10: For information on electrical resistance trace heating for hazardous (classified), Informational Note No. BATTERY ENERGY STORAGE SYSTEMBESS) The flash point determines if an area needs to be classified. A spark or high heat must also be present. These areas are classified solely for the purpose of ensuring the safe and proper specification and installation of electrical/electronic equipment. 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. 1994-2020, W.W. Grainger, Inc. All Rights Reserved. SPARTANs Zone 1 part code begins SPX, Zone 2 SPZ and industrial products having a SPI prefix. | For Dust this would be Zone 22. The definition of the hazardous area zones represent the likelihood of hazardous gas, dust or other hazards being present in a working area. There are two systems in place, including the traditional North American Division system as well as the alternative Zone system. The disadvantage of standards with example installations, is that a huge safety factor is incorporated and thus relative large hazardous area are defined. 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. Temperature classification, except for intrinsically safe apparatus. In the US, the National Electrical Manufacturers Association (NEMA) defines standards for enclosure types for a variety of applications. Dust or other small particles suspended in air can explode. A high level of protection is ensured. Identifying Zone 0, Zone 1, and Zone 2 Hazardous Areas. There are several ways of how to perform hazardous area classification, all described in several standards or codes of practise. Where there is potential for an explosive atmosphere, special precautions are needed to prevent fires and explosions. Zones. So it is quite obvious that explosions should be prevented as much as possible and still work has to be done to achieve this. A60 Classification of Hazardous Areas 0 100 200 300 400 500 600 T1 >450C T2 >300C 450C T3 >200C 300C T4 >135C 200C . All equipment in Division 1 areas must have an approval label, but certain materials, such as rigid metallic conduit, does not have a specific label indicating the Cl./Div.1 suitability and their listing as approved method of installation in the NEC serves as the permission. The 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). Fundamentally, for an explosion to take place, flammable or explosive gases, vapours, mists or dusts will be present. September 2022 In ambient conditions it is assured that oxygen is always present and thus not a factor that has to be incorporated within the hazardous area assessment. Several protection strategies exist. Electrical equipment can and does cause fires and/or explosions in certain atmospheres. The Zone system for classifying hazardous locations used in NFPA 70 NEC, IEC 60079, and the Canadian Electrical Code indicates the level of probability that a flammable concentration of a hazardous substance may be present. ignitable concentrations of dust, fibers, or flyings are present for long periods of time, ignitable concentrations of dust, fibers, or flyings are likely to exist under normal conditions, ignitable concentrations of dust, fibers, or flyings unlikely to exist under normal conditions, Metal dusts, such as magnesium (Division 1 only), Carbonaceous dusts, such as carbon & charcoal, Non-conductive dusts, such as flour, grain, wood & plastic, Ignitible fibers/flyings, such as cotton lint, flax & rayon, Ignitible fibers or flyings, such as cotton lint, flax & rayon. Protecting against fire and explosion is of interest for both personnel safety as well as reliability reasons. These areas are in North America (United States and Canada) historically classified with the Class/Division system. 1.1 Scope. An area where combustible dusts or ignitable fibers and flyings are not likely to occur under normal operating conditions and do so only for a short period of time. Flameproof "d" - This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. 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 example the EI 15 and API 500/505 describe specific installations and several conditions for the oil and gas industry. 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. All rights reserved. of the autoignition temperature of the hazardous atmosphere. Since this fuel can only combust in the presence of oxygen, enough oxygen must be available for the rapid combustion to take place. [4], Flammability of combustible liquids are defined by their flash-point. The term equipment is applied both for fixed equipment and mobile equipment that are operated in such area. 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. December 2020 October 2022 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. Atmospheres containing acetylene, hydrogen, carbon disulphide or gases and vapors of equivalent hazard. Area ClassificationThe max surface temp. Explosion Hazardous Areas are divided into zones according to risk probabilities. 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. In the United Kingdom, Sira and Baseefa are the most well known such bodies. lk) are places where fire or explosion hazards may exist. Equipment is placed into protection level categories according to manufacture method and suitability for different situations. Zone 1 is an area in which an explosive atmosphere is likely to occur occasionally in normal operation. May 2022 In effect it is any method which can be shown to have the required degree of safety in use. National Electrical Code (NEC) and the 1998 Canadian Electrical Code (CEC) now recognize the use of the Zone system for classification of hazardous areas. Sources of 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. Groups E, F, and G are for dusts and flyings (Class II or III). If you want to promote your products or services in the Engineering ToolBox - please use Google Adwords. Temporary Refuge (TR) Shelter Substances characterization Consequences . That flammable gas or vapor . But first, we must consider what is likely to cause an explosion in the first place. 9: For additional information concerning the installation of, Informational Note No. These generally give rise to areas classied as Zones 0, 1, and 2 respectively. Non-hazardous or ordinary locations. NEGATIVE PRESSURE Zone 0 - Explosive atmospheres present continuously long periods or frequently. Use this hazardous area guide to NFPA 70 location classes, divisions & groups to understand potentially dangerous situations at a glance. eg Production Area, area surrounding zone 0. 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. >> NEC: Class I, Division 2, Group D. | IEC: Zone 2, Group II. This is also one of the first steps when composing an Explosion Protection Document. LIFTING TEST Refrigerated Container A: Yes. Category 2 equipment may be used in zone 1 or zone 2 areas. Hazardous Area Classifications D103222X012 Product Bulletin 9.2:001 . Hazardous area equipment is categorized into category-1 for Zone 0 or Zone 20, category-2 for Zone 1 or Zone 21, and category-3 for Zone 2 or Zone 22. Zone 2. In North America the suitability of equipment for the specific hazardous area must be tested by a Nationally Recognized Testing Laboratory, such as UL, FM Global, CSA Group, or Intertek (ETL). Those guidelines address electric wiring, equipment, and systems installed in hazardous (classified) locations and contain specific provisions for the following: wiring methods, wiring connections; conductor insulation, flexible cords, sealing and drainage, transformers, capacitors, switches, circuit breakers, fuses, motor controllers, receptacles, attachment plugs, meters, relays, instruments, resistors, generators, motors, lighting fixtures, storage battery charging equipment, electric cranes, electric hoists and similar equipment, utilization equipment, signaling systems, alarm systems, remote control systems, local loud speaker and communication systems, ventilation piping, live parts, lightning surge protection, and grounding. Recommendat ions. These are typically process areas where gases are more likely to be present. 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 type (0/1/2/ 20/21/ 22) Zone extent. Hazardous Environment Classifications: NEC vs IEC, IEC (International Electrotechnical Commission), Group E Metal dusts (eg. 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. - 1 2 (Class 1, . The value is represented is volume percentage of oxygen. Group II is for explosive gases (Zone 0, 1 and 2) and Group III is for explosive dusts (Zone 20, 21 and 22). The a subdivisions have the most stringent safety requirements, taking into account more than one independent component faults simultaneously. Atmospheres containing propane, acetone, benzene, butane, methane, petrol, hexane, paint solvents or gases and vapors of equivalent hazard. Choose the right method for Hazardous Area Classification! At least two British mine explosions were attributed to an electric bell signal system. Motors, lighting, junction boxes, electronic equipment, This method, being by definition special, has no specific rules. a headlamp, rather than a dedicated fixed luminaire. 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. Safety is ensured in the event of frequently occurring disturbances or equipment faults which normally have to be taken into account. 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 less than 0.45 mm or MIC ratio is less than 0.40. The surface of a high pressure steam pipe may be above the autoignition temperature of some fuel-air mixtures. Also known as non-hazardous or ordinary locations, these locations are determined to be neither Class I, Division 1 or Division 2; Zone 0, Zone 1 or Zone 2; or any combination thereof. Article 505 National Electrical Code (NEC), Article 506 National Electrical Code (NEC). What is an Explosion Protection Document? Equipment that is listed for a Zone 1 location may be installed in a Zone 2 location of the same gas or vapor. 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). It is an Americanized version of the International Electrochemical Commissions (IEC) Zone system which maintains the NEC wiring methods and protection techniques. 1910.307 (g) (2) Zone 0 is an area in which an explosive atmosphere is present continuously for long periods of time or will frequently occur. 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. gas, vapours, mists and dusts). May 2021 Click on the zone to learn more about the classification according to IEC 60079-10 standards. Oil Immersion "o" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. HAZARDOUS VS. Atmosphere containing carbonaceous dusts, Atmosphere containing combustible dust not included in Group E & F - such as. Home About Us News Hazardous Environment Classifications: NEC vs IEC, Posted March 11, 2019 by springercontrols. Arc-producing elements can be isolated from the atmosphere, by encapsulation in, Heat-producing elements can be designed to limit their maximum temperature below the. | For Dust this would be Zone 21. The Zone system has wider use in the chemical and petrochemical industries. Standards for electrical installations have been established and are governed by a variety of organizations throughout the world to ensure safe electrical systems in hazardous locations. 41 gas explosions per year occur within the UK and app. Beside the Lower Explosion Limit, each substance also has an Upper Explosion Limit (UEL). No. 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. 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 Within a working area or installation an ignition can be created by many factors. 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. As world trade becomes more globalized, international standards are slowly converging, so that a wider range of acceptable techniques can be approved by national regulatory agencies. Group defines thetypeof hazardous material and partly thelocationof the surrounding atmosphere . area in which an explosive gas atmosphere is likely to occur occasionally in normal operation. Intrinsic safety designs equipment to operate using minimal energy, insufficient to cause ignition. Comments. April 2021 NEC 2 Divisions (Div 1 2) Division I Comprising of Area Same as Zone 0 1. 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". 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 plan may contain the list of chemicals with their group and temperature rating. This temperature is used for classification for industry and technology applications.[6]. March 2021 Type of protection "n" is further subdivided into nA, nC, and nR. Zone 1 (unless separated by a fire wall)P.G.Sreejith, Kerala. [1] NEC article 500 describes the NEC Division classification system, while articles 505 and 506 describe the NEC Zone classification system. The specific hazardous materials within each group and their automatic ignition temperatures can be found in Article 500 of the National Electrical Code and in NFPA 497. coal and charcoal), Group G Nonconductive dusts (eg. NFPA 70, the National Electrical Code (NEC), defines area classification and installation principles. These hazardous (classified) locations are assigned the following designations: For definitions of these locations, see 1910.399. National Electric Code 2020 edition National Fire Protection Association. . For explosion hazards caused by flammable liquids or gases, the following zones are defined: So a zone 0 is the most hazardous zone and a zone 2 is a less hazardous zone. Drop Test . Division 1 and 2 Zone 0, 1 and 2 A (acetylene) IIC (acetylene & hydrogen) B (hydrogen) C (ethylene) IIB (ethylene) This rapid expansion of volume is caused by the combustion of a fuel, like e.g. SEWAGE TREATMENT ), Group F Carbon-based (eg. Hazardous area classification. January 2023 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. Type of protection "n" -- This protection technique is permitted for equipment in the Class I, Zone 2 locations for which it is approved. Atmospheres containing combustible flyings. In Europe and the rest of the world - but also more and more in North America - the Zone system is used. Hazardous areas are those defined as areas of potential explosion risk due to the presence of flammable gas or vapor. Entire Vapour space of storage tank. [10][11] Some of these are specifically for hazardous locations: All equipment certified for use in hazardous areas must be labelled to show the type and level of protection applied. RP 505 is referred to as the zone system. Determining the Class, Division and Group or Zone and Group is critical to correctly applying the requirements for a given hazardous location. For gases, vapours and mists the zone classifications are recognised as Zone 0, Zone 1 and Zone 2 areas. The process of determining the type and size of hazardous locations is called classification. 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. 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 Purged and pressurized -- This protection technique is permitted for equipment in the Class I, Zone 1 or Zone 2 locations for which it is approved. 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. An old British standard used letters to designate zones. 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. Under the "Zone" system, hazards are defined for gas as Zone 0, 1 or 2, with 0 as the highest hazard, and for dust as Zone 20, 21 or 22, with 20 as the . 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. Sources For Zone 1 applications, Pyroban uses . Locations are thus classified by type and risk of release of gas, vapor, or dust. This concentration is substance specific and lies normally somewhere between the LEL and UEL. A light switch may cause a small, harmless spark when switched on or off. Substance properties are specific for the amount of fuel needed to get an explosion when all other conditions are met. May 2019 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. November 2020 2: For Group IIIC combustible dusts or metal combustible fibers/flyings, there shall only be Zone 20 or 21 locations. Zone 0Ignitable concentrations of flammable gases or vapors which are present continuously or for long periods of time. 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). 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. 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,. 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. 2: Through the exercise of ingenuity in the layout of electrical installations for hazardous (classified), Refrigerant machinery rooms that contain ammonia refrigeration systems and are equipped with adequate mechanical ventilation that operates continuously or is initiated by a detection system at a concentration not exceeding 150 ppm shall be permitted to be classified as "unclassified". 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. Informational Note: For further information regarding classification and ventilation of areas involving closed-circuit ammonia refrigeration systems, see ANSI/IIAR 2-2014. . It is good to be aware of the fact that the mixture of flammable gas with oxygen has an optimum point where the combustion is most severe and leads to the highest explosion pressure. (between 0,1 and 10% of the time). WELDING INSPECTION Q: Can equipment approved for a Class I hazardous location be used in a Class II hazardous location? Equipment provided with threaded entries for field wiring connection shall be installed in accordance with paragraph (g)(2)(iv)(A) or (g)(2)(iv)(B) of this section. Controls can be fitted to detect dangerous concentrations of hazardous gas, or failure of countermeasures. Category 1 equipment may be used in zone 0, zone 1 or zone 2 areas. Increased safety "e" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. As to the classification, they are the same. Comparison of Zones and Divisions. Laboratory Container POSITIVE PRESSURE taper per foot. This was accompanied by electrically-initiated explosions of flammable gas such as fire damp (methane) and suspended coal dust. A potential few examples of this are: The air space inside a tank of petrol When the concentration of gas or vapor is above the UEL the gas mixture is too rich to burn.
hazardous area classification zone 0, 1, 2