Polypropylene has light weight, high impact strength and good weldability. It also has good abrasion resistance, weathering qualities and offers good electrical and thermal insulation. It is also suitable for handling foodstuffs.
Temperature and Pressure
The main advantage that polypropylene posesses is it ability to withstand higher temperatures than PVC-U. It will withstand temperatures up to 90oC and for a limited time up to 110oC. As with all thermo-plastics there is a relationship between temperature and pressure ie the higher the temp the less pressure the pipework will withstand.
For water and other inert media there are tables which relate temperature, life expectancy and different pressure rated pipe.
The chemical resistance properties of polypropylene are very good. It is resistant to aqueous solutions of acids, alkalis and salts and a large number of organic salts.
It is not however suitable for concentrated oxidising acids.
Socket Fusion Welding
The end of the pipe and the socket of the fitting are heated on a heating tool for a predetermined time until the correct fusion temperature is reached. The two parts are then brought together and pushed into full engagement. This method of jointing can be used for sizes up to 63mm dia. For larger sizes a machine should be used to enable an even pressure to be applied and to give good alignment between the pipe and the fitting.