Evaluation of electrostatic hazards associated with non-conducting materials

Abstract

Non-metallic materials have a multiplicity of uses (storage vessels, packages, pipelines, etc.) and a procedure is described whereby the electrostatic hazard arising from their use in flammable atmospheres can be evaluated. Consideration is given to the discharge from the non-conducting surface, the problem of efficient earthing of metals and the effects produced by the storage of liquids and powders insulated inside non-metallic containers. A new concept for electrostatic earthing procedures is described and the control of hazard linked to the Zone Classification of flammable atmospheres used for electrical equipment. It is concluded that there need be few restrictions on the use of plastic materials provided that the new earthing concept is adopted and maximum use made of conducting non-metallic materials.