TWI Industrial Member Report Summary 568/1996
M J Troughton and G S Booth
A review of the research which has been undertaken, both in industry and academia, regarding the structural integrity of butt fusion welds in polyethylene pressure pipes has revealed that current tests are inadequate for assessing the service performance of such joints.
In many industrial situations, plastics are being used to replace traditional materials such as metals, both for economic reasons and for their improved performance and processing characteristics. They are being applied increasingly for more demanding applications such as the use of polyethylene (PE) in pressurised pipe systems for transporting water, gas and chemicals. Such developments place a heavy requirement on the provision of adequate design data to give the user confidence in safety of the system.
The life of a plastics pipe system depends upon a number of factors, the most important being the properties of the pipe material and joints, flaws and stresses in the system and the service temperature. Ideally, design data should take into account these factors when assessing durability of the system.
A great deal of work has been performed over the past 20 years to assess the durability of the pipes themselves. Considerably less work has been performed on the welded joints.
- To review the current situation regarding methods for assessing the structural integrity of butt fusion welds in PE pipes.