ABSTRACT
Water mains have been manufactured from a variety of materials. The material selected must be compatible with the water constituents, otherwise corrosion and decomposition of the pipes may occur. The main is drilled and tapped live with special equipment, which leaves a plug valve ready for connection to the communication pipe. The indirect system of cold water supply has only one drinking water outlet, at the sink. The cold water storage cistern has a minimum capacity of 230 litres, for location in the roof space. The high-rise cold water supply systems have a non-return valve fitted to the outlet of each booster pump. This essential fitting will prevent reversal of the flow by gravitation when the pump is inactive. Water flow reversal into the break tank would be wasteful, potentially damaging to the plant room and, with a significant head of water, the pressure could burst pump seals, gaskets and other joints.
