If equipment is marked, for example, Ex e II T4 then it is suitable for all subgroups IIA, IIB and IIC. October 2022 Use this hazardous area guide to NFPA 70 location classes, divisions & groups to understand potentially dangerous situations at a glance. Group II is for explosive gases (Zone 0, 1 and 2) and Group III is for explosive dusts (Zone 20, 21 and 22). March 2021 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. The Raytec SPARTAN range includes dedicated luminaires for both Zone 1 and Zone 2 areas as well as industrial applications. July 2020 October 2020 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. Zones 1 or 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. Zone 1 - Explosive atmospheres are likely to occur. Figures show that appr. 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. Area Classification - Hazardous Locations are classified by the likelihood of an ignitable concentration of combustible material being present. 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. POSITIVE PRESSURE The Zone system has three levels of hazard for gas or dust where the Division system has two. 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. The following Equipment Groups and Categories are applicable: Equipment in this category is only intended for use in the underground areas of mines, as well as those areas of surface installations of such mines endangered by firedamp and/or combustible dusts. Those guidelines address electric wiring, equipment, and systems installed in hazardous (classified) locations and contain specific provisions for the following: wiring methods, wiring connections; conductor insulation, flexible cords, sealing and drainage, transformers, capacitors, switches, circuit breakers, fuses, motor controllers, receptacles, attachment plugs, meters, relays, instruments, resistors, generators, motors, lighting fixtures, storage battery charging equipment, electric cranes, electric hoists and similar equipment, utilization equipment, signaling systems, alarm systems, remote control systems, local loud speaker and communication systems, ventilation piping, live parts, lightning surge protection, and grounding. 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. 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. These ways of protection are specified in detail within several IEC standards (IEC 60079 series) for electrical equipment. For specific industries, the specific codes for that industry are important to use. Drop Test August 2021 Zone 0 Zone 1 Zone 2 Fluid Occurrence of explosive atmosphere Gas mixtures Dust mixtures Not likely to occur or only for short period Zone 2 Zone 22 . Hazardous Environment Classifications: NEC vs IEC, IEC (International Electrotechnical Commission), Group E Metal dusts (eg. 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. September 2021 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. And there are three corresponding zones for dust: Zone 20, Zone 21 and Zone 22. Zone 0, 1, and 2 locations shall include those specified in 505.5 (B) (1), (B) (2), and (B) (3). 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. You can target the Engineering ToolBox by using AdWords Managed Placements. 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. 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. Group is divided in three groups where Group I is reserved for mining locations. The choice of which standard to use for the hazardous area classification is something which is very important. 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. 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. Examples are: production facilities in the food industry, chemical plants, oil & gas, and the pharmaceutical industry etc. April 2021 *unless risk assessment states a higher or lower category is required. Refrigerated As to the classification, they are the same. Many items of EEx rated equipment will employ more than one method of protection in different components of the apparatus. Only emails and answers are saved in our archive. NEGATIVE PRESSURE The minimum concentration of oxygen, necessary for the combustion to take place, is called the Limiting Oxygen Concentration. The two general approaches are: Several techniques of flame-proofing exist, and they are often used in combination: Equipment has flameproof gaps (max 0.006" (150m) propane/ethylene, 0.004" (100m) acetylene/hydrogen), Equipment can be installed in ANY housing provided to IP54.A 'Zener Barrier', opto-isolator or galvanic unit may be used to assist with certification. with hazardous areas EC-Type Examination Certificate BAS 01 ATEX 7251 , for additional certificates see www.pepperl-fuchs.com Group, category, type of protection II (1) G D [EEx ia] IIB (-20 C Ta 60 C) [circuit(s) in zone 0/1/2] Output EEx ia IIB Voltage U0 25.9 V Current I0 184 mA Power P0 1.2 W Type of protection [EEx ia] 11: For information on electric skin effect trace heating for hazardous (classified), Informational Note No. Standards and regulations exist to identify such locations, classify the hazards, and design equipment for safe use in such locations. Controls can be fitted to detect dangerous concentrations of hazardous gas, or failure of countermeasures. Pit will be considered as Zone 1. 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. 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. 1.1.2 This recommended practice provides information on specific flammable gases and vapors, flammable liquids . Zone 0 is an area in which an explosive atmosphere is present continuously for long periods of time or will frequently occur. All areas in the facility that are not Zone 0, Zone 1, or Zone 2 are considered unclassified. 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). To make this even easier to understand, take a look at the diagram of a typical petrol station below where we have identified the areas that are classified as Zone 0, Zone 1 and Zone 2. October 2021 Determining the Class, Division and Group or Zone and Group is critical to correctly applying the requirements for a given hazardous location. (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. September 2022 Area ClassificationThe max surface temp. PROCESS OF CONTAINER In effect it is any method which can be shown to have the required degree of safety in use. 7: For further information on application of electrical, Informational Note No. 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. A Class I, Division 1 or Division 2 location may be reclassified as a Class I, Zone 0, Zone 1, or Zone 2 location only if all of the space that is classified because of a single flammable gas or vapor source is reclassified. 29 CFR 1910.399 Definitions Applicable to Subpart S
Beside the Lower Explosion Limit, each substance also has an Upper Explosion Limit (UEL). Requirements for good HAC Drawings and Plans. 3: For further information on the classification of, Informational Note No. No other aspect of safety receives more attention in the form of codes and standards. Hazardous Area Classifications D103222X012 Product Bulletin 9.2:001 . No long-term contract. The Zone system is based on Article 505/506 of the National Electrical Code (NEC) and follows the international method of area classification as developed by the International Electrotechnical Commission (IEC).
. Specific types of protection being used will also be marked. Electrical equipment can and does cause fires and/or explosions in certain atmospheres. Directly adjacent on the label one will find the mark of the listing agency. 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.
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