The handling of flammable conductive dusts almost always represents a hazard with a possible explosion hazard. Therefore, these areas must be marked separately and must be free of possible potential sources of ignition. This identification is usually carried out by the relevant specialist bodies (notified bodies). All information on the relevant substances should be stored and available in the respective explosion protection document.
In principle, users should have and understand the relevant information sheets from the trade association for the raw materials and chemical industry (BG RCI).
Users and manufacturers of aluminum powders, for example, can have a free analysis and risk assessment of the substance carried out by the relevant trade association.
Flammable conductive dusts contain all of the above-mentioned hazard potentials. Flammable conductive dusts are often of metallic origin. The fineness of the dust is of particular importance. The smaller the grain size of the combustible conductive dust, the greater the possibility of improved oxygen binding, which facilitates the ignition process.
In addition, chemical reactions (base metals) in connection with other media (e.g. aluminum powder and water / see appendix) are of great importance.
It should also be noted that some of the deposited dusts have a lower ignition temperature than when they were whirled up.
In the event of improper handling and under certain circumstances, a combustible, conductive amount of dust can self-ignite when its own (built-up) energy potential is dissipated.
Combustible dusts are to be viewed differently. Depending on their nature, these are difficult or highly flammable. Flammable substances are divided into different explosion groups (see appendix). In order to ignite a substance, an appropriate ignition source is required that emits sufficient energy for the ignition process. The basic unit of energy in the SI system of units is joule. The minimum ignition energy (MIE) of a substance is given in millijoules (mJ). The lower this value, the easier it is to ignite the product.
Oxygen is of course also required for ignition.
Conductive dusts can be deposited in insufficiently insulated terminal or fuse boxes and lead to a bridging of the separate current phases. This can cause a short circuit or a spark.
In some cases, the conductive dust conducts the current through the smallest gaps from the fuse box to the outside, which is a health hazard and a possible electric shock.
Conductive dust builds up charges in contact with non-conductive surfaces. If these charges are not diverted directly through a conductive connection to the earth potential, a very high charge potential could develop in an insulated container, for example. This electrostatic charge would suddenly discharge (spark) if it came into contact with an earthed component.