Safety in forest fire fighting action: a new radiometric model to evaluate the safety distance for firemen working with hand-operated systems.

Fire event management always needs human intervention in order to extinguish forest fires. Firemen equipment reached high performance and safety standards but high temperatures occurring in proximity of a forest fire may cause bodily temperature increase and dehydration. Therefore it is important to identify a distance limit at which an operator can work without problems and complications due to the heat during forest fire fighting actions. This work describes an new approach to find a safety limit for firemen. The distance limit at which the operators can work without any consequence is evaluated considering the bodily temperature increase of a man exposed for a period of time at the thermal radiations coming from the fire. The main characteristic of the model is the use of radiometry to evaluate the amount of thermal energy transferred. By varying the distance between the fire and the operator it is possible to evaluate the bodily temperature increase. Safety distance limit is identified when human body temperature starts to be dangerous (38.5 °C). In order to evaluate the distance safety value a fire model and an operator model are given. The fire model is based on the international Brown and Davis forest fire classification in order to consider some various realistic forest fire types. The fire fighter representation is established according to physiological and medical data in order to have a good representation of a real fireman. The results of the model have been compared with the ones coming from other models used for the same purpose based on probabilistic methods and the comparison confirms the good validity of the presented model. This fact, together with the simplicity of the model structure and the practicality of the safety distance as a reference limits allows the model to be used in future applications in order to identify and prevent some possible dangerous situations for operator engaged in forest fire fighting.