Volume 7, Issue 8 (September 2010)
Guided Side-Bend: An Alternative Qualification Method for Butt Fusion Joining of Polyethylene Pipe and Fittings
Historically, the procedure for butt fusion joining of polyethylene pipe has been qualified on the basis of two fundamental tests that are widely recognized within the industry. These are the tensile-impact (T-I) test method found in ASTM F2634-07 and the reverse-bend (RB) or bend-back test as described in ASTM F2620-06. Both of these test methods have been extensively utilized within the industry, and both have some specific limitations as it relates to qualification of butt fusion joining conducted in the field. ASTM F2634-07 is a highly sophisticated testing method involving precision instrumented laboratory equipment. This makes it impractical for an on-site qualification for butt fusion procedures in the field. The bend-back test, on the other hand, lends itself to field implementation, but as the method is applied to a larger diameter, heavy-walled pipe, the practicality of performing the test and safety considerations become a limiting factor. This paper will examine an alternative test method referred to as guided side-bend or full-face testing that appears very promising as an alternative to the RB test as described in ASTM F2620-06. The test method will be fully described, and data will be presented comparing T-I results and traditional bend-back results to those obtained using the side-bend test method. The discussion of the test results and safety considerations of the proposed test method will be addressed, and conclusions will be drawn regarding its future applicability.