Explosion hazards due to electrostatic charge accumulation on layer of adhesive powder

Fires and explosions occurring on industrial plants where powder products are handled or processed have a huge financial cost and in some cases can cause damage to people or to the environment. Static electricity can be one of the ignition sources from which these accidents originate. A specific electrostatic phenomenon deserving attention and which presents an explosion risk is due to the occurrence of propagating brush discharges at the surface of a thin layer of adhesive powder accumulated on a wall. A study, carried out as part of an EEC project (Brite Euram) enables this adhesive phenomena to be quantified using an experimental apparatus. Different industrial products were compared. In addition, on site measurements enable the electrostatic charge transfer level related to this double layer configuration to be determined. Measurements were carried out with insulating powder flowing in the pipe to allow the ignition energy of this kind of discharge to be evaluated