I believe, for the AHJ, the most important text included in the NEC related to area classification is found in 500.4(A) and 505.4(A). Division 1 - There is a high probability of an explosive atmosphere in normal operation. 54 Elizabeth St. #10 Red Hook, NY 12571 (845) 758-0700 www.customheatersandresearch.com ZONE 1 - an area in which an explosive gas-air mixture is likely to occur in normal operations. Code (NEC) or other applicable code. Definition of Hazardous Locations. Classes indicate the type of hazardous substance that is or may be present in the air in quantities sufficient to produce explosive or ignitable mixtures. The National Electrical Code(NEC) defines hazardous locations as those areas "where fire or explosion hazards may exist due to flammable gases or vapors, flammable liquids, combustible dust, or ignitable fibers or flyings." A substantial part of the NEC is devoted to the discussion of hazardous locations. Class I, Division 1: There are three different situations that could exist to classify an area as a Class I, Division 1 location: 1910.307 (g) (1) Scope. In the USA, all regulations related to manufacturing facilities at risk are found in the National Electrical Code (NEC) Handbook. II, and III depending on the type of material present. Simply put, a hazardous location is an area where the possibility of an explosion, fire or electrocution exists, which can be created by the presence of flammable vapors, gases, moisture, combustible dust, or easily ignitable fibers. lk) are places where fire or explosion hazards may exist. Class Designators Class identifies the physical nature of the hazard. The National Electrical Code (NEC) along with the National Fire Protection Association (NFPA) and Underwriters Laboratories (UL) have published a guide along with codes that classify hazardous areas into classes, divisions and zones. This table indicates that the area extending up to 450 mm (18 in.) As a general rule equipment should be marked as follows: Company/Manufacturers name Class I, II and/or III Division 1 and/or 2 Group A, B, C, D, E, F and/or G Approving NRTL (Nationally Recognized Testing Laboratory) logo Product identification Serial number Other relevant safety information Enclosure Type Rating Finally Finally the end. NEC Classes Classes define the general nature of the hazardous material that may be in the surrounding atmosphere. For example, a Class 1, Div 1 area where Group A may be present would be defined as an area where flammable gases or vapors may be present under normal . 510 - 517). Classification of Hazardous Areas - NEC System. ZONE 10 - an explosive atmosphere, resulting from dust which is present continuously or for long periods of time. The "Combustion" or "Fire" Triangle is used to classify Hazardous Locations in the Explosion-Proof industry. Division 1 hazardous locations are defined (as per NEC code Article 500) as follows: 1. It refers to a part of the overall hazardous area of the plant or facility, where hazardous mixtures of gases and/or vapors (Class 1 hazardous materials) are present sometimes (as opposed to most of the time as in a Division 1 area). Hazardous (Classified) Locations The National Electrical Code (NEC) defines hazardous locations as those areas "where fire or . cotton mealybug; chemical control kidde smoke and carbon monoxide alarm beeping. Class I: Flash point below 37.8 C (100 F) Class II: Flash point above 37.8 C (100 F) and below 60 C (140 F) Class III: Flash point above 60 C (140 F) Class I flammable liquids can produce large quantities of vapor, especially if released at elevated temperatures, but tend to disperse fairly rapidly into the atmosphere. Classification of a Hazardous Location The hazardous locations covered by Chapter 5 of the National Electrical Code (NEC) are classified in accordance with the properties of flammable liquids, gases, vapors, combustible dust, or ignitable fibers or flyings that may be present in the area where electrical equipment may be installed. Flammability properties within that area (Art. The following are explanations of the two systems: Hazardous Location Coding System - NEC 500. The National Electrical Code (NEC) defines hazardous locations as those areas "where fire or explosion hazards may exist due to flammable gases or vapors, flammable liquids, combustible dust, or ignitable fibers or flyings." Hazardous locations are classified in three ways by the NEC: type, condition, and nature. above grade level within 6.0 m (20 ft) horizontally of an edge of the dispenser enclosure is a Class I, Division 2 location. Before going to the step -by-step method for performing electrical area classification, it should be explained that a classified (hazardous) area is defined by three parameters; these being 1) class, 2) group, and 3) division. In this system, areas are classified and grouped according to the flammable/combustible materials, which may be present. Hazardous Location Types - Classes Electrical equipment installed in such locations could provide an ignition source, due to electrical arcing, or high temperature. Although OSHA does not provide a definition of group classifications in 29 CFR 1910.307 or 399 they do provide a note under 29 CFR 1910.307 (c) (1) that states: " NFPA 70, the National Electrical Code, lists or defines hazardous gases, vapors, and dusts by "Groups" characterized by their ignitable or combustible properties." Note that . 500 - 506). Class I - flammable gases or vapors Class II - combustible dust Class III - easily ignitable fibers or flyings In this article, we'll look at how locations are classified according to flammability properties. NFPA 70 helps us define potentially dangerous areas by giving them a code, which typically includes a class, a division, and groups of materials that may be used within those parameters. Class I / II / III, Division 1 / 2 Type of Protection XP = Explosionproof This text, first included in NEC 1999, reads: "(A) Documentation. Two different Hazardous Location rating systems are defined by Articles 500 and 505 of the National Electrical Code . hazardous area classification zone 0, 1, 2 Dr. Carin Gribetz : Board Certified Dermatologist : 969 Park Avenue #1C, New York, NY 10028 | Contact: 212-289-3300 Board Certified Dermatologist | Super Doctor 2012-2019 |Manhattan | Upper East Side | Skin Cancer . The Class and Division taxonomy defines classified areas in terms of hazard type and hazard probability. Some typical Class II Class/Division System The Class/Division/Group system is based on Article 500 of the National Electrical Code (NEC) where The hazardous area classification system determines required protection techniques and methods for electrical installations in the location. Areas that are not classified are considered unclassified or non hazardous. Each "Class" contains (or may contain) different types of potentially explosive substances: Class I is for gases or vapors, Class II is for combustible dusts, and Class III is for flammable fibers. Areas are generally hazardous (classified) locations if ignitable concentrations of flammable gases, flammable liquid-produced vapors, combustible liquid-produced vapors, combustible dust, or ignitable fibers/flyings either in suspension in the air or other accumulations that present explosion or fire hazards exist or could exist. Hazardous Area Classification is a study, in which is assessed, at witch locations of a plant, factory or company, high concentrations of flammable gases are present or can be released, in order to create an explosion hazard. Division 2 - There is a low probability of an explosive atmosphere present during normal operation. In the NEC, the word "hazardous" denotes the way a particular location is classified due to either: 1. So what does a Class 1 Division 2 location mean? These are referred to in the Code as "Class II Locations." Finely pulverized material, suspended in the atmosphere, can cause as powerful an explosion as one occurring at a petroleum refinery. Employers may use the zone classification system as an alternative to the division classification system for electric and electronic equipment and wiring for all voltage in Class I, Zone 0, Zone 1, and Zone 2 hazardous (classified) locations where fire or explosion hazards may exist due to flammable gases, vapors, or . . Each hazardous area is classified according to Class, Group and Division. This can be for part of the time, up to all the time. The Occupational Safety and Health Administration (OSHA) has adopted these hazardous classifications from the NEC and they are defined in 29 Code of Federal Register (CFR) 1910.399. Therefor Hazardous Area Classification (HAC) is the first important step in achieving an explosion safe installation or . Thus, hazardous areas are found in a variety of industries including oil & gas Specific use of that area (Art. With that information, the installer and/or design team can plan an electrical design or installation for the dispensing equipment. Those locations in which ignitable concentrations of flammable gases or vapours can exist under normal operating conditions. The second type of hazard listed by the National Electrical Code is those areas made hazardous by the presence of combustible dust. The Practical Guide to Hazardous Area Classification Hazardous Areas are those areas of a plant or facility, which contain large quantities of volatile and inflammable liquids, explosive gases or even fine dust which can cause explosions. The following Groups only apply to Class II hazardous locations: Group E Metal dusts that are both conductive and explosive Includes aluminum, magnesium, and other metals with similar natures Group F Charcoal and coke dusts, carbon black, and coal While only some of these materials are conductive, all are explosive Group G Grain dusts ZONE 2 - an area in which an explosive gas-air mixture is not likely to occur and if it does, it is only for a short period of time. Sources of such hazards include gases, vapors, dust, fibers, and flyings, which are combustible or flammable. It does not necessarily reflect the views or policies of the U.S . Hazardous Area Classification Area classification is divided into three designators: Class, Group and Division. Table 5 shows the classification of the hazardous locations according to NEC 500 - 505 articles . Class I - flammable gases or vapors Class II - combustible dust Class III - easily ignitable fibers or flyings Classes indicate the type of hazardous substance that is or may be present in the air in quantities sufficient to produce explosive or ignitable mixtures. . 2. All areas designated as hazardous (classified) locations shall be properly documented. This material was produced under grant number SH-16615-07-60-F-12 from the Occupational Safety and Health Administration, U.S. Department of Labor. For example, an area containing gasoline could be classified Class I, Group D,