An essential part of all sprinkler, medium and high velocity waterspray systems is an adequate water supply. The “Town’s Main” is the most economical method of ensuring an adequate water supply, providing there is always sufficient volume of water and pressure available for the waterspray system to operate at full demand until the fire has been eradicated. Tyco’s estimating team can advise on the most cost effective, suitable and most reliable water supplies for your firewater system.
Where this water supply requirement is not practical or achievable from a “Town’s Main” supply, Tyco can provide an LPCB approved water supplies system drawn from a galvanised water storage tank, reservoirs, rivers or canals or other sources by electric motor driven or diesel engine driven fire pumps.
Water Storage Tanks
The size of the water storage tank and the water supply pump is designed to provide a fully hydraulically calculated water supply operating on full demand to deal with the fire emergency.
Sprinkler systems are initially charged with a primary supply of fresh water from a cylindrical pressure tank. The average pressure tank has a capacity of 2979 litres. The normal fill is about 1500 litres.
Tank pressure is obtained by pumping air into the tank. The air supply delivery pipe incorporates a check valve and stop valve. Tank pressure is maintained at approx 8.3 bar. The pressure tank delivery connection to the trunk main is fitted with two stop valves, a non-return valve and a drain valve. The stop valves should normally be strapped open. The non-return valve prevents the admission of salt water into the pressure tank.
A level gauge is fitted to the tank to ensure the required level of water is maintained. The fresh water supply is usually taken from the vessel’s portable water system through a 40mm feed pipe, fitted with a stop valve and check valve.
Where fresh water and/or compressed air are not available on board the ship, a dedicated “sea water” pump and compressor can be supplied. The pump has an average flow capacity of about 1530 l/min. On large passenger ships, marine regulations may require both a primary fresh water supply and an additional “sea water” supply.
These systems use a Fire Authority approved bladder to store foam concentrate.
System water pressure squeezes the bladder, providing foam concentrate at the same pressure to the proportioner. No external power source is required and little maintenance is needed