Class I hazardous locations are identified by zones as follows: * Zone 0 a location in which explosive gas atmospheres are present continuously or for long periods of time. 1994-2020, W.W. Grainger, Inc. All Rights Reserved. Canada has a similar system with CSA Group standard C22.1, the Canadian Electrical Code, which defines area classification and installation principles. 5: For further information on ventilation, see NFPA 30-2018, Informational Note No. 10: For information on electrical resistance trace heating for hazardous (classified), Informational Note No. The Class/Division/Group system is based on Article 500 of the National Electrical Code (NEC) where. 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! Zone 0 is an area in which an explosive atmosphere is present continuously for long periods of time or will frequently occur. All areas in the facility that are not Zone 0, Zone 1, or Zone 2 are considered unclassified. Outside of the United States, the IEC uses two different classifications: Gas & Vapor (Zones 0, 1, or 2) Dust (Zones 20, 21, or 22) Step 2: The next step is to determine how often the hazardous substance (s) is/are present. Pressurised Container The last requirement for the explosion is the presence of an ignition source, like a spark or hot surface. Beside sufficient fuel, also sufficient oxygen is needed for combustion of the mixture. This rapid expansion of volume is caused by the combustion of a fuel, like e.g. These generally give rise to areas classied as Zones 0, 1, and 2 respectively. may exist under normal or abnormal conditions because of the presence of flammable gases or vapors, combustible dusts or ignitable fibers or flyings. Vertical. October 2018 September 2018 One of the hazards of working with flammable substances is an explosion, mostly hand in hand with fire. 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. Area Classification. Reefer Container When equipment must be placed in a hazardous location, it can be designed to reduce the risk of fire or explosion. Zones. November 2021 For equipment with metric threaded entries, such entries shall be identified as being metric, or listed adaptors to permit connection to conduit of NPT-threaded fittings shall be provided with the equipment. October 2022 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. May 2021 | For Dust this would be Zone 21. May 2019 August 2021 Enclosures can be pressurized with clean air or inert gas, displacing any hazardous substance. Area's are divided into zones. 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. This was accompanied by electrically-initiated explosions of flammable gas such as fire damp (methane) and suspended coal dust. >> NEC: Class II, Division 1, Group F. | IEC: Zone 20, Group IIC. Readers with specific questions should refer to the applicable standards or consult with an attorney. The flash point determines if an area needs to be classified. For example the EI 15 and API 500/505 describe specific installations and several conditions for the oil and gas industry. Where pyrophoric materials are the only materials used or handled, these locations need not be classified. Hazardous classified locations are areas where the possibility of fire or explosion hazards may exist under normal or abnormal conditions because of the presence of flammable, combustible or ignitable gases, vapors, liquids, dust, or fibers/flyings. Equipment should be tested to ensure that it does not exceed 80%[according to whom?] Within the European Union, these are defined by IEC/EN standards (IEC/EN 60079-10-1 or 2) as directed by ATEX. Oil Immersion "o" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. August 2020 0. The hazardous area classification system determines required protection techniques and methods for electrical installations in the location. It is good to be aware of the fact that the mixture of flammable gas with oxygen has an optimum point where the combustion is most severe and leads to the highest explosion pressure. Non-hazardous or ordinary locations. 7: For further information on application of electrical, Informational Note No. We don't save this data. 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. Terminology for both hazards and protective measures can vary. Arc-producing elements can be isolated from the atmosphere, by encapsulation in, Heat-producing elements can be designed to limit their maximum temperature below the. Independent test housesNotified Bodiesare established in most European countries, and a certificate from any of these will be accepted across the EU. Informational Note No. Whenever you are filling up your tank you are standing in a Zone 1 hazardous area. July 2019 Container Test Not only are hazardous areas classified by Class (nature of the hazardous material,) and Division . Area's are divided into zones. Source: Rules and Regulations for the Classification of Mobile Offshore Units, Part 7, Safety Systems, Hazardous Areas and Fire, June 2013, Lloyd's Register, Global Standards. Areas with possible fire or explosion risks due to explosive atmospheres and/or mixtures - are called hazardous (or classified) locations or areas. Type of protection "n" -- This protection technique is permitted for equipment in the Class I, Zone 2 locations for which it is approved. A material may have a relatively low autoignition temperature yet if its flash-point is above the ambient temperature, then the area may not need to be classified. Examples are: In another blog we, will explain how to perform Hazardous Area Classification according to the Standard EN-IEC 60079-10-1. coal and charcoal), Group G Nonconductive dusts (eg. AddThis use cookies for handling links to social media. Zone 1 - A place in which an explosive atmosphere is likely to occur in normal operation occasionally 29 CFR 1910.307 Hazardous (classified) Locations
Equipment used in hazardous area must comply to certain Ex standards. Since the changes to the code, hazardous locations with gases or vapors (Class I) present can be reclassified as Zone 0, 1 or 2. [4], Flammability of combustible liquids are defined by their flash-point. Standards for electrical installations have been established and are governed by a variety of organizations throughout the world to ensure safe electrical systems in hazardous locations. Home About Us News Hazardous Environment Classifications: NEC vs IEC, Posted March 11, 2019 by springercontrols. Informational Note No. So it is quite obvious that explosions should be prevented as much as possible and still work has to be done to achieve this. >> For Gas/Vapor this would be Zone 0. Atmosphere containing a flammable gas, a flammable liquid produced vapor, or a combustible liquid produced vapor mixed with air that may burn or explode, having either a MESG (Maximum Experimental Safe Gap)1) value less than or equal to 0.45 mm or aMIC (Minimum Igniting Current)2) ratio less than or equal to 0.40 - such as hydrogen or fuel and combustible process gases containing more than 30% hydrogen by volume - or gases of equivalent hazard such as butadiene, ethylene oxide, propylene oxide and acrolein. eg Production Area, area surrounding zone 0. Zone 1 - Explosive atmospheres are likely to occur. Fundamentally, for an explosion to take place, flammable or explosive gases, vapours, mists or dusts will be present. >> For Gas/Vapor this would be Zone 2. For specific industries, the specific codes for that industry are important to use. Various regulations use terms such as class, division, zone, and group to differentiate the various hazards. 1910.307 (g) (2) area in which an explosive gas atmosphere is not likely to occur in normal operation, but, if it does occur, will exist for a short period only (less than 0,1% of the time), Window breakage, cracks plaster, light damage to buildings, Collapse of wood or asbestos siding of homes, Collapse of walls made of concrete blocks, Reinforced concrete structures severely damaged, Flames and hot gases (including hot particles), Mechanically generated impact, friction and abrasion, Stray electric currents, cathodic corrosion protection, Radio frequency (RF) electromagnetic waves from 10, Exothermic reactions, including self-ignition of dusts, EI 15 Energy Institute 15, mostly for on- and offshore oil and gas applications. Group define the type of hazardous material and (partly) the location of the surrounding atmosphere. Informational Note No. Which Standards to use for Hazardous Area Classification. The design of the equipment must ensure protection, even in the event of rare incidents relating to the equipment. Ignitable concentrations of flammable gases or vapors which are likely to occur under normal operating conditions. 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. of the autoignition temperature of the hazardous atmosphere. Several protection strategies exist. For equipment provided with threaded entries for NPT threaded conduit or fittings, listed conduit, conduit fittings, or cable fittings shall be used. 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. All equipment in Division 1 areas must have an approval label, but certain materials, such as rigid metallic conduit, does not have a specific label indicating the Cl./Div.1 suitability and their listing as approved method of installation in the NEC serves as the permission. Hazardous area classification. Type of protection "n" is further subdivided into nA, nC, and nR. A special standard for instrumentation is IEC/EN 60079-27, describing requirements for Fieldbus Intrinsically Safe Concept (FISCO) (zone 0, 1 or 2) (This special standard has been withdrawn, and has been partially replaced by: IEC/EN60079-11:2011 and IEC/EN60079-25:2010)[1], A special standard for instrumentation is IEC/EN 60079-27, describing requirements for Fieldbus Non-Incendive Concept (FNICO) (zone 2) (This special standard has been withdrawn, and has been partially replaced by: IEC/EN60079-11:2011 and IEC/EN60079-25:2010)[9]. No representation is made that the information or references are complete or remain current. Guidance on assessment of hazards is given in NFPA497 (explosive gas) and NFPA499 (dust). In the US, the independent National Fire Protection Association (NFPA) publishes several relevant standards, and they are often adopted by government agencies. The CE mark is complemented with the Ex mark: A yellow-filled hexagon with the Greek letters (epsilon chi), followed by the Group, Category, and, if Group II, G or D (gas or dust). In this system, two bare wires were run along the length of a drift, and any miner desiring to signal the surface would momentarily touch the wires to each other or bridge the wires with a metal tool. NEW METHODS FOR HAZARDOUS AREA CLASSIFICATION FOR EXPLOSIVE GAS . As world trade becomes more globalized, international standards are slowly converging, so that a wider range of acceptable techniques can be approved by national regulatory agencies. The housing may be strong enough to contain and cool any combustion gases produced internally. The Raytec SPARTAN range includes dedicated luminaires for both Zone 1 and Zone 2 areas as well as industrial applications. Controls can be fitted to detect dangerous concentrations of hazardous gas, or failure of countermeasures. These areas are classified solely for the purpose of ensuring the safe and proper specification and installation of electrical/electronic equipment. For Zone 1 applications, Pyroban uses . Electrical equipment installed in such locations can provide an ignition source, due to electrical arcing, or high temperatures. Category 1 equipment may be used in zone 0, zone 1 or zone 2 areas. September 2020 The key difference between Divisions and Zones relate to terminations. 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. The definition of the hazardous area zones represent the likelihood of hazardous gas, dust or other hazards being present in a working area. 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. Zone 0, 1, and 2 locations shall include those specified in 505.5 (B) (1), (B) (2), and (B) (3). 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. area in which an explosive gas atmosphere is present continuously, or for long periods, or frequently (more than 10% of the time).