The rate of the heat loss of hot water carried through pipe-work is affected by many factors including the thermal conductivity of the pipe material. This Guideline calculates the R value of the pipe and insulation by taking into account the dimensions and thermal conductivities of the pipe and insulation. The heat transfer coefficients of the water flowing through the pipe and of the air on the outside of the insulation are not considered, and therefore the true heat loss of the system is not defined by the calculated R value.
These guidelines have been prepared for the jetting of plastics pipe systems, to provide information based on experience and research, as to the maximum pressures that may be used to avoid damage to plastics pipes in good condition. They do not provide detailed instructions on water jet cleaning procedures, and are not intended to replace the pipe manufacturers’ specific recommendations, which should be sought in the first instance.
It is accepted that the expected service life of plastics pipes used in infrastructure work exceeds 100 years. This document considers whether it is reasonable to expect elastomeric seals used in both water and sewerage applications to match this performance.