A potential few examples of this are: The air space inside a tank of petrol Read more in our blogWhich Standards to use for Hazardous Area Classification. Ignitable concentrations of flammable gases or vapors which are present continuously or for long periods of time. 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. Definition of hazardous area zones (AS/NZS 60079.10): Zone 0 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 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. Class I, Zone 0 or Zone 1 locations may not abut Class I, Division 1 or Division 2 locations. 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. The Class/Division/Group system is based on Article 500 of the National Electrical Code (NEC) where. . Sources of such hazards include gases, vapors, dust, fibers, and flyings, which are combustible or flammable. 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. Specific types of protection being used will also be marked. 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 1) MESG (Maximum Experimental Safe Gap) - The maximum clearance between two parallel metal surfaces that has been found under specified test conditions to prevent an explosion in a test chamber from being propagated to a secondary chamber containing the same gas or vapor at the same concentration. Flammable atmosphere expected to be present inside the storage tank continuously, hence it has been classified as zone 0. This is exactly defined as the limiting concentration of oxygen below which combustion is not possible, independent of the concentration of fuel. Equipment in this category is intended for use in Zone 0 areas (gases) or Zone 20 (dusts), and must ensure a very high level of protection (i.e. Hazardous area classification is a rigorous method of determining where an explosive environment may be present. In the United States, the NEC uses 2 different classifications: Quick Tips #124.1. It may exist because of repair, maintenance operations, or leakage. 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. Hazardous locations can also be described as those locations where electrical equipment Many items of EEx rated equipment will employ more than one method of protection in different components of the apparatus. June 2019 Zone 1 (unless separated by a fire wall)P.G.Sreejith, Kerala. 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. hazardous areas as the following: An area where a potential hazard (e.g., a fire, an explosion, etc.) Division II Comprising of Area Same as Zone 2. The more hazardous the area to more safety measures have to be taken in order to prevent equipment becoming an effective source of ignition. Atmospheres containing ethylene, propylene oxide, ethylene oxide, butadiene, cyclopropane, ethyl ether, or gases and vapors of equivalent hazard. When the concentration of gas or vapor is above the UEL the gas mixture is too rich to burn. Zone 2. 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. We don't save this data. . Hazardous Area Classifications D103222X012 Product Bulletin 9.2:001 September 2019. * Zone 2 a . Equipment is placed into protection level categories according to manufacture method and suitability for different situations. Zone 2 - Explosive atmospheres are unlikely to occur or present only infrequently and for a short period only. . Area Classification - Hazardous Locations are classified by the likelihood of an ignitable concentration of combustible material being present. 2: For Group IIIC combustible dusts or metal combustible fibers/flyings, there shall only be Zone 20 or 21 locations. Atmosphere containing a flammable gas, a flammable liquid produced vapor or a combustible liquid-produced vapor whose MESG is greater than 0.75 mm or MIC ratio is greater than 0.40 and less than 0.80 - such as carbon monoxide, ether, hydrogen sulfide, morphline, cyclopropane, ethyl, isoprene, acetaldhyde and ethylene or gases of equivalent hazard. This is presented by the Lower Explosion Limit (LEL) of a substance. The Regulations define 3 zones that can exist within a hazardous area: Zone 0 - A place in which an explosive atmosphere is present continuously or for long periods. In other cases, the atmosphere is normally non-hazardous, but a dangerous concentration can be reasonably foreseensuch as operator error or equipment failure. And there are three corresponding zones for dust: Zone 20, Zone 21 and Zone 22. 11: For information on electric skin effect trace heating for hazardous (classified), Informational Note No. Have a think about it next time youre filling up! | For Dust this would be Zone 22. Atmospheres containing acetylene, hydrogen, carbon disulphide or gases and vapors of equivalent hazard. 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. Where pyrophoric materials are the only materials used or handled, these locations need not be classified. August 2020 What are 'Dark Factories,' and Do They Really Exist? Where there is potential for an explosive atmosphere, special precautions are needed to prevent fires and explosions. A list must be drawn up of every explosive material that is on the refinery or chemical complex and included in the site plan of the classified areas. 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. 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. The minimum concentration of oxygen, necessary for the combustion to take place, is called the Limiting Oxygen Concentration. Zone 1 2. A high level of protection is ensured. Entire Vapour space of storage tank. 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. When the concentration of gas or vapor is beneath the LEL the gas mixture is too lean to burn. Also included in the marking are the manufacturers name or trademark and address, the apparatus type, name and serial number, year of manufacture and any special conditions of use. 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. Dust or other small particles suspended in air can explode. Table 1. Various regulations use terms such as class, division, zone, and group to differentiate the various hazards. . Analysers, motors, control boxes, computers, Any arcs or sparks in this equipment has insufficient energy (heat) to ignite a vapour. 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. CUTTING SKIPS Much early equipment having Ex s protection was designed with encapsulation and this has now been incorporated into IEC 60079-18 [Ex m]. 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 equipment housing may be sealed to prevent entry of flammable gas or dust into the interior. NFPA 70 NEC Zone Classification System The Zone Classification System is offered as an alternative to the Class and Division system. The disadvantage of standards with example installations, is that a huge safety factor is incorporated and thus relative large hazardous area are defined. Class defines the type of explosive or ignitable substances which are present in the atmosphere. 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). Atmospheres containing non-conductive dust. Hazards in this group gas can be ignited very easily indeed. 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. You will find this equipment in paint factories, a warehouse or around a bag dump station. Group defines thetypeof hazardous material and partly thelocationof the surrounding atmosphere . In recent years also the EPL is specified for several kinds of protection. Recommendat ions. August 2018 This classification method provides a description of the hazardous material that may be present, and the probability that it is present, so that the appropriate equipment may be selected, and safe installation practices followed. Identifying Zone 0, Zone 1, and Zone 2 Hazardous Areas. Terminology for both hazards and protective measures can vary. In the IEC standards hazardous areas are classified into zones based upon the frequency and duration of an explosive atmosphere. As to the classification, they are the same. 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. The substance referred to by classhas a low probability of producing an explosive or ignitable mixture and is present only during abnormal conditions for a short period of time - such as a container failure or system breakdown. Arcing electrical equipment in unclassified . 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. a headlamp, rather than a dedicated fixed luminaire. In an industrial plant, such as a refinery or chemical plant, handling of large quantities of flammable liquids and gases creates a risk of exposure. 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. A light switch may cause a small, harmless spark when switched on or off. 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. Although every application is different, for the ease of monitoring and specification each hazardous area is classified as a particular level or zone. NEGATIVE PRESSURE Category 2 equipment may be used in zone 1 or zone 2 areas. Determined to be none of the above. As a guide for Zone 0, this can be defined as over 1,000 hours/year or >10% of the time. 10/1/20 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]. Note to paragraph (g)(4) of this section: Low ambient conditions require special consideration. Which system is preferred depends on the users preference, how the areas are classified, and the wiring system used. Atmospheres containing propane, acetone, benzene, butane, methane, petrol, hexane, paint solvents or gases and vapors of equivalent hazard. >> For Gas/Vapor this would be Zone 0. Methane has a LEL of 4,4 vol%. 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 Google use cookies for serving our ads and handling visitor statistics. Shown below is a summary of the applicable NEC Articles to reference to ensure the proper requirements are applied. 1.1 Scope. Informational Note No. The basis for the classification into zones is the duration of the presence of the potentially explosive atmosphere: The longer it is present, the more critical the zone. Requirements for good HAC Drawings and Plans. Electrical equipment installed in such locations can provide an ignition source, due to electrical arcing, or high temperatures. Q: Can equipment approved for a Class I hazardous location be used in a Class II hazardous location? It is always balancing between not defining such areas too large (with highly costs for prevention of ignition sources) or too small (unsafe situations). Zone 0 is an area in which an explosive atmosphere is present continuously for long periods of time or will frequently occur. August 2021 Fundamentally, for an explosion to take place, flammable or explosive gases, vapours, mists or dusts will be present. Temperature classification, except for intrinsically safe apparatus. This temperature is used for classification for industry and technology applications.[6]. September 2021 . Australia and New Zealand use the same IEC-60079 standards (adopted as AS/NZS60079), however the CE mark is not required. 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. 5: For further information on ventilation, see NFPA 30-2018, Informational Note No. ". Adapters shall be used for connection to conduit or NPT-threaded fittings. Photo 2. Coal mines, grain mills, elevators, and similar facilities likewise present the risk of a clouds of dust. Hazardous areas are those defined as areas of potential explosion risk due to the presence of flammable gas or vapor. Click on the zone to learn more about the classification according to IEC 60079-10 standards. Then, the level of risk of an explosion is based on the frequency and duration of the occurrence of an explosive atmosphere. Group defines the type of the hazardous material in the surrounding atmosphere. THE CURRENT STANDARD . 10: For information on electrical resistance trace heating for hazardous (classified), Informational Note No. - 1 2 (Class 1, . CLASSIFIED LOCATIONS: AREA CLASSIFICATION: AREA CLASSES: AREA GROUPS: LOCATION AS PER DIVISIONS: DIVISION 1 - Class I, Division 1 hazardous locations are defined (as per NEC code Article 500) as follows: DIVISION 2 - Class I Division 2 Locations are as follows: Area Classification by ZONES: DEFINITIONS: HAZARDOUS LOCATIONS: And safety must be guaranteed in the case of two faults occurring independently of each other. A special standard for instrumentation is IEC/EN 60079-27, describing requirements for Fieldbus Intrinsically Safe Concept (FISCO) (zone 0, 1 or 2) (This special standard has been withdrawn, and has been partially replaced by: IEC/EN60079-11:2011 and IEC/EN60079-25:2010)[1], A special standard for instrumentation is IEC/EN 60079-27, describing requirements for Fieldbus Non-Incendive Concept (FNICO) (zone 2) (This special standard has been withdrawn, and has been partially replaced by: IEC/EN60079-11:2011 and IEC/EN60079-25:2010)[9]. The design of the equipment must ensure protection, even in the event of rare incidents relating to the equipment. may exist under normal or abnormal conditions because of the presence of flammable gases or vapors, combustible dusts or ignitable fibers or flyings. Intrinsic safety -- This protection technique is permitted for equipment in the Class I, Zone 0 or Zone 1 locations for which it is approved. The following content is only related to flammable substances and not to pyrotechnic substances or other instable substances, among those who can decompose. . 29 CFR 1910.399 Definitions Applicable to Subpart S In some cases, it must be certified as meeting that standard. EN 16985 concerning spray cabins and powder coating cabins, EN 12779 related to extraction systems for hot sawdust and chips, EN 60079-10 series, 2020 version for gas and dust explosion hazard, NPR 7910 series for gas and dust explosion hazard based on EN 60079-10-1, 2015 version, EN 13617 for fuel dispensers at filling stations. | For Dust this would be Zone 21. 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. |MWD/LWD Cabin In Northerm America, instead of the zone classification system, the Class/Division system is used. The Zone system has wider use in the chemical and petrochemical industries. 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. In Europe the label must show the CE mark and the code number of the certifying/notified body). Upon detection, appropriate action is automatically taken, such as removing power, or providing notification. No. The Raytec SPARTAN range includes dedicated luminaires for both Zone 1 and Zone 2 areas as well as industrial applications. 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. February 2023 No hidden fees. When the concentration of methane is beneath the LEL, an explosion cannot occur, even when an ignition source is present. area in which an explosive gas atmosphere is likely to occur occasionally in normal operation. 1: For examples of area classification drawings, see ANSI/API RP 505-2018, Informational Note No. . LIFTING TEST So a zone 0 is the most hazardous zone and a zone 2 is a less hazardous zone. February 2019 . That is why the use of mobile phones on petrol forecourts are banned. Youre phone isnt rated for use in hazardous areas. Area ClassificationThe max surface temp. 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. 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. October 2021 As a guide for Zone 0, this can be defined as over 1000 hours/year or >10% of the time. 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. The types of protection are subdivided into several sub classes, linked to EPL: ma and mb, px, py and pz, ia, ib and ic. 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. 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. A spark or high heat must also be present. The value is represented is volume percentage of oxygen. Zone 0Ignitable concentrations of flammable gases or vapors which are present continuously or for long periods of time. The hazardous area classification system determines required protection techniques and methods for electrical installations in the location. Non-hazardous or ordinary locations. 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. Zones compares to classes and divisions in the Class/Division system. Determining the Class, Division and Group or Zone and Group is critical to correctly applying the requirements for a given hazardous location. March 2022 For example the EI 15 and API 500/505 describe specific installations and several conditions for the oil and gas industry. A room with a propane gas installation will typically be classified with the. This value of this LOC differs per substance and depends also on the inert gas for achieving a low oxygen concentration. The codes and standards used in this process provide guidance for selecting,. But first, we must consider what is likely to cause an explosion in the first place. Division defines the probability of the hazardous material being present in an ignitable concentration in the surrounding atmosphere. 1994-2020, W.W. Grainger, Inc. All Rights Reserved. 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. Refer to Fig.3 which shows the hazardous area zone classification based on hazardous gas release grade. 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. 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. For methane this is shown in the following figure. gas, vapours, mists and dusts). Magnesium, Aluminum, Titanium etc. 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. National Electrical Code (NEC) and the 1998 Canadian Electrical Code (CEC) now recognize the use of the Zone system for classification of hazardous areas. PROCESS OF CONTAINER Zone 0, 1 2 . This can be achieved by blanketing with nitrogen or carbondioxide. Category 1 equipment may be used in zone 0, zone 1 or zone 2 areas. Ignitable concentrations of flammable gases or vapors which are likely to occur under normal operating conditions. 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. ESS Container 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. Flour, wood/sawdust, plastic dust), IIC Conductive dusts (eg. 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. Carbon monoxide, ether, hydrogen sulfide, . Please read Google Privacy & Terms for more information about how you can control adserving and the information collected. Refrigerated Container ethanol, methane or hydrogen. An area where combustible dusts or ignitable fibers and flyings are likely to occur under normal operating conditions. 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.

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