Joint Integrity of Plastic Pressure Pipes in Municipal Service

Abstract

Plastic pressure pipes have been in use in North America for at least 40 years. Thermosetting plastics and thermoplastics commonly utilized in municipal pressure applications include fiberglass reinforced plastic pipes (FRP), polyvinyl chloride (PVC), high density polyethylene (HDPE), and more recently, fusible polyvinyl chloride (FPVC). Typically, these materials undergo hydrostatic pressure testing first in the manufacturing facility, then a second time in the field following installation. For field hydrostatic leakage testing, most pipe materials have an associated “allowable makeup water” or “allowable leakage” to accommodate the unique characteristics of the material as well as other irregularities during testing such as air in the line, temperature variations, and even instrument inaccuracies. Test methods and formulas for calculating makeup water usually vary based on the pipe material-specific standards. The wide discrepancies that exist for makeup water between different pipe materials do not place them on a level playing field for a given application. This paper is a review of both in-plant and in-field hydrostatic pressure testing and the topic of makeup water as outlined in AWWA standards for plastic materials. Quality control and qualification tests for joints of each pipe material standard are also reviewed. Recommendations are made for consideration by the Specification Engineering community for future revisions of standards pertaining to the field testing of plastic pipelines.