Nitrile rubber is a highly flexible elastomeric material which is quick and easy to install. It has a closed cell structure which has a built in vapour barrier with a high resistance to water vapour transmission enabling the insulation material to maintain a higher level of energy conservation efficiency. It has an excellent fire safety performance achieving BS476 part 6 1989 for low fire propagation minimal contribution to the overall heat release, and BS476 part 7 1989 for zero surface spread of flame.