Equipment used in hazardous area must comply to certain Ex standards. Youre phone isnt rated for use in hazardous areas. It is an Americanized version of the International Electrochemical Commissions (IEC) Zone system which maintains the NEC wiring methods and protection techniques. The temperature classification on the electrical equipment label will be one of the following (in degree Celsius): The above table shows that the surface temperature of a piece of electrical equipment with a temperature classification of T3 will not rise above 200C. Zone 2: An area in which an explosive atmosphere is not likely to occur in normal operation, but if it does . Groups A, B, C, and D are for gases (Class I only). Division defines the probability of the hazardous material being present in an ignitable concentration in the surrounding atmosphere. [3], Different explosive atmospheres have chemical properties that affect the likelihood and severity of an explosion. Hazardous Area Classification (HAC) is as follows: Definitions of hazardous area are different as per IEC and NEC. Equipment that is safe for the location shall be of a type and design that the employer demonstrates will provide protection from the hazards arising from the combustibility and flammability of vapors, liquids, gases, dusts, or fibers involved. Atmospheres containing ethylene, propylene oxide, ethylene oxide, butadiene, cyclopropane, ethyl ether, or gases and vapors of equivalent hazard. [1] NEC article 500 describes the NEC Division classification system, while articles 505 and 506 describe the NEC Zone classification system. In the US, the National Electrical Manufacturers Association (NEMA) defines standards for enclosure types for a variety of applications. Class I: hazardous because flammable gases or vapors are present in the air in quantities sufficient to produce explosive or ignitable mixtures: . . >> For Gas/Vapor this would be Zone 2. 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. You will find this equipment in paint factories, a warehouse or around a bag dump station. Class 1/Div 2 ATEX Zone 2 Computers. | For Dust this would be Zone 22. 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 We will go deeper into ignition assessments in another blog. The a subdivisions have the most stringent safety requirements, taking into account more than one independent component faults simultaneously. We don't collect information from our users. Zone 22 Zone 21 Zone20 A hazardous atmosphere formed by dust cloud in air is not likely to occur in . 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. 29 CFR 1910.307 Hazardous (classified) Locations The last requirement for the explosion is the presence of an ignition source, like a spark or hot surface. Division defines the likelihood of the hazardous material being present in an explosive or ignitable concentration.Class I flammable gases and vapors are grouped into one of four groups(Groups A, B, C or D)based on their physical properties and the ease in which they can be ignited. 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. . 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. of When equipment must be placed in a hazardous location, it can be designed to reduce the risk of fire or explosion. August 2020 So the following conditions must be met for an explosion to occur: Represented by the following explosion triangle. Sources of It may exist because of repair, maintenance operations, or leakage. Atmospheres containing combustible flyings. Entire Vapour space of storage tank. 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. Protecting against fire and explosion is of interest for both personnel safety as well as reliability reasons. ". Drop Test 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. The zone classification for gases is divided into three zones, namely Zone 0, Zone 1 and Zone 2 and for dusts Zone 20, Zone 21 and Zone 22. National Electrical Code, NFPA 70, Chapter 5, Article 500, 29 CFR 1910 Subpart S, Electrical 1910.307, NFPA 497, "Classification of Gases, Vapors, and Dusts for Electrical Equipment in Hazardous Classified Locations", NFPA Handbook, "Electrical Installations in Hazardous Locations, " by P. J. Schram and M. W. Earley, NFPA 70E, Chapter 5, "Hazardous (Classified) Locations", ANSI/UL 913, "Intrinsically Safe Apparatus", NFPA 496, "Purged and Pressurized Enclosure for Electrical Equipment in Hazardous Locations. The prevention of explosions in working environments is in most countries regulated in national laws and directives. September 2018 Where there is potential for an explosive atmosphere, special precautions are needed to prevent fires and explosions. Atmospheres containing acetylene, hydrogen, carbon disulphide or gases and vapors of equivalent hazard. Division 2 is equivalent to Zone 2, while Division 1 is either Zone 0 or 1. The key difference between Divisions and Zones relate to terminations. Type of protection "n" -- This protection technique is permitted for equipment in the Class I, Zone 2 locations for which it is approved. (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. The definition of the hazardous area zones represent the likelihood of hazardous gas, dust or other hazards being present in a working area. November 2021 And there are three corresponding zones for dust: Zone 20, Zone 21 and Zone 22. WHEN YOU NEED THEM. 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 . . 9: For additional information concerning the installation of, Informational Note No. Zones. That flammable gas or vapor . National Electric Code 2020 edition National Fire Protection Association. In Europe the ATEX 114 Directive (2014/34/EU) is applicable to equipment that is used in hazardous area's. August 2022 Area which are not devided into Atex zones, are called non-hazardous area's. Class / Division System In Northerm America, instead of the zone classification system, the Class/Division system is used. Equipment is pressurised to a positive pressure relative to the surrounding atmosphere with air or an inert gas, thus the surrounding ignitable atmosphere can not come in contact with energized parts of the apparatus. Click on the zone to learn more about the classification according to IEC 60079-10 standards. 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. 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 . A major safety concern in all workplaces is the occurrence of fires and explosions. Zone 1 2. The Class/Division/Group system is based on Article 500 of the National Electrical Code (NEC) where. - 1 2 (Class 1, . Flour, wood/sawdust, plastic dust). NFPA 70 NEC establishes area classifications based on Classes, Divisions and Groups that when combined delineate the hazardous conditions of a specific area. These areas are classified solely for the purpose of ensuring the safe and proper specification and installation of electrical/electronic equipment. Conversely if the same material is heated and handled above its flash-point, the area must be classified for proper electrical system design, as it will then form an ignitable mixture.[5]. No long-term contract. The flash point determines if an area needs to be classified. 6: For further information on electrical systems for hazardous (classified), Informational Note No. Electrical equipment installed in such locations can provide an ignition source, due to electrical arcing, or high temperatures. 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. There are three necessary components for an explosion to occur; This needs to be present in a relatively high quantity to produce an explosive mixture (e.g. For gases, vapours and mists the zone classifications are recognised as Zone 0, Zone 1 and Zone 2 areas. January 2022 Informational Note No. Offshore Accommodation Module A light switch may cause a small, harmless spark when switched on or off. Zone 2 - Explosive atmospheres are unlikely to occur or present only infrequently and for a short period only. These ways of protection are specified in detail within several IEC standards (IEC 60079 series) for electrical equipment. Container Test SPARTANs Zone 1 part code begins SPX, Zone 2 SPZ and industrial products having a SPI prefix. 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. Magnesium, Aluminum, Titanium etc. The overpressure is monitored, maintained and controlled. Determined to be none of the above. 1994-2020, W.W. Grainger, Inc. All Rights Reserved. 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. Methane has a UEL of 17 vol%, which means when the concentration of methane in air is above the 17 vol% an explosion cannot occur even when an ignition source is present. 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. The American Petroleum Institute publishes analogous standards in RP500 andRP505. [12], International Electrotechnical Commission, Occupational Safety and Health Administration, National Electrical Manufacturers Association, "Hazardous Area Classification and Control of Ignition Sources", "Hazardous (Classified) Locations NEC Articles 500 through 517", https://en.wikipedia.org/w/index.php?title=Electrical_equipment_in_hazardous_areas&oldid=1134828101, ignitable concentrations of combustible dust can exist, under normal conditions, ignitable concentrations of combustible dust are unlikely to exist normally, ignitable fibers, or materials producing combustible flyings, are handled, manufactured or used, easily ignitable fibers are stored or handled. Areas with possible fire or explosion risks due to explosive atmospheres and/or mixtures - are called hazardous (or classified) locations or areas. In Europe and the rest of the world - but also more and more in North America - the Zone system is used. The relation between that system and de zone classification system is clarified within the following table (only for gases and liquids are displayed, not for dusts and fibers). How to perform Hazardous Area Classification? An oversimplification of this example is shown in Table 1. 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 >> NEC: Class I, Division 2, Group D. | IEC: Zone 2, Group II. Beside sufficient fuel, also sufficient oxygen is needed for combustion of the mixture. NFPA 70, the National Electrical Code (NEC), defines area classification and installation principles. 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. . For methane this is shown in the following figure. 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. 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). .14 . Zone 1 (unless separated by a fire wall)P.G.Sreejith, Kerala. In Northerm America, instead of the zone classification system, the Class/Division system is used. No. In Europe the label must show the CE mark and the code number of the certifying/notified body). 1.1.2 This recommended practice provides information on specific flammable gases and vapors, flammable liquids . The colour of the luminaire body indicates the level of protection. This page was last edited on 20 January 2023, at 22:32. Definition of hazardous area zones (AS/NZS 60079.10): Zone 0 Since this fuel can only combust in the presence of oxygen, enough oxygen must be available for the rapid combustion to take place. Class II combustible dusts are grouped into one of three (3) groups: E combustible metal dusts, F combustible carbonaceous dusts or G other combustible dusts. For dusts: Zone 20, Zone 21 and Zone 22. . So it is quite obvious that explosions should be prevented as much as possible and still work has to be done to achieve this. 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). Magnesium, Titanium), IIB Nonconductive dusts (eg. March 2021 A Zone 0 location is a location in which one of the following . Explosion Hazardous Areas are divided into zones according to risk probabilities. Not only are hazardous areas classified by Class (nature of the hazardous material,) and Division . Typical gas hazards are from hydrocarbon compounds, but hydrogen and ammonia are also common industrial gases that are flammable. So for an explosion there must be enough fuel. Atmospheres containing non-conductive dust. Guidance on assessment of hazards is given in NFPA497 (explosive gas) and NFPA499 (dust). 41 gas explosions per year occur within the UK and app. Flammable atmosphere expected to be present inside the storage tank continuously, hence it has been classified as zone 0. For non-ambient conditions, like process reactors or other enclosed systems, the Limiting Oxygen Concentration is often used for the prevention of explosive atmospheres within those enclosed 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: Refrigerated Container What is an Explosion Protection Document? Zone 0 (hazardous area) An area in which an explosive gas-air mixture is continuously present or present for long periods. 15 4. Zone 2 is a place in which an explosive atmosphere is not likely to occur in normal operation but, if it does occur, will persist for a short period only. 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). When the concentration of gas or vapor is above the UEL the gas mixture is too rich to burn. 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. The codes and standards used in this process provide guidance for selecting,. Other ignition sources can also be present, like static electricity. The most standards and codes of practise for Hazardous Area Classification describe typical installations and work environments and their hazardous areas. Zone 0/20: An area in which an explosive atmosphere is present continuously or for long periods or frequently. 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. There are two systems in place, including the traditional North American Division system as well as the alternative Zone system. 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. Flour, wood/sawdust, plastic dust), IIC Conductive dusts (eg. 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. Zone 0 is an area in which an explosive atmosphere is present continuously for long periods of time or will frequently occur. Australia and New Zealand use the same IEC-60079 standards (adopted as AS/NZS60079), however the CE mark is not required. NFPA 70 NEC Articles 500 through 503 cover the requirements for electrical/electronic equipment and wiring for all voltages in Class I, Divisions 1 and 2; Class II, Divisions 1 and 2; and Class III, Divisions 1 and 2 locations. Please read AddThis Privacy for more information. May 2019 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. For Zone 1 applications, Pyroban uses . Ways to ensure this level of safety are non-arcing design and limitation of the temperature of the equipment. Independent test housesNotified Bodiesare established in most European countries, and a certificate from any of these will be accepted across the EU. Iso Container Please read Google Privacy & Terms for more information about how you can control adserving and the information collected. Classification of areas and selection of equipment and wiring methods shall be under the supervision of a qualified registered professional engineer. Where pyrophoric materials are the only materials used or handled, these locations need not be classified. 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. Exception No. The following content is only related to flammable substances and not to pyrotechnic substances or other instable substances, among those who can decompose. The more hazardous the area to more safety measures have to be taken in order to prevent equipment becoming an effective source of ignition. Flameproof "d" - This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. taper per foot. 1: The term "Class I" was originally included as a prefix to, Informational Note No. The NEMA enclosure rating or IP code may also be indicated, but it is usually independent of the Classified Area suitability. These generally give rise to areas classied as Zones 0, 1, and 2 respectively. Powder Filling "q" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. . Table 1. 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. WATER TIGHTNESS May 2022 NEGATIVE PRESSURE Many people have heard terms like Class I, Division 2, Group E, or ATEX zone 21 but many of our customers only know what certification they require with little understanding of what they mean, so we thought it would be appropriate to write a blog post to help customers understand the broader implications of these terms. RP 505 is referred to as the zone system. It is essential to know which zone you are working in, so that you can specify the most appropriate equipment. The last condition for an explosion is the presence of an effective ignition source in the direct contact with the fuel/air mixture. 3: For further information on the classification of, Informational Note No. Zone 1: An area in which an explosive atmosphere is likely to occur in normal operation. A: When comparing Divisions and Zones, Division 2 is equivalent to Zone 2, but Division 1 is equivalent to either Zone 0 or 1. Within a working area or installation an ignition can be created by many factors. Hazardous area classification is a rigorous method of determining where an explosive environment may be present. If you require more information on the different variants in the SPARTAN range, or you would like to discuss your application in more detail, you can call us on +44 (0) 1670 520055 or send an email to sales@raytecled.comwhere we will happily answer any questions you have.
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