Fire Water Supplies

The water supply to the fire pump in fire sprinkler installations must fulfil the requirements for flow, pressure and duration. Sources can be public water mains, water storage tanks and inexhaustible sources like lakes, rivers and canals

Sufficient water supply to fire pumps is essential. Depending on the hazards, single - or duplicate water supplies, have to be installed to ensure adequate and reliable water source for the fire-pumps. A duplicate water supply could be from two different public water mains or one public water + one storage tank. There is typically one suction line installed to each fire-pump from the water supply to avoid interference between the pumps. These design criterias are described in the various fire sprinkler installation standards
The water must be free of objects and sufficiently clean to be handled by the fire sprinkler installation. In order to avoid undesired objects getting in to the system a strainer located at the inlet to the suction pipe for the fire pumps should to be installed. Or, ideally a strainer is fitted on any suction pipework that feeds into a break tank to prevent any sediment from building up in the stored water.
Most installations prescribe a max 40° C for water supply temperature and 25 °C for submersible fire-pumps.   
The sources can be :
-          public water mains
-          water storage tanks
-          reservoirs
-          gravity tanks 
-          inexhaustible sources like lakes, rivers and canals