Class defines the general nature (or properties) of the hazardous material in the surrounding atmosphere. Raytec do not currently offer any lighting solutions for Zone 0. Dn 1 - a Ce e . a headlamp, rather than a dedicated fixed luminaire. NFPA 70, the National Electrical Code (NEC), defines area classification and installation principles. A high level of protection is ensured. Zone 1 - A place in which an explosive atmosphere is likely to occur in normal operation occasionally This was accompanied by electrically-initiated explosions of flammable gas such as fire damp (methane) and suspended coal dust. 4: For further information on protection against static electricity and lightning hazards in hazardous (classified). Zone 1 2. Ex Zone. Zones 1 or 2. Within the European Union, these are defined by IEC/EN standards (IEC/EN 60079-10-1 or 2) as directed by ATEX. The last requirement for the explosion is the presence of an ignition source, like a spark or hot surface. Zones. Flammable liquids with a high flash point are less hazardous than liquids To minimize the risk of these fires or explosions, electrical/electronic equipment must be designed, tested and labeled as being acceptable for use in the areas in which it is installed. Group II is for explosive gases (Zone 0, 1 and 2) and Group III is for explosive dusts (Zone 20, 21 and 22). Requirements for good HAC Drawings and Plans. The temperature classification on the electrical equipment label will be one of the following (in degree Celsius): The above table shows that the surface temperature of a piece of electrical equipment with a temperature classification of T3 will not rise above 200C. 1: As a guide to classification of Zone 22 locations, refer to ANSI/ISA 60079-10-2 (12.10.05)-2013, Explosive Atmospheres Part 10-2: Classification of areas Combustible dust atmospheres. Equipment that is listed for a Zone 0 location may be installed in a Zone 1 or Zone 2 location of the same gas or vapor. This paper will discuss and review the current approaches and solutions of dealing with these HSE concerns, especially with the involvement of hazardous and potentially flammable and explosive chemicals. In North America the suitability of equipment for the specific hazardous area must be tested by a Nationally Recognized Testing Laboratory, such as UL, FM Global, CSA Group, or Intertek (ETL). NFPA 70 NEC Articles 500 through 503 cover the requirements for electrical/electronic equipment and wiring for all voltages in Class I, Divisions 1 and 2; Class II, Divisions 1 and 2; and Class III, Divisions 1 and 2 locations. If equipment is marked, for example, Ex e II T4 then it is suitable for all subgroups IIA, IIB and IIC. NEC has created an Americanized version of the IEC/CENELEC Zone system in a stand-alone article (Article 505). February 2021 This rapid expansion of volume is caused by the combustion of a fuel, like e.g. No representation is made that the information or references are complete or remain current. International Electrotechnical Committee (IEC) Hazardous Area Classification. In general, all types of equipment installed within the hazardous area shall be . 11: For information on electric skin effect trace heating for hazardous (classified), Informational Note No. Determined to be none of the above. Intrinsic safety designs equipment to operate using minimal energy, insufficient to cause ignition. In the US, the independent National Fire Protection Association (NFPA) publishes several relevant standards, and they are often adopted by government agencies. The overpressure is monitored, maintained and controlled. Ignition sources can be divided in 13 categories (acc. The lower explosion limit of a substance is the lowest concentration (in volume percentages for gases and liquids) of a gas or a vapor in air of producing a flash of fire in the presence of an ignition source. Intrinsic safety -- This protection technique is permitted for equipment in the Class I, Zone 0 or Zone 1 locations for which it is approved. Zone 0 describes an area in which a combustible gas will be present continuously while zone 20 describes an area in which combustible dust will be present continuously (the '2' in 'zone 20' indicates dust as opposed to gas). Zone 2 - Explosive atmospheres are unlikely to occur or present only infrequently and for a short period only. ethanol, methane or hydrogen. Increased safety "e" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. Readers with specific questions should refer to the applicable standards or consult with an attorney. . API 500/505 mostly for onshore and offshore oil and gas applications. The Zone system is based on Article 505/506 of the National Electrical Code (NEC) and follows the international method of area classification as developed by the International Electrotechnical Commission (IEC). .14 . 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 liquids. A room with a propane gas installation will typically be classified with the. The IEC standard EN 60079-33 is made public and is expected to become effective soon, so that the normal Ex certification will also be possible for Ex-s, Zone depending upon manufacturer's certification, explosive atmosphere between 10 and 1000 hrs/yr, explosive atmosphere between 1 and 10 hrs/yr, explosive surface between 10 and 1000 hrs/yr, explosive surface between 1 and 10 hrs/yr, Certified and labeled for use in indoor locations rated NEC Class I, Groups A, B, C, and D, Certified and labeled for use in locations rated NEC Class I, Groups A, B, C, and D; both indoors and outdoors, Certified and labeled for use in locations rated NEC Class II, Groups E, F, or G, Explosion protected, Group 2, Category 1, Gas, Type ia, Group 2C gases, Temperature class 4, Type n, non-sparking, Group 2 gases, Temperature class 3, special conditions apply. As mentioned, the first important step of achieving a safe work environment in relation to explosion safety is to identify and classify those areas, where a concentration of flammable gases or vapors within the flammable range can be present. Two possible classifications are described, in Section 18 (Zones), and Appendix J (Divisions). Magnesium, Aluminum, Titanium etc. 14 4. July 2020 Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro .Add the Engineering ToolBox extension to your SketchUp from the SketchUp Pro Sketchup Extension Warehouse! Standards and regulations exist to identify such locations, classify the hazards, and design equipment for safe use in such locations. Pit will be considered as Zone 1. In this article we will look at what defines Zone 0, Zone 1 and Zone 2 hazardous area classifications and the considerations for specifying lighting into each area. . July 2022 The flash point determines if an area needs to be classified. Refer to Fig.3 which shows the hazardous area zone classification based on hazardous gas release grade. SIGN UP FOR EMAILGet more great content in your inbox. September 2018 The substance referred to by classhas a low probability of producing an explosive or ignitable mixture and is present only during abnormal conditions for a short period of time - such as a container failure or system breakdown. Flameproof "d" - This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. . A60 July 2021 Note to paragraph (g)(4) of this section: Low ambient conditions require special consideration. Hazards in this group gas can be ignited very easily indeed. Classification of Hazardous Areas 0 100 200 300 400 500 600 T1 >450C T2 >300C 450C T3 >200C 300C T4 >135C 200C . Note to paragraph (g)(5)(ii)(B) of this section: An example of such a required marking is "Class I, Zone 0, AEx ia IIC T6." Have a think about it next time youre filling up! June 2022 3: For further information on the classification of, Informational Note No. This process is called hazardous area classification. 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. To meet OSHAs marking requirement, the marking must include the hazardous group the equipment is approved to operate in. - 1 2 (Class 1, . The Occupational Safety and Health Administration (OSHA) has adopted these hazardous classifications and all except Groups are defined in 29 Code of Federal Register (CFR) 1910.399. the National Fire Protection Association (NFPA) 70, National Electric Code(NEC). This is because Zone 0 usually classifies areas for gas storage or containment, and any lighting required would be used on a small and portable basis for visual inspection, e.g. Drop Test Hazardous Environment Classifications: NEC vs IEC, IEC (International Electrotechnical Commission), Group E Metal dusts (eg. January 2023 Flour, wood/sawdust, plastic dust), IIC Conductive dusts (eg. It is essential to know which zone you are working in, so that you can specify the most appropriate equipment. Zone 1 is an area in which an explosive atmosphere is likely to occur occasionally in normal operation. Offshore Living Quarter coal and charcoal), Group G Nonconductive dusts (eg. The first thing to understand is that much like the metric vs imperial measuring systems, the United States uses its own methodology which differs from much of the world. Equipment approved for use in Class I hazardous locations cannot be used in Class II hazardous locations. An explosion is a rapid expansion in volume associated with an extremely vigorous outward release of energy, usually with the generation of high temperatures and release of high-pressure gases (wikipedia (https://en.wikipedia.org/wiki/Explosion). Informational Note: For further information regarding classification and ventilation of areas involving closed-circuit ammonia refrigeration systems, see ANSI/IIAR 2-2014. Class 1/Div 2 ATEX Zone 2 Computers. I Flammable gases or vapors may be present, 1 Ignitable concentrations of hazards exist under normal operation conditions and/or where the hazard is caused by frequent maintenance or repair work or frequent equipment failure, E Combustible metal dusts: aluminum, commercial alloys and magnesium, III Easily ignitable fibers or flyings may be present, 0 Ignitable concentrations of flammable gases or vapors which are present continuously or for long periods of time, 1 Ignitable concentrations of flammable gases or vapors which are likely to occur under normal operating conditions; may exist frequently because of repair/maintenance operations or leakage; or equipment is operated in a manner that equipment breakdown/faulty operations could result in the release of ignitable concentrations of flammable gases or vapors and failure of the equipment, 2 Ignitable concentrations of flammable gases or vapors which are not likely to occur under normal operating conditions and if they do will only persist for a short period of time; or volatile flammable liquids, gases, or vapors are confined within closed containers/systems and can escape only as a result of an accidental rupture; or volatile flammable liquids, gases, or vapors are normally prevented by positive mechanical ventilation, but may become hazardous due to system failure, 20 Combustible dusts or ignitable fibers/flyings are present continuously or for long periods of time, 21 Combustible dusts or ignitable fibers/flyings are likely to occur under normal operating conditions; or may exist frequently because of repair/maintenance operations or leakage; or equipment is operated in a manner that breakdown/faulty operations could result in the release of ignitable concentrations of combustible dust or fibers/flyings and failure of the equipment, 22 Combustible dusts or ignitable fibers/flyings are likely to occur under normal operating conditions; or may exist frequently because of repair/maintenance operations or leakage; or equipment is operated in a manner that breakdown/faulty operations could result in the release of ignitable concentrations of combustible dust or fibers/flyings and failure of the equipment, Mines susceptible to firedamp (flammable mixture of gases naturally occurring in a mine, Explosive dusts Group III equipment is subdivided into three subgroups, A Atmospheres containing acetone, ammonia, ethyl alcohol, gasoline, methane, propane, or gases/vapors of equivalent hazard, A Atmospheres containing solid particles and fibers greater than 500 microns that could be suspended in air and settle out, B Atmospheres containing acetaldehyde, ethylene, or gases / vapors of equivalent hazard, B Atmospheres containing combustible dusts other than combustible metal dusts, C Atmospheres containing acetylene, hydrogen, or gases/vapors of equivalent hazard, C Atmospheres containing combustible metal dusts. D8.1.3 Hazardous areas are subdivided into Zones 0,1 or 2, the definitions of each cate-gory being as follows: Zone 0 an area in which an explosive gas-air mixture is continuously present or present for long periods. Entire Vapour space of storage tank. * Zone 2 a . Methane has a UEL of 17 vol%, which means when the concentration of methane in air is above the 17 vol% an explosion cannot occur even when an ignition source is present. Sources Arcing electrical equipment in unclassified . Informational Note No. Zone 1 - Explosive atmospheres are likely to occur. Classification of areas and selection of equipment and wiring methods shall be under the supervision of a qualified registered professional engineer. For equipment provided with threaded entries for NPT threaded conduit or fittings, listed conduit, conduit fittings, or cable fittings shall be used. 2) MIC (Minimum Igniting Current) Ratio - The ratio of the minimum current required from an inductive spark discharge to ignite the most easily ignitable mixture of a gas or vapor, divided by the minimum current required from an inductive spark discharge to ignite methane under the same test conditions. Unlike ATEX which uses numbers to define the safety "Category" of equipment, namely (1,2 3), the IEC continued to utilise the method used for defining the safe levels of intrinsic safety namely "a" for zone 0, "b" for zone 1 and "c" for zone 2 and apply this Equipment Level of Protection to all equipment for use in hazardous areas since 2009. Area Classification - Hazardous Locations are classified by the likelihood of an ignitable concentration of combustible material being present. Typical gas hazards are from hydrocarbon compounds, but hydrogen and ammonia are also common industrial gases that are flammable. . An area where combustible dusts or ignitable fibers and flyings are present continuously or for long periods of time. Sources of such hazards include gases, vapors, dust, fibers, and flyings, which are combustible or flammable. Zone 1 is an area in which an explosive atmosphere is likely to occur occasionally in normal operation. Hazardous areas are classified into 3 zones based upon the frequency of the occurrence and duration of an explosive gas atmosphere, as follows: Zone 0 Area in which an explosive gas atmosphere is present continuously or for long periods or frequently. No hidden fees. 29 CFR 1910.399 Definitions Applicable to Subpart S This article is not a substitute for review of current applicable government regulations, industry standards, or other standards specific to your business and/or activities and should not be construed as legal advice or opinion. Group II is for explosive gases (Zone 0, 1 and 2) and Group III is for explosive dusts (Zone 20, 21 and 22). . The value is represented is volume percentage of oxygen. The following content is only related to flammable substances and not to pyrotechnic substances or other instable substances, among those who can decompose. 1994-2020, W.W. Grainger, Inc. All Rights Reserved. September 2021 2: Where gas detection, Informational Note No. There are two sets of Zones: Zones 0 thru 2 are used for gases, vapors, and mists, and Zones 20 thru 22 are .
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