November 2021 Class I, Zone 0 = Area Classification, AEx = Symbol for equipment built to American specifications, ia = Type of protection designations, IIC = Gas classification group (as required), T6 = Temperature Classification, [46 FR 4056, Jan. 16, 1981; 46 FR 40185, Aug. 7, 1981; 72 FR 7210, Feb. 14, 2007], Occupational Safety & Health Administration. Other ignition sources can also be present, like static electricity. 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." [10][11] Some of these are specifically for hazardous locations: All equipment certified for use in hazardous areas must be labelled to show the type and level of protection applied. Zone 0 is reserved for those areas continuously hazardous (e.g., inside a vented fuel tank), so other Division 1 areas would be classified as Zone 1. a headlamp, rather than a dedicated fixed luminaire. Some other standards have more quantitative methods which require more knowledge of the plant, an example is the IEC standard 60079-10-1. July 2020 TLS OFFSHORE CONTAINER Comments. 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. The Raytec SPARTAN range includes dedicated luminaires for both Zone 1 and Zone 2 areas as well as industrial applications. The temperature marking may not exceed the ignition temperature of the specific gas or vapor to be encountered. Zone 0, 1 2 . Equipment that is safe for the location shall be of a type and design that the employer demonstrates will provide protection from the hazards arising from the combustibility and flammability of vapors, liquids, gases, dusts, or fibers involved. WATER TIGHTNESS Class defines the type of explosive or ignitable substances which are present in the atmosphere. Hazardous locations can also be described as those locations where electrical equipment Independent test housesNotified Bodiesare established in most European countries, and a certificate from any of these will be accepted across the EU. The classification process requires the participation of operations, maintenance, safety, electrical and instrumentation professionals; and the use of process diagrams, material flows, safety data sheets, and other pertinent documents. Atmospheres containing combustible flyings. Where pyrophoric materials are the only materials used or handled, these locations need not be classified. In the United States, the most commonly followed system is the NEC (National Electric Code), while the rest of the world generally follows the IEC (International Electrotechnical Commission). Accommodation Cabin Zone Hazardous Location 2 Table of . No. 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. A light switch may cause a small, harmless spark when switched on or off. In the United Kingdom, Sira and Baseefa are the most well known such bodies. Pressurised Container This was accompanied by electrically-initiated explosions of flammable gas such as fire damp (methane) and suspended coal dust. Zone 2 Explosive Mixtures not likely to occur /occur short duration in normal operation (lt10 Hrs/ Yr). September 2018 Flour, wood/sawdust, plastic dust). Then, the level of risk of an explosion is based on the frequency and duration of the occurrence of an explosive atmosphere. . The surface of a high pressure steam pipe may be above the autoignition temperature of some fuel-air mixtures. 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. may exist under normal or abnormal conditions because of the presence of flammable gases or vapors, combustible dusts or ignitable fibers or flyings. The inductance of the signal bell coils, combined with breaking of contacts by exposed metal surfaces, resulted in sparks, causing an explosion. Two possible classifications are described, in Section 18 (Zones), and Appendix J (Divisions). A Zone 1 hazardous area is classified as a place in which an explosive atmosphere consisting of a mixture with air or flammable substances in the form of gas, vapour or mist is likely to occur in normal operation occasionally. d : HA - ha ea OA - oa Area classification - Divisions vs. zones Continuous hazard Intermittent hazard Hazard under abnormal conditions Zone 0 Zone 1 Zone 2 Division 1 Division 1 Division 2 Hazardous locations - CEC classifications Class I Ignitable concentrations of flammable gases or vapors which are present continuously or for long periods of time. The above groups are formed in order of how explosive the material would be if it was ignited, with IIC being the most explosive zone system gas group and IIA being the least. Informational Note No. WELDING INSPECTION For gases, vapours and mists the zone classifications are recognised as Zone 0, Zone 1 and Zone 2 areas. All threaded conduit shall be threaded with an NPT (National (American) Standard Pipe Taper) standard conduit cutting die that provides -in. Quick Tips #124.1. But beside electrical equipment also mechanical equipment must be Ex certified, e.g. >> For Gas Vapor this would be Zone 1. Upon detection, appropriate action is automatically taken, such as removing power, or providing notification. Adapters shall be used for connection to conduit or NPT-threaded fittings. But first, we must consider what is likely to cause an explosion in the first place. Class 1/Div 2 ATEX Zone 2 Computers. The equipment group . But when we take a closer look at the graph and table, we can conclude that any explosion, can easily lead to severe damage. In ambient conditions it is assured that oxygen is always present and thus not a factor that has to be incorporated within the hazardous area assessment. These areas only become hazardous in case of an accident or some unusual operating condition. 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. NFPA 70 NEC Articles 505 and 506 cover the requirements for the Americanized Zone classification system as an alternative to the Class and Division classification system. Equipment should be tested to ensure that it does not exceed 80%[according to whom?] Directly adjacent on the label one will find the mark of the listing agency. . SEWAGE TREATMENT Cookies are only used in the browser to improve user experience. Article 505 National Electrical Code (NEC), Article 506 National Electrical Code (NEC). Zones 1 or 2. June 2022 The following content is only related to flammable substances and not to pyrotechnic substances or other instable substances, among those who can decompose. Zone 0 Zone 1 Zone 2 Fluid Occurrence of explosive atmosphere Gas mixtures Dust mixtures Not likely to occur or only for short period Zone 2 Zone 22 . Atmosphere containing flammable gas, flammable liquid produced vapor, or combustible liquid produced vapor mixed with air that may burn or explode, having either a MESG value greater than 0.75 mm or a MIC ratio greater than 0.80 - such as gasoline, acetone, ammonia, benzene, butane, ethanol, hexane, methanol, methane, vinyl chloride, natural gas, naphtha, propane or gases of equivalent hazard. This equipment is intended for use in Zone 1 (gases) or Zone 21 (dusts). Atmospheres containing propane, acetone, benzene, butane, methane, petrol, hexane, paint solvents or gases and vapors of equivalent hazard. Group C materials have a MESG less than 0.75mm and a MIC ratio less than 0.80 (but greater than 0.40, which would put it in Group B.) NFPA 70 NEC uses the familiar Class/Division system and has added an Americanized version of the International Electrochemical Commissions (IEC) IEC Zone system which maintains the NEC wiring methods and protection techniques. This classification method provides a description of the hazardous material that may be present, and the probability that it is present, so that the appropriate equipment may be selected, and safe installation practices followed. The upper explosion limit of a substance is the highest concentration (in volume percentages for gases and liquids) of a gas or a vapor in air capable of producing a flash of fire in the presence of an ignition source. The basis for the classification into zones is the duration of the presence of the potentially explosive atmosphere: The longer it is present, the more critical the zone. There are three zones for gas: Zone 0, Zone 1 and Zone 2. This temperature is used for classification for industry and technology applications.[6]. Group II is for explosive gases (Zone 0, 1 and 2) and Group III is for explosive dusts (Zone 20, 21 and 22). To make this even easier to understand, take a look at the diagram of a typical petrol station below where we have identified the areas that are classified as Zone 0, Zone 1 and Zone 2. of THE CURRENT STANDARD . 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. For more detailed assessments or for situations where no specific industry standards are available , like the chemical or pharmaceutical sector and also specific installation for oil and gas industries, a more quantitative approach can be used. 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). Raytec do not currently offer any lighting solutions for Zone 0. 11: For information on electric skin effect trace heating for hazardous (classified), Informational Note No. Classification of locations, testing and listing of equipment, and inspection of installation, is typically overseen by governmental bodies. Zone 0 - Explosive atmospheres present continuously long periods or frequently. No hidden fees. Ways to ensure this level of safety are non-arcing design and limitation of the temperature of the equipment. Ignitable concentrations of flammable gases or vapors which are not likely to occur under normal operating conditions and do so only for a short period of time. Flameproof "d" - This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. Informational Note No. This page was last edited on 20 January 2023, at 22:32. Non-hazardous or ordinary locations. As a guide for Zone 0, this can be defined as over 1000 hours/year or >10% of the time. Groups E, F, and G are for dusts and flyings (Class II or III). area in which an explosive gas atmosphere is likely to occur occasionally in normal operation. November 2022 1. February 2023 9: For additional information concerning the installation of, Informational Note No. In an ordinary household this is of no concern, but if a flammable atmosphere is present, the arc might start an explosion. Therefor Hazardous Area Classification (HAC) is the first important step in achieving an explosion safe installation or work environment. National Electrical Code, NFPA 70, Chapter 5, Article 500, 29 CFR 1910 Subpart S, Electrical 1910.307, NFPA 497, "Classification of Gases, Vapors, and Dusts for Electrical Equipment in Hazardous Classified Locations", NFPA Handbook, "Electrical Installations in Hazardous Locations, " by P. J. Schram and M. W. Earley, NFPA 70E, Chapter 5, "Hazardous (Classified) Locations", ANSI/UL 913, "Intrinsically Safe Apparatus", NFPA 496, "Purged and Pressurized Enclosure for Electrical Equipment in Hazardous Locations. Hazards in this group gas can be ignited very easily indeed. 4: For further information on protection against static electricity and lightning hazards in hazardous (classified). Several protection strategies exist. Figures show that appr. Area Classification - Hazardous Locations are classified by the likelihood of an ignitable concentration of combustible material being present. September 2020 You can target the Engineering ToolBox by using AdWords Managed Placements. Division defines the probability of the hazardous material being present in an ignitable concentration in the surrounding atmosphere. Both external and internal temperatures are taken into consideration. Where there is potential for an explosive atmosphere, special precautions are needed to prevent fires and explosions. . How to perform Hazardous Area Classification? Division 2 is equivalent to Zone 2, while Division 1 is either Zone 0 or 1. Class defines the general nature (or properties) of the hazardous material in the surrounding atmosphere. This is also one of the first steps when composing an Explosion Protection Document. When working in or specifying equipment for use in hazardous environments, we see a lot of confusion in the industry regarding the different certifications and requirements. It may exist because of repair, maintenance operations, or leakage. These are typically process areas where gases are more likely to be present. Various regulations use terms such as class, division, zone, and group to differentiate the various hazards. In effect it is any method which can be shown to have the required degree of safety in use. The key difference between Divisions and Zones relate to terminations. BATTERY ENERGY STORAGE SYSTEMBESS) Zones compares to classes and divisions in the Class/Division system. December 2021 The zone classification for gases is divided into three zones, namely Zone 0, Zone 1 and Zone 2 and for dusts Zone 20, Zone 21 and Zone 22. [12], International Electrotechnical Commission, Occupational Safety and Health Administration, National Electrical Manufacturers Association, "Hazardous Area Classification and Control of Ignition Sources", "Hazardous (Classified) Locations NEC Articles 500 through 517", https://en.wikipedia.org/w/index.php?title=Electrical_equipment_in_hazardous_areas&oldid=1134828101, ignitable concentrations of combustible dust can exist, under normal conditions, ignitable concentrations of combustible dust are unlikely to exist normally, ignitable fibers, or materials producing combustible flyings, are handled, manufactured or used, easily ignitable fibers are stored or handled. That flammable gas or vapor . Class II combustible dusts are grouped into one of three (3) groups: E combustible metal dusts, F combustible carbonaceous dusts or G other combustible dusts. Offshore Accommodation Module A: No. 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. Equipment that the employer demonstrates will provide protection from the hazards arising from the flammability of the gas or vapor and the zone of location involved and will be recognized as providing such protection by employees need not be marked. International Electrotechnical Committee (IEC) Hazardous Area Classification. 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. Readers with specific questions should refer to the applicable standards or consult with an attorney. But every hazardous area is different and each has specific requirements depending on the nature of the atmosphere and the elements that are present. Equipment approved for Class I, Division 1 or Class 1, Division 2 shall, in addition to being marked in accordance with (c)(2)(ii), be marked with the following: Class I, Zone 1 or Class I, Zone 2 (as applicable); Applicable gas classification groups; and. Hazardous Area Classification (HAC) is as follows: Definitions of hazardous area are different as per IEC and NEC. Area which are not devided into Atex zones, are called non-hazardous area's. There are three necessary components for an explosion to occur; This needs to be present in a relatively high quantity to produce an explosive mixture (e.g. So for an explosion there must be enough fuel. 29 CFR 1910.307 Hazardous (classified) Locations 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! The substance referred to by classhas a high probability of producing an explosive or ignitable mixture due to it being present continuously, intermittently, or periodically or fromthe equipment itself under normal operating conditions. Much early equipment having Ex s protection was designed with encapsulation and this has now been incorporated into IEC 60079-18 [Ex m]. The Zone system of hazardous area classification, defines the probability of the hazardous material, gas, or dust, being present in sufficient quantities that can generate explosive or ignitable mixtures. Division 1 and 2 Zone 0, 1 and 2 A (acetylene) IIC (acetylene & hydrogen) B (hydrogen) C (ethylene) IIB (ethylene) Intrinsic safety designs equipment to operate using minimal energy, insufficient to cause ignition. | For Dust this would be Zone 22. Division defines the likelihood of the hazardous material being present in an explosive or ignitable concentration.Class I flammable gases and vapors are grouped into one of four groups(Groups A, B, C or D)based on their physical properties and the ease in which they can be ignited. 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. 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. Therefore, it is very important to make sure that you are using a suitable luminaire for your application by choosing your fitting based on its suitability for the Zone in which it will be located. Temporary Refuge (TR) Shelter Note to paragraph (c)(2)(i) of this section: NFPA 70, the National Electrical Code, lists or defines hazardous gases, vapors, and dusts by "Groups" characterized by their ignitable or combustible properties. These would be then labeled with each of the individual methods. A hazardous area classification drawing (also known as an area classification drawing) outlines the classifications of areas where flammable liquids, gasses or vapors are handed, processed or stored. >> For Gas/Vapor this would be Zone 2. When equipment must be placed in a hazardous location, it can be designed to reduce the risk of fire or explosion. WHEN YOU NEED THEM. Zone 22 Zone 21 Zone20 A hazardous atmosphere formed by dust cloud in air is not likely to occur in . 10: For information on electrical resistance trace heating for hazardous (classified), Informational Note No. August 2021 However, at low ambient temperatures, flammable concentrations of vapors may not exist in a location classified Class I, Zone 0, 1, or 2 at normal ambient temperature. Equipment shall be approved not only for the class of location, but also for the ignitable or combustible properties of the specific gas, vapor, dust, or fiber that will be present. September 2022 |MWD/LWD Cabin 2: For the requirements for electrical and electronic. The a subdivisions have the most stringent safety requirements, taking into account more than one independent component faults simultaneously. Classification of areas and selection of equipment and wiring methods shall be under the supervision of a qualified registered professional engineer. Also included in the marking are the manufacturers name or trademark and address, the apparatus type, name and serial number, year of manufacture and any special conditions of use. A more quantitative method is described in IEC 60079-10-1 but also more sophisticated numeric mathematical models can be used like Computational Fluid Dynamics. The housing may be strong enough to contain and cool any combustion gases produced internally. Hazardous areas are those defined as areas of potential explosion risk due to the presence of flammable gas or vapor. Vertical. In an industrial plant, such as a refinery or chemical plant, handling of large quantities of flammable liquids and gases creates a risk of exposure. IEC 60079-10.1 Classification of areas - Explosive gas atmospheres. A Zone 0 location is a location in which one of the following . If you require more information on the different variants in the SPARTAN range, or you would like to discuss your application in more detail, you can call us on +44 (0) 1670 520055 or send an email to sales@raytecled.comwhere we will happily answer any questions you have. Note to paragraph (g)(5)(ii)(C) of this section: The National Electrical Code, NFPA 70, contains guidelines for determining the type and design of equipment and installations that will meet this provision. Equipment marked as suitable for IIB is also suitable for IIA but NOT for IIC. In 29 CFR 1910.307(c)(2)(ii), OSHA requires all equipment used in a hazardous location to be marked with the class, group and operating temperature or temperature range for which it is approved. The Zone system has three levels of hazard for gas or dust. Area (mm2) CFD BS EN 60079-10-1:2009 1 5.0 5.0 0.0936 12.3 - 61.7 2 5.0 2.5 0.0326 6.17 - 30.8 December 2020 with hazardous areas EC-Type Examination Certificate BAS 01 ATEX 7251 , for additional certificates see www.pepperl-fuchs.com Group, category, type of protection II (1) G D [EEx ia] IIB (-20 C Ta 60 C) [circuit(s) in zone 0/1/2] Output EEx ia IIB Voltage U0 25.9 V Current I0 184 mA Power P0 1.2 W Type of protection [EEx ia] Zone 1 - Explosive atmospheres are likely to occur. 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. The overpressure is monitored, maintained and controlled. Powder Filling "q" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. SIGN UP FOR EMAILGet more great content in your inbox. MCC Shelter Zone 0: flammable atmosphere highly likely to be present - may be present for long periods or even continuously . Division II Comprising of Area Same as Zone 2. NFPA 70 NEC Classes, Divisions and Groups. You will find this equipment in paint factories, a warehouse or around a bag dump station. October 2020 hazardous areas as the following: An area where a potential hazard (e.g., a fire, an explosion, etc.) Container Test to EN 1127-1): After the hazard area classification is completed, then the ignition assessment starts. February 2021 Safe for the hazardous (classified) location. Dry Container The plan may contain the list of chemicals with their group and temperature rating. Atmosphere containing a flammable gas, a flammable liquid produced vapor or a combustible liquid-produced vapor whose MESG is greater than 0.75 mm or MIC ratio is greater than 0.40 and less than 0.80 - such as carbon monoxide, ether, hydrogen sulfide, morphline, cyclopropane, ethyl, isoprene, acetaldhyde and ethylene or gases of equivalent hazard. Area's are divided into zones. Note to paragraph (g)(4) of this section: Low ambient conditions require special consideration. The simplest is to minimize the amount of electrical equipment installed in a hazardous location, either by keeping the equipment out of the area altogether, or by making the area less hazardous (for example, by process changes, or ventilation with clean air). The codes and standards used in this process provide guidance for selecting,.
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