Hazardous areas are defined as areas where concentrations of flammable gases, vapors or dusts may occur, either constantly (Zones 0 and 20), under normal operating conditions (Zones 1 and 21) or unusually (Zones 2 and 22). A whole series of additional conditions relating to the temperature classification and the auto-ignition temperatures of the type of gas or dust to be found ensure that any equipment will not initiate an explosion or fire.
Hazardous areas are to be found in a very wide range of manufacturing industries, far beyond the obvious petrochemical plants. Food, pharmaceutical and cosmetic manufacture all involve processing potentially explosive substances, while the problems of explosions in grain silos and sugar processing plants are very well documented.
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There are two methods to ensure that alarm sounders or strobes do not cause an explosion in a hazardous area: using either explosion-proof or intrinsically safe devices.
In simple terms, intrinsically safe devices limit the input energy to a level where any arcing or sparking within the device cannot generate enough heat to ignite an explosion. On the other hand, the explosion-proof approach involves enclosing the equipment in a robust housing to prevent internal explosions from reaching the outside. Naturally, explosion-proof devices tend to be bulkier, heavier, and more robust than intrinsically safe ones. Consequently, they are more suitable for external applications and are often sealed to IP66 or IP67 standards for the required level of protection.
For Zones 2 and 22, 'increased safety' devices are necessary. E2S provides cost-effective and powerful explosion sounders and beacons designed for these environments.
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