9: For additional information concerning the installation of, Informational Note No. Identifying Zone 0, Zone 1, and Zone 2 Hazardous Areas. These areas are in North America (United States and Canada) historically classified with the Class/Division system. 1) MESG (Maximum Experimental Safe Gap) - The maximum clearance between two parallel metal surfaces that has been found under specified test conditions to prevent an explosion in a test chamber from being propagated to a secondary chamber containing the same gas or vapor at the same concentration. 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. When comparing Divisions and Zones, Division 2 is equivalent to Zone 2, but Division 1 is equivalent to either Zone 0 or 1. To prevent explosions from happening in harsh environments whereby flammable gases or combustible dusts are present directives and guidelines are put in place to protect both the public, workforce, and environment. 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 . a headlamp, rather than a dedicated fixed luminaire. 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 Refrigerated Type of protection "n" -- This protection technique is permitted for equipment in the Class I, Zone 2 locations for which it is approved. Informational Note No. CUTTING SKIPS Areas with possible fire or explosion risks due to explosive atmospheres and/or mixtures - are called hazardous (or classified) locations or areas. 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. The NEMA enclosure rating or IP code may also be indicated, but it is usually independent of the Classified Area suitability. A60 In the United States, the NEC uses 2 different classifications: Zone 1 is an area in which an explosive atmosphere is likely to occur occasionally in normal operation. POSITIVE PRESSURE 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. Since the changes to the code, hazardous locations with gases or vapors (Class I) present can be reclassified as Zone 0, 1 or 2. Atmosphere containing carbonaceous dusts, Atmosphere containing combustible dust not included in Group E & F - such as. Class I: hazardous because flammable gases or vapors are present in the air in quantities sufficient to produce explosive or ignitable mixtures: . THE PRODUCTS YOU NEED, Equipment provided with threaded entries for field wiring connection shall be installed in accordance with paragraph (g)(2)(iv)(A) or (g)(2)(iv)(B) of this section. Several protection strategies exist. But beside electrical equipment also mechanical equipment must be Ex certified, e.g. 4: For further information on protection against static electricity and lightning hazards in hazardous (classified). 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. . But when we take a closer look at the graph and table, we can conclude that any explosion, can easily lead to severe damage. Informational Note: For further information regarding classification and ventilation of areas involving closed-circuit ammonia refrigeration systems, see ANSI/IIAR 2-2014. August 2022 This concentration is substance specific and lies normally somewhere between the LEL and UEL. 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. MCC Shelter The disadvantage of standards with example installations, is that a huge safety factor is incorporated and thus relative large hazardous area are defined. The a subdivisions have the most stringent safety requirements, taking into account more than one independent component faults simultaneously. This is an important factor in the classification of hazardous areas. . CLASSIFIED LOCATIONS: AREA CLASSIFICATION: AREA CLASSES: AREA GROUPS: LOCATION AS PER DIVISIONS: DIVISION 1 - Class I, Division 1 hazardous locations are defined (as per NEC code Article 500) as follows: DIVISION 2 - Class I Division 2 Locations are as follows: Area Classification by ZONES: DEFINITIONS: HAZARDOUS LOCATIONS: IEC 60079-10-1 covers classification of explosive gas atmospheres, and IEC 60079-10-2 explosive dust. What are 'Dark Factories,' and Do They Really Exist? . In instances of areas within the same facility classified separately, Class I, Zone 2 locations may abut, but not overlap, Class I, Division 2 locations. Informational Note No. And safety must be guaranteed in the case of two faults occurring independently of each other. May 2021 No hidden fees. The inductance of the signal bell coils, combined with breaking of contacts by exposed metal surfaces, resulted in sparks, causing an explosion. Industrial electrical equipment for hazardous area has to conform to appropriate parts of standard: IEC-60079 for gas hazards, and IEC-61241 for dust hazards. 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] The hazardous area classification system determines required protection techniques and methods for electrical installations in the location. Flammable atmosphere expected to be present inside the storage tank continuously, hence it has been classified as zone 0. The key difference between Divisions and Zones relate to terminations. The Zone Classification System is offered as an alternative to the Class and Division system. These hazardous (classified) locations are assigned the following designations: For definitions of these locations, see 1910.399. .14 . Ex Zone. It is obvious to use those standards within these industries. 1: Normal operation is considered the situation when plant, Informational Note No. Quick Tips #124.1. This page was last edited on 20 January 2023, at 22:32. Each chemical gas or vapour used in industry is classified into a gas group. Zone 0 (hazardous area) An area in which an explosive gas-air mixture is continuously present or present for long periods. >> For Gas/Vapor this would be Zone 2. . When the concentration of gas or vapor is above the UEL the gas mixture is too rich to burn. [1] NEC article 500 describes the NEC Division classification system, while articles 505 and 506 describe the NEC Zone classification system. IECEx Karandikar Certification There are two sets of Zones: Zones 0 thru 2 are used for gases, vapors, and mists, and Zones 20 thru 22 are . Equipment used in hazardous area must comply to certain Ex standards. This value of this LOC differs per substance and depends also on the inert gas for achieving a low oxygen concentration. A spark or high heat must also be present. 1910.307 - Hazardous (classified) locations. 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. 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. 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. This equipment is intended for use in Zone 1 (gases) or Zone 21 (dusts). . Equipment approved for use in Class I hazardous locations cannot be used in Class II hazardous locations. There are several ways of how to perform hazardous area classification, all described in several standards or codes of practise. 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. AddThis use cookies for handling links to social media. There are three zones for gas: Zone 0, Zone 1 and Zone 2. In order to understand hazardous area classification it is important to understand which factors contribute to the occurrence of an explosion. Hazardous area classification is a rigorous method of determining where an explosive environment may be present. Q: Are Divisions and Zones equivalent to one another? Equipment shall be marked in accordance with paragraph (g)(5)(ii)(A) and (g)(5)(ii)(B) of this section, except as provided in (g)(5)(ii)(C). Division defines the probability of the hazardous material being present in an ignitable concentration in the surrounding atmosphere. FEA Some manufacturers claim "suitability" or "built-to" hazardous areas in their technical literature, but in effect lack the testing agency's certification and thus unacceptable for the AHJ (Authority Having Jurisdiction) to permit operation of the electrical installation/system. Ex s is a coding referenced in IEC 60079-0. Terminology for both hazards and protective measures can vary. Sources of such hazards include gases, vapors, dust, fibers, and flyings, which are combustible or flammable. February 2021 In Europe the label must show the CE mark and the code number of the certifying/notified body). September 2022 class correct, Motors, lighting, junction boxes, electronics, Equipment is very robust and components are made to a high quality, Equipment components are completely submerged in oil, Equipment components are completely covered with a layer of sand, powder or quartz, Equipment components of the equipment are usually encased in a resin type material. according to ISO standard 80079 series. Non-hazardous or ordinary locations. It is always balancing between not defining such areas too large (with highly costs for prevention of ignition sources) or too small (unsafe situations). In the IEC standards hazardous areas are classified into zones based upon the frequency and duration of an explosive atmosphere.
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