Requirement for Fire Fighting:

With increase in density of population or at a place, where hazardous activities occur, chances of fire are more. For hazardous industries, like as explosive factories and etc., special arrangements are made for fire fighting. For towns and cities, in common, arrangement of additional water supply is made for fire fighting for an accidental fire break out in the locality.

Municipalities and corporations make provisions for fire hydrants and for multistorey private buildings in a thickly populated city, some mandatory provisions are enforced for fire fighting. Fire hydrants are generally provided with the water mains at a distance of around 150 meter apart. Fire fighting pumps are connected into them as soon as fire breaks out in the locality. Since pumps throw water on the fire at a very high pressure, the minimum water pressure available at fire hydrants should be around 1.5 kg/sq.cm. and this pressure should be available for around 4 to 5 hours of constant use of the fire hydrant.

As per the existing provisions one third of the fire fighting water requirement should be from storage reservoirs. The balance may be distributed in several static tanks at strategic point, which may be filled by nearest source of water such as streams, ponds or water tankers and etc.

For cities, having population more than 50,000, water required can be estimated as per the equation:

Q = 100 √P

where Q is water required in m3 and P is population in thousands.

Rate of fire demands can be calculated by Kuichling's formula which gives amount of water required in litres/minute

Q′ = 3182 √P

where, Q′ = Amount of water requirement in litres/min, and

P = Population in thousands.