A high temperature pre-insulated piping system is shown which can withstand conveyance temperatures in excess of 250.degree. F. The piping system includes a first and second length of insulated and jacketed pipe. Each pipe length includes an inner metal pipe having an interior surface and an exterior surface and having an envelope of foamed insulation surrounding the inner pipe exterior surface. A special release agent is applied between the metal pipe exterior and the surrounding layer of foamed insulation. The release agent causes intentional disbondment of the foamed insulation layer from the inner metal pipes under certain conditions of environmental stress.
The present invention relates generally to an apparatus and method for preventing disbondment in an insulated piping system that is used for conveying high temperature fluids. More specifically, an external slip wrap is shown, capable of surrounding the outer protective jacket of the insulated piping system at a location along the piping before an elbow shaped or angular change in direction. The slip wrap comprises a loosely received outer sleeve which surrounds the outer protective jacket of the piping without being bonded thereto, thereby allowing the insulated and jacketed pipe to move axially relative to the slip wrap for a selected distance once the pipe is buried in the ground.
