15 4. Zone 1 is an area in which an explosive atmosphere is likely to occur occasionally in normal operation. That is why the use of mobile phones on petrol forecourts are banned. Identifying Zone 0, Zone 1, and Zone 2 Hazardous Areas Definition of hazardous area zones (AS/NZS 60079.10): Zone 0 Hazardous area classification is a rigorous method of determining where an explosive environment may be present. Hazardous Area Classification is a study, in which is assessed, at witch locations of a plant, factory or company, high concentrations of flammable gases are present or can be released, in order to create an explosion hazard. Area classification - atozwiki.com February 2023 Area Classification for Mechanical Data Sheet - API 610 The Zone system of hazardous area classification, defines the probability of the hazardous material, gas, or dust, being present in sufficient quantities that can generate explosive or ignitable mixtures. Flour, wood/sawdust, plastic dust). The label will always list the class, division and may list the group and temperature code. 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. 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). Analysers, motors, control boxes, computers, Any arcs or sparks in this equipment has insufficient energy (heat) to ignite a vapour. 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. hazardous area classification - PowerPoint PPT Presentation - PowerShow Much early equipment having Ex s protection was designed with encapsulation and this has now been incorporated into IEC 60079-18 [Ex m]. It is created based on input from the Process Flow Diagrams, Piping & Instrumentation Diagrams and the Equipment Location Plan . In some cases, the hazardous atmosphere is present all the time, or for long periods. 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". In the United States, the hazardous location classification system is defined by the National Fire Protection Association (NFPA) 70, National Electric Code(NEC). As a guide for Zone 0, this can be defined as over 1,000 hours/year or >10% of the time. January 2021 Area which are not devided into Atex zones, are called non-hazardous area's. Class / Division System In Northerm America, instead of the zone classification system, the Class/Division system is used. 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. Division defines the probability of the hazardous material being present in an ignitable concentration in the surrounding atmosphere. In general, all types of equipment installed within the hazardous area shall be . The part codes for each SPARTAN variant also differ depending on the level of protection required. Each chemical gas or vapour used in industry is classified into a gas group. Such properties include flame temperature, minimum ignition energy, upper and lower explosive limits, and molecular weight. Motors, lighting, junction boxes, electronic equipment, This method, being by definition special, has no specific rules. Hazardous Area Classification Questions - Inst Tools 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. Hazardous Areas - North America Classification - Engineering ToolBox October 2020 Zone 0/20: An area in which an explosive atmosphere is present continuously or for long periods or frequently. This is presented by the Lower Explosion Limit (LEL) of a substance. RP 505 is referred to as the zone system. 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. 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. Comparisons between the two systems are not easily accomplished. A high level of protection is ensured. The a subdivisions have the most stringent safety requirements, taking into account more than one independent component faults simultaneously. The more hazardous the area to more safety measures have to be taken in order to prevent equipment becoming an effective source of ignition. Many items of EEx rated equipment will employ more than one method of protection in different components of the apparatus. PDF HazLoc Hand Chart Hazardous Area Zone Classification - EUTEX International 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. 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). Typical gas hazards are from hydrocarbon compounds, but hydrogen and ammonia are also common industrial gases that are flammable. The minimum concentration of oxygen, necessary for the combustion to take place, is called the Limiting Oxygen Concentration. | For Gas/Vapor this would be Zone 0. . >> For Gas/Vapor this would be Zone 0. No other aspect of safety receives more attention in the form of codes and standards. This can be achieved by blanketing with nitrogen or carbondioxide. When equipment must be placed in a hazardous location, it can be designed to reduce the risk of fire or explosion. For Zone 1 applications, Pyroban uses . Electrical equipment installed in such locations can provide an ignition source, due to electrical arcing, or high temperatures. Horizontal. 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. ), Group F Carbon-based (eg. Note to paragraph (g)(5)(ii)(C) of this section: The National Electrical Code, NFPA 70, contains guidelines for determining the type and design of equipment and installations that will meet this provision. (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. Hazards in this group gas can be ignited very easily indeed. Classification of locations, testing and listing of equipment, and inspection of installation, is typically overseen by governmental bodies. It may exist because of repair, maintenance operations, or leakage. Hazardous area classification. Informational Note No. Zone 0 is an area in which an explosive atmosphere is present continuously for long periods of time or will frequently occur. Oxygen is required in high quantities and in combination with the flammable substance to produce an explosive atmosphere. A light switch may cause a small, harmless spark when switched on or off. Practical guidelines for determining electrical area classification Fundamentally, for an explosion to take place, flammable or explosive gases, vapours, mists or dusts will be present. PDF Class/Division Hazardous Location - Rockwell Automation 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. gas, vapours, mists and dusts). . In Europe the ATEX 114 Directive (2014/34/EU) is applicable to equipment that is used in hazardous area's. 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. 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. 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). July 2021 Division defines the likelihood of the hazardous material being present in an explosive or ignitable concentration.Class I flammable gases and vapors are grouped into one of four groups(Groups A, B, C or D)based on their physical properties and the ease in which they can be ignited. Pit will be considered as Zone 1. Equipment is placed into protection level categories according to manufacture method and suitability for different situations. Hazardous Area Classification and Control of Ignition Sources - HSE National Electric Code 2020 edition National Fire Protection Association. For equipment provided with threaded entries for NPT threaded conduit or fittings, listed conduit, conduit fittings, or cable fittings shall be used. MCC Shelter This is also one of the first steps when composing an Explosion Protection Document. NFPA 70 NEC Zone Classification System The Zone Classification System is offered as an alternative to the Class and Division system. Equipment used in hazardous area must comply to certain Ex standards. Areas with possible fire or explosion risks due to explosive atmospheres and/or mixtures - are called hazardous (or classified) locations or areas. 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. Overview of Hazardous Areas | Expo Technologies February 2019 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. . Hazardous area classification for electrical systems - PetroWiki Flammable liquids with a high flash point are less hazardous than liquids The International Electrotechnical Commission publishes the 60079 series of standards[2] which defines a system for classification of locations, as well as categorizing and testing of equipment designed for use in hazardous locations, known as "Ex equipment". Division II Comprising of Area Same as Zone 2. Class 1 / Division 2 and ATEX Zone 2 Explained - Assured Systems There are two sets of Zones: Zones 0 thru 2 are used for gases, vapors, and mists, and Zones 20 thru 22 are . Ignitable concentrations of flammable gases or vapors which are likely to occur under normal operating conditions. Hazardous areas are those defined as areas of potential explosion risk due to the presence of flammable gas or vapor. These areas only become hazardous in case of an accident or some unusual operating condition. These areas are classified solely for the purpose of ensuring the safe and proper specification and installation of electrical/electronic equipment. 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 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 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. The American Petroleum Institute publishes analogous standards in RP500 andRP505. Article 505 National Electrical Code (NEC), Article 506 National Electrical Code (NEC). 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. Then, the level of risk of an explosion is based on the frequency and duration of the occurrence of an explosive atmosphere. December 2013, All Hazardous Area Classification - [PPT Powerpoint] Controls can be fitted to detect dangerous concentrations of hazardous gas, or failure of countermeasures. Atmospheres containing non-conductive dust. Raytec do not currently offer any lighting solutions for Zone 0. FREEZER 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. 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. For example, within the U.K. in the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR) and in the U.S. in the Occupational Safety and Health Act of 1970 (OSHA). . 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. Increased safety "e" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. But every hazardous area is different and each has specific requirements depending on the nature of the atmosphere and the elements that are present. June 2022 A hazardous area can be defined as any location where there is risk of an explosion. Equipment of the nonheat-producing type, such as junction boxes, conduit, and fittings, and equipment of the heat-producing type having a maximum temperature not more than 100 C (212 F) need not have a marked operating temperature or temperature range; Electric equipment suitable for ambient temperatures exceeding 40 C (104 F) shall be marked with both the maximum ambient temperature and the operating temperature or temperature range at that ambient temperature; and. LIFTING TEST 1. Methane has a LEL of 4,4 vol%. Container Accessories 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. Ex s is a coding referenced in IEC 60079-0. NEGATIVE PRESSURE 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. Often an area classification plan view is provided to identify equipment ratings and installation techniques to be used for each classified area. 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 Well recognized and clear IEC Standard IEC 60079-10-2:2015 Hazardous Area Classification for explosive dusts Significant influence on spending's for safety . Hazardous Area Classifications: What You Need to Know 3: Text that is followed by a reference in brackets has been extracted from NFPA 497-2017, All other applicable rules contained in this, Where the term "Class I" is used with respect to, Informational Note: The term "Class I" was originally included as a prefix to, All areas in industrial occupancies designated as hazardous (classified). 1: As a guide to classification of Zone 22 locations, refer to ANSI/ISA 60079-10-2 (12.10.05)-2013, Explosive Atmospheres Part 10-2: Classification of areas Combustible dust atmospheres. Gases, Vapors and Mists. 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 . The definition of the hazardous area zones represent the likelihood of hazardous gas, dust or other hazards being present in a working area. Hazardous Area Classifications D103222X012 Product Bulletin 9.2:001 . As mentioned, the first important step of achieving a safe work environment in relation to explosion safety is to identify and classify those areas, where a concentration of flammable gases or vapors within the flammable range can be present. And safety must be guaranteed in the case of two faults occurring independently of each other. 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. less than 0.45 mm or MIC ratio is less than 0.40. What is an Explosion Protection Document? In an ordinary household this is of no concern, but if a flammable atmosphere is present, the arc might start an explosion. 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. July 2020 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). Substance properties are specific for the amount of fuel needed to get an explosion when all other conditions are met. March 2021 | For Dust this would be Zone 21. In the United States, the most commonly followed system is the NEC (National Electric Code), while the rest of the world generally follows the IEC (International Electrotechnical Commission). The term equipment is applied both for fixed equipment and mobile equipment that are operated in such area. Zone 1 - Explosive atmospheres are likely to occur. Zone 1 an area in which an explosive gas-air mixture is likely to occur in normal operating conditions. May 2021 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. Temporary Refuge Zone 2 hazardous areas are typically storage areas but can also be process areas. Table 1. National Electrical Code (NEC) and the 1998 Canadian Electrical Code (CEC) now recognize the use of the Zone system for classification of hazardous areas. Zone 2 - Explosive atmospheres are unlikely to occur or present only infrequently and for a short period only. It is always balancing between not defining such areas too large (with highly costs for prevention of ignition sources) or too small (unsafe situations). 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. An area where combustible dusts or ignitable fibers and flyings are not likely to occur under normal operating conditions and do so only for a short period of time. Hazardous Location Classification Guide: NEC vs. IEC Ex Zone. Offshore Workshop Container Empirical testing is done to determine parameters such as the maximum experimental safe gap (MESG), minimum igniting current (MIC) ratio, explosion pressure and time to peak pressure, spontaneous ignition temperature, and maximum rate of pressure rise. Refer to Fig.3 which shows the hazardous area zone classification based on hazardous gas release grade. HAZARDOUS VS. 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. When the concentration of methane is beneath the LEL, an explosion cannot occur, even when an ignition source is present. Pressurised Container
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