wastewater, groundwater, and process safty.
 
 
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