Fire Load Calculation for Chemical Company

Please view the Fire load calculation given in the attachment. For many no. of chemicals used in the plant you may consider…

QUANTITY: The total quantity of all material used in the area

CALORIFIC VALUE: The average calorific value of the all materials (or) if the difference is minimal we may consider the highest calorific value of one any one material.

Definition of FIRE LOAD:

  • The weight of combustible material per square foot of floor space.


  • The combustible contents or interior finish of a building per unit floor area, often expressed as pounds per square foot or as Btu per square foot.


  • The amount of fuel within a building which has the potential of burning and releasing heat to feed the growth of a fire.

Fire load can be calculated as follows:-
Weight of material in Kg (mass) X Calorific value of the material – Answer in Kj
For example:

1 tonne of propane @ a calorific value of 47.3 x 103 Kj/Kg
= 1000 x 47.3 x 103 = 47300 Kj
If you want to relate this to wood equivalent the formula is:-
mass x calorific value divided by the calorific value of wood,

for example (with the calculation above):
1000 x 47.3 x 103 divided by the C of wood (17.6 x 103)
= 47300000 divided by 17600
= 2.7 tonnes (wood equivalent)


Calculating the Fire Loading of a Compartment

The fire loading of a compartment is a way of establishing the severity of a fire and the measurement (kj) is related to the heat output. As stated by Drysdale (1985) the formula for calculating the fire loading is noted as:


Calorific Value x Mass (or volume)       =      Area Fire Loading Kj/m2

Floor Area


Ex: 1 tonne of propane stored in a room having 240m2 area (10mx8mx3m)

47.3   x   1000        =       197.08 Kj/m2


Information on the mass of materials should be obtained from a number of sources using different methods, these included: contacting the manufacturer, consulting information currently available at the location and using relevant standards. The classification of the fire load in each area should be shown using the above formula.


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