Heat shrinkable tubing as sewer pipe joints

Preliminary testing had indicated that commercial sewer pipe might be coupled in tight waterproof joints using the heat shrinkable plastic tubing (HST) developed and used extensively in the electronics and aerospace industries. Laboratory studies of such materials and joints were conducted to determine their characteristics and their operational and economic feasibility. A wide variety of HST materials and joints were tested in addition to conventional joints for clay, concrete and asbestos-cement pipes. The results of both small scale tests and full scale tests using commercial 8-inch sewer pipe indicated that a polyolefin with a polymeric base hot melt adhesive produced the most durable, watertight joints and were significantly superior in performance compared to existing pipe joining mechanisms.