Protection in vehicles

Fatality and near miss incidents involving firefighters in vehicles are more common in Australia although records of near misses are difficult to find. In recent years most of these incidents have involved volunteer firefighters. Incidents that I have investigated have involved aggressive fire fighting under dangerous conditions, unnecessary risk taking and poor understanding of potential fire behaviour.

In one instance, Grays Point NSW 1983, the provision of protective shelters would probably have saved the firefighters from death and injury but so would a number of other factors including better work practice by the brigade captain, and a vehicle capable of accommodating all the crew in the cabin3. The NSW Bush Fire Council took the path of up-grading the standard of tanker. In other instances, e.g. Ash Wednesday fires near Upper Beaconsfield, it is my opinion that the severity of the fire at the point of entrapment would have resulted in the death of firefighters even with better tanker design or protective shelters.

Forest authorities have been well aware of the vulnerability of fire tankers to forest fires. Trials exposing vehicles to high radiation loads of 40 kW m-2 for 4 minutes ignited the seals and door linings and rapidly filled the car with dense black smoke (Cheney 1972). Recent experiments in the US produced similar results (Mangan 1997). Flame envelopment may involve radiation fluxes in excess of 100 kW m-2. Thus the research bears out the practical experience that vehicles generally provide satisfactory protection in grass fires where the duration of flames is around 10 seconds but will not provide adequate protection in forest fires where flame durations are several minutes and the burnout time may be any thing up to an hour depending on the level of drought and the fuel load.