ISO/NP 25301

Thermoplastics piping systems for non-pressure underground drainage and sewerage — Test method for the determination of the stress crack resistance of structured-wall Type B corrugated polyethylene (PE) and polypropylene (PP) pipe materials with recyclates using Un-notched Constant Ligament Stress (UCLS) test.

Scope

This document specifies a test method to determine the slow crack growth (SCG) behaviour (also known as the stress crack resistance) of polyethylene (PE) and polypropylene (PP) materials, incorporating recyclates, used in structured-wall Type B corrugated pipe for non-pressure gravity flow drainage applications.
The test method is appropriate to post-consumer recyclates (PCR) of PE and PP materials, and post-industrial recyclates (PIR) of PE and PP materials and blends of such materials with virgin and/or reworked PE or PP, respectively.
The test method is not intended for reworked material, or blends of virgin materials with reworked materials, where the reworked material is sourced from the manufacturer’s own production and is of known composition.
The test method is conducted on un-notched specimens in deionized water and evaluates both the crack initiation and crack propagation phases of the SCG mechanism.
The test method utilizes standard testing equipment utilized for other stress crack tests in the drainage pipe industry. Specifically, test method utilizes a lever-arm loading mechanism, typically with a 5:1 mechanical advantage, to apply a constant load to a dog-bone shaped test specimen immersed in an elevated temperature water bath.