Fire Load in fire safety

Fire Load

It is the Total Amount of heat energy that can be released by all combustible materials in a given space during a fire. This fire load is very important factor in calculating in fire safety engineering and helps to find out fire risk, fire resistance requirement and in fire fighting strategies.

Formula of Fire Load

Fire Load Density (FLD):

∑ (W_i × C_i)
Floor Area (m²)

• ∑ = This is the sum symbol
• wi = Weight of the combustible material (kg )
• Ci = Calorific value of Material ( MJ/kg )

Steps for Fire Load Calculation

• List of Materials: Identify all combustible materials in the space or area and make a list of all combustible material which are present there.
  • List of combustible materials :- Wood, Paper, Plastic, Rubber, Textile, Diesel, Lpg , cardboard, coal, cooking oil, alcohol, cotton, paint, foam, straw.
• Determine Weight: Measure all the list of material in weighing machine.
• Find Calorific Values: Use standard tables or use Fire Load Calculator for finding calorific value .
• Calculate Total Heat: multiply the calorific value with weight of the materials as given in the formula or use Fire Load Calculator.
• Divide by the area: After multiplying divide that value with area in which this list of material kept (eg: hall, Kitchen and etc).

Example:

• Combustible Material:
  • Wood: 600 kg, Calorific value: 17.5 MJ/kg
  • Paper: 200 kg, calorific value: 16.2 MJ/kg
• Floor Area = 50 m²
• Fire Load = (600 x 17.5) + (200 x 16.2) / 50
• = 13740 / 50
• = 274.8 MJ/m²
• This is moderate hazards as per fire load classification.

Fire Load Classification ( as Per NFPA & IS 1641:1988)

Fire Load Density (MJ/m2)	Fire Hazard Level
Less than 200	Low Hazard
200 – 400	Moderate Hazard
More than 400	High Hazard

Importance of Fire Load Calculation

• Its helps in taking out fire risk assessment
• It is helps in designing of fire protection systems (eg: sprinkler)
• It is helps in Compliance to ensure adherence to fire safety code and standards
• It is helps in emergency planing in case of evacuation and response strategies.

Factor Affecting Fire Load

• Fire Load Affect by type and quantity of combustibles material.
• It is arrangement & Stacking of materials.
• Ventilation and fire protection Systems.
• and materials of building and its insulation.