The Zones are based on how often the hazard is present rather than upon normal versus abnormal conditions. Employers may use the zone classification system as an alternative to the division classification system for electric and electronic equipment and wiring for all voltage in Class I, Zone 0, Zone 1, and Zone 2 hazardous (classified) locations where fire or explosion hazards may exist due to flammable gases, vapors, or liquids. March 2021 . 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. What Are All Those Gadgets On A Multitool? This has been replaced by a European numerical system, as set out in directive 1999/92/EU implemented in the UK as the Dangerous Substances and Explosives Atmospheres Regulations 2002. Adapters shall be used for connection to conduit or NPT-threaded fittings. 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 locations are identified by zones as follows: * Zone 0 a location in which explosive gas atmospheres are present continuously or for long periods of time. September 2020 Two possible classifications are described, in Section 18 (Zones), and Appendix J (Divisions). This is exactly defined as the limiting concentration of oxygen below which combustion is not possible, independent of the concentration of fuel. Since the changes to the code, hazardous locations with gases or vapors (Class I) present can be reclassified as Zone 0, 1 or 2. 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. Where there is potential for an explosive atmosphere, special precautions are needed to prevent fires and explosions. 1910.307 - Hazardous (classified) locations. 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. THE PRODUCTS YOU NEED, October 2022 For dusts: Zone 20, Zone 21 and Zone 22. Hazards in this group gas can be ignited very easily indeed. Zone 0 - Explosive atmospheres present continuously long periods or frequently. If equipment is marked, for example, Ex e II T4 then it is suitable for all subgroups IIA, IIB and IIC. Explosion Hazardous Areas are divided into zones according to risk probabilities. 6: For further information on electrical systems for hazardous (classified), Informational Note No. . 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. >> For Gas Vapor this would be Zone 1. If you want to promote your products or services in the Engineering ToolBox - please use Google Adwords. Informational Note No. Q: Are Divisions and Zones equivalent to one another? It is essential to know which zone you are working in, so that you can specify the most appropriate equipment. There are three zones for gas: Zone 0, Zone 1 and Zone 2. 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). 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. Zone 2 Explosive Mixtures not likely to occur /occur short duration in normal operation (lt10 Hrs/ Yr). Classification of locations, testing and listing of equipment, and inspection of installation, is typically overseen by governmental bodies. Flammable liquids with a high flash point are less hazardous than liquids These areas are in North America (United States and Canada) historically classified with the Class/Division system. Choose the right method for Hazardous Area Classification! NEC has created an Americanized version of the IEC/CENELEC Zone system in a stand-alone article (Article 505). 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. For specific industries, the specific codes for that industry are important to use. Zones 1 or 2. Area which are not devided into Atex zones, are called non-hazardous area's. Equipment is placed into protection level categories according to manufacture method and suitability for different situations. For example the EI 15 and API 500/505 describe specific installations and several conditions for the oil and gas industry. FREEZER Ex s is a coding referenced in IEC 60079-0. April 2022 There are several ways of how to perform hazardous area classification, all described in several standards or codes of practise. June 2019 Zone 1 is an area that is classified 'as a place in which an explosive atmosphere consisting of a mixture with air or flammable substances in the form of gas, vapours and mists is likely to occur occasionally during normal operation', whereas Zone 2 is an area that is classified 'as a place in which an explosive atmosphere consisting of a mixture Hazardous classified locations are areas where the possibility of fire or explosion hazards may exist under normal or abnormal conditions because of the presence of flammable, combustible or ignitable gases, vapors, liquids, dust, or fibers/flyings. This is presented by the Lower Explosion Limit (LEL) of a substance. Area Classification. AddThis use cookies for handling links to social media. Informational Note No. When the concentration of methane is beneath the LEL, an explosion cannot occur, even when an ignition source is present. Category 1 equipment may be used in zone 0, zone 1 or zone 2 areas. Copryright 2023 Springer Controls Company . 3: Text that is followed by a reference in brackets has been extracted from NFPA 497-2017, All other applicable rules contained in this, Where the term "Class I" is used with respect to, Informational Note: The term "Class I" was originally included as a prefix to, All areas in industrial occupancies designated as hazardous (classified). ESS Container WHEN YOU NEED THEM. Electrical equipment can and does cause fires and/or explosions in certain atmospheres. A major safety concern in all workplaces is the occurrence of fires and explosions. 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. Class defines the type of explosive or ignitable substances which are present in the atmosphere. 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. All threaded conduit shall be threaded with an NPT (National (American) Standard Pipe Taper) standard conduit cutting die that provides -in. Comparison of Zone 2 and Division 2 TABLE 1 - AREA CLASSIFICATIONS Division 1: Where ignitable concentrations can exist all of the time or some . Informational Note No. | For Dust this would be Zone 22. October 2019 (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. Since this fuel can only combust in the presence of oxygen, enough oxygen must be available for the rapid combustion to take place. 2: For the requirements for electrical and electronic. An area where combustible dusts or ignitable fibers and flyings are likely to occur under normal operating conditions. Many items of EEx rated equipment will employ more than one method of protection in different components of the apparatus. Hazardous Area Classifications D103222X012 Product Bulletin 9.2:001 September 2019. Within a working area or installation an ignition can be created by many factors. 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 So it is quite obvious that explosions should be prevented as much as possible and still work has to be done to achieve this. National Electrical Code (NEC) and the 1998 Canadian Electrical Code (CEC) now recognize the use of the Zone system for classification of hazardous areas. Atmospheres containing propane, acetone, benzene, butane, methane, petrol, hexane, paint solvents or gases and vapors of equivalent hazard. [4], Flammability of combustible liquids are defined by their flash-point. 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. Ways to ensure this level of safety are non-arcing design and limitation of the temperature of the equipment. (between 0,1 and 10% of the time). >> NEC: Class I, Division 2, Group D. | IEC: Zone 2, Group II. The Zone system of hazardous area classification, defines the probability of the hazardous material, gas, or dust, being present in sufficient quantities that can generate explosive or ignitable mixtures. This paper will discuss and review the current approaches and solutions of dealing with these HSE concerns, especially with the involvement of hazardous and potentially flammable and explosive chemicals. 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 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. Atmospheres containing acetylene, hydrogen, carbon disulphide or gases and vapors of equivalent hazard. Terminology for both hazards and protective measures can vary. November 2020 Figures show that appr. Lets take a look at what defines each zone. Electrical equipment installed in such locations can provide an ignition source, due to electrical arcing, or high temperatures. hazardous areas as the following: An area where a potential hazard (e.g., a fire, an explosion, etc.) The surface of a high pressure steam pipe may be above the autoignition temperature of some fuel-air mixtures. Areas with possible fire or explosion risks due to explosive atmospheres and/or mixtures - are called hazardous (or classified) locations or areas. (Hazardous Area Classification) . Determined to be none of the above. Gases, Vapors and Mists. the inside of tank truck or the interior of a dust filter). 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. The information contained in this article is intended for general information purposes only and is based on information available as of the initial date of publication. A: When comparing Divisions and Zones, Division 2 is equivalent to Zone 2, but Division 1 is equivalent to either Zone 0 or 1. 1. It is always balancing between not defining such areas too large (with highly costs for prevention of ignition sources) or too small (unsafe situations). 15 4. Example - Hazardous Area Classification A room with a propane gas installation will typically be classified with the Class/Division system as: Class I, Division 2, Group D Zone system as: Zone 2, Group IIA Zone 0 (hazardous area) An area in which an explosive gas-air mixture is continuously present or present for long periods. Where pyrophoric materials are the only materials used or handled, these locations need not be classified. Gas a. In electrical and safety engineering hazardous locations HazLoc pronounced hazlk are places where fire or explosion hazards may exist. Therefor Hazardous Area Classification (HAC) is the first important step in achieving an explosion safe installation or work environment. Ambient Temperature (-20C to +40C if not marked) Establish Zone Based on "IEC 60079-10". August 2020 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. Atmosphere containing carbonaceous dusts, Atmosphere containing combustible dust not included in Group E & F - such as. Oil Immersion "o" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. In the US, the independent National Fire Protection Association (NFPA) publishes several relevant standards, and they are often adopted by government agencies. 1: The term "Class I" was originally included as a prefix to, Informational Note No. 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. November 2021 Such properties include flame temperature, minimum ignition energy, upper and lower explosive limits, and molecular weight. 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. The flash-point is the temperature at which the material will generate sufficient quantity of vapor to form an ignitable mixture. 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. Entire Vapour space of storage tank. Controls can be fitted to detect dangerous concentrations of hazardous gas, or failure of countermeasures. We will go deeper into ignition assessments in another blog. Explosion protection must be ensured during normal operation. Then, the level of risk of an explosion is based on the frequency and duration of the occurrence of an explosive atmosphere. NEW METHODS FOR HAZARDOUS AREA CLASSIFICATION FOR EXPLOSIVE GAS . This process is called hazardous area classification. 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. In the United States, the NEC uses 2 different classifications: To minimize the risk of these fires or explosions, electrical/electronic equipment must be designed, tested and labeled as being acceptable for use in the areas in which it is installed. The above groups are formed in order of how explosive the material would be if it was ignited, with IIC being the most explosive zone system gas group and IIA being the least. 41 gas explosions per year occur within the UK and app. 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. 7: For further information on application of electrical, Informational Note No. Drop Test Several protection strategies exist. 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. Photo 2. Vertical. Table 1. Google use cookies for serving our ads and handling visitor statistics. We don't collect information from our users. So, it is good to know that when a flammable substance concentration exceeds the LEL, it will not automatically lead to an explosion with the highest Pmax. Beside sufficient fuel, also sufficient oxygen is needed for combustion of the mixture. 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. Safe for the hazardous (classified) location. October 2021 In an ordinary household this is of no concern, but if a flammable atmosphere is present, the arc might start an explosion. 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. NFPA 70, the National Electrical Code (NEC), defines area classification and installation principles. Refrigerated Locations are thus classified by type and risk of release of gas, vapor, or dust. Zone 1 an area in which an explosive gas-air mixture is likely to occur in normal operating conditions. Zone 1 is an area in which an explosive atmosphere is likely to occur occasionally in normal operation. . Type of protection "n" is further subdivided into nA, nC, and nR. 4: For further information on protection against static electricity and lightning hazards in hazardous (classified). Sources of 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. A: Yes. 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. Equipment that is listed for a Zone 1 location may be installed in a Zone 2 location of the same gas or vapor. Category 3 equipment may only be used in zone 2 areas. 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. Intrinsic safety designs equipment to operate using minimal energy, insufficient to cause ignition. * Zone 1 a location in which explosive gas atmospheres are likely to occur during normal operation, or which is adjacent to a Zone 0 location. But beside electrical equipment also mechanical equipment must be Ex certified, e.g. Other ignition sources can also be present, like static electricity. Therefore, it is very important to make sure that you are using a suitable luminaire for your application by choosing your fitting based on its suitability for the Zone in which it will be located. A60 As a guide for Zone 0, this can be defined as over 1,000 hours/year or >10% of the time. In effect it is any method which can be shown to have the required degree of safety in use. Zone 1 . 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. The autoignition temperature is the lowest temperature at which the substance will ignite without an additional heat or ignition source (at atmospheric pressure). Zone 0, 1, and 2 locations shall include those specified in 505.5 (B) (1), (B) (2), and (B) (3). When the concentration of gas or vapor is above the UEL the gas mixture is too rich to burn. The definition of the hazardous area zones represent the likelihood of hazardous gas, dust or other hazards being present in a working area. Zone 0Ignitable concentrations of flammable gases or vapors which are present continuously or for long periods of time. Which system is preferred depends on the users preference, how the areas are classified, and the wiring system used. 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. 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). 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). Cookies are only used in the browser to improve user experience. . Article 505 National Electrical Code (NEC), Article 506 National Electrical Code (NEC). 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. May 2022 Feedback From Clients Zone 2 hazardous areas are typically storage areas but can also be process areas. Examples are: production facilities in the food industry, chemical plants, oil & gas, and the pharmaceutical industry etc. This means that the electrical equipment is safe for use within these area by applying special protection strategies. the National Fire Protection Association (NFPA) 70, National Electric Code(NEC). 1: For examples of area classification drawings, see ANSI/API RP 505-2018, Informational Note No. Flammable atmosphere expected to be present inside the storage tank continuously, hence it has been classified as zone 0. The classification process requires the participation of operations, maintenance, safety, electrical and instrumentation professionals; and the use of process diagrams, material flows, safety data sheets, and other pertinent documents. Hazardous areas are those defined as areas of potential explosion risk due to the presence of flammable gas or vapor. The substance referred to by classhas a high probability of producing an explosive or ignitable mixture due to it being present continuously, intermittently, or periodically or fromthe equipment itself under normal operating conditions. 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. The Zone Classification System is offered as an alternative to the Class and Division system. It is obvious to use those standards within these industries. Magnesium, Aluminum, Titanium etc. Laboratory Container When equipment must be placed in a hazardous location, it can be designed to reduce the risk of fire or explosion. January 2022 Hazardous Environment Classifications: NEC vs IEC, IEC (International Electrotechnical Commission), Group E Metal dusts (eg. Atmospheres containing non-conductive dust. Classification of Hazardous Areas 0 100 200 300 400 500 600 T1 >450C T2 >300C 450C T3 >200C 300C T4 >135C 200C . 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. The equipment group . Container Test Zone 1 if gas group & temp. The definition of Zone 2 is a hazardous area classified as an atmosphere where a mixture of air and flammable substances in the form of gas, vapour or mist is not likely to occur in normal operation, but if it does occur, will persist for a short period only.
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