Electrical equipment installed in such locations can provide an ignition source, due to electrical arcing, or high temperatures. 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. Article 505 National Electrical Code (NEC), Article 506 National Electrical Code (NEC). Zone 0/20: An area in which an explosive atmosphere is present continuously or for long periods or frequently. 10: For information on electrical resistance trace heating for hazardous (classified), Informational Note No. Equipment meeting one or more of the protection techniques described in paragraph (g)(3) of this section shall be marked with the following in the order shown: Class, except for intrinsically safe apparatus; Zone, except for intrinsically safe apparatus; Occupational Safety and Health Administration, Outreach Training Program (10- and 30-hour Cards), OSHA Training Institute Education Centers, Severe Storm and Flood Recovery Assistance. All areas in the facility that are not Zone 0, Zone 1, or Zone 2 are considered unclassified. Readers with specific questions should refer to the applicable standards or consult with an attorney. 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. The flash-point is the temperature at which the material will generate sufficient quantity of vapor to form an ignitable mixture. October 2020 June 2022 In other cases, the atmosphere is normally non-hazardous, but a dangerous concentration can be reasonably foreseensuch as operator error or equipment failure. What are 'Dark Factories,' and Do They Really Exist? 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. .14 . the inside of tank truck or the interior of a dust filter). 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. September 2019 Zone 1 . As a guide for Zone 0, this can be defined as over 1000 hours/year or >10% of the time. In the US, the National Electrical Manufacturers Association (NEMA) defines standards for enclosure types for a variety of applications. 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. Only emails and answers are saved in our archive. The required protection level is linked to the intended use in the zones described below: The equipment category indicates the level of protection offered by the equipment. 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. Class I Zone 2 Hazardous Areas. a headlamp, rather than a dedicated fixed luminaire. As to the classification, they are the same. Empirical testing is done to determine parameters such as the maximum experimental safe gap (MESG), minimum igniting current (MIC) ratio, explosion pressure and time to peak pressure, spontaneous ignition temperature, and maximum rate of pressure rise. 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. There are two systems in place, including the traditional North American Division system as well as the alternative Zone system. An area where combustible dusts or ignitable fibers and flyings are present continuously or for long periods of time. 7: For further information on application of electrical, Informational Note No. . THE CURRENT STANDARD . This means that the electrical equipment is safe for use within these area by applying special protection strategies. Zones. All rights reserved. Group is divided in three groups where Group I is reserved for mining locations. For specific industries, the specific codes for that industry are important to use. July 2019 Area which are not devided into Atex zones, are called non-hazardous area's. For Zone 1 applications, Pyroban uses . Carbon monoxide, ether, hydrogen sulfide, . Zone 0 - Explosive atmospheres present continuously long periods or frequently. Two possible classifications are described, in Section 18 (Zones), and Appendix J (Divisions). All emergency versions, whether Zone 1 or Zone 2 can also be easily visually identified by their red end cap, encapsulating the emergency battery back-up. July 2022 - 1 2 (Class 1, . Q: Can equipment approved for a Class I hazardous location be used in a Class II hazardous location? Documentation requirements likewise vary. The colour of the luminaire body indicates the level of protection. CUTTING SKIPS Also known as non-hazardous or ordinary locations, these locations are determined to be neither Class I, Division 1 or Division 2; Zone 0, Zone 1 or Zone 2; or any combination thereof. 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. ), Group F Carbon-based (eg. Copryright 2023 Springer Controls Company . Under the "Zone" system, hazards are defined for gas as Zone 0, 1 or 2, with 0 as the highest hazard, and for dust as Zone 20, 21 or 22, with 20 as the . Controls can be fitted to detect dangerous concentrations of hazardous gas, or failure of countermeasures. 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." The a subdivisions have the most stringent safety requirements, taking into account more than one independent component faults simultaneously. Protecting against fire and explosion is of interest for both personnel safety as well as reliability reasons. August 2020 Beside the Lower Explosion Limit, each substance also has an Upper Explosion Limit (UEL). 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. We don't save this data. Identifying Zone 0, Zone 1, and Zone 2 Hazardous Areas. Equipment marked as suitable for Group IIC is also suitable for IIB and IIA. 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. Explosion-proofing designs equipment to contain ignition hazards, prevent entry of hazardous substances, and, contain any fire or explosion that could occur. Ignition sources can be divided in 13 categories (acc. Areas with possible fire or explosion risks due to explosive atmospheres and/or mixtures - are called hazardous (or classified) locations or areas. Comparison of Zones and Divisions. Groups A, B, C, and D are for gases (Class I only). NEC Div 1 Zone 1 Div 2 Zone 2Flammable during normal operation Most Safer Zone IEC Zone 0 DESRIPTIONHighly Flammable for long period DEFINITIONFlammable atmosphere present continuously (Typically 1000 hours / year). 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. 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. These areas are in North America (United States and Canada) historically classified with the Class/Division system. Those guidelines address electric wiring, equipment, and systems installed in hazardous (classified) locations and contain specific provisions for the following: wiring methods, wiring connections; conductor insulation, flexible cords, sealing and drainage, transformers, capacitors, switches, circuit breakers, fuses, motor controllers, receptacles, attachment plugs, meters, relays, instruments, resistors, generators, motors, lighting fixtures, storage battery charging equipment, electric cranes, electric hoists and similar equipment, utilization equipment, signaling systems, alarm systems, remote control systems, local loud speaker and communication systems, ventilation piping, live parts, lightning surge protection, and grounding. But every hazardous area is different and each has specific requirements depending on the nature of the atmosphere and the elements that are present. Zone 1 - Explosive atmospheres are likely to occur. These areas are classified solely for the purpose of ensuring the safe and proper specification and installation of electrical/electronic equipment. Hazardous Area Classifications D103222X012 Product Bulletin 9.2:001 September 2019. These areas only become hazardous in case of an accident or some unusual operating condition. Zone 1 an area in which an explosive gas-air mixture is likely to occur in normal operating conditions. Comparisons between the two systems are not easily accomplished. The use of EPL and ATEX Category directly is an alternative for "s" marking. May 2019 Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications! December 2020 August 2021 Entire Vapour space of storage tank. Hazardous area classification is a rigorous method of determining where an explosive environment may be present. December 2021 Arcing electrical equipment in unclassified . The Zone system has three levels of hazard for gas or dust where the Division system has two. API 500/505 mostly for onshore and offshore oil and gas applications. And there are three corresponding zones for dust: Zone 20, Zone 21 and Zone 22. Container Test The conduit shall be made wrench tight to prevent sparking when fault current flows through the conduit system and to ensure the explosionproof or flameproof integrity of the conduit system where applicable. Locations are thus classified by type and risk of release of gas, vapor, or dust. Offshore Living Quarter This concentration is substance specific and lies normally somewhere between the LEL and UEL. Various regulations use terms such as class, division, zone, and group to differentiate the various hazards. 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. 5: For further information on ventilation, see NFPA 30-2018, Informational Note No. No. October 2022 Sources Enclosures can be pressurized with clean air or inert gas, displacing any hazardous substance. Directly adjacent on the label one will find the mark of the listing agency. Pressurised Container Informational Note: For further information regarding classification and ventilation of areas involving closed-circuit ammonia refrigeration systems, see ANSI/IIAR 2-2014. So for an explosion there must be enough fuel. Not only are hazardous areas classified by Class (nature of the hazardous material,) and Division . Hazardous Area Classifications D103222X012 Product Bulletin 9.2:001 .
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