For explosion hazards caused by flammable liquids or gases, the following zones are defined: So a zone 0 is the most hazardous zone and a zone 2 is a less hazardous zone. A: When comparing Divisions and Zones, Division 2 is equivalent to Zone 2, but Division 1 is equivalent to either Zone 0 or 1. Hazardous Area Classifications D103222X012 Product Bulletin 9.2:001 September 2019. Zone 0 is an area in which an explosive atmosphere is present continuously for long periods of time or will frequently occur. Equipment used in hazardous area must comply to certain Ex standards. 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. The IEC 60079 standard set has been adapted for use in Australia and New Zealand and is published as the AS/NZS 60079 standard set. The choice of which standard to use for the hazardous area classification is something which is very important. Area's are divided into zones. IEC 60079-10-1 covers classification of explosive gas atmospheres, and IEC 60079-10-2 explosive dust. The simplest is to minimize the amount of electrical equipment installed in a hazardous location, either by keeping the equipment out of the area altogether, or by making the area less hazardous (for example, by process changes, or ventilation with clean air). 5: For further information on ventilation, see NFPA 30-2018, Informational Note No. a headlamp, rather than a dedicated fixed luminaire. 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. Recommendat ions. 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. Protecting against fire and explosion is of interest for both personnel safety as well as reliability reasons. Within a working area or installation an ignition can be created by many factors. Area's are divided into zones. Informational Note: For further information regarding classification and ventilation of areas involving closed-circuit ammonia refrigeration systems, see ANSI/IIAR 2-2014. Groups E, F, and G are for dusts and flyings (Class II or III). The disadvantage of standards with example installations, is that a huge safety factor is incorporated and thus relative large hazardous area are defined. A: Yes. Container Accessories Directly adjacent on the label one will find the mark of the listing agency. Copryright 2023 Springer Controls Company . 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. Category 2 equipment may be used in zone 1 or zone 2 areas. 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. This concentration is substance specific and lies normally somewhere between the LEL and UEL. 1: The term "Class I" was originally included as a prefix to, Informational Note No. Which system is preferred depends on the users preference, how the areas are classified, and the wiring system used. The types of protection are subdivided into several sub classes, linked to EPL: ma and mb, px, py and pz, ia, ib and ic. 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 THE PRODUCTS YOU NEED, 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. Some other standards have more quantitative methods which require more knowledge of the plant, an example is the IEC standard 60079-10-1. Temperature classification, except for intrinsically safe apparatus. The prevention of explosions in working environments is in most countries regulated in national laws and directives. 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. Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications! If equipment is marked, for example, Ex e II T4 then it is suitable for all subgroups IIA, IIB and IIC. the National Fire Protection Association (NFPA) 70, National Electric Code(NEC). This can be achieved by blanketing with nitrogen or carbondioxide. Therefor Hazardous Area Classification (HAC) is the first important step in achieving an explosion safe installation or work environment. . 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. Flour, wood/sawdust, plastic dust), IIC Conductive dusts (eg. If equipment has been approved for use in a Division 1 hazardous location, it can be used in a Division 2 hazardous location, providing it is in the same class and group. Much early equipment having Ex s protection was designed with encapsulation and this has now been incorporated into IEC 60079-18 [Ex m]. Read more in our blogWhich Standards to use for Hazardous Area Classification. . October 2021 Typical gas hazards are from hydrocarbon compounds, but hydrogen and ammonia are also common industrial gases that are flammable. 15 4. For Zone 1 applications, Pyroban uses . 1.1.2 This recommended practice provides information on specific flammable gases and vapors, flammable liquids . So for an explosion there must be enough fuel. Temporary Refuge (TR) Shelter January 2022 2: For Group IIIC combustible dusts or metal combustible fibers/flyings, there shall only be Zone 20 or 21 locations. [1] NEC article 500 describes the NEC Division classification system, while articles 505 and 506 describe the NEC Zone classification system. . Have a think about it next time youre filling up! Standards and regulations exist to identify such locations, classify the hazards, and design equipment for safe use in such locations. 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. Offshore Workshop Container The temperature marking may not exceed the ignition temperature of the specific gas or vapor to be encountered. 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. Determining the Class, Division and Group or Zone and Group is critical to correctly applying the requirements for a given hazardous location. The autoignition temperature is the lowest temperature at which the substance will ignite without an additional heat or ignition source (at atmospheric pressure). Hazardous Area Classification (HAC) is as follows: Definitions of hazardous area are different as per IEC and NEC. The Zone system has wider use in the chemical and petrochemical industries. Where there is potential for an explosive atmosphere, special precautions are needed to prevent fires and explosions. CUTTING SKIPS December 2021 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. 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). June 2019 August 2021 Other ignition sources can also be present, like static electricity. Division 2 is equivalent to Zone 2, while Division 1 is either Zone 0 or 1. 6: For further information on electrical systems for hazardous (classified), Informational Note No. Encapsulation "m" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. 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). 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. 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. Carbon monoxide, ether, hydrogen sulfide, . area in which an explosive gas atmosphere is not likely to occur in normal operation, but, if it does occur, will exist for a short period only (less than 0,1% of the time), Window breakage, cracks plaster, light damage to buildings, Collapse of wood or asbestos siding of homes, Collapse of walls made of concrete blocks, Reinforced concrete structures severely damaged, Flames and hot gases (including hot particles), Mechanically generated impact, friction and abrasion, Stray electric currents, cathodic corrosion protection, Radio frequency (RF) electromagnetic waves from 10, Exothermic reactions, including self-ignition of dusts, EI 15 Energy Institute 15, mostly for on- and offshore oil and gas applications. Often an area classification plan view is provided to identify equipment ratings and installation techniques to be used for each classified area. 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. 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. Cookies are only used in the browser to improve user experience. Each chemical gas or vapour used in industry is classified into a gas group. 1910.307 (g) (2) July 2020 - 1 2 (Class 1, . d : HA - ha ea OA - oa Area classification - Divisions vs. zones Continuous hazard Intermittent hazard Hazard under abnormal conditions Zone 0 Zone 1 Zone 2 Division 1 Division 1 Division 2 Hazardous locations - CEC classifications Class I In some cases, it must be certified as meeting that standard. Adapters shall be used for connection to conduit or NPT-threaded fittings. Arcing electrical equipment in unclassified . 0. 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. In the United States, the hazardous location classification system is defined by the National Fire Protection Association (NFPA) 70, National Electric Code(NEC). Zone 1 an area in which an explosive gas-air mixture is likely to occur in normal operating conditions. Group II is for explosive gases (Zone 0, 1 and 2) and Group III is for explosive dusts (Zone 20, 21 and 22). For dusts: Zone 20, Zone 21 and Zone 22. 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.

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