A method is shown for installing a heat tube on a section of pre-insulated piping. A metal carrier pipe is covered with a first layer of foam insulation. Next, a wire brush is used to cut a longitudinal slot along the length of the pipe so that the pipe exterior surface is exposed from the insulation. A heat tube is then installed within the longitudinal slot, whereby the heat tube contacts the exterior surface of the metal carrier pipe. A second layer of foam insulation is then sprayed onto the exterior of the metal carrier pipe, covering the previously formed longitudinal slot and installed heat tube. A polyolefin coating is then applied over the insulation to form a protective outer jacket for the insulated pipe.

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.

A reinforced foam block features a body of foam material forming a main body having a volume enclosed by at least one peripheral face. At least one body of reinforcing material, being more pressure resistant than the foam material before incurring permanent shape change and forming a sheet, is embedded in the body of foam material so as to be carried by the body of foam material in prescribed position within the main body. The respective body of reinforcing material provides strength to the main body against force applied to the main body in a direction transversely with respect to the prescribed surface area of the respective body of reinforcing material.