August 2022 Flour, wood/sawdust, plastic dust), IIC Conductive dusts (eg. December 2020 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. January 2022 For Zone 1 applications, Pyroban uses . 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. Explosion-proofing designs equipment to contain ignition hazards, prevent entry of hazardous substances, and, contain any fire or explosion that could occur. In the United States, the NEC uses 2 different classifications: How to perform Hazardous Area Classification? 2: Where gas detection, Informational Note No. 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". 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. Refrigerated Informational Note No. the inside of tank truck or the interior of a dust filter). 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. Classification of locations, testing and listing of equipment, and inspection of installation, is typically overseen by governmental bodies. Zone 1 fittings are supplied as silver, Zone 2 as dark grey and industrial fittings as white. AddThis use cookies for handling links to social media. 9: For additional information concerning the installation of, Informational Note No. Table 1. Electrical equipment installed in such locations can provide an ignition source, due to electrical arcing, or high temperatures. No long-term contract. July 2021 In order to understand hazardous area classification it is important to understand which factors contribute to the occurrence of an explosion. It is always balancing between not defining such areas too large (with highly costs for prevention of ignition sources) or too small (unsafe situations). The types of protection are subdivided into several sub classes, linked to EPL: ma and mb, px, py and pz, ia, ib and ic. There are three zones for gas: Zone 0, Zone 1 and Zone 2. This value of this LOC differs per substance and depends also on the inert gas for achieving a low oxygen concentration. 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". 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. Read more in our blogWhich Standards to use for Hazardous Area Classification. Lets take a look at what defines each zone. These applications will - due to browser restrictions - send data between your browser and our server. September 2022 Note to paragraph (c)(2)(i) of this section: NFPA 70, the National Electrical Code, lists or defines hazardous gases, vapors, and dusts by "Groups" characterized by their ignitable or combustible properties. 2: This classification usually includes, (B) Special Occupancies, Zone 0, 1, and 2 Locations, Article 505 Special Occupancies, Zone 0, 1, and 2 Locations, (B) Special Occupancies, Class I, Zone 0, 1, and 2 Locations, National Electrical Code 2020 of Illinois, National Electrical Code 2017 of Illinois, Ignitible concentrations of flammable gases or vapors are present continuously, Ignitible concentrations of flammable gases or vapors are present for long periods of time, In which ignitible concentrations of flammable gases or vapors are likely to exist under normal operating conditions; or, In which ignitible concentrations of flammable gases or vapors may exist frequently because of repair or maintenance operations or because of leakage; or, In which ignitible concentrations of flammable gases or vapors are not likely to occur in normal operation and, if they do occur, will exist only for a short period; or, In which volatile flammable liquids, flammable gases, or flammable vapors are handled, processed, or used but in which the liquids, gases, or vapors normally are confined within closed containers of closed systems from which they can escape, only as a result of accidental rupture or breakdown of the containers or system, or as a result of the abnormal operation of the, In which ignitible concentrations of flammable gases or vapors normally are prevented by positive mechanical ventilation but which may become hazardous as a result of failure or abnormal operation of the ventilation. 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). 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. Division II Comprising of Area Same as Zone 2. (Hazardous Area Classification) . Definition of hazardous area zones (AS/NZS 60079.10): Zone 0 API 500/505 mostly for onshore and offshore oil and gas applications. Oil Immersion "o" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. Type of protection "n" -- This protection technique is permitted for equipment in the Class I, Zone 2 locations for which it is approved. Youre phone isnt rated for use in hazardous areas. May 2019 Intrinsic safety -- This protection technique is permitted for equipment in the Class I, Zone 0 or Zone 1 locations for which it is approved. If equipment is marked, for example, Ex e II T4 then it is suitable for all subgroups IIA, IIB and IIC. Controls can be fitted to detect dangerous concentrations of hazardous gas, or failure of countermeasures. We don't save this data. 29 CFR 1910.399 Definitions Applicable to Subpart S
When equipment must be placed in a hazardous location, it can be designed to reduce the risk of fire or explosion. a headlamp, rather than a dedicated fixed luminaire. Some other standards have more quantitative methods which require more knowledge of the plant, an example is the IEC standard 60079-10-1. 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. A light switch may cause a small, harmless spark when switched on or off. Hazardous Area Classifications D103222X012 Product Bulletin 9.2:001 September 2019. 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. Zone 0/20: An area in which an explosive atmosphere is present continuously or for long periods or frequently. NFPA 70 NEC Articles 500 through 503 cover the requirements for electrical/electronic equipment and wiring for all voltages in Class I, Divisions 1 and 2; Class II, Divisions 1 and 2; and Class III, Divisions 1 and 2 locations. 11: For information on electric skin effect trace heating for hazardous (classified), Informational Note No. When the concentration of gas or vapor is above the UEL the gas mixture is too rich to burn. | For Gas/Vapor this would be Zone 0. In Europe the ATEX 114 Directive (2014/34/EU) is applicable to equipment that is used in hazardous area's. Two possible classifications are described, in Section 18 (Zones), and Appendix J (Divisions). Area's are divided into zones. November 2019 It uses the familiar Class/Division system and adapts the IEC/CENELEC Zones into it while maintaining NEC wiring methods and . The American Petroleum Institute publishes analogous standards in RP500 andRP505. It is essential to know which zone you are working in, so that you can specify the most appropriate equipment. [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. Area classification documentations are reviewed and updated to reflect process changes. 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 In the US, the independent National Fire Protection Association (NFPA) publishes several relevant standards, and they are often adopted by government agencies. December 2013, All The value is represented is volume percentage of oxygen. Within the European Union, these are defined by IEC/EN standards (IEC/EN 60079-10-1 or 2) as directed by ATEX. 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. Equipment is placed into protection level categories according to manufacture method and suitability for different situations. IEC 60079-10.1 Classification of areas - Explosive gas atmospheres. 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. Coal mines, grain mills, elevators, and similar facilities likewise present the risk of a clouds of dust. 41 gas explosions per year occur within the UK and app. Accommodation Cabin When the concentration of methane is beneath the LEL, an explosion cannot occur, even when an ignition source is present. . 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. Classification of Hazardous Areas 0 100 200 300 400 500 600 T1 >450C T2 >300C 450C T3 >200C 300C T4 >135C 200C . Zone 0Ignitable concentrations of flammable gases or vapors which are present continuously or for long periods of time. 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. Sources of Equipment that is safe for the location shall be of a type and design that the employer demonstrates will provide protection from the hazards arising from the combustibility and flammability of vapors, liquids, gases, dusts, or fibers involved. 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. FEA Pressurised Container Ignitable concentrations of flammable gases or vapors which are likely to occur under normal operating conditions. For example, a socket outlet labeled EEx'de' might have a case made to EEx 'e' and switches that are made to EEx 'd'. The Class/Division/Group system is based on Article 500 of the National Electrical Code (NEC) where. An oversimplification of this example is shown in Table 1. This rapid expansion of volume is caused by the combustion of a fuel, like e.g. 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). 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. Zone 1 . Division defines the likelihood of the hazardous material being present in an explosive or ignitable concentration.Class I flammable gases and vapors are grouped into one of four groups(Groups A, B, C or D)based on their physical properties and the ease in which they can be ignited. [3], Different explosive atmospheres have chemical properties that affect the likelihood and severity of an explosion. In effect it is any method which can be shown to have the required degree of safety in use. 1994-2020, W.W. Grainger, Inc. All Rights Reserved. December 2021 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. Hazardous Environment Classifications: NEC vs IEC, IEC (International Electrotechnical Commission), Group E Metal dusts (eg. The prevention of explosions in working environments is in most countries regulated in national laws and directives. 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. National Electrical Code (NEC) and the 1998 Canadian Electrical Code (CEC) now recognize the use of the Zone system for classification of hazardous areas. Vertical. The groups also indicate how much energy is required to ignite the material by energy or thermal effects, with IIA requiring the most energy and IIC the least for zone system gas groups. The process of determining the type and size of hazardous locations is called classification. Many items of EEx rated equipment will employ more than one method of protection in different components of the apparatus. The zone classification for gases is divided into three zones, namely Zone 0, Zone 1 and Zone 2 and for dusts Zone 20, Zone 21 and Zone 22. Group define the type of hazardous material and (partly) the location of the surrounding atmosphere. [12], International Electrotechnical Commission, Occupational Safety and Health Administration, National Electrical Manufacturers Association, "Hazardous Area Classification and Control of Ignition Sources", "Hazardous (Classified) Locations NEC Articles 500 through 517", https://en.wikipedia.org/w/index.php?title=Electrical_equipment_in_hazardous_areas&oldid=1134828101, ignitable concentrations of combustible dust can exist, under normal conditions, ignitable concentrations of combustible dust are unlikely to exist normally, ignitable fibers, or materials producing combustible flyings, are handled, manufactured or used, easily ignitable fibers are stored or handled. The part codes for each SPARTAN variant also differ depending on the level of protection required. Offshore Accommodation Module The design of the equipment must ensure protection, even in the event of rare incidents relating to the equipment. Specific types of protection being used will also be marked. With the advent of electric power, electricity was introduced into coal mines for signaling, illumination, and motors. Atmosphere containing carbonaceous dusts, Atmosphere containing combustible dust not included in Group E & F - such as. NFPA 70 NEC Classes, Divisions and Groups. Examples are: In another blog we, will explain how to perform Hazardous Area Classification according to the Standard EN-IEC 60079-10-1. 5: For further information on ventilation, see NFPA 30-2018, Informational Note No. There are three necessary components for an explosion to occur; This needs to be present in a relatively high quantity to produce an explosive mixture (e.g. It is created based on input from the Process Flow Diagrams, Piping & Instrumentation Diagrams and the Equipment Location Plan . * 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. All areas in the facility that are not Zone 0, Zone 1, or Zone 2 are considered unclassified. 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). 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. 3: For further information on the classification of, Informational Note No. Reefer Container A Zone 0 location is a location in which one of the following . 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. Equipment that is listed for a Zone 1 location may be installed in a Zone 2 location of the same gas or vapor. October 2019 This is an important factor in the classification of hazardous areas. Then, the level of risk of an explosion is based on the frequency and duration of the occurrence of an explosive atmosphere. There are several ways of how to perform hazardous area classification, all described in several standards or codes of practise. May 2022 These would be then labeled with each of the individual methods. What Are All Those Gadgets On A Multitool? Flour, wood/sawdust, plastic dust). The last condition for an explosion is the presence of an effective ignition source in the direct contact with the fuel/air mixture. This is exactly defined as the limiting concentration of oxygen below which combustion is not possible, independent of the concentration of fuel. MCC Shelter For liquids, gases and vapours: Zone 0, Zone 1 and Zone 2. This means that the electrical equipment is safe for use within these area by applying special protection strategies. So the flammable range of a substance is the concentration of gases and vapors in air between the Lower Explosion Limit and the Upper Explosion Limit. Safety is ensured in the event of frequently occurring disturbances or equipment faults which normally have to be taken into account. Zone 1 - A place in which an explosive atmosphere is likely to occur in normal operation occasionally 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. Dust or other small particles suspended in air can explode. March 2022 Dn 1 - a Ce e . NEC 2 Divisions (Div 1 2) Division I Comprising of Area Same as Zone 0 1. But beside electrical equipment also mechanical equipment must be Ex certified, e.g. April 2022 The Zones are based on how often the hazard is present rather than upon normal versus abnormal conditions. This leads to a lot of the confusion in the global marketplace because certifying equipment to these different systems can be time consuming and expensive, so many companies may only certify to one or the other. In some cases, the hazardous atmosphere is present all the time, or for long periods. 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. Click on the zone to learn more about the classification according to IEC 60079-10 standards. Where pyrophoric materials are the only materials used or handled, these locations need not be classified. The IEC standard EN 60079-33 is made public and is expected to become effective soon, so that the normal Ex certification will also be possible for Ex-s, Zone depending upon manufacturer's certification, explosive atmosphere between 10 and 1000 hrs/yr, explosive atmosphere between 1 and 10 hrs/yr, explosive surface between 10 and 1000 hrs/yr, explosive surface between 1 and 10 hrs/yr, Certified and labeled for use in indoor locations rated NEC Class I, Groups A, B, C, and D, Certified and labeled for use in locations rated NEC Class I, Groups A, B, C, and D; both indoors and outdoors, Certified and labeled for use in locations rated NEC Class II, Groups E, F, or G, Explosion protected, Group 2, Category 1, Gas, Type ia, Group 2C gases, Temperature class 4, Type n, non-sparking, Group 2 gases, Temperature class 3, special conditions apply. A potential few examples of this are: The air space inside a tank of petrol This article covers the requirements for the, Informational Note No. 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. 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. Terminology for both hazards and protective measures can vary. 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. 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. Zone 0 is an area in which an explosive atmosphere is present continuously for long periods of time or will frequently occur. - 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 . Raytec do not currently offer any lighting solutions for Zone 0. Groups A, B, C, and D are for gases (Class I only). Wide known is that al electrical equipment within hazardous areas must be Ex certified for use in the appropriate hazardous area (zone or class/division). Marking "EEx d" in Accordance with EN 50 0 14 and 50 018 . 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. Equipment shall be marked to show the class, group, and operating temperature or temperature range, based on operation in a 40-degree C ambient, for which it is approved. Which Standards to use for Hazardous Area Classification. These areas only become hazardous in case of an accident or some unusual operating condition. Magnesium, Titanium), IIB Nonconductive dusts (eg. The first thing to understand is that much like the metric vs imperial measuring systems, the United States uses its own methodology which differs from much of the world. June 2019 according to ISO standard 80079 series. 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. This was accompanied by electrically-initiated explosions of flammable gas such as fire damp (methane) and suspended coal dust. Not only are hazardous areas classified by Class (nature of the hazardous material,) and Division . 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. 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. Hazards in this group gas can be ignited very easily indeed. Atmosphere containing a flammable gas, a flammable liquid produced vapor, or a combustible liquid produced vapor mixed with air that may burn or explode, having either a MESG (Maximum Experimental Safe Gap)1) value less than or equal to 0.45 mm or aMIC (Minimum Igniting Current)2) ratio less than or equal to 0.40 - such as hydrogen or fuel and combustible process gases containing more than 30% hydrogen by volume - or gases of equivalent hazard such as butadiene, ethylene oxide, propylene oxide and acrolein. The surface of a high pressure steam pipe may be above the autoignition temperature of some fuel-air mixtures. 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. These generally give rise to areas classied as Zones 0, 1, and 2 respectively. Hazardous area classification. Ignition sources can be divided in 13 categories (acc.