Three Purposes of Casing Spacers
PSI’s casing spacers/isolators are used on long distance transmission pipelines for three purposes. When a pipeline intersects with a railroad right-of-way, highway, waterway or any other thoroughfare the pipeline usually passes under or is buried beneath the obstruction. For protection in these areas, the carrier pipe is placed inside a casing pipe in an effort to “double contain” the fluid that is passing through the carrier pipe. If a leak or break were to occur, the fluid would be directed to a safe distance away from beneath the thoroughfare. In fact, many local Governmental Agencies require this procedure almost anywhere when volatile or hazardous fluids are flowing through the carrier pipe.
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 detrimental 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.