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. Please read Google Privacy & Terms for more information about how you can control adserving and the information collected. November 2020 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. Division 2 is equivalent to Zone 2, while Division 1 is either Zone 0 or 1. Table 1. 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). A high level of protection is ensured. Although OSHA does not provide a definition of group classifications in 29 CFR 1910.307 or 399 they do provide a note under 29 CFR 1910.307(c)(1) that states: NFPA 70, the National Electrical Code, lists or defines hazardous gases, vapors, and dusts by Groups characterized by their ignitable or combustible properties. To meet OSHAs marking requirement, the marking must include the hazardous group the equipment is approved to operate in. Class I: hazardous because flammable gases or vapors are present in the air in quantities sufficient to produce explosive or ignitable mixtures: . As a result, all hazardous area equipment must be designed with hazardous area zone classifications in mind, as the zone governs the level of protection and precaution required. Often an area classification plan view is provided to identify equipment ratings and installation techniques to be used for each classified area. NEGATIVE PRESSURE The Zone Classification System is offered as an alternative to the Class and Division system. (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. 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. When the concentration of gas or vapor is beneath the LEL the gas mixture is too lean to burn. The housing may be strong enough to contain and cool any combustion gases produced internally. Offshore Workshop Container . Canada has a similar system with CSA Group standard C22.1, the Canadian Electrical Code, which defines area classification and installation principles. Zone 0 is an area in which an explosive atmosphere is present continuously for long periods of time or will frequently occur. Dust or other small particles suspended in air can explode. A spark or high heat must also be present. 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. The last requirement for the explosion is the presence of an ignition source, like a spark or hot surface. [1] NEC article 500 describes the NEC Division classification system, while articles 505 and 506 describe the NEC Zone classification system. 1910.307 (g) (2) Hazardous locations can also be described as those locations where electrical 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. Carbon monoxide, ether, hydrogen sulfide, . 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. A: No. Is intended for us in Zone 2 (gases) or Zone 22 (dusts). 2: For Group IIIC combustible dusts or metal combustible fibers/flyings, there shall only be Zone 20 or 21 locations. Equipment construction is such that it can withstand an internal explosion and provide relief of the external pressure via flamegap(s) such as the labyrinth created by threaded fittings or machined flanges. 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). The codes and standards used in this process provide guidance for selecting,. In the US, the National Electrical Manufacturers Association (NEMA) defines standards for enclosure types for a variety of applications. 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. The Zones are based on how often the hazard is present rather than upon normal versus abnormal conditions. Safety is ensured in the event of frequently occurring disturbances or equipment faults which normally have to be taken into account. Reefer Container gas, vapours, mists and dusts). These applications will - due to browser restrictions - send data between your browser and our server. 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. You can target the Engineering ToolBox by using AdWords Managed Placements. Hazardous Area Classification, Gas Vapours and Dust Groups, Temperature Class | Simple Science Simple Science 8.81K subscribers Join Subscribe 28K views 2 years ago This video explains. Exception No. Unlike ATEX which uses numbers to define the safety "Category" of equipment, namely (1,2 3), the IEC continued to utilise the method used for defining the safe levels of intrinsic safety namely "a" for zone 0, "b" for zone 1 and "c" for zone 2 and apply this Equipment Level of Protection to all equipment for use in hazardous areas since 2009. In Northerm America, instead of the zone classification system, the Class/Division system is used. The use of EPL and ATEX Category directly is an alternative for "s" marking. 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. January 2022 This rapid expansion of volume is caused by the combustion of a fuel, like e.g. Equipment is non-incendive or non-sparking. 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 3: For further information on the classification of, Informational Note No. Coal mines, grain mills, elevators, and similar facilities likewise present the risk of a clouds of dust. In the US, the independent National Fire Protection Association (NFPA) publishes several relevant standards, and they are often adopted by government agencies. Enclosures can be pressurized with clean air or inert gas, displacing any hazardous substance. Zone 1 is an area in which an explosive atmosphere is likely to occur occasionally in normal operation. Iso Container 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. Adapters shall be used for connection to conduit or NPT-threaded fittings. Informational Note No. A room with a propane gas installation will typically be classified with the. The definition of the hazardous area zones represent the likelihood of hazardous gas, dust or other hazards being present in a working area. 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. The lower explosion limit of a substance is the lowest concentration (in volume percentages for gases and liquids) of a gas or a vapor in air of producing a flash of fire in the presence of an ignition source. When the concentration of gas or vapor is above the UEL the gas mixture is too rich to burn. Zone 0, 1, and 2 locations shall include those specified in 505.5 (B) (1), (B) (2), and (B) (3). Refer to Fig.3 which shows the hazardous area zone classification based on hazardous gas release grade. 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 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.) But first, we must consider what is likely to cause an explosion in the first place. 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. Comparison of Zone 2 and Division 2 TABLE 1 - AREA CLASSIFICATIONS Division 1: Where ignitable concentrations can exist all of the time or some . 1: Normal operation is considered the situation when plant, Informational Note No. 14 4. The temperature marking may not exceed the ignition temperature of the specific gas or vapor to be encountered. Q: Can I use a piece of equipment approved for use in a Division 1 hazardous location in a Division 2 hazardous location? Zone 1 (unless separated by a fire wall)P.G.Sreejith, Kerala. Zone 0 is an area in which an explosive atmosphere is present continuously for long periods of time or will frequently occur. We will go deeper into ignition assessments in another blog. This level of risk is represented by classifying the hazardous area as Zone 0, Zone 1 or Zone 2 (for gas, vapour and mist atmospheres) or Zone 21 or Zone 22 for dust atmospheres. July 2021 Lets take a look at what defines each zone. One of the hazards of working with flammable substances is an explosion, mostly hand in hand with fire. Electronic equipment, including lighting, needs to be purpose designed for use in hazardous areas to prevent a spark occurring and igniting any flammable substances. An oversimplification of this example is shown in Table 1. 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. Within a working area or installation an ignition can be created by many factors. If equipment is marked, for example, Ex e II T4 then it is suitable for all subgroups IIA, IIB and IIC. The autoignition temperature is the lowest temperature at which the substance will ignite without an additional heat or ignition source (at atmospheric pressure). Equipment approved for Class I, Division 1 or Class 1, Division 2 shall, in addition to being marked in accordance with (c)(2)(ii), be marked with the following: Class I, Zone 1 or Class I, Zone 2 (as applicable); Applicable gas classification groups; and. Refrigerated Container 286 natural gas explosions per year in the U.S. causing substantial damage, severe injury or loss of lives. The Raytec SPARTAN range includes dedicated luminaires for both Zone 1 and Zone 2 areas as well as industrial applications. Ways to ensure this level of safety are non-arcing design and limitation of the temperature of the equipment. If you want to promote your products or services in the Engineering ToolBox - please use Google Adwords. An explosion is a rapid expansion in volume associated with an extremely vigorous outward release of energy, usually with the generation of high temperatures and release of high-pressure gases (wikipedia (https://en.wikipedia.org/wiki/Explosion). This is exactly defined as the limiting concentration of oxygen below which combustion is not possible, independent of the concentration of fuel. Some equipment in Division 2 areas do not require a specific label, such as standard 3 phase induction motors that do not contain normally arcing components. 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]. The Zone system has three levels of hazard for gas or dust. 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. 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). Group II is for explosive gases (Zone 0, 1 and 2) and Group III is for explosive dusts (Zone 20, 21 and 22). Two possible classifications are described, in Section 18 (Zones), and Appendix J (Divisions). Hazardous Environment Classifications: NEC vs IEC, IEC (International Electrotechnical Commission), Group E Metal dusts (eg. Class defines the general nature (or properties) of the hazardous material in the surrounding atmosphere. WHEN YOU NEED THEM. 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. Type of protection "n" is further subdivided into nA, nC, and nR. 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. 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. Beside sufficient fuel, also sufficient oxygen is needed for combustion of the mixture. For methane this is shown in the following figure. Atmospheres containing acetylene, hydrogen, carbon disulphide or gases and vapors of equivalent hazard. ADNOC Zone 1 - Explosive atmospheres are likely to occur. NFPA 70 NEC Zone Classification System The Zone Classification System is offered as an alternative to the Class and Division system. Container Accessories For example, a Class 1, Div 1 area where Group A may be present would be defined as an area where flammable gases or vapors may be present under normal operating conditions. Group defines thetypeof hazardous material and partly thelocationof the surrounding atmosphere . As a guide for Zone 0, this can be defined as over 1,000 hours/year or >10% of the time. You will find this equipment in paint factories, a warehouse or around a bag dump station. 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. Specific types of protection being used will also be marked. . Guidance on assessment of hazards is given in NFPA497 (explosive gas) and NFPA499 (dust). Informational Note No. to EN 1127-1): After the hazard area classification is completed, then the ignition assessment starts. IEC 60079-10.1 Classification of areas - Explosive gas atmospheres. 11: For information on electric skin effect trace heating for hazardous (classified), Informational Note No. 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). 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. . Laboratory Container Zone 1 fittings are supplied as silver, Zone 2 as dark grey and industrial fittings as white. Home About Us News Hazardous Environment Classifications: NEC vs IEC, Posted March 11, 2019 by springercontrols. Equipment that is listed for a Zone 1 location may be installed in a Zone 2 location of the same gas or vapor. Explosion Hazardous Areas are divided into zones according to risk probabilities. Temperature Control October 2022 Powder Filling "q" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. 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. Use this hazardous area guide to NFPA 70 location classes, divisions & groups to understand potentially dangerous situations at a glance. December 2020 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. Standards and regulations exist to identify such locations, classify the hazards, and design equipment for safe use in such locations. 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. These would be then labeled with each of the individual methods. Hazardous Area Classifications D103222X012 Product Bulletin 9.2:001 . The value is represented is volume percentage of oxygen. 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. Google use cookies for serving our ads and handling visitor statistics. 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 level of risk is represented by classifying the hazardous area as Zone 0, Zone 1 or Zone 2 (for gas, vapour and mist atmospheres) or Zone 21 or Zone 22 for dust atmospheres. 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. 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). It is essential to know which zone you are working in, so that you can specify the most appropriate equipment. Equipment is placed into protection level categories according to manufacture method and suitability for different situations. Identifying Zone 0, Zone 1, and Zone 2 Hazardous Areas. Class II, Div 2 Class III, Div 1 nR 3G Zone 2 Gc Class III, Div 2 Pressurised Room px 60079-13 2G Zone 1 Gb Zone 21 Db 2D Pressurised Room FM3611 NFPA 496 Class I, Div 1 Class I, Div 2 Class II, Div 1 Class II, Div 2 py 2G Zone 1 Gb pz 3G Zone 2 Gc Zone 22 Dc 3D pv Non-hazardous Gb/GC Optical Radiation op sh 60079-28 1G Zone 0 Ga Zone 20 Da 1D . 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. November 2019 Flour, wood/sawdust, plastic dust). When working in or specifying equipment for use in hazardous environments, we see a lot of confusion in the industry regarding the different certifications and requirements. Zone 2. >> For Gas/Vapor this would be Zone 2. less than 0.45 mm or MIC ratio is less than 0.40. 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. Some other standards have more quantitative methods which require more knowledge of the plant, an example is the IEC standard 60079-10-1. The process of determining the type and size of hazardous locations is called classification. It is always balancing between not defining such areas too large (with highly costs for prevention of ignition sources) or too small (unsafe situations). Whenever you are filling up your tank you are standing in a Zone 1 hazardous area. The Zone system has three levels of hazard for gas or dust where the Division system has two. May 2022 This level of risk is represented by classifying the hazardous area as Zone 0, Zone 1 or Zone 2 (for gas, vapour and mist atmospheres) or Zone 21 or Zone 22 for dust atmospheres. 0,1 or 2: II B: I: 1 or 2: C: Acetone Benzene Butane Hexane . Temporary Refuge (TR) Shelter 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. 2: Where gas detection, Informational Note No. Q: Are Divisions and Zones equivalent to one another? 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. This concentration is substance specific and lies normally somewhere between the LEL and UEL. We don't save this data. Classification of locations, testing and listing of equipment, and inspection of installation, is typically overseen by governmental bodies. What is an Explosion Protection Document? MCC Shelter The Zone system has wider use in the chemical and petrochemical industries. Various regulations use terms such as class, division, zone, and group to differentiate the various hazards. 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. . WATER TIGHTNESS 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. February 2023 For dusts: Zone 20, Zone 21 and Zone 22. POSITIVE PRESSURE In effect it is any method which can be shown to have the required degree of safety in use. This process is called hazardous area classification. The equipment housing may be sealed to prevent entry of flammable gas or dust into the interior. Much early equipment having Ex s protection was designed with encapsulation and this has now been incorporated into IEC 60079-18 [Ex m]. Zone 0 - Explosive atmospheres present continuously long periods or frequently. Zones compares to classes and divisions in the Class/Division system. Workshop Container, Intelligent pressurised container | MUD logging cabin, Battery energy storage system (BESS) container, Laboratory container | workshop container | Equipment containers, Temporary refuge shelter | Toxic gas refuge | Safe haven, Offshore accommodation cabin | office container, Reefer container | Refrigerated container, Intelligent waste water treatment container, IDENTIFYING ZONE 0, ZONE 1, AND ZONE 2 HAZARDOUS AREAS, Temporary refuge (TR) shelter, toxic gas refuge (TGR), Containerised waste water treatment plant. In Europe the ATEX 114 Directive (2014/34/EU) is applicable to equipment that is used in hazardous area's. API 500/505 mostly for onshore and offshore oil and gas applications. These areas are classified solely for the purpose of ensuring the safe and proper specification and installation of electrical/electronic equipment. 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. This is an important factor in the classification of hazardous areas. . See below for further details: Division system sample marking The design of the equipment must ensure protection, even in the event of rare incidents relating to the equipment. January 2023 Examples are: production facilities in the food industry, chemical plants, oil & gas, and the pharmaceutical industry etc. Hazardous areas are classified into zones based on an assessment of the frequency of the occurrence and duration of an explosive gas atmosphere, as shown in the illustration below.