15 4. Equipment can be designed or modified for safe operation in hazardous locations. 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. No other aspect of safety receives more attention in the form of codes and standards. 1: For examples of area classification drawings, see ANSI/API RP 505-2018, Informational Note No. Hazardous Area Classification, Gas Vapours and Dust Groups, Temperature Class | Simple Science Simple Science 8.81K subscribers Join Subscribe 28K views 2 years ago This video explains. Equipment should be tested to ensure that it does not exceed 80%[according to whom?] June 2022 November 2021 29 CFR 1910.399 Definitions Applicable to Subpart S
NEC 2 Divisions (Div 1 2) Division I Comprising of Area Same as Zone 0 1. 10: For information on electrical resistance trace heating for hazardous (classified), Informational Note No. >> For Gas Vapor this would be Zone 1. A major safety concern in all workplaces is the occurrence of fires and explosions. 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. The groups also indicate how much energy is required to ignite the material by energy or thermal effects, with IIA requiring the most energy and IIC the least for zone system gas groups. Hazardous Area Classification (HAC) is as follows: Definitions of hazardous area are different as per IEC and NEC. 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. The Raytec SPARTAN range includes dedicated luminaires for both Zone 1 and Zone 2 areas as well as industrial applications. 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. | For Dust this would be Zone 22. 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. Comparison of Zone 2 and Division 2 TABLE 1 - AREA CLASSIFICATIONS Division 1: Where ignitable concentrations can exist all of the time or some . 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. With the advent of electric power, electricity was introduced into coal mines for signaling, illumination, and motors. International Electrotechnical Committee (IEC) Hazardous Area Classification. Temperature Control 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. Read more in our blogWhich Standards to use for Hazardous Area Classification. Laboratory Container 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 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. Flammable liquids with a high flash point are less hazardous than liquids Zone 1 is an area in which an explosive atmosphere is likely to occur occasionally in normal operation. Zone 0 - Explosive atmospheres present continuously long periods or frequently. 10/1/20 . This can be achieved by blanketing with nitrogen or carbondioxide. The choice of which standard to use for the hazardous area classification is something which is very important. Every substance has a differing combination of properties but it is found that they can be ranked into similar ranges, simplifying the selection of equipment for hazardous areas. Zone 0 describes an area in which a combustible gas will be present continuously while zone 20 describes an area in which combustible dust will be present continuously (the '2' in 'zone 20' indicates dust as opposed to gas). Zone 1 . I Flammable gases or vapors may be present, 1 Ignitable concentrations of hazards exist under normal operation conditions and/or where the hazard is caused by frequent maintenance or repair work or frequent equipment failure, E Combustible metal dusts: aluminum, commercial alloys and magnesium, III Easily ignitable fibers or flyings may be present, 0 Ignitable concentrations of flammable gases or vapors which are present continuously or for long periods of time, 1 Ignitable concentrations of flammable gases or vapors which are likely to occur under normal operating conditions; may exist frequently because of repair/maintenance operations or leakage; or equipment is operated in a manner that equipment breakdown/faulty operations could result in the release of ignitable concentrations of flammable gases or vapors and failure of the equipment, 2 Ignitable concentrations of flammable gases or vapors which are not likely to occur under normal operating conditions and if they do will only persist for a short period of time; or volatile flammable liquids, gases, or vapors are confined within closed containers/systems and can escape only as a result of an accidental rupture; or volatile flammable liquids, gases, or vapors are normally prevented by positive mechanical ventilation, but may become hazardous due to system failure, 20 Combustible dusts or ignitable fibers/flyings are present continuously or for long periods of time, 21 Combustible dusts or ignitable fibers/flyings are likely to occur under normal operating conditions; or may exist frequently because of repair/maintenance operations or leakage; or equipment is operated in a manner that breakdown/faulty operations could result in the release of ignitable concentrations of combustible dust or fibers/flyings and failure of the equipment, 22 Combustible dusts or ignitable fibers/flyings are likely to occur under normal operating conditions; or may exist frequently because of repair/maintenance operations or leakage; or equipment is operated in a manner that breakdown/faulty operations could result in the release of ignitable concentrations of combustible dust or fibers/flyings and failure of the equipment, Mines susceptible to firedamp (flammable mixture of gases naturally occurring in a mine, Explosive dusts Group III equipment is subdivided into three subgroups, A Atmospheres containing acetone, ammonia, ethyl alcohol, gasoline, methane, propane, or gases/vapors of equivalent hazard, A Atmospheres containing solid particles and fibers greater than 500 microns that could be suspended in air and settle out, B Atmospheres containing acetaldehyde, ethylene, or gases / vapors of equivalent hazard, B Atmospheres containing combustible dusts other than combustible metal dusts, C Atmospheres containing acetylene, hydrogen, or gases/vapors of equivalent hazard, C Atmospheres containing combustible metal dusts. Class I, Zone 0 = Area Classification, AEx = Symbol for equipment built to American specifications, ia = Type of protection designations, IIC = Gas classification group (as required), T6 = Temperature Classification, [46 FR 4056, Jan. 16, 1981; 46 FR 40185, Aug. 7, 1981; 72 FR 7210, Feb. 14, 2007], Occupational Safety & Health Administration. (Hazardous Area Classification) . This means that the electrical equipment is safe for use within these area by applying special protection strategies. Within the European Union, these are defined by IEC/EN standards (IEC/EN 60079-10-1 or 2) as directed by ATEX. Hazardous Area Classifications D103222X012 Product Bulletin 9.2:001 . In Europe the label must show the CE mark and the code number of the certifying/notified body). ethanol, methane or hydrogen. This blog post will focus on the different hazardous location classifications and well follow up with another that discusses how equipment can be constructed and certified for use in these environments. An explosion is a rapid expansion in volume associated with an extremely vigorous outward release of energy, usually with the generation of high temperatures and release of high-pressure gases (wikipedia (https://en.wikipedia.org/wiki/Explosion). . . So for an explosion there must be enough fuel. IECEx Karandikar Certification It may exist because of repair, maintenance operations, or leakage. October 2018 >> For Gas/Vapor this would be Zone 0. There are two systems in place, including the traditional North American Division system as well as the alternative Zone system. October 2022 These generally give rise to areas classied as Zones 0, 1, and 2 respectively. Ignition sources can be divided in 13 categories (acc. Comparisons between the two systems are not easily accomplished. The last requirement for the explosion is the presence of an ignition source, like a spark or hot surface. Equipment that is listed for a Zone 1 location may be installed in a Zone 2 location of the same gas or vapor. Group defines the type of the hazardous material in the surrounding atmosphere. 29 CFR 1910.307 Hazardous (classified) Locations
5mm -750C Electrical Resistivity. You can target the Engineering ToolBox by using AdWords Managed Placements. Group defines thetypeof hazardous material and partly thelocationof the surrounding atmosphere . 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: When comparing Divisions and Zones, Division 2 is equivalent to Zone 2, but Division 1 is equivalent to either Zone 0 or 1. Electrical equipment can and does cause fires and/or explosions in certain atmospheres. It is essential to know which zone you are working in, so that you can specify the most appropriate equipment. These are typically process areas where gases are more likely to be present. In general, all types of equipment installed within the hazardous area shall be . For specific industries, the specific codes for that industry are important to use. 2: Where gas detection, Informational Note No. The use of EPL and ATEX Category directly is an alternative for "s" marking. Specific types of protection being used will also be marked. >> NEC: Class II, Division 1, Group F. | IEC: Zone 20, Group IIC. September 2020 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. (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. Is intended for us in Zone 2 (gases) or Zone 22 (dusts). Hazardous areas are classified into zones based on an assessment of the frequency of the occurrence and duration of an explosive gas atmosphere, as shown in the illustration below. 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. | For Gas/Vapor this would be Zone 0. a headlamp, rather than a dedicated fixed luminaire. Zone type (0/1/2/ 20/21/ 22) Zone extent. Beside the Lower Explosion Limit, each substance also has an Upper Explosion Limit (UEL). Group II is for explosive gases (Zone 0, 1 and 2) and Group III is for explosive dusts (Zone 20, 21 and 22). 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. Informational Note No. Oil Immersion "o" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. February 2023 Zone 0 Zone 1 Zone 2 Fluid Occurrence of explosive atmosphere Gas mixtures Dust mixtures Not likely to occur or only for short period Zone 2 Zone 22 . .14 . It may exist because of repair, maintenance operations, or leakage. As to the classification, they are the same. 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. You will find these zones at the manifold of a tank truck or the interior of a silo. Equipment in this category is intended for use in Zone 0 areas (gases) or Zone 20 (dusts), and must ensure a very high level of protection (i.e. In this article we will look at what defines Zone 0, Zone 1 and Zone 2 hazardous area classifications and the considerations for specifying lighting into each area. 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. The design of the equipment must ensure protection, even in the event of rare incidents relating to the equipment. A: No. Area classification is not simply intended to identify hazardous areas on process plants where design has already been completed using only operational and economic factors as influence,. Table 1. Hazardous area classification is a rigorous method of determining where an explosive environment may be present. Classification of areas and selection of equipment and wiring methods shall be under the supervision of a qualified registered professional engineer. The equipment housing may be sealed to prevent entry of flammable gas or dust into the interior. Motors, lighting, junction boxes, electronic equipment, This method, being by definition special, has no specific rules. 1. Encapsulation "m" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. Other ignition sources can also be present, like static electricity. A: When comparing Divisions and Zones, Division 2 is equivalent to Zone 2, but Division 1 is equivalent to either Zone 0 or 1. Please read AddThis Privacy for more information. Zone 2. The escaping (hot) gases must sufficiently cool down along the escape path that by the time they reach the outside of the enclosure not to be a source of ignition of the outside, potentially ignitable surroundings. Terminology for both hazards and protective measures can vary. Reefer Container Have a think about it next time youre filling up! 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. However, at low ambient temperatures, flammable concentrations of vapors may not exist in a location classified Class I, Zone 0, 1, or 2 at normal ambient temperature. 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. Cookies are only used in the browser to improve user experience. 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. Offshore Workshop Container * Zone 2 a . Zones 1 or 2. The four steps involved in hazardous area classification are: Determine the type of hazard or "class" that might be presentcombustible gas (Class I), combustible dust (Class II), or fibers (Class III). Safe for the hazardous (classified) location. Atmospheres containing ethylene, propylene oxide, ethylene oxide, butadiene, cyclopropane, ethyl ether, or gases and vapors of equivalent hazard. Equipment used in hazardous area must comply to certain Ex standards. Independent test housesNotified Bodiesare established in most European countries, and a certificate from any of these will be accepted across the EU. The surface of a high pressure steam pipe may be above the autoignition temperature of some fuel-air mixtures. Zone 2: An area in which an explosive atmosphere is not likely to occur in normal operation, but if it does . It is an Americanized version of the International Electrochemical Commissions (IEC) Zone system which maintains the NEC wiring methods and protection techniques. 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. Equipment construction is such that it can withstand an internal explosion and provide relief of the external pressure via flamegap(s) such as the labyrinth created by threaded fittings or machined flanges. These ways of protection are specified in detail within several IEC standards (IEC 60079 series) for electrical equipment. Group is divided in three groups where Group I is reserved for mining locations. The overpressure is monitored, maintained and controlled. Container Standards 14 4. 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. Choose the right method for Hazardous Area Classification! Zone 1 (unless separated by a fire wall)P.G.Sreejith, Kerala. In the United States, the most commonly followed system is the NEC (National Electric Code), while the rest of the world generally follows the IEC (International Electrotechnical Commission). 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. Groups E, F, and G are for dusts and flyings (Class II or III). All threaded conduit shall be threaded with an NPT (National (American) Standard Pipe Taper) standard conduit cutting die that provides -in. 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. April 2022 Flour, wood/sawdust, plastic dust), IIC Conductive dusts (eg. Hazardous areas are defined as: " Zones " under worldwide IEC standards (and their local versions, such as ATEX in Europe) " Divisions " under North American NEC standards. Definition of hazardous area zones (AS/NZS 60079.10): Zone 0 For example the EI 15 and API 500/505 describe specific installations and several conditions for the oil and gas industry. 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". This was accompanied by electrically-initiated explosions of flammable gas such as fire damp (methane) and suspended coal dust. You will find this equipment in paint factories, a warehouse or around a bag dump station. Atmospheres containing acetylene, hydrogen, carbon disulphide or gases and vapors of equivalent hazard. August 2022 September 2019 Since this fuel can only combust in the presence of oxygen, enough oxygen must be available for the rapid combustion to take place. The plan may contain the list of chemicals with their group and temperature rating. 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. NEC has created an Americanized version of the IEC/CENELEC Zone system in a stand-alone article (Article 505). The Hazardous Area Classification presents in this guide is based on the following items as reference: API: API RP 505 Recommended Practice for Classification of Locations for Electrical. 1.1.1 This recommended practice applies to those locations where flammable gases or vapors, flammable liquids, or combustible liquids are processed or handled; and where their release into the atmosphere could result in their ignition by electrical systems or equipment. 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. 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. 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. A light switch may cause a small, harmless spark when switched on or off. Electronic equipment, including lighting, needs to be purpose designed for use in hazardous areas to prevent a spark occurring and igniting any flammable substances. . Much early equipment having Ex s protection was designed with encapsulation and this has now been incorporated into IEC 60079-18 [Ex m]. . Atmospheres containing propane, acetone, benzene, butane, methane, petrol, hexane, paint solvents or gases and vapors of equivalent hazard. Classification of Hazardous Areas 0 100 200 300 400 500 600 T1 >450C T2 >300C 450C T3 >200C 300C T4 >135C 200C . In recent years also the EPL is specified for several kinds of protection. Temporary Refuge Groups A, B, C, and D are for gases (Class I only). Which system is preferred depends on the users preference, how the areas are classified, and the wiring system used. 1910.307 (g) (2) Dn 1 - a Ce e . July 2019 Note to paragraph (g)(4) of this section: Low ambient conditions require special consideration. June 2019 Division II Comprising of Area Same as Zone 2. 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. The Zone system has wider use in the chemical and petrochemical industries. FREEZER As a guide for Zone 0, this can be defined as over 1000 hours/year or >10% of the time. Safety is ensured in the event of frequently occurring disturbances or equipment faults which normally have to be taken into account. area in which an explosive gas atmosphere is present continuously, or for long periods, or frequently (more than 10% of the time). - 1 2 (Class 1, . Many items of EEx rated equipment will employ more than one method of protection in different components of the apparatus. December 2020 If equipment has been approved for use in a Division 1 hazardous location, it can be used in a Division 2 hazardous location, providing it is in the same class and group. November 2019 In the US, the National Electrical Manufacturers Association (NEMA) defines standards for enclosure types for a variety of applications. There are two sets of Zones: Zones 0 thru 2 are used for gases, vapors, and mists, and Zones 20 thru 22 are . 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. Class I: hazardous because flammable gases or vapors are present in the air in quantities sufficient to produce explosive or ignitable mixtures: . HAZARDOUS VS. 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. 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. October 2020 Several protection strategies exist. gas, vapours, mists and dusts). An area where combustible dusts or ignitable fibers and flyings are likely to occur under normal operating conditions. Examples are: production facilities in the food industry, chemical plants, oil & gas, and the pharmaceutical industry etc. Get more great content like this sent to your inbox. February 2022 . the inside of tank truck or the interior of a dust filter). A high level of protection is ensured. 1: As a guide in determining when flammable gases or vapors are present continuously or for long periods of time, refer to ANSI/API RP 505-2018, Informational Note No. Q: Are Divisions and Zones equivalent to one another? hazardous areas as the following: An area where a potential hazard (e.g., a fire, an explosion, etc.) Workshop Container, Intelligent pressurised container | MUD logging cabin, Battery energy storage system (BESS) container, Laboratory container | workshop container | Equipment containers, Temporary refuge shelter | Toxic gas refuge | Safe haven, Offshore accommodation cabin | office container, Reefer container | Refrigerated container, Intelligent waste water treatment container, IDENTIFYING ZONE 0, ZONE 1, AND ZONE 2 HAZARDOUS AREAS, Temporary refuge (TR) shelter, toxic gas refuge (TGR), Containerised waste water treatment plant. Horizontal. Note to paragraph (c)(3) 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 requirement. Class II, Div 2 Class III, Div 1 nR 3G Zone 2 Gc Class III, Div 2 Pressurised Room px 60079-13 2G Zone 1 Gb Zone 21 Db 2D Pressurised Room FM3611 NFPA 496 Class I, Div 1 Class I, Div 2 Class II, Div 1 Class II, Div 2 py 2G Zone 1 Gb pz 3G Zone 2 Gc Zone 22 Dc 3D pv Non-hazardous Gb/GC Optical Radiation op sh 60079-28 1G Zone 0 Ga Zone 20 Da 1D . Marking "EEx d" in Accordance with EN 50 0 14 and 50 018 . This is exactly defined as the limiting concentration of oxygen below which combustion is not possible, independent of the concentration of fuel.
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