FINDING THE RIGHT PIPE TEST FOR POLYETHYLENE WITH RAISED RESISTANCE TO SLOW CRACK GROWTH

Mei 17, 2022 by admin in Uncategorized

Ernst van der Stok

# 2021 Amsterdam

For PE 100-RC, two tests are still under development for pipes: the point load test (PLT) and the accelerated notch pipe test (aNPT). The PLT was developed by a project group consisting of manufacturers and end users. The PLT determines the resistance to point loads as they can occur in practice. An earlier study showed that the average lifespan of PE 50 pipes under point loading can be estimated fairly accurately. A new study has determined that large scale failures in second-generation PE pipes due to point loads are not likely to occur in the coming decades. In another study, the results for the PLT were promising but a clear comparison between the three different laboratories and a conclusion regarding the right detergent for proper acceleration of the test was lacking. In a new study, three different laboratories tested PE 100 pipe material from two manufacturers with Arkopal N100. These pipes were also used to experiment with new detergents to accelerate the test. The results of the investigations will be used for the new PLT standard (ISO/CD 22102) and the revision of PE pipe standards such as EN 1555 and ISO 4437. In the aNPT, the crack growth resistance from an initial notch is measured. This test is performed in exactly the same way as in the standard NPT (ISO 13479), but with one important difference: instead of using water, the pipe is placed in a detergent solution. To keep the test eco-friendly, the amount of detergent is minimized by creating small containers for each individual pipe. This test method is currently being standardized as an annex to ISO 13479. A round robin investigation was therefore initiated.

article sources: https://www.pe100plus.com/PPCA/FINDING-THE-RIGHT-PIPE-TEST-FOR-POLYETHYLENE-WITH-RAISED-RESISTANCE-TO-SLOW-CRACK-GROWTH-p1736.html