The last requirement for the explosion is the presence of an ignition source, like a spark or hot surface. No. Groups E, F, and G are for dusts and flyings (Class II or III). April 2021 Several protection strategies exist. SPARTANs Zone 1 part code begins SPX, Zone 2 SPZ and industrial products having a SPI prefix. Explosions can cause significant damage along with severe injury or worse loss of life. The Zone system has wider use in the chemical and petrochemical industries. These areas are classified solely for the purpose of ensuring the safe and proper specification and installation of electrical/electronic equipment. So for an explosion there must be enough fuel. 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. Equipment in this category is intended for use in areas in which explosive atmospheres caused by gases, vapours, mists or air/dust mixtures are likely to occur occasionally. 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. Zones compares to classes and divisions in the Class/Division system. In Northerm America, instead of the zone classification system, the Class/Division system is used. So a zone 0 is the most hazardous zone and a zone 2 is a less hazardous zone. Increased safety "e" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. Often an area classification plan view is provided to identify equipment ratings and installation techniques to be used for each classified area. Container Accessories ), Group F Carbon-based (eg. Feedback From Clients Refrigerated Informational Note No. . Division 2 is equivalent to Zone 2, while Division 1 is either Zone 0 or 1. Table 1. Other ignition sources can also be present, like static electricity. Category 1 equipment may be used in zone 0, zone 1 or zone 2 areas. .14 . The NEC Zone system was created to harmonize with IEC classification system, and therefore reduce the complexity of management. [4], Flammability of combustible liquids are defined by their flash-point. What is an Explosion Protection Document? Equipment that the employer demonstrates will provide protection from the hazards arising from the flammability of the gas or vapor and the zone of location involved and will be recognized as providing such protection by employees need not be marked. 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). 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 . 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 may exist under normal or abnormal conditions because of the presence of flammable gases or vapors, combustible dusts or ignitable fibers or flyings. August 2022 International Electrotechnical Committee (IEC) Hazardous Area Classification. The temperature classification on the electrical equipment label will be one of the following (in degree Celsius): The above table shows that the surface temperature of a piece of electrical equipment with a temperature classification of T3 will not rise above 200C. The disadvantage of standards with example installations, is that a huge safety factor is incorporated and thus relative large hazardous area are defined. coal and charcoal), Group G Nonconductive dusts (eg. A hazardous area classification drawing (also known as an area classification drawing) outlines the classifications of areas where flammable liquids, gasses or vapors are handed, processed or stored. August 2020 Informational Note No. In the United States, the hazardous location classification system is defined by the National Fire Protection Association (NFPA) 70, National Electric Code(NEC). (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. The equipment housing may be sealed to prevent entry of flammable gas or dust into the interior. 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. Encapsulation "m" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. It is obvious to use those standards within these industries. Arcing electrical equipment in unclassified . August 2021 of the autoignition temperature of the hazardous atmosphere. An area where combustible dusts or ignitable fibers and flyings are likely to occur under normal operating conditions. This concentration is substance specific and lies normally somewhere between the LEL and UEL. These generally give rise to areas classied as Zones 0, 1, and 2 respectively. The Occupational Safety and Health Administration (OSHA) has adopted these hazardous classifications and all except Groups are defined in 29 Code of Federal Register (CFR) 1910.399. There are two systems in place, including the traditional North American Division system as well as the alternative Zone system. 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. In order to understand hazardous area classification it is important to understand which factors contribute to the occurrence of an explosion. August 2018 The housing may be strong enough to contain and cool any combustion gases produced internally. Methane has a LEL of 4,4 vol%. WELDING INSPECTION March 2021 Zone 2 - Explosive atmospheres are unlikely to occur or present only infrequently and for a short period only. Get more great content like this sent to your inbox. Vertical. 41 gas explosions per year occur within the UK and app. Group define the type of hazardous material and (partly) the location of the surrounding atmosphere. In general, all types of equipment installed within the hazardous area shall be . For gases, vapours and mists the zone classifications are recognised as Zone 0, Zone 1 and Zone 2 areas. POSITIVE PRESSURE The classification process requires the participation of operations, maintenance, safety, electrical and instrumentation professionals; and the use of process diagrams, material flows, safety data sheets, and other pertinent documents. . Group defines thetypeof hazardous material and partly thelocationof the surrounding atmosphere . - Zone 0: An area where an explosive gas-air mixture is continuously present or present for long time (continuous hazard, whose estimated duration is higher than 1000 hours/year) - Zone 1: An area where an explosive gas-air mixture is likely to occur during normal . 6: For further information on electrical systems for hazardous (classified), Informational Note No. The more hazardous the area to more safety measures have to be taken in order to prevent equipment becoming an effective source of ignition. Zone 1 2. PROCESS OF CONTAINER Refrigerated Container Equipment shall be approved not only for the class of location, but also for the ignitable or combustible properties of the specific gas, vapor, dust, or fiber that will be present. (between 0,1 and 10% of the time). hazardous areas as the following: An area where a potential hazard (e.g., a fire, an explosion, etc.) The hazardous area classification system determines required protection techniques and methods for electrical installations in the location. 15 4. (1) Zone 0. 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). The prevention of explosions in working environments is in most countries regulated in national laws and directives. Equipment shall be marked in accordance with paragraph (g)(5)(ii)(A) and (g)(5)(ii)(B) of this section, except as provided in (g)(5)(ii)(C). 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. In some cases, the hazardous atmosphere is present all the time, or for long periods. The Zone system has three levels of hazard for gas or dust where the Division system has two. This temperature is used for classification for industry and technology applications.[6]. Laboratory Container Area Classification - Hazardous Locations are classified by the likelihood of an ignitable concentration of combustible material being present. The overpressure is monitored, maintained and controlled. 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. For methane this is shown in the following figure. These generally give rise to areas classied as Zones 0, 1, and 2 respectively. Locations shall be classified depending on the properties of the flammable vapors, liquids, or gases that may be present and the likelihood that a flammable or combustible concentration or quantity is present. Since the changes to the code, hazardous locations with gases or vapors (Class I) present can be reclassified as Zone 0, 1 or 2. See below for further details: Division system sample marking That is why the use of mobile phones on petrol forecourts are banned. 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". May 2019 July 2020 In Europe the ATEX 114 Directive (2014/34/EU) is applicable to equipment that is used in hazardous area's. NFPA 70 NEC Classes, Divisions and Groups. area in which an explosive gas atmosphere is present continuously, or for long periods, or frequently (more than 10% of the time). The choice of which standard to use for the hazardous area classification is something which is very important. Choose the right method for Hazardous Area Classification! Iso Container 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.) 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. 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. 0. Atmospheres containing acetylene, hydrogen, carbon disulphide or gases and vapors of equivalent hazard. 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. 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". A: Yes. Coal mines, grain mills, elevators, and similar facilities likewise present the risk of a clouds of dust. Offshore Accommodation Module Dn 2 - a Ce d e r . There are several ways of how to perform hazardous area classification, all described in several standards or codes of practise. The definition of Zone 2 is a hazardous area classified as an atmosphere where a mixture of air and flammable substances in the form of gas, vapour or mist is not likely to occur in normal operation, but if it does occur, will persist for a short period only. 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. Zone 0Ignitable concentrations of flammable gases or vapors which are present continuously or for long periods of time. Equipment provided with threaded entries for field wiring connection shall be installed in accordance with paragraph (g)(2)(iv)(A) or (g)(2)(iv)(B) of this section. 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. Q: Can I use a piece of equipment approved for use in a Division 1 hazardous location in a Division 2 hazardous location? No representation is made that the information or references are complete or remain current. 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. Note to paragraph (c)(2)(i) of this section: NFPA 70, the National Electrical Code, lists or defines hazardous gases, vapors, and dusts by "Groups" characterized by their ignitable or combustible properties. Photo 2. Shown below is a summary of the applicable NEC Articles to reference to ensure the proper requirements are applied. TLS OFFSHORE CONTAINER The a subdivisions have the most stringent safety requirements, taking into account more than one independent component faults simultaneously. Atmospheres containing combustible flyings. These areas only become hazardous in case of an accident or some unusual operating condition. Then, the level of risk of an explosion is based on the frequency and duration of the occurrence of an explosive atmosphere. Which system is preferred depends on the users preference, how the areas are classified, and the wiring system used. Hazardous Area Classification (HAC) is as follows: Definitions of hazardous area are different as per IEC and NEC. 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. 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 NEW METHODS FOR HAZARDOUS AREA CLASSIFICATION FOR EXPLOSIVE GAS . In the United States, the NEC uses 2 different classifications: 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 CUTTING SKIPS Note to paragraph (g)(5)(ii)(B) of this section: An example of such a required marking is "Class I, Zone 0, AEx ia IIC T6." Zone 0, 1 2 . April 2022 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. 1.1.1 This recommended practice applies to those locations where flammable gases or vapors, flammable liquids, or combustible liquids are processed or handled; and where their release into the atmosphere could result in their ignition by electrical systems or equipment. Zone 1 fittings are supplied as silver, Zone 2 as dark grey and industrial fittings as white. Area which are not devided into Atex zones, are called non-hazardous area's. Magnesium, Titanium), IIB Nonconductive dusts (eg. WATER TIGHTNESS Zone 1 an area in which an explosive gas-air mixture is likely to occur in normal operating conditions. For example the EI 15 and API 500/505 describe specific installations and several conditions for the oil and gas industry. So it is quite obvious that explosions should be prevented as much as possible and still work has to be done to achieve this. Explosion Hazardous Areas are divided into zones according to risk probabilities. Substances characterization Consequences . Q: Can equipment approved for a Class I hazardous location be used in a Class II hazardous location? Zone 2 Explosive Mixtures not likely to occur /occur short duration in normal operation (lt10 Hrs/ Yr). That flammable gas or vapor . Unlike ATEX which uses numbers to define the safety "Category" of equipment, namely (1,2 3), the IEC continued to utilise the method used for defining the safe levels of intrinsic safety namely "a" for zone 0, "b" for zone 1 and "c" for zone 2 and apply this Equipment Level of Protection to all equipment for use in hazardous areas since 2009. Class I, Zone 0 = Area Classification, AEx = Symbol for equipment built to American specifications, ia = Type of protection designations, IIC = Gas classification group (as required), T6 = Temperature Classification, [46 FR 4056, Jan. 16, 1981; 46 FR 40185, Aug. 7, 1981; 72 FR 7210, Feb. 14, 2007], Occupational Safety & Health Administration. 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.