Plastics pipes in fires — the debate heats up
Doubts about the validity of fire tests on plastics pipes — Frank Jones of the Plastics Pipes Group.
The very low fire risk presented by plastic pipes in real situations is not in doubt says the Plastics Pipes Group (PPG) of the British Plastics Federation in response to tests carried out in Germany indicating that the use of plastics-based pipes for above-ground drainage aids the spread of fire (Modern Building Services, November 2004, page 32). The tests were carried out by IZEG in Germany to compare the performance of cast iron and plastics in a fire. Frank Jones, director of PPG, says, ‘The video footage [of the tests] refers to and shows the pipework being installed “in accordance with local building regulations”. This would refer to German, as opposed to UK, regulations. Furthermore, there is no mention of service ductwork, which is a common method of installation in the UK. ‘The conclusion supported by the video footage, which relates specifically to ‘industrial, commercial and public buildings’, shows the testing of exposed pipes, open both top and bottom. This is clearly an unrealistic situation — affecting the results and their subsequent portrayal.’ Accepting that plastic pipes are not non-combustible, PPG argues that in a real situation, the use of exposed pipework within a room is extremely unlikely and points out that the regulations strongly suggest that pipes should be installed within a duct, so that they are concealed behind a material of specified fire resistance. PPG also alleges that cast-iron pipe can help spread fire by conducting heat and igniting combustible material in contact with the pipe on the other side of a compartment wall or floor. Concern is expressed that the intumescent collars referred to in the German test were either not approved to UK standards or not installed in accordance with UK regulations. All intumescent products, including pipe collars, for use in the UK have been independently tested and must be installed strictly in accordance with manufacturers’ instructions. The testing procedure is set out in BS EN 1366 Part 3 and requires satisfactory performance of the fire collar for a specified period of time. Plastics-based above-ground drainage systems have a 40-year track record in the UK and now account for about 90% of the above-ground drainage. Feedback from the PPG indicates that during this period there has been no report that the use of this material has contributed to death, injury or increased risk to property in the event of a fire.