Minimum Explosible Concentration - MEC

The lowest concentration of a dispersed dust cloud that will support a dust cloud
deflagration is the Minimum Explosible Concentration, or MEC. The ASTM E1515
Standard Test Method for Explosible Concentration of Combustible Dusts is
used to determine values of MEC. Dust samples are ignited at progressively
reduced dust cloud concentrations until the criteria for a dust deflagration can
no longer be met. 

Tests are conducted on fine dry dusts. Test standards recommend that the test
be conducted on fine dusts, i.e., dust passing through a No. 200 sieve screen
(or a No. 230 sieve screen when testing in accordance to EN requirements).
If the moisture content is more than 5% then the sample is dried.

Sample size: 500 g