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
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.