Fatigue testing of GRP and UPVC pipes subjected to pressure surge

Abstract

There is considerable interest in replacing metal pipes with plastic pipework. The perceived advantages are: (a) it is lightweight and easy to handle, (b) it is chemically inert to many materials, (c) it is relatively easy to join. However, before any replacements can be considered tests have to be conducted to ensure the pipes are capable of withstanding any surge pressures that are likely to occur. This paper gives details of a test programme to investigate the effect of surge pressures on the survivability and damage resistance of 0.15 m diameter plastic pipe (GRP and uPVC). The objectives of the project were to apply surge pressures to investigate6the effect of repeated surges i) at less than the failure pressure, and ii) to measure the failure pressures within the test facility limitations. The tests were conducted in the BHR Group pressure surge test facility. This unique, (‘Bustapipe’) relies on a collapsing vapour cavity to generate large pressure surges. The Bustapipe facility is pressure rated to a maximum of 40 bar. Both the surge pressure and duration can be varied in order to investigate the influence of these on the pipe behaviour. The tests demonstrated that plastic pipes can quite safely take the place of metal pipes provided care is taken over the selection of plastic type and method of construction.