Zoning of Hazardous Locations To protect installations from potential explosions, a method of analysing and classifying a potentially hazardous area is required. The correct selection and installation of equipment can help in preventing an explosion and to ensure safety of life. The methods used to classify an installation can vary depending upon which part of the world it is located, but generally, there are two main types of classification. In countries that have adopted the IEC (International Electrotechnical Commission) philosophy, this is referred to as Zoning, whilst in North America installations are classified by Classes, Divisions and Groups to ascertain the level of safety required. There are different 'zones' for gas, vapour and mist, and combustible dust. For gas, vapour or mist: 0 - Explosive atmosphere in air with gas, vapour or mists present continuously or for long periods of time. 1 - Explosive atmosphere in air with gas, vapour or mist present occasionally during normal operations 2 - Explosive atmosphere in air with gas, vapour or mist not likely to occur in normal operations, but if it does, will be for a short period. For combustible dust: 20 - Explosive atmosphere in air with combustible dust present continuously or for long periods of time. 21 - Explosive atmosphere in air with combustible dust present occasionally during normal operations 22 - Explosive atmosphere in air with combustible dust presence not likely to occur in normal operations, but if it does, will be for a short period.
Maintenance of plant, equipment, and electrical supplies Poorly maintained plant and equipment can cause fires. Things to consider include: • Good housekeeping, such as preventing ventilation points on machinery becoming clogged with dust or other materials, can avoid equipment overheating. • Regular servicing of electrical equipment in order to prevent breakdown and sparks. Which may lead to a fire.
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