Experimental method for studying the fire and explosion dangerous characteristics provides the determination of critical conditions of flame spread in the conditions of uniform distribution dust cloud at varying the temperature of initiating ignition source. This allows conducting more accurate substance rating and so development of measures on fire and explosion risk.

The possibility of occurrence of “cold” flame at ignition of air coal dust mixture and its transition in “hot” flame at increasing the dust concentration has been shown. This is important for theory of fire safety engineering.