Drop Test SEWAGE TREATMENT Informational Note No. Equipment marked as suitable for IIB is also suitable for IIA but NOT for IIC. Atmospheres containing propane, acetone, benzene, butane, methane, petrol, hexane, paint solvents or gases and vapors of equivalent hazard. 286 natural gas explosions per year in the U.S. causing substantial damage, severe injury or loss of lives. Zone defines the general nature - if it is a gas or dust - and the probability of hazardous material being present in an ignitable concentration in the surrounding atmosphere. There are two sets of Zones: Zones 0 thru 2 are used for gases, vapors, and mists, and Zones 20 thru 22 are . Zone 0 is an area in which an explosive atmosphere is present continuously for long periods of time or will frequently occur. Group defines the type of the hazardous material in the surrounding atmosphere. So the following conditions must be met for an explosion to occur: Represented by the following explosion triangle. August 2018 Recommendat ions. The NEMA enclosure rating or IP code may also be indicated, but it is usually independent of the Classified Area suitability. These ways of protection are specified in detail within several IEC standards (IEC 60079 series) for electrical equipment. | For Dust this would be Zone 21. 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. 1994-2020, W.W. Grainger, Inc. All Rights Reserved. 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. So for an explosion there must be enough fuel. Temporary Refuge Dry Container Hazardous Area Classification is a study, in which is assessed, at witch locations of a plant, factory or company, high concentrations of flammable gases are present or can be released, in order to create an explosion hazard. January 2022 Locations shall be classified depending on the properties of the flammable vapors, liquids, or gases that may be present and the likelihood that a flammable or combustible concentration or quantity is present. 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. Division defines the probability of the hazardous material being present in an ignitable concentration in the surrounding atmosphere. 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. Whenever you are filling up your tank you are standing in a Zone 1 hazardous area. 5mm -750C Electrical Resistivity. 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. 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. Q: Are Divisions and Zones equivalent to one another? February 2022 Many items of EEx rated equipment will employ more than one method of protection in different components of the apparatus. may exist under normal or abnormal conditions because of the presence of flammable gases or vapors, combustible dusts or ignitable fibers or flyings. 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. Shown below is a summary of the applicable NEC Articles to reference to ensure the proper requirements are applied. Read more in our blogWhich Standards to use for Hazardous Area Classification. 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. 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,. 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). Hazardous Area Classifications D103222X012 Product Bulletin 9.2:001 . NEC Div 1 Zone 1 Div 2 Zone 2Flammable during normal operation Most Safer Zone IEC Zone 0 DESRIPTIONHighly Flammable for long period DEFINITIONFlammable atmosphere present continuously (Typically 1000 hours / year). Horizontal. See Figure S-1 for an explanation of this marking. Have a think about it next time youre filling up! Terminology for both hazards and protective measures can vary. Informational Note No. December 2022 Zone 1 an area in which an explosive gas-air mixture is likely to occur in normal operating conditions. It uses the familiar Class/Division system and adapts the IEC/CENELEC Zones into it while maintaining NEC wiring methods and . Such properties include flame temperature, minimum ignition energy, upper and lower explosive limits, and molecular weight. 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. Documentation requirements likewise vary. 2: This classification includes, Informational Note No. 14 4. . 2: For Group IIIC combustible dusts or metal combustible fibers/flyings, there shall only be Zone 20 or 21 locations. . 1. AddThis use cookies for handling links to social media. ethanol, methane or hydrogen. Iso Container Substance properties are specific for the amount of fuel needed to get an explosion when all other conditions are met. 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. Zone 1 (unless separated by a fire wall)P.G.Sreejith, Kerala. Informational Note No. Atmospheres containing ethylene, propylene oxide, ethylene oxide, butadiene, cyclopropane, ethyl ether, or gases and vapors of equivalent hazard. January 2023 The Occupational Safety and Health Administration (OSHA) has adopted these hazardous classifications and all except Groups are defined in 29 Code of Federal Register (CFR) 1910.399. Classification of Hazardous Areas 0 100 200 300 400 500 600 T1 >450C T2 >300C 450C T3 >200C 300C T4 >135C 200C . Magnesium, Titanium), IIB Nonconductive dusts (eg. March 2022 The process of determining the type and size of hazardous locations is called classification. 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. Zones also have the added benefit of including the area classification with the zone description. . WHEN YOU NEED THEM. 1: As a guide to classification of Zone 22 locations, refer to ANSI/ISA 60079-10-2 (12.10.05)-2013, Explosive Atmospheres Part 10-2: Classification of areas Combustible dust atmospheres. The colour of the luminaire body indicates the level of protection. Group C materials have a MESG less than 0.75mm and a MIC ratio less than 0.80 (but greater than 0.40, which would put it in Group B.) . What are 'Dark Factories,' and Do They Really Exist? We don't collect information from our users. Comparisons between the two systems are not easily accomplished. When the concentration of gas or vapor is beneath the LEL the gas mixture is too lean to burn. Electrical equipment installation in atmosphere with flammable gases or vapors, flammable liquids, combustible dusts, ignitable fibers or flyings represents a risk for fire and explosion. Hazardous Environment Classifications: NEC vs IEC, IEC (International Electrotechnical Commission), Group E Metal dusts (eg. Zone 0: flammable atmosphere highly likely to be present - may be present for long periods or even continuously . December 2021 When the concentration of methane is beneath the LEL, an explosion cannot occur, even when an ignition source is present. LIFTING TEST ". Canada has a similar system with CSA Group standard C22.1, the Canadian Electrical Code, which defines area classification and installation principles. The NEC Zone system was created to harmonize with IEC classification system, and therefore reduce the complexity of management. Various regulations use terms such as class, division, zone, and group to differentiate the various hazards. Container Standards 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. Equipment approved for use in Class I hazardous locations cannot be used in Class II hazardous locations. The equipment group . A light switch may cause a small, harmless spark when switched on or off. Equipment that is listed for a Zone 1 location may be installed in a Zone 2 location of the same gas or vapor. Ex s is a coding referenced in IEC 60079-0. Other ignition sources can also be present, like static electricity. The housing may be strong enough to contain and cool any combustion gases produced internally. October 2018 HAZARDOUS VS. Then, the level of risk of an explosion is based on the frequency and duration of the occurrence of an explosive atmosphere. November 2022 >> For Gas Vapor this would be Zone 1. Flammable liquids with a high flash point are less hazardous than liquids eg Production Area, area surrounding zone 0. Comparison of Zones and Divisions. 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). . Class I: hazardous because flammable gases or vapors are present in the air in quantities sufficient to produce explosive or ignitable mixtures: . Zone 0, 1, and 2 locations shall include those specified in 505.5 (B) (1), (B) (2), and (B) (3). Atmospheres containing non-conductive dust. area in which an explosive gas atmosphere is likely to occur occasionally in normal operation. 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. This is presented by the Lower Explosion Limit (LEL) of a substance. Where pyrophoric materials are the only materials used or handled, these locations need not be classified. For equipment provided with threaded entries for NPT threaded conduit or fittings, listed conduit, conduit fittings, or cable fittings shall be used. 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. 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. International Electrotechnical Committee (IEC) Hazardous Area Classification. In effect it is any method which can be shown to have the required degree of safety in use. 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. 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 A, B, C, and D are for gases (Class I only). Q: Can I use a piece of equipment approved for use in a Division 1 hazardous location in a Division 2 hazardous location? 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 Vertical. In the US, the independent National Fire Protection Association (NFPA) publishes several relevant standards, and they are often adopted by government agencies. A Zone defines the general nature - if it is a gas or dust - and the probability of hazardous material being present in an ignitable concentration in the surrounding atmosphere. . 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. Area's are divided into zones. The overpressure is monitored, maintained and controlled. 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. There are several ways of how to perform hazardous area classification, all described in several standards or codes of practise. 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. To prevent explosions from happening in harsh environments whereby flammable gases or combustible dusts are present directives and guidelines are put in place to protect both the public, workforce, and environment. 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. May 2019 (between 0,1 and 10% of the time). Informational Note No. 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. Pit will be considered as Zone 1. No long-term contract. It is obvious to use those standards within these industries. Only emails and answers are saved in our archive. Within the European Union, these are defined by IEC/EN standards (IEC/EN 60079-10-1 or 2) as directed by ATEX. Since this fuel can only combust in the presence of oxygen, enough oxygen must be available for the rapid combustion to take place. Directly adjacent on the label one will find the mark of the listing agency. Zone 2. area in which an explosive gas atmosphere is present continuously, or for long periods, or frequently (more than 10% of the time). * Zone 2 a . 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. Cookies are only used in the browser to improve user experience. These areas only become hazardous in case of an accident or some unusual operating condition. 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. 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. The hazardous area classification system determines required protection techniques and methods for electrical installations in the location. Please read Google Privacy & Terms for more information about how you can control adserving and the information collected. Type of protection "n" is further subdivided into nA, nC, and nR. This is also one of the first steps when composing an Explosion Protection Document. The Zone Classification System is offered as an alternative to the Class and Division system. 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]. Groups E, F, and G are for dusts and flyings (Class II or III). 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. 41 gas explosions per year occur within the UK and app. NEW METHODS FOR HAZARDOUS AREA CLASSIFICATION FOR EXPLOSIVE GAS . Dn 1 - a Ce e . 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. A: Yes. We don't save this data. October 2019 Choose the right method for Hazardous Area Classification! 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 But every hazardous area is different and each has specific requirements depending on the nature of the atmosphere and the elements that are present. The minimum concentration of oxygen, necessary for the combustion to take place, is called the Limiting Oxygen Concentration. 2: Where gas detection, Informational Note No. Informational Note No. The choice of which standard to use for the hazardous area classification is something which is very important. Equipment that the employer demonstrates will provide protection from the hazards arising from the flammability of the gas or vapor and the zone of location involved and will be recognized as providing such protection by employees need not be marked. Oil Immersion "o" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. These would be then labeled with each of the individual methods. A high level of protection is ensured. Beside sufficient fuel, also sufficient oxygen is needed for combustion of the mixture. . 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. Temporary Refuge (TR) Shelter Different countries have approached the standardization and testing of equipment for hazardous areas in different ways. For more detailed assessments or for situations where no specific industry standards are available , like the chemical or pharmaceutical sector and also specific installation for oil and gas industries, a more quantitative approach can be used. The International Electrotechnical Commission publishes the 60079 series of standards[2] which defines a system for classification of locations, as well as categorizing and testing of equipment designed for use in hazardous locations, known as "Ex equipment". No. Specific types of protection being used will also be marked. Please read AddThis Privacy for more information. When the concentration of gas or vapor is above the UEL the gas mixture is too rich to burn. Ignitable concentrations of flammable gases or vapors which are likely to occur under normal operating conditions. Flour, wood/sawdust, plastic dust). For dusts: Zone 20, Zone 21 and Zone 22. An old British standard used letters to designate zones. 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). Article 505 National Electrical Code (NEC), Article 506 National Electrical Code (NEC). These applications will - due to browser restrictions - send data between your browser and our server. Zone 1 is an area in which an explosive atmosphere is likely to occur occasionally in normal operation. according to ISO standard 80079 series. Copryright 2023 Springer Controls Company . 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). The surface of a high pressure steam pipe may be above the autoignition temperature of some fuel-air mixtures. A more quantitative method is described in IEC 60079-10-1 but also more sophisticated numeric mathematical models can be used like Computational Fluid Dynamics. 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. Zones compares to classes and divisions in the Class/Division system. Explosion protection must be ensured during normal operation. 1: For examples of area classification drawings, see ANSI/API RP 505-2018, Informational Note No. 1.1 Scope. Atmosphere containing flammable gas, flammable liquid produced vapor, or combustible liquid produced vapor mixed with air that may burn or explode, having either a MESG value greater than 0.75 mm or a MIC ratio greater than 0.80 - such as gasoline, acetone, ammonia, benzene, butane, ethanol, hexane, methanol, methane, vinyl chloride, natural gas, naphtha, propane or gases of equivalent hazard. But when we take a closer look at the graph and table, we can conclude that any explosion, can easily lead to severe damage. Gases, Vapors and Mists. The use of EPL and ATEX Category directly is an alternative for "s" marking. Equipment can be designed or modified for safe operation in hazardous locations. So it is quite obvious that explosions should be prevented as much as possible and still work has to be done to achieve this. Atmospheres containing acetylene, hydrogen, carbon disulphide or gases and vapors of equivalent hazard. Area Classification - Hazardous Locations are classified by the likelihood of an ignitable concentration of combustible material being present. 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 . 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). Non-hazardous or ordinary locations. Youre phone isnt rated for use in hazardous areas. Feedback From Clients
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