Competing product representatives have opined that PVC has limitations in handling occasional surges. This has lead to a false belief by some designers that it is necessary to dramatically derate PVC from its assigned pressure rating. It is important to check the facts before making these design decisions. PVC's performance capabilities in relation to occasional surge are well thought out and taken into account within the AWWA standards C900 and C905.
The PVC Pipe Association set out to prove PVC’s capabilities in instances of occasional surge pressure by using a design example to compare 8” Ductile Iron PC 350 psi to 8” DR18 PVC Pipe PC 235 psi. The project conditions included a “working pressure” of 160 psi and an occasional surge pressure based on an instantaneous change with a flow velocity= 7.0 fps, the flow volume being 1110 gpm. In these working conditions, here’s how ductile iron and PVC pipe performed, head-to-head.
It’s clear that PVC not only met, but exceeded expectations, however, the same cannot be said about ductile iron.
To learn more about the comparison between ductile iron and PVC in an occasional surge situation, please feel free to visit the article published by thePVC Pipe Association or consult us here at Diamond Plastics for more information.