Experimental investigation of a smouldering fire in an under-ventilated silo

Abstract : An experimental bench was built and run to investigate the behaviour of a smouldering fire in an under‐ventilated silo. This smouldering fire was initiated by placing an electrical resistance at a given depth in the tested grain. The grain was successively corn, wheat, barley, oilseed rape, and sunflower. None of the tests resulted in an open fire but they all showed that the smouldering fire could generate an explosive atmosphere in the top part of the silo. When the venting conditions were kept unchanged within the silo, the tests also showed that the smouldering fire could become dormant resulting in no longer flammable gas concentration being measured in the silo. This phenomenon is associated with the formation of a carbonised rock around the heating resistance.