Therefor Hazardous Area Classification (HAC) is the first important step in achieving an explosion safe installation or work environment. It is always balancing between not defining such areas too large (with highly costs for prevention of ignition sources) or too small (unsafe situations). 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. If equipment is marked, for example, Ex e II T4 then it is suitable for all subgroups IIA, IIB and IIC. Class defines the general nature (or properties) of the hazardous material in the surrounding atmosphere. October 2021 Which Standards to use for Hazardous Area Classification. Example - Hazardous Area Classification A room with a propane gas installation will typically be classified with the Class/Division system as: Class I, Division 2, Group D Zone system as: Zone 2, Group IIA Zone 0 is an area in which an explosive atmosphere is present continuously for long periods of time or will frequently occur. 9: For additional information concerning the installation of, Informational Note No. Groups E, F, and G are for dusts and flyings (Class II or III). There are two sets of Zones: Zones 0 thru 2 are used for gases, vapors, and mists, and Zones 20 thru 22 are . One of the hazards of working with flammable substances is an explosion, mostly hand in hand with fire. Ex Zone. IEC 60079-10.1 Classification of areas - Explosive gas atmospheres. Area Classification. 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. Read more in our blogWhich Standards to use for Hazardous Area Classification. PROCESS OF CONTAINER Locations are thus classified by type and risk of release of gas, vapor, or dust. A60 . FEA [4], Flammability of combustible liquids are defined by their flash-point. Where pyrophoric materials are the only materials used or handled, these locations need not be classified. Intrinsic safety -- This protection technique is permitted for equipment in the Class I, Zone 0 or Zone 1 locations for which it is approved. 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). 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. . Examples are: In another blog we, will explain how to perform Hazardous Area Classification according to the Standard EN-IEC 60079-10-1. Methane has a LEL of 4,4 vol%. In an ordinary household this is of no concern, but if a flammable atmosphere is present, the arc might start an explosion. THE CURRENT STANDARD . 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. A differentiation is made between gas Ex zones and dust Ex zones: Gas Ex zones are 0/1/2 and dust Ex zones are 20/21/22. Not only are hazardous areas classified by Class (nature of the hazardous material,) and Division . taper per foot. 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. June 2020 Although OSHA does not provide a definition of group classifications in 29 CFR 1910.307 or 399 they do provide a note under 29 CFR 1910.307(c)(1) that states: NFPA 70, the National Electrical Code, lists or defines hazardous gases, vapors, and dusts by Groups characterized by their ignitable or combustible properties. To meet OSHAs marking requirement, the marking must include the hazardous group the equipment is approved to operate in. There are three zones for gas: Zone 0, Zone 1 and Zone 2. Area's are divided into zones. Substances characterization Consequences . 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. Equipment can be designed or modified for safe operation in hazardous locations. Atmospheres containing combustible flyings. TLS OFFSHORE CONTAINER The last condition for an explosion is the presence of an effective ignition source in the direct contact with the fuel/air mixture. AddThis use cookies for handling links to social media. July 2022 In some cases, the hazardous atmosphere is present all the time, or for long periods. Equipment should be tested to ensure that it does not exceed 80%[according to whom?] This level of risk is represented by classifying the hazardous area as Zone 0, Zone 1 or Zone 2 (for gas, vapour and mist atmospheres) or Zone 21 or Zone 22 for dust atmospheres. Ex s is a coding referenced in IEC 60079-0. National Electric Code 2020 edition National Fire Protection Association. Explosion protection must be ensured during normal operation. 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. NFPA 70 NEC establishes area classifications based on Classes, Divisions and Groups that when combined delineate the hazardous conditions of a specific area. >> NEC: Class II, Division 1, Group F. | IEC: Zone 20, Group IIC. 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. When the concentration of methane is beneath the LEL, an explosion cannot occur, even when an ignition source is present. Zone 0: flammable atmosphere highly likely to be present - may be present for long periods or even continuously . This has been replaced by a European numerical system, as set out in directive 1999/92/EU implemented in the UK as the Dangerous Substances and Explosives Atmospheres Regulations 2002. . A: No. 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. 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. It is an Americanized version of the International Electrochemical Commissions (IEC) Zone system which maintains the NEC wiring methods and protection techniques. 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. .14 . . Standards and regulations exist to identify such locations, classify the hazards, and design equipment for safe use in such locations. We don't collect information from our users. Offshore Accommodation Module Ex LIGHTER-THAN-AIR GASES & VAPOURS Vapour density of 0.75 is considered as the boundary between lighter and heavier gases / vapours as a safety measure HA of a leak source located in air Source of hazard 4.5 m. 8.0 m R 4.5 m H What Are All Those Gadgets On A Multitool? 2: For the requirements for electrical and electronic. 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. For example, in the US by the Occupational Safety and Health Administration. Informational Note: For further information regarding classification and ventilation of areas involving closed-circuit ammonia refrigeration systems, see ANSI/IIAR 2-2014. Various regulations use terms such as class, division, zone, and group to differentiate the various hazards. National Electrical Code (NEC) and the 1998 Canadian Electrical Code (CEC) now recognize the use of the Zone system for classification of hazardous areas. So for an explosion there must be enough fuel. [3], Different explosive atmospheres have chemical properties that affect the likelihood and severity of an explosion. 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 spark or high heat must also be present. Zones. Classification of Hazardous Areas 0 100 200 300 400 500 600 T1 >450C T2 >300C 450C T3 >200C 300C T4 >135C 200C . The following Equipment Groups and Categories are applicable: Equipment in this category is only intended for use in the underground areas of mines, as well as those areas of surface installations of such mines endangered by firedamp and/or combustible dusts. Division defines the probability of the hazardous material being present in an ignitable concentration in the surrounding atmosphere. API RP 505, Recommended Practice for Classification of Locations for Electrical Installations at Petroleum Facilities Classified as Class I, Zone 0, Zone 1, and Zone 2 (as incorporated by reference in 250.198). Zones 0, 1 and 2: Atmospheres with explosive gases and vapours (AS2380; AS/NZS/IEC 60079) Zone 0 Area The definition according to IEC60079-10-1 is "an area in which an explosive gas atmosphere is present continuously or for long periods or frequently". * Zone 1 a location in which explosive gas atmospheres are likely to occur during normal operation, or which is adjacent to a Zone 0 location. An area where combustible dusts or ignitable fibers and flyings are likely to occur under normal operating conditions. API 500/505 mostly for onshore and offshore oil and gas applications. eg Production Area, area surrounding zone 0. Area's are divided into zones. 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 Definition of hazardous area zones (AS/NZS 60079.10): Zone 0 In effect it is any method which can be shown to have the required degree of safety in use. This level of risk is represented by classifying the hazardous area as Zone 0, Zone 1 or Zone 2 (for gas, vapour and mist atmospheres) or Zone 21 or Zone 22 for dust atmospheres. D8.1.3 Hazardous areas are subdivided into Zones 0,1 or 2, the definitions of each cate-gory being as follows: Zone 0 an area in which an explosive gas-air mixture is continuously present or present for long periods. Sources
Category 3 equipment may only be used in zone 2 areas. Adapters shall be used for connection to conduit or NPT-threaded fittings. Zone 1 - Explosive atmospheres are likely to occur. The NEC Zone system was created to harmonize with IEC classification system, and therefore reduce the complexity of management. Recommendat ions. It may exist because of repair, maintenance operations, or leakage. These would be then labeled with each of the individual methods. Informational Note No. 15 4. Zone 1 (unless separated by a fire wall)P.G.Sreejith, Kerala. Wide known is that al electrical equipment within hazardous areas must be Ex certified for use in the appropriate hazardous area (zone or class/division). Equipment in this category is intended for use in areas in which explosive atmospheres caused by gases, vapours, mists or air/dust mixtures are likely to occur occasionally. Powder Filling "q" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. So it is quite obvious that explosions should be prevented as much as possible and still work has to be done to achieve this. . 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. 286 natural gas explosions per year in the U.S. causing substantial damage, severe injury or loss of lives. 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. Q: Can I use a piece of equipment approved for use in a Division 1 hazardous location in a Division 2 hazardous location? 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. Article 505 National Electrical Code (NEC), Article 506 National Electrical Code (NEC). Directly adjacent on the label one will find the mark of the listing agency. June 2022 Hazardous areas are classified into zones based on an assessment of the frequency of the occurrence and duration of an explosive gas atmosphere, as follows: Zone 0: An area in which an. 1910.307 - Hazardous (classified) locations. Group defines thetypeof hazardous material and partly thelocationof the surrounding atmosphere . (equivalent to NEC Class I, Groups A and B), (equivalent to NEC Class II, Groups F and G), Group IIC is the most severe zone system gas group. Independent test housesNotified Bodiesare established in most European countries, and a certificate from any of these will be accepted across the EU. July 2021 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. Specific types of protection being used will also be marked. A light switch may cause a small, harmless spark when switched on or off. Google use cookies for serving our ads and handling visitor statistics. No. Encapsulation "m" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. September 2021 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. Zone 0 Area The definition according to IEC60079-10-1 is "an area in which an explosive gas atmosphere is present continuously or for long periods or frequently". Explosion Hazardous Areas are divided into zones according to risk probabilities. Zone 0 is an area in which an explosive atmosphere is present continuously for long periods of time or will frequently occur. 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. Explosion-proofing designs equipment to contain ignition hazards, prevent entry of hazardous substances, and, contain any fire or explosion that could occur. July 2020 In the IEC standards hazardous areas are classified into zones based upon the frequency and duration of an explosive atmosphere. 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. | For Dust this would be Zone 21. The colour of the luminaire body indicates the level of protection. A Class I, Division 1 or Division 2 location may be reclassified as a Class I, Zone 0, Zone 1, or Zone 2 location only if all of the space that is classified because of a single flammable gas or vapor source is reclassified. 41 gas explosions per year occur within the UK and app. What is an Explosion Protection Document? This was accompanied by electrically-initiated explosions of flammable gas such as fire damp (methane) and suspended coal dust. For Zone 1 applications, Pyroban uses . September 2022 In many industrial, commercial, and scientific settings, the presence of such an atmosphere is a common, or at least commonly possible, occurrence. This process is called hazardous area classification. 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.
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