There are several ways of how to perform hazardous area classification, all described in several standards or codes of practise. 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. Standards and regulations exist to identify such locations, classify the hazards, and design equipment for safe use in such locations. Group is divided in three groups where Group I is reserved for mining locations. Non-hazardous or ordinary locations. September 2020 >> For Gas Vapor this would be Zone 1. Informational Note: For further information regarding classification and ventilation of areas involving closed-circuit ammonia refrigeration systems, see ANSI/IIAR 2-2014. The definition of Zone 2 is a hazardous area classified as an atmosphere where a mixture of air and flammable substances in the form of gas, vapour or mist is not likely to occur in normal operation, but if it does occur, will persist for a short period only. Atmospheres containing ethylene, propylene oxide, ethylene oxide, butadiene, cyclopropane, ethyl ether, or gases and vapors of equivalent hazard. 4: For further information on protection against static electricity and lightning hazards in hazardous (classified). The process of determining the type and size of hazardous locations is called classification. . What is an Explosion Protection Document? Click on the zone to learn more about the classification according to IEC 60079-10 standards. Hazardous area classification. WHEN YOU NEED THEM. 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. 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. Group defines the type of the hazardous material in the surrounding atmosphere. Hazardous Areas - North America Classification, international method of area classification, Protection Techniques for Hazardous Areas - North America, Hazardous because combustible or conductive, Atmosphere containing combustible metal dusts, including. Methane has a LEL of 4,4 vol%. the inside of tank truck or the interior of a dust filter). Adapters shall be used for connection to conduit or NPT-threaded fittings. 1994-2020, W.W. Grainger, Inc. All Rights Reserved. Within a working area or installation an ignition can be created by many factors. | For Dust this would be Zone 22. A high level of protection is ensured. One of the hazards of working with flammable substances is an explosion, mostly hand in hand with fire. Increased safety "e" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. For specific industries, the specific codes for that industry are important to use. In Europe the ATEX 114 Directive (2014/34/EU) is applicable to equipment that is used in hazardous area's. An area where combustible dusts or ignitable fibers and flyings are not likely to occur under normal operating conditions and do so only for a short period of time. A list must be drawn up of every explosive material that is on the refinery or chemical complex and included in the site plan of the classified areas. Hazardous Area Classifications D103222X012 Product Bulletin 9.2:001 September 2019. NEW METHODS FOR HAZARDOUS AREA CLASSIFICATION FOR EXPLOSIVE GAS . Class I, Zone 0 or Zone 1 locations may not abut Class I, Division 1 or Division 2 locations. 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. What Are All Those Gadgets On A Multitool? 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. Typical gas hazards are from hydrocarbon compounds, but hydrogen and ammonia are also common industrial gases that are flammable. Class defines the general nature (or properties) of the hazardous material in the surrounding atmosphere. POSITIVE PRESSURE There are four zones in the IEC classification system: Zone 0: An area in which an explosive atmosphere is present continuously or for long periods. As a result, all hazardous area equipment must be designed with hazardous area zone classifications in mind, as the zone governs the level of protection and precaution required. THE CURRENT STANDARD . In the US, the National Electrical Manufacturers Association (NEMA) defines standards for enclosure types for a variety of applications. Ex Zone. When the concentration of methane is beneath the LEL, an explosion cannot occur, even when an ignition source is present. | For Gas/Vapor this would be Zone 0. February 2019 For equipment provided with threaded entries for NPT threaded conduit or fittings, listed conduit, conduit fittings, or cable fittings shall be used. It is essential to know which zone you are working in, so that you can specify the most appropriate equipment. Google use cookies for serving our ads and handling visitor statistics. In Europe the label must show the CE mark and the code number of the certifying/notified body). 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. Areas with possible fire or explosion risks due to explosive atmospheres and/or mixtures - are called hazardous (or classified) locations or areas. In the United States, the NEC uses 2 different classifications: ". FEA Comparison of Zones and Divisions. These hazardous (classified) locations are assigned the following designations: For definitions of these locations, see 1910.399. November 2022 The Class/Division/Group system is based on Article 500 of the National Electrical Code (NEC) where. The equipment group . 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. National Electric Code 2020 edition National Fire Protection Association. Offshore Workshop Container 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. Zone 0, 1, and 2 locations are those in which flammable gases or vapors are or may be present in the air in quantities sufficient to produce explosive or ignitible mixtures. taper per foot. 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. Classification of locations, testing and listing of equipment, and inspection of installation, is typically overseen by governmental bodies. The IEC 60079 standard set has been adapted for use in Australia and New Zealand and is published as the AS/NZS 60079 standard set. Flameproof "d" - This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. 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. However, the following provisions modify this marking requirement for specific equipment: Fixed lighting fixtures marked for use in Class I, Division 2 or Class II, Division 2 locations only need not be marked to indicate the group; Fixed general-purpose equipment in Class I locations, other than lighting fixtures, that is acceptable for use in Class I, Division 2 locations need not be marked with the class, group, division, or operating temperature; Fixed dust-tight equipment, other than lighting fixtures, that is acceptable for use in Class II, Division 2 and Class III locations need not be marked with the class, group, division, or operating temperature; and. 2: Where gas detection, Informational Note No. Zone 1 fittings are supplied as silver, Zone 2 as dark grey and industrial fittings as white. 10: For information on electrical resistance trace heating for hazardous (classified), Informational Note No. Quick Tips #124.1. Zone 1 (unless separated by a fire wall)P.G.Sreejith, Kerala. So the following conditions must be met for an explosion to occur: Represented by the following explosion triangle. Much early equipment having Ex s protection was designed with encapsulation and this has now been incorporated into IEC 60079-18 [Ex m]. That is why the use of mobile phones on petrol forecourts are banned. The last condition for an explosion is the presence of an effective ignition source in the direct contact with the fuel/air mixture. A major safety concern in all workplaces is the occurrence of fires and explosions. 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. Zone 1 is an area in which an explosive atmosphere is likely to occur occasionally in normal operation. 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. December 2022 Equipment is placed into protection level categories according to manufacture method and suitability for different situations. Zone 1 2. Choose the right method for Hazardous Area Classification! Magnesium, Aluminum, Titanium etc. Group define the type of hazardous material and (partly) the location of the surrounding atmosphere. EN 16985 concerning spray cabins and powder coating cabins, EN 12779 related to extraction systems for hot sawdust and chips, EN 60079-10 series, 2020 version for gas and dust explosion hazard, NPR 7910 series for gas and dust explosion hazard based on EN 60079-10-1, 2015 version, EN 13617 for fuel dispensers at filling stations. 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). These areas are classified solely for the purpose of ensuring the safe and proper specification and installation of electrical/electronic equipment. A: No. In general, all types of equipment installed within the hazardous area shall be . Definition of hazardous area zones (AS/NZS 60079.10): Zone 0 . This is an important factor in the classification of hazardous areas. March 2021 Identifying Zone 0, Zone 1, and Zone 2 Hazardous Areas. Youre phone isnt rated for use in hazardous areas. In many industrial, commercial, and scientific settings, the presence of such an atmosphere is a common, or at least commonly possible, occurrence. Not only are hazardous areas classified by Class (nature of the hazardous material,) and Division . Copryright 2023 Springer Controls Company . These are typically process areas where gases are more likely to be present. The two general approaches are: Several techniques of flame-proofing exist, and they are often used in combination: Equipment has flameproof gaps (max 0.006" (150m) propane/ethylene, 0.004" (100m) acetylene/hydrogen), Equipment can be installed in ANY housing provided to IP54.A 'Zener Barrier', opto-isolator or galvanic unit may be used to assist with certification. Temporary Refuge In order to understand hazardous area classification it is important to understand which factors contribute to the occurrence of an explosion. Zone 0 is an area in which an explosive atmosphere is present continuously for long periods of time or will frequently occur. Canada has a similar system with CSA Group standard C22.1, the Canadian Electrical Code, which defines area classification and installation principles. Zone 0 - Explosive atmospheres present continuously long periods or frequently. 1: The term "Class I" was originally included as a prefix to, Informational Note No. 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.

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