A deep-seated hot spot in bulk storage can be very difficult to extinguish. Earlier detection is key when combating a silo/bunker fire. Fixed CO monitoring equipment has been proven to be the most effective tool in detecting the early signs of combustion.
The principle of this protection is to push CO2 vapour through the coal, reach the level of absorption, and fill all the void spaces between the coal particlestoreduce the oxygen available to the fire to near zero. Holding this condition long enough will effect fire extinguishment. To inert the coal, CO2 vapours used. CO2 injected in to the bottom of the bunker has been reported effective in smoothening fires.
Use of a laser pyrometer or thermal imaging camera will greatly improve the ability to quickly locate the seat of the fire and identify where the smouldering coal exists in a large bunker or coal feeder body.