Danger of fire and explosion

Fire, explosion, and detonation are forms of combustion, which generally differ in their development. Fire is characterized mainly by a stationary burning flame in an open atmosphere and leads to an explosion when an ignition occurs in a combustible atmosphere within an enclosed space, for example, a tank. Starting from the ignition source the flame-front runs through the entire space with a speed of about 10 m/s. The heating effect of the flame causes a pressure of about 10 bar (1.0 MPa) to build up, which diminishes during subsequent cooling. If the ignition starts in a rigidly confined space, for example, a pipe the heat of reaction causes a pre-compression which leads to a fast explosion ordetonation with a flame-propagating speed of up to 1 km/s. In this case, the pressure may rise to 100 bar (10.0 MPa) resulting in a shot-like noise and, quite often, devastating damage. This chapter explains the components required for an explosion. The presence of fuel, oxygen and an ignition source (danger triangle) alone is not sufficient to cause a fire or an explosion; they have to interact in a prescribed manner.