The most widely used material in pipe installations is Unplasticised Polyvinyl Chloride. It can be used for both interior and exterior applications. Its chemical resistance is high and combined with its smooth bore there is virtually no build up of scale or residue and gives very good flow characteristics.
PVC-U is odourless and tasteless which makes it ideal for transporting foodstuffs and drinking water. It has high abrasion and weathering resistance.
Finally PVC-U gives good electrical and thermal resistance as well as being light and clean to handle and can be easily jointed.
PVC-U has a tin stabilised compound conforming to all EEC safety standards for the material VCM (Vinyl Chloride Monomer) and the WRc requirements for potable water use.
The chemical resistance properties of PVC-U are excellent. It is resistant to most solutions of acids, alkalis, salts and solutions which can be mixed with water. PVC-U is not resistant to aromatic and chlorinated hydrocarbons.
Temperature and Pressure
The permissable working temperature range for PVC-U is from 0-60oC.
Pressure ratings of pipe and fittings are usually quoted at a temperature of 20oC. It can be used at higher temperature but there will be a corresponding drop in the maximum pressure allowed. This is a fundamental principle of plastic pipework.
The Solvent cement used for jointing PVC-U fittings and pipe need to be a gap filling cement with a thick consistency. Non Gap-filling cements MUST not be used. The cement creates a chemical bond between the pipe and fitting. It is a simple and effective method of jointing and as it is permanent it is important to follow the correct procedure
To ensure maximum service life from the pipe and fitting transporting all manner of substances it is important to use the most effective Cement avaliable. The cement which we use is DYTEX which will ensure maximum service life and a very high degree of resistance.
However prolonged exposure of the inside joint to any of the following acid concentrations may eventually lead to some deterioration of the cement bonding
- Sulphuric acid over 70%
- Hydrochloric acid over 25%
- Nitric acid over 20%
- Hydrofluoric acid in all concentrations