In the research report SP Rapport 2009:21 "Acceptance criteria for scratches and indentations in plastic pipes" it was concluded that pipes manufactured from modern materials of polyethylene (PE) and polypropylene (PP) can withstand scratches and indentations considerably better then certain older material types. The results show that a good rule of thumb when deciding if a scratched pipe made of modern materials is acceptable is that the scratch depth should be ten percent or less of the pipe wall thickness.
Scratches and indentations can occur during pipe manufacturing, transport, pipefitting, and also during repairs after breakdowns. In the research project, which includes four parts of study, SP evaluated how scratches in polyethylene pipes and scratches and indentations in polypropylene affects the technical lifetime of the pipes. Further, a method for the evaluation of the scratch resistance of different materials was developed and a simple gauge to estimate the scratch depth in the field with reasonable accuracy was developed. The research project was financed by the Swedish Gas Centre / Swedish Energy Agency, Swedish Water and Waste Water Association, SP Technical Research Institute of Sweden, Borealis, pipe manufacturers through the Nordic Plastic Pipe Association and the Swedish District Heating Association.
In December 2009 an article was published in the paper Svenskt Vatten no 6.