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I NTRODUCT I ON HAZARDOUS LOCATION DATA

Area Classification All facilities that process, handle, or use flammable gases, vapors or liquids, combustible dusts, or ignitable fibers or flyings are required to have an area classification performed and documented. (The specific rules, applicable Codes and Standards, other requirements and legislation depends on the local authority having jurisdiction over such facilities). Area classification is essentially a risk assessment. It is a detailed evaluation that considers multiple factors such as the materials expected to be present, their physical properties, ignition temperatures, sources of release, velocity of release, dispersion patterns, mitigation measures (such as ventilation and gas detection), surrounding atmosphere and wind patterns, etc. and lightning protection. Several industry guidelines recommend area classification be carried out by those who understand the properties of flammable materials and those familiar with the process and the equipment in consultation with safety, electrical, mechanical and other qualified engineering personnel. In some jurisdictions, those performing the area classification are required to have third party credentials (e.g., IECEx CoPC, CompEx, etc.) to verify that they are competent to perform this task. In all cases, common sense, experience and sound Electrical codes and equipment standards for hazardous locations have evolved into two different systems. In North America, hazardous areas were first identified in the electrical codes in the 1920s and in the 1930s the “Class/Division System” was introduced. Similar systems emerged in other countries around the same time. Work began by the International Electrotechnical Commission® (IEC) on a different system in the 1960s that used the term “Zone” that is different than the Class/Division systems. The Class/Division System separates hazardous locations into three “Classes” based on physical properties of the material that may be present. Each “Class” is separated into two “Divisions” based on the risk that the explosive material is present in sufficient quantities for an explosion to occur. It further separates the materials into multiple “Groups” based on their physical properties. In contrast, the Zone System separates the same materials into two material types, “gases” and “dusts”, and defines three areas of risk that the explosive material is present in sufficient quantities for an explosion to occur.

engineering judgement are extremely important when defining and documenting an area classification. An accurate area classification is critical for selecting electrical equipment that is suitable for the location, determining the appropriate installation requirements, defining any mandatory maintenance procedures, personnel health and safety requirements, issuing work permits, vehicle access, etc. While not a complete list, the following are examples of commonly used documents that provide guidance on area classification: • For explosive gas atmospheres: American Petroleum Institute (API) RP 500 and RP 505, National Fire Protection Association (NFPA) 497, IEC 60079-10-1, Energy Institute Code of Practice (Part 15) • For explosive dust atmospheres: NFPA 499, 654, and IEC 6007910-2 • For specific types of facilities with explosive atmospheres: NFPA 664 (Prevention of Fires and Explosions in Wood Processing and Woodworking Facilities), NFPA 829 (Standard for Fire Protection in Wastewater Treatment and Collection Facilities). ANSI/CAN/UL/ULC 1389 (Plant Oil Extraction Facilities i.e., Cannabis Operations). While there are some slight country specific differences, the rest of the world uses the “Zone System” which is based on the IEC 60079 Series of Standards. The United States and Canada are similar (but not identical) in their hazardous area requirements, including area classification, product standards and acceptable wiring methods. While specific requirements differ, both the United States and Canada have incorporated the IEC Zone System of Area Classification into their electrical codes. Both the Class/Division system and Zone system provide effective solutions for electrical equipment used in hazardous locations and both have excellent safety records. In the United States, NEC Articles 500 through 517 contain the installation Rules for Hazardous (Classified) Locations which permits the use of either the Division System or Zone System.

General Information on Hazardous Locations

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