Empirical formulas for fire demand

DEMAND FOR WATER

EMPIRICAL FORMULAS FOR FIRE DEMAND

A)    KULCHILING'S FORMULA : It states that

Q   3182  p

(at a demand rate to be maintained at hydrants of 1-1.5 kg km² lasting For 3 hrs) where

Q = amount of water required in litres/min P = population in thousands.

B) FREEMAN FORMULA : It states that

Where

y   = period of occurrences of fire in years

Q and „p? are same as above

C)    NATIONAL BOARD OF FIRE UNDERWRITER'S FORMULA

FCPA central congested high valued city

ii. When population is > 2,0,000 a provision for 54600 litres/ min may be made with an extra additional provision of 9100 to 30400 litres/min for a second fire.

For a Residential City            

1.       Small low buildings   = 2200 litres/min     

2.       Large and higher buildings      = 4500 litres/min 

3.       High value Residences apartment and tenements = 7650-1350 litres/min

4.       Three storeyed buildings         = 27,000 litres/min

D) BUSTON'S FORMULA - It states that

Q = 5663  p

All the above formulae suffer from the drawback, that they are not related with the type of area served. These formulas therefore give equal results for industrial and non industrial areas, although the possibility of occurrence of a fire with of given duration is more for an industrial area as compared to the non-industrial area.-