Conditions of Combustion
The system of combustion conditions is widely known as the so-called „combustion triangle”. The term includes that three factors must be available simultaneously in space and time to occurring combustion (Figure 1).
Figure 1.: Conditions of combustion
In case of fire, flammable material and the oxidant must be at the appropriate concentration (i.e. within ignition limits) and the ignition source must have sufficient energy to ignite the fuel-oxidant mixture. In open-air, the duration of fire is usually determined by the required time to consume fuel (i.e. to fully oxidize). In the combustion of solids, such as coal or wood, the rate of combustion is determined by diffusion processes that limit the rate of access of the oxidizing medium to the remaining unburned fuel. Depending on the size of the fuel particle, the combustion process can take hours.
Properties of static dust layer have a special role in the planning of combustion safety measures.