It has been found that travel time increases with the square root of the distance for short trips and increases linearly for longer trips. Other factors considered in the submodel include the street arrangement and traffic volume, the distance of the fire location from a public road, the weather conditions, and the experience and local knowledge of the firefighters. The set-up time depends on the type of equipment required, the size of the crew arriving at the fire scene, the availability of water supplies and their location, the location of the fire in the building, building access to firefighters and the training and experience of the firefighters. In the submodel, the set-up time is given as an input and is obtained from statistical data. Intervention time With the above calculations, the submodel computes the intervention time which is the time from the moment the fire starts to the time when the firefighting activities begin.
Experience shows that the longer the intervention time, the higher the human and property losses.
The effectiveness of fire extinguishment depends on the status of fire at the intervention time and the availability of water and firefighter resources. The status of the fire is computed by the fire growth submodel. In the case of non-flashover fires, the firefighting effectiveness will be 1. In the case of flashover fires, firefighting effectiveness decreases as the intervention time goes well beyond the flashover time. The probability of extinguishment in terms of fire status on arrival is further modified to reflect the availability of water and manpower resources.