Measuring Surface Indications in Polyethylene Piping

Replication techniques offer a simple, accurate and effective way to measure attributes of indications discovered in polyethylene piping. Replication involves making an impression of an indication with a quick curing compound. After the compound has cured the impression can be peeled off of the surface of the pipe to provide a negative image of the indication. This technique is very valuable when indications are discovered during fabrication and installation of piping. Characterization of indications is important for piping installed in accordance with Code Case N-755 to assure compliance with limits imposed for indication depth. This technique is easily adaptable to field use. The replicant sample also provides a permanent record of the indication for future reference. This paper summarizes the replication technique for determination of indication attributes in polyethylene piping. It also provides a summary of typical attributes of indications found in polyethylene piping.