EXAMINATIONS CONCERNING THE SQUEEZE-OFF OF PIPES MADE OF PE 80, PE 100 AND PE-Xa

摘要

This paper is about the squeeze-off tests on pipes made of PE 80, PE 100 and PE-Xa of different dimensions. After having squeezed off the pipes to a rate of 0.8 the air and water impermeability of the squeezed point is examined at different pressures and the leakage rates are determined. After reforming the pipe resistance towards long-term hydrostatic pressure is tested. It has been ascertained that up to a pipe wall thickness of approx. 10 mm the pipe materials examined could be squeezed-off sufficiently regarding air and water impermeability. For thicker pipe walls the squeezed-off point is not tight anymore due to the large formation of wrinkles inside the pipe resulting in a lasting damage of the pipe. During the long-term hydrostatic pressure test the pipes squeezed off to a rate of 0.8 and afterwards reformed have all met the standard requirements.