Assessment of the Service Life of Polyethylene Pipes with Controlled Defects Using Internal Pressure Test

Controlled geometry defects can be volumetric defects, usually located on the outer surface of the pipe, having different orientations and lengths and identical depths. This type of defect corresponds to the type obtained using a damage mechanism, as presented by API 579-1/ASME FFS-1, Part 9, called crack-type defects. The research presented in this paper was intended to evaluate the influence of controlled defects on the strength of an HDPE water pipe, PE100 (Ø 90 × 5.4), SDR 17, PN 10 bar, subjected to internal pressure. The methods applied were the internal pressure test and numerical simulation. The article's main findings were the critical pressure P_cr, the critical time t_cr, the critical depth of defect a_cr, and the remaining service life t. The remaining service life was approximately 83 years for the pipe with a defect oriented circumferentially, and 69 years for the pipe with a defect oriented longitudinally.