Enter the total mass, the calories, and the area into the calculator to determine the fire load.

Fire Load Formula

The following equation is used to calculate the Fire Load.

FL = (M*C)/A

  • Where FL is the fire load (kJ/m^2)
  • M is the mass of the material (kg)
  • C is the calories in the material (kJ/kg)
  • A is the total area (m^2)

To calculate the fire load, multiply the mass of the materials in the building by the calories in the material, then divide by the total area.

What is Fire Load?


Building fire load refers to the combustible combination of materials in a building that, when ignited, increases the likelihood of a fire’s rapid spread and intensity. Broadly speaking, building materials are either combustible or noncombustible.

Combustible materials include wood, paper and fabric. Non-combustible materials include masonry, concrete and steel. Combustibles can readily ignite and burn, while non-combustibles will not ignite or burn under normal circumstances. Many of the elements in a building are considered combustible or non-combustible based on their relative proportion of combustibles versus non-combustibles.

For example, the combustible content of a brick wall (about 80%) is significantly higher than that of a cement block wall (about 20%), hence brick walls typically have higher fire load ratings than cement block walls.