Recent developments in the safety consideration of electrostatic spraying processes

Electrostatic coating processes apply high voltages of the order of 100 kV to electrically charge the spraying material which is then precipitated on the surface of the work piece to be coated, making use of the resulting electrostatic attractive forces. A variety of electrostatic spraying equipment is in use, ranging from the hand-held electrostatic spray guns to the large electrostatic installations for painting car bodies. The materials are liquid paint, powders and flock. As these materials are flammable, their use may constitute an ignition hazard. Moreover, as high voltages are applied there may be the risk of electric shock to persons. In this survey, the major safety requirements for the prevention of both the risk of ignition and the risk of electric shock are dealt with, due regard being given to the different types of spraying equipment and spraying materials. In addition, special problems such as the use of triboelectric spray guns or the use of water-based paints have been given some considerations. The safety requirements are based on the European Standards EN 50176 and EN50177 for automatic electrostatic spraying installations and further standards which are still in preparation.