Fire load energy densities for risk-based design of car parking buildings

• We use a Monte Carlo analysis to determine the expected fire load energy density in car parking buildings.
• The fire load energy density is directly related to the static efficiency.
• An 80% fractile fire load energy density of 260 MJ/m2 is recommended as an appropriate design value.

The time-equivalence method is one way to determine the appropriate fire severity in buildings. One of the input parameters required is the fire load energy density (FLED) and in a deterministic design this is taken to be a fixed value. This paper illustrates the use of a simple Monte Carlo tool that accounts for statistical variations in car energy content as a function of vehicle size to determine probabilistic FLED values for a risk-based calculation approach to the design of car parking buildings. The paper briefly discusses FLED values for car parking buildings that can be found in the literature and results from the Monte Carlo tool suggest that 260 MJ/m2 could be used as an appropriate design value in lieu of using a probabilistic approach.