A real time fire and explosion detection system is presented in this paper, using data acquired from a Wireless Sensor Network inside a room. First it is filtered to remove the noise. Then, the stochastic process is modelled in real time. The model is also used to predict the future temperature. The outputs of the model are used to detect sensor faults, this way assuring the reliability of the data. Fires are detected using a change detection method three being proposed in this paper, but just one being recommended. Finally, explosions are identified using the predicted data.