Minimal Ignition Energy of a dust cloud
The minimal ignition energie mostly ebbreveated to MIE is the lowest ammount of energy at wich a dustcloud can explode. It is different for each individual type of dust as it is depenfding om moisture, particle size and other factors.
Why is it important to know the minimal Ignition Energy?
In an factory several posible ignition sources can be found. For instance electrical installation, electrical switches, mechinical sparks but also electrostatic sparks. These ignition sources caused by various types of equipment differ in the energy they generate. To make a good risk analyis it is very important to know if these energy levels are above or below the minimal ignition energy of the dust that is being processed. Equipment that can produce energy levels above the minimal ignition energy must be replaced by explosion proof equipment. However if equipment can not ignite the dust cloud it might not be neccezary to replace the equipment. A sound risk analysis suffices in this case. In short: you can use ignition energy as a tool to choose what the best place is to invest in safety.
How is MIE determined?
The minimal ignition energy is determined in a so called Hartmann tube. Inside the tube a airbon dust is created At different energy levels variing from 1 until 1000 mJ it is attempted to ignite the dustcloud. The test starts at 1000 mJ and until the energy level at wich the dust does no longer ignite. Each energy level is tested 10 times.