scope:

Scope and Purpose

This technical note illustrates differences between the North American ASTM/PPI and ISO methods for pressure rating polyethylene (PE) water distribution pipe. This note focuses specifically on pressure rating of PE water pipe because different recommended operating pressures are obtained for the same polyethylene pipe depending on which method is utilized.

This technical note provides general information, background and guidance for comparing ASTM/PPI and ISO-based pressure-rating methods for polyethylene water pipe. It is not an in depth technical comparison of ASTM/PPI and ISO long term stress rating methods. Other documents such as PPI Technical Note 7 (TN-7) and Technical Report 9 (TR-9) and various published technical papers serve this purpose. This note focuses specifically on how the long-term stress ratings determined under the ASTM/PPI and the ISO systems are applied to determine pressure ratings for a polyethylene pressure pipe using these two widely recognized industry protocols.