A New Method for Quantifying Fire Growth Rates Using Statistical and Empirical Data – Applied to Determine the Effect of Arson

When designing fire safety of buildings the fire growth rate is an important parameter, in large affecting the overall fire safety level within the building. Generally, a deterministic fire growth rate is used raising the question whether the resulting design arrives at a reasonable level of safety. A method was developed to obtain distributions of fire growth rates in specific building types. The new method uses data from two sources: fire statistics, and fire growth rates on single objects obtained by calorimetry experiments. In addition, the method was demonstrated by a case study investigating whether the overall fire growth rate is faster for commercial buildings if arson fires are included than if they are not. The results show that there is a considerably higher fire growth rate when arson fires are accounted for, e.g. designing for a fast fire growth rate of 0.047 kW/s2 covers 97% of accidental fires (arson excluded) but only 91% of all fires (arson included). The results indicate that there is a need to account for arson fires when designing buildings when the probability of arson is high. The developed method provides means to account for arson in fire safety engineering, and to further quantify the achieved fire safety level.