The research presented in this paper focuses on the importance of the prevention and mitigation of dust explosions by knowing the effect of single and combined parameters on the explosion severity. Experiments and a companion modelling study were conducted at varying the size fractions, the ignition source, the initial turbulence level, the concentration of flammable gas/vapour. The results quantitatively show the increased hazard posed by fine particle sizes of dust and admixture of flammable gas to a combustible dust. The effect of turbulence on deflagration index is minor in standard test conditions, while it is significant at high initial turbulence level. The model proposed gives a good prediction of the deflagration index at varying the dust diameter.