Minimum explosible concentration

Minimum Explosible Concentration (MFC) The lowest concentration of combustible dust necessary to produce an explosion. 

Dust Minimum ignition temperature (°C) Minimum explosible concentration (g/l)... 

Material Median particle size, pm Minimum explosive concentration g/m= p max bar ga (dp/dt)max> ba r/sec Ksi bar-m sec Dust Hazard Class... 

Material Median particle size, Mm Minimum explosive concentration g/m3 P oux bar ga (dP/dl)max, bar/sec KSt Dust bar-m Hazard sec Class ... 

Dost Minimum ignition temperature (°C) Minimum explosible concentration (g/l) Minimum ignition energy (m)) Maximum explosion pressure Maximum rate of pressure rise (psi/s) Maximum Notes oxygen cor>centration to prevent ignition (% by volume)... 

Table 5. Representative ignition temperatures, minimum explosion concentration, and minimum ignition energy for selected dusts, from NFPA Fire Protection Handbook (National Fire Protection Association, 1986) and other sources.

Minimum explosive concentration for explosive and pyrotechnic dusts have been reported in the range of 40 to 1000 gm/mm, (40 to 1000 oz/ft ). With the exception of location 5 in Building 1619 at Louisiana AAP, all the dust concentrations determined for the various plants were below the maximum average concentrations. 

The lower explosive limit and minimum explosive concentrations of flax, wool, cotton, jute, hemp and sisal fibres are of the same order of magnitude as those of highly explosive dusts [15], The explosibility of pyrites dusts with sulfur contents above 20% was evaluated experimentally. Dusts of 30% sulfur content gave explosion pressures of 3 bar at pressure rise rates of 16 bar/sec. Mixtures of 60% pyrites and 40% powdered limestone still showed significant pressure effects, and the proportion of limestone actually needed to suppress explosions was considerably above the values currently accepted by mining industries [16], Effects of mixtures of particle sizes in combustible dusts upon minimum ignition temperature (T ") and upon presence or absence of explosion were studied. Presence of 30% of fines in a coarse dust lowers Tf significantly [17], Experimental explosions of polyethylene,... 

Maximum ignition energy, mJ Minimum explosive concentration, g/m3 Minimum energy, mJ... 

Figure 20.6 Effect of moisture on the minimum explosive concentration of grain. (Cross and Farrer, 1982.)...

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