Note to paragraph (g)(4) of this section: Low ambient conditions require special consideration. Zones also have the added benefit of including the area classification with the zone description. - Zone 0: An area where an explosive gas-air mixture is continuously present or present for long time (continuous hazard, whose estimated duration is higher than 1000 hours/year) - Zone 1: An area where an explosive gas-air mixture is likely to occur during normal . 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. Choose the right method for Hazardous Area Classification! In the US, the National Electrical Manufacturers Association (NEMA) defines standards for enclosure types for a variety of applications. 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. The a subdivisions have the most stringent safety requirements, taking into account more than one independent component faults simultaneously. And there are three corresponding zones for dust: Zone 20, Zone 21 and Zone 22. Zone 2 - Explosive atmospheres are unlikely to occur or present only infrequently and for a short period only. [4], Flammability of combustible liquids are defined by their flash-point. 2: For the requirements for electrical and electronic. September 2022 Then, the level of risk of an explosion is based on the frequency and duration of the occurrence of an explosive atmosphere. 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. At least two British mine explosions were attributed to an electric bell signal system. 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. 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. 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. Atmospheres containing non-conductive dust. The housing may be strong enough to contain and cool any combustion gases produced internally. In general, all types of equipment installed within the hazardous area shall be . These areas are classified solely for the purpose of ensuring the safe and proper specification and installation of electrical/electronic equipment. THE PRODUCTS YOU NEED, Flammable liquids with a high flash point are less hazardous than liquids Oxygen is required in high quantities and in combination with the flammable substance to produce an explosive atmosphere. September 2018 It is obvious to use those standards within these industries. 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. The Regulations define 3 zones that can exist within a hazardous area: Zone 0 - A place in which an explosive atmosphere is present continuously or for long periods. 10: For information on electrical resistance trace heating for hazardous (classified), Informational Note No. NEC 2 Divisions (Div 1 2) Division I Comprising of Area Same as Zone 0 1. What is an Explosion Protection Document? Hazardous locations can also be described as those locations where electrical equipment Hazardous Area Classifications D103222X012 Product Bulletin 9.2:001 September 2019. 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]. 41 gas explosions per year occur within the UK and app. Explosions can cause significant damage along with severe injury or worse loss of life. Many items of EEx rated equipment will employ more than one method of protection in different components of the apparatus. This temperature is used for classification for industry and technology applications.[6]. It may exist because of repair, maintenance operations, or leakage. *unless risk assessment states a higher or lower category is required. If you want to promote your products or services in the Engineering ToolBox - please use Google Adwords. 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. 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. The more hazardous the area to more safety measures have to be taken in order to prevent equipment becoming an effective source of ignition. NEC has created an Americanized version of the IEC/CENELEC Zone system in a stand-alone article (Article 505). area in which an explosive gas atmosphere is likely to occur occasionally in normal operation. For specific industries, the specific codes for that industry are important to use. Zone defines thegeneral nature if it is a gas or dust and theprobabilityof hazardous material being present in an ignitable concentration in the surrounding atmosphere. Such areas include a residence or office where the only risk of a release of explosive or flammable gas would be such things as the propellant in an aerosol spray. >> For Gas/Vapor this would be Zone 0. Determining the Class, Division and Group or Zone and Group is critical to correctly applying the requirements for a given hazardous location. ethanol, methane or hydrogen. These areas are in North America (United States and Canada) historically classified with the Class/Division system. In some cases, it must be certified as meeting that standard. The Class/Division/Group system is based on Article 500 of the National Electrical Code (NEC) where. International Electrotechnical Committee (IEC) Hazardous Area Classification. When equipment must be placed in a hazardous location, it can be designed to reduce the risk of fire or explosion. 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. As to the classification, they are the same. Drop Test . Sources of An old British standard used letters to designate zones. Where there is potential for an explosive atmosphere, special precautions are needed to prevent fires and explosions. SIGN UP FOR EMAILGet more great content in your inbox. Accommodation Cabin Hazardous Area Classification (HAC) is as follows: Definitions of hazardous area are different as per IEC and NEC. Offshore Living Quarter Examples are: production facilities in the food industry, chemical plants, oil & gas, and the pharmaceutical industry etc. 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. June 2022 WATER TIGHTNESS January 2023 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). Not only are hazardous areas classified by Class (nature of the hazardous material,) and Division . Group is divided in three groups where Group I is reserved for mining locations. Hazardous area classification. Definition of hazardous area zones (AS/NZS 60079.10): Zone 0 Class I Zone 2 Hazardous Areas. Zone 1 is an area in which an explosive atmosphere is likely to occur occasionally in normal operation. August 2018 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. These generally give rise to areas classied as Zones 0, 1, and 2 respectively. All threaded conduit shall be threaded with an NPT (National (American) Standard Pipe Taper) standard conduit cutting die that provides -in. Reefer Container The NEC Zone system was created to harmonize with IEC classification system, and therefore reduce the complexity of management. 6: For further information on electrical systems for hazardous (classified), Informational Note No. 29 CFR 1910.307 Hazardous (classified) Locations Q: Can I use a piece of equipment approved for use in a Division 1 hazardous location in a Division 2 hazardous location? The Raytec SPARTAN range includes dedicated luminaires for both Zone 1 and Zone 2 areas as well as industrial applications. The types of protection are subdivided into several sub classes, linked to EPL: ma and mb, px, py and pz, ia, ib and ic. 4: For further information on protection against static electricity and lightning hazards in hazardous (classified). Group II is for explosive gases (Zone 0, 1 and 2) and Group III is for explosive dusts (Zone 20, 21 and 22). The two general approaches are: Several techniques of flame-proofing exist, and they are often used in combination: Equipment has flameproof gaps (max 0.006" (150m) propane/ethylene, 0.004" (100m) acetylene/hydrogen), Equipment can be installed in ANY housing provided to IP54.A 'Zener Barrier', opto-isolator or galvanic unit may be used to assist with certification. Q: Are Divisions and Zones equivalent to one another? 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. 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. December 2013, All The overpressure is monitored, maintained and controlled. The Zone system is based on Article 505/506 of the National Electrical Code (NEC) and follows the international method of area classification as developed by the International Electrotechnical Commission (IEC). But when we take a closer look at the graph and table, we can conclude that any explosion, can easily lead to severe damage. 7: For further information on application of electrical, Informational Note No. These areas only become hazardous in case of an accident or some unusual operating condition. A Zone 1 hazardous area is classified as a place in which an explosive atmosphere consisting of a mixture with air or flammable substances in the form of gas, vapour or mist is likely to occur in normal operation occasionally. Hazards in this group gas can be ignited very easily indeed. gas, vapours, mists and dusts). Vertical. 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. Flour, wood/sawdust, plastic dust), IIC Conductive dusts (eg. The Zone system has wider use in the chemical and petrochemical industries. Zone 0 is reserved for those areas continuously hazardous (e.g., inside a vented fuel tank), so other Division 1 areas would be classified as Zone 1. Within the European Union, these are defined by IEC/EN standards (IEC/EN 60079-10-1 or 2) as directed by ATEX. This equipment is intended for use in Zone 1 (gases) or Zone 21 (dusts). 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. lk) are places where fire or explosion hazards may exist. When working in or specifying equipment for use in hazardous environments, we see a lot of confusion in the industry regarding the different certifications and requirements. An area where combustible dusts or ignitable fibers and flyings are present continuously or for long periods of time. This page was last edited on 20 January 2023, at 22:32. April 2022 Group defines the type of the hazardous material in the surrounding atmosphere. Electrical equipment installed in such locations can provide an ignition source, due to electrical arcing, or high temperatures. In 29 CFR 1910.307(c)(2)(ii), OSHA requires all equipment used in a hazardous location to be marked with the class, group and operating temperature or temperature range for which it is approved. The minimum concentration of oxygen, necessary for the combustion to take place, is called the Limiting Oxygen Concentration. This is exactly defined as the limiting concentration of oxygen below which combustion is not possible, independent of the concentration of fuel. In other cases, the atmosphere is normally non-hazardous, but a dangerous concentration can be reasonably foreseensuch as operator error or equipment failure. July 2019 Flameproof "d" - This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. Encapsulation "m" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. With the advent of electric power, electricity was introduced into coal mines for signaling, illumination, and motors. Zone 2 hazardous areas are typically storage areas but can also be process areas. POSITIVE PRESSURE Group II is for explosive gases (Zone 0, 1 and 2) and Group III is for explosive dusts (Zone 20, 21 and 22). The CE mark is complemented with the Ex mark: A yellow-filled hexagon with the Greek letters (epsilon chi), followed by the Group, Category, and, if Group II, G or D (gas or dust). Readers with specific questions should refer to the applicable standards or consult with an attorney. 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. Beside sufficient fuel, also sufficient oxygen is needed for combustion of the mixture. Zone 0 (hazardous area) An area in which an explosive gas-air mixture is continuously present or present for long periods. Often an area classification plan view is provided to identify equipment ratings and installation techniques to be used for each classified area. October 2018 A light switch may cause a small, harmless spark when switched on or off. October 2019 The American Petroleum Institute publishes analogous standards in RP500 andRP505. One of the hazards of working with flammable substances is an explosion, mostly hand in hand with fire. 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. We will go deeper into ignition assessments in another blog. November 2019 So for an explosion there must be enough fuel. Division II Comprising of Area Same as Zone 2. SEWAGE TREATMENT Iso Container For example, a Class 1, Div 1 area where Group A may be present would be defined as an area where flammable gases or vapors may be present under normal operating conditions. February 2023 The design of the equipment must ensure protection, even in the event of rare incidents relating to the equipment. 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. In the United Kingdom, Sira and Baseefa are the most well known such bodies. Explosion protection must be ensured during normal operation. NFPA 70 NEC establishes area classifications based on Classes, Divisions and Groups that when combined delineate the hazardous conditions of a specific area. 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 . a headlamp, rather than a dedicated fixed luminaire. 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 November 2020 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 Hazardous Environment Classifications: NEC vs IEC, IEC (International Electrotechnical Commission), Group E Metal dusts (eg. Table 1. 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. Intrinsic safety -- This protection technique is permitted for equipment in the Class I, Zone 0 or Zone 1 locations for which it is approved. 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. Examples are: In another blog we, will explain how to perform Hazardous Area Classification according to the Standard EN-IEC 60079-10-1. What are 'Dark Factories,' and Do They Really Exist? Zones compares to classes and divisions in the Class/Division system. This was accompanied by electrically-initiated explosions of flammable gas such as fire damp (methane) and suspended coal dust. Dn 2 - a Ce d e r . Australia and New Zealand use the same IEC-60079 standards (adopted as AS/NZS60079), however the CE mark is not required. NFPA 70 NEC Classes, Divisions and Groups. These generally give rise to areas classied as Zones 0, 1, and 2 respectively. 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." Equipment can be designed or modified for safe operation in hazardous locations. NEGATIVE PRESSURE Flour, wood/sawdust, plastic dust). | For Dust this would be Zone 22. 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). 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. For example, within the U.K. in the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR) and in the U.S. in the Occupational Safety and Health Act of 1970 (OSHA). 10/1/20 Copryright 2023 Springer Controls Company . . Zone 0, 1 2 . 2: This classification includes, Informational Note No. For methane this is shown in the following figure. Dry Container Is intended for us in Zone 2 (gases) or Zone 22 (dusts). However, the following provisions modify this marking requirement for specific equipment: Fixed lighting fixtures marked for use in Class I, Division 2 or Class II, Division 2 locations only need not be marked to indicate the group; Fixed general-purpose equipment in Class I locations, other than lighting fixtures, that is acceptable for use in Class I, Division 2 locations need not be marked with the class, group, division, or operating temperature; Fixed dust-tight equipment, other than lighting fixtures, that is acceptable for use in Class II, Division 2 and Class III locations need not be marked with the class, group, division, or operating temperature; and. Quick Tips #124.1. BATTERY ENERGY STORAGE SYSTEMBESS) Outside of the United States, the IEC uses two different classifications: Gas & Vapor (Zones 0, 1, or 2) Dust (Zones 20, 21, or 22) Step 2: The next step is to determine how often the hazardous substance (s) is/are present. There are two sets of Zones: Zones 0 thru 2 are used for gases, vapors, and mists, and Zones 20 thru 22 are . Area classification documentations are reviewed and updated to reflect process changes. Class I: hazardous because flammable gases or vapors are present in the air in quantities sufficient to produce explosive or ignitable mixtures: . These areas only become hazardous in case of an accident or some unusual operating condition. Figures show that appr. May 2022 When the concentration of gas or vapor is above the UEL the gas mixture is too rich to burn. [3], Different explosive atmospheres have chemical properties that affect the likelihood and severity of an explosion. So the following conditions must be met for an explosion to occur: Represented by the following explosion triangle. Class defines the general nature (or properties) of the hazardous material in the surrounding atmosphere. Specific types of protection being used will also be marked. Each room, section, or area shall be considered individually in determining its classification. To make this even easier to understand, take a look at the diagram of a typical petrol station below where we have identified the areas that are classified as Zone 0, Zone 1 and Zone 2.

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