Fire and Explosion Protection for the Combustible Dust Processing Industries. A spark by itself is not dangerous. For a fire or explosion to occur, there must be three essential ingredients - a combustible material, oxygen, and an ignition source. If one of these three is eliminated, then so is the potential for fire or explosion.In today's production plants, we often have to cope with all of the components that lead to a fire or cause an explosion. Dust/fume extraction systems and pneumatic conveyors increase the danger of fire. Once sparks or glowing embers are created, the pneumatic extraction system conveys these hazards to other areas. At this point, two of the three ingredients for the creation of fires and/or explosions are transported. When this conveyed danger meets a supply of combustible materials (filter cloth, deposited dust or the material in the separator or silo) it becomes more likely that the feared reaction will occur. Increased environmental protection measures regarding dust emissions and tightened regulations for air pollution have lead to the increased use of filter systems, and has increased the danger of dust explosions and fires due to the concentration of the combustible material at the filter. Because of the high cost of heating and cooling plant buildings, many air systems return the clean air directly back into the production facility. This practice, although energy efficient, presents an additional hazard if the collector catches fire. This fire will be propagated via the return air duct into the plant structure with devastating consequences.