METHOD FOR FORMING PRESSURE-TESTABLE FIELD JOINT BETWEEN PRE-INSULATED PIPE SECTIONS, AND PIPING SYSTEM WITH PRESURE-TESTABLE FIELD JOINT

摘要

A method for forming a field joint between pipe sections is provided, preferably for pre-insulated pipe sections containing a carrier pipe surrounded by insulation and an outer jacket. The carrier pipes are joined, and an air tube is positioned so that its first end is within the joint area, and its second end extends beyond the joint area. A sleeve is sealed over the joint area, joining the jackets, with the sleeve positioned to cover the first end but not the second end of the tube. Air is injected into the tube to pressurize the cavity within the jacket, and the tube bore is sealed to allow air pressure testing. If the testing shows no loss of air pressure, the bore of the tube is sealed permanently to complete the seal on the field joint. Also provided is a piping system having a field joint formed by this method.