This practice covers the procedures for the rehabilitation of sewer lines and conduits 4 in. (102 mm) to 18 in. (457 mm) in diameter by the insertion of a folded/formed PVC pipe that is heated, pressurized, and expanded to conform to the wall of the original conduit forming a new structural pipe-within-a-pipe. This rehabilitation process can be used in a variety of gravity applications such as sanitary sewers, storm sewers, and process piping. This practice is to be used with the material specified in Section of Specification F 1871. The values stated in inch-pound units are to be regarded as the standard. The SI units given in parentheses are provided for information only. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. There is no similar or equivalent ISO Standard.