Listed below are definitions and acronyms to common words and phrases we use in hazardous locations. Hazardous Locations are defined as areas where potentially explosive or combustible gases, dusts or fibers and flyings exist or may exists.  This definition is taken from the National Electric code, however the definition is just about the same any place in the world. Zones are used in many countries to define hazardous locations. Zones define the conditions under which flammable or explosive gases are present in an area.   The 1999 NEC (US) and the 1998 CEC (Canada) have adapted the Zone area classification system of the IEC as part of their code. Divisions are used in the United States define the conditions, frequency or duration a explosive or flammable substance is present. Explosionproof is a generic (often misused) term used to describe a component, product or system that is suitable for use in a hazardous locations.  It sometimes also refers to a type of explosion protection that uses the containment method. Flameproof is an IEC or European term that usually refers to a type of explosion protection that uses the containment method EEx d. Increased Safety is a type of explosion protection applied to electrical apparatus that does not produce arcs or sparks in normal service, in which additional measures are applied so as to give increased security against the possibility of excessive temperatures and of the occurrence of arcs and sparks. Intrinsic Safety is a method of protection that limits the energy passing into the hazardous area. The energy limitation is provided by the use of safety barriers which are mounted in the safe area. Because of the energy limitation, regardless of the fault in the hazardous area, sufficient energy cannot be released to ignite the explosive atmosphere. Pressurization is the process of supplying sealed electrical enclosures with a protective gas to prevent the entrance of flammable gases while maintaining a positive enclosure pressure. Purging is the sub-routine of expelling flammable gases in  a Class I location. Nonincendive is a method of protection used for contacts, systems, circuits and equipment that is incapable of releasing sufficient electrical or thermal energy to ignite flammable gases or vapors under NORMAL operation and environmental conditions.  Nonincendive equipment should be certified and can be installed in division 2 locations.  Nonincendive devices need no special enclosure or other physical safeguard. CENELEC is the European Committee for Electrotechnical Standardization. It was set up in 1973 as a non-profit-making organization under Belgian Law. It has been officially recognized as the European Standards Organization in its field by the European Commission in Directive 83/189 EEC. Its members have been working together in the interests of European harmonization since the late fifties, developing alongside the European Economic Community. CENELEC works with 40,000 technical experts from 19 EC and EFTA countries to publish standards for the European market. BASEEFA.  British Approvals Service for Electrical Equipment in flammable Atmospheres. IEC.  International Electrotechnical Commission NEC.  National Electric Code CEC.  Canadian Electric Code UL.  Underwriters Laboratories CSA.  Canadian Standards Association FM.  Factory Mutual NFPA.  National Fire Protection Agency NEMA.  National Electrical Manufacturers Association ISA.  Instrument Society of America ISO.  International Organization for Standardization