14 October 2019

Kiwa develops eco-friendly accelerated notch pipe test (aNPT)

Kiwa has developed the eco-friendly accelerated notch pipe test (aNPT) to test PE100-RC pipes. The test is carried out in the same way as the normal NPT (ISO 13479), but with an important difference: instead of using loads of water, the pipe is placed in a detergent solution.


Normally hundreds of liters of soap would be used in a bursting pressure bath to perform a notch pipe test (NPT). However, Kiwa specializes in high-quality PE testing facilities and therefore does it different. To keep the test eco-friendly, smaller containers for each pipe are created to minimize the detergent amounts. The big challenge was the homogenous mixture of the detergent. As you can see in the video below, a special colorant is used to test this:

Round Robin

Kiwa will participate in the next Round Robin for the aNPT that is initiated by the PE100+ Association. The results will be used as input for a brand-new Annex in ISO 13479 where ISO/TC138/SC5/WG20 is working on. If everything is successful, the aNPT could be used in the revised EN 1555 and EN 12201, and later also ISO 4437 and ISO 4427, which are the standards for polyethylene for the supply of gaseous fuels and for the water supply respectively. Of course, Kiwa is actively involved to share experiences and expertise.

World-leading expert

Even if the Round Robin results are successful and the test finds its way in the standards, the aNPT will not be the only test that will determine if a PE grade is a PE100-RC. Several test methods have already been developed over time, both for resin and pipes. Kiwa is a world-leading expert in this field and has a well-equipped laboratory and many experts to accurately, reliably and quickly test the resistance to slow crack growth (SCG), even for these best-performing grades. These tests include the strain hardening test (SHT), the cyclic cracked round bar test (CRB), the accelerated full notch creep test (aFNCT) and the point load test (PLT).

Download our ‘Fast Test for Slow Cracks’ leaflet for more information.