General ~ when planning or designing any water installation the
basic physical laws must be considered:-
Water is subject to the force of gravity and will find its own
level.
To overcome friction within the conveying pipes water which is
stored prior to distribution will require to be under pressure
and this is normally achieved by storing the water at a level
above the level of the outlets. The vertical distance between
these levels is usually called the head.
Water becomes less dense as its temperature is raised, therefore
warm water will always displace colder water whether in a closed
or open circuit.
Direct Cold Water Systems ~ the cold water is supplied to the
outlets at mains pressure; the only storage requirements is a small
capacity cistern to feed the hot water storage tank. These
systems are suitable for districts which have high level reservoirs
with a good supply and pressure. The main advantage is that
drinking water is available from all cold water outlets,
disadvantages include lack of reserve in case of supply cut off, risk
of back syphonage due to negative mains pressure and a risk of
reduced pressure during peak demand periods.
Cold Water Installations