# 1992 Eindhoven
The influence of time and temperature on the long term strength of a multilayer pressure pipe has been investigated. The pipe consists of five layers, one of which is an aluminium foil while the other four layers are polyethylene based and form the significant ( > 8 5 % ) part of the pipe wall. In respect of strength these macrocomposite pipes behave as do conventionally extruded all plastics pipes; increasing the time under load and/or test temperature decreases strength. This allows the procedures developed by the plastics pipe industry for describing the influence of time and temperature on the strength of conventional, homogeneously structured plastics pipes, t o be applied t o these macrocomposite pipes. This helps the identification of the long term strength of these novel multilayer pressure pipes.