Secondly, the casing spacer/isolator is used to electrically isolate the carrier pipe from the casing pipe. In most cases a corrosion mitigation program is in place to protect the carrier pipe from the detremental effects of the environment and surrounding soil. Any outside influence of stray electrons can render the corrosion mitigation completely ineffective. A casing spacer/isolator ensures that no metal to metal contact is made between the carrier pipe and casing pipe which ensures the integrity of the corrosion mitigation program.
Thirdly, casing spacers include low coefficient of friction runners on all surfaces making contact with the casing pipe which facilitates easy insertion of the carrier pipe into the casing, an especially important feature when making long pulls/pushes with heavy pipe. PSI's runners have a tensile strength of 17,600psi, a flexural strength of 25,300psi and a compression strength of 18,000psi.