Type of protection "n" is further subdivided into nA, nC, and nR. The types of protection are subdivided into several sub classes, linked to EPL: ma and mb, px, py and pz, ia, ib and ic. coal and charcoal), Group G Nonconductive dusts (eg. Independent test housesNotified Bodiesare established in most European countries, and a certificate from any of these will be accepted across the EU. In Europe the label must show the CE mark and the code number of the certifying/notified body). Australia and New Zealand use the same IEC-60079 standards (adopted as AS/NZS60079), however the CE mark is not required. Get more great content like this sent to your inbox. December 2022 Documentation requirements likewise vary. Atmospheres containing acetylene, hydrogen, carbon disulphide or gases and vapors of equivalent hazard. WHEN YOU NEED THEM. Flammable atmosphere expected to be present inside the storage tank continuously, hence it has been classified as zone 0. 5: For further information on ventilation, see NFPA 30-2018, Informational Note No. Different countries have approached the standardization and testing of equipment for hazardous areas in different ways. August 2020 This is presented by the Lower Explosion Limit (LEL) of a substance. | For Dust this would be Zone 21. 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. Some other standards have more quantitative methods which require more knowledge of the plant, an example is the IEC standard 60079-10-1. The more hazardous the area to more safety measures have to be taken in order to prevent equipment becoming an effective source of ignition. . Oxygen is required in high quantities and in combination with the flammable substance to produce an explosive atmosphere. 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. 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. 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. 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. 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 also one of the first steps when composing an Explosion Protection Document. These generally give rise to areas classied as Zones 0, 1, and 2 respectively. 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. In the US, the National Electrical Manufacturers Association (NEMA) defines standards for enclosure types for a variety of applications. Atmospheres containing propane, acetone, benzene, butane, methane, petrol, hexane, paint solvents or gases and vapors of equivalent hazard. Offshore Living Quarter A differentiation is made between gas Ex zones and dust Ex zones: Gas Ex zones are 0/1/2 and dust Ex zones are 20/21/22. The Zone system has wider use in the chemical and petrochemical industries. Sources (Hazardous Area Classification) . So the following conditions must be met for an explosion to occur: Represented by the following explosion triangle. For gases, vapours and mists the zone classifications are recognised as Zone 0, Zone 1 and Zone 2 areas. In the United Kingdom, Sira and Baseefa are the most well known such bodies. 0,1 or 2: II B: I: 1 or 2: C: Acetone Benzene Butane Hexane . At least two British mine explosions were attributed to an electric bell signal system. 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. 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. Equipment is non-incendive or non-sparking. Equipment that is listed for a Zone 1 location may be installed in a Zone 2 location of the same gas or vapor. 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 In some cases, the hazardous atmosphere is present all the time, or for long periods. Q: Are Divisions and Zones equivalent to one another? 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). Dry Container Temporary Refuge Equipment that is listed for a Zone 0 location may be installed in a Zone 1 or Zone 2 location of the same gas or vapor. 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. . RP 505 is referred to as the zone system. 11: For information on electric skin effect trace heating for hazardous (classified), Informational Note No. Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications! 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. These areas are in North America (United States and Canada) historically classified with the Class/Division system. With the advent of electric power, electricity was introduced into coal mines for signaling, illumination, and motors. 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. Dn 2 - a Ce d e r . Refrigerated Container IECEx Karandikar Certification 1. Category 3 equipment may only be used in zone 2 areas. Zone 2 - Explosive atmospheres are unlikely to occur or present only infrequently and for a short period only. Zone 2: An area in which an explosive atmosphere is not likely to occur in normal operation, but if it does . Category 1 equipment may be used in zone 0, zone 1 or zone 2 areas. Marking "EEx d" in Accordance with EN 50 0 14 and 50 018 . Hazardous classified locations are areas where the possibility of fire or explosion hazards may exist under normal or abnormal conditions because of the presence of flammable, combustible or ignitable gases, vapors, liquids, dust, or fibers/flyings. 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.) Equipment should be tested to ensure that it does not exceed 80%[according to whom?] Other ignition sources can also be present, like static electricity. 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. 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]. 1910.307 (g) (2) The process of determining the type and size of hazardous locations is called classification. Flameproof "d" - This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. 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. Equipment is placed into protection level categories according to manufacture method and suitability for different situations. 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: 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. Methane has a UEL of 17 vol%, which means when the concentration of methane in air is above the 17 vol% an explosion cannot occur even when an ignition source is present. 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. That flammable gas or vapor . Hazardous areas are classified into 3 zones based upon the frequency of the occurrence and duration of an explosive gas atmosphere, as follows: Zone 0 Area in which an explosive gas atmosphere is present continuously or for long periods or frequently. That is why the use of mobile phones on petrol forecourts are banned. Encapsulation "m" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. [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. API 500/505 mostly for onshore and offshore oil and gas applications. Entire Vapour space of storage tank. 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. We don't collect information from our users. This article covers the requirements for the, Informational Note No. Hazardous area equipment is categorized into category-1 for Zone 0 or Zone 20, category-2 for Zone 1 or Zone 21, and category-3 for Zone 2 or Zone 22. The escaping (hot) gases must sufficiently cool down along the escape path that by the time they reach the outside of the enclosure not to be a source of ignition of the outside, potentially ignitable surroundings. 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. September 2021 2: This classification includes, Informational Note No. 14 4. Zone 0, 1, and 2 locations shall include those specified in 505.5 (B) (1), (B) (2), and (B) (3). Beside sufficient fuel, also sufficient oxygen is needed for combustion of the mixture. The plan may contain the list of chemicals with their group and temperature rating. 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). In this system, two bare wires were run along the length of a drift, and any miner desiring to signal the surface would momentarily touch the wires to each other or bridge the wires with a metal tool. In effect it is any method which can be shown to have the required degree of safety in use. 2: For Group IIIC combustible dusts or metal combustible fibers/flyings, there shall only be Zone 20 or 21 locations. But first, we must consider what is likely to cause an explosion in the first place. Ways to ensure this level of safety are non-arcing design and limitation of the temperature of the equipment. of Groups A, B, C, and D are for gases (Class I only). And there are three corresponding zones for dust: Zone 20, Zone 21 and Zone 22. July 2020 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". FREEZER . Division 2 is equivalent to Zone 2, while Division 1 is either Zone 0 or 1. CUTTING SKIPS Sources of such hazards include gases, vapors, dust, fibers, and flyings, which are combustible or flammable. 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. Increased safety "e" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. For example, in the US by the Occupational Safety and Health Administration. IEC 60079-10-1 covers classification of explosive gas atmospheres, and IEC 60079-10-2 explosive dust. . In Europe and the rest of the world - but also more and more in North America - the Zone system is used. >> NEC: Class I, Division 2, Group D. | IEC: Zone 2, Group II. The design of the equipment must ensure protection, even in the event of rare incidents relating to the equipment. Q: Can I use a piece of equipment approved for use in a Division 1 hazardous location in a Division 2 hazardous location? Hazardous areas are classified into zones based on an assessment of the frequency of the occurrence and duration of an explosive gas atmosphere, as follows: Zone 0: An area in which an. February 2021 May 2019 ), Group F Carbon-based (eg. Area which are not devided into Atex zones, are called non-hazardous area's. 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. Equipment can be designed or modified for safe operation in hazardous locations. 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. Electrical equipment can and does cause fires and/or explosions in certain atmospheres. 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. Area's are divided into zones. SEWAGE TREATMENT Offshore Workshop Container 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. In Northerm America, instead of the zone classification system, the Class/Division system is used. Explosion protection must be ensured during normal operation. 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. Electrical equipment installed in such locations can provide an ignition source, due to electrical arcing, or high temperatures. Division II Comprising of Area Same as Zone 2. 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. Hazardous area classification. It uses the familiar Class/Division system and adapts the IEC/CENELEC Zones into it while maintaining NEC wiring methods and . However, the following provisions modify this marking requirement for specific equipment: Fixed lighting fixtures marked for use in Class I, Division 2 or Class II, Division 2 locations only need not be marked to indicate the group; Fixed general-purpose equipment in Class I locations, other than lighting fixtures, that is acceptable for use in Class I, Division 2 locations need not be marked with the class, group, division, or operating temperature; Fixed dust-tight equipment, other than lighting fixtures, that is acceptable for use in Class II, Division 2 and Class III locations need not be marked with the class, group, division, or operating temperature; and. Group is divided in three groups where Group I is reserved for mining locations. The colour of the luminaire body indicates the level of protection. A high level of protection is ensured. Group defines the type of the hazardous material in the surrounding atmosphere. Protecting against fire and explosion is of interest for both personnel safety as well as reliability reasons. February 2019 Zone 1 an area in which an explosive gas-air mixture is likely to occur in normal operating conditions. Zone 1 is an area in which an explosive atmosphere is likely to occur occasionally in normal operation. October 2020 A60 Shown below is a summary of the applicable NEC Articles to reference to ensure the proper requirements are applied. A: Yes. The equipment group . area in which an explosive gas atmosphere is present continuously, or for long periods, or frequently (more than 10% of the time). Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro .Add the Engineering ToolBox extension to your SketchUp from the SketchUp Pro Sketchup Extension Warehouse! If you want to promote your products or services in the Engineering ToolBox - please use Google Adwords. Gases, Vapors and Mists. PROCESS OF CONTAINER You will find these zones at the manifold of a tank truck or the interior of a silo. Often an area classification plan view is provided to identify equipment ratings and installation techniques to be used for each classified area. Fundamentally, for an explosion to take place, flammable or explosive gases, vapours, mists or dusts will be present. 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. Zone 0 is an area in which an explosive atmosphere is present continuously for long periods of time or will frequently occur. So for an explosion there must be enough fuel. Comparison of Zones and Divisions. The American Petroleum Institute publishes analogous standards in RP500 andRP505. 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. In many industrial, commercial, and scientific settings, the presence of such an atmosphere is a common, or at least commonly possible, occurrence. There are several ways of how to perform hazardous area classification, all described in several standards or codes of practise. For methane this is shown in the following figure. March 2022 The definition of the hazardous area zones represent the likelihood of hazardous gas, dust or other hazards being present in a working area. For Zone 1 applications, Pyroban uses . Choose the right method for Hazardous Area Classification! 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. Temperature Control The surface of a high pressure steam pipe may be above the autoignition temperature of some fuel-air mixtures.