| For Dust this would be Zone 21. Standards for electrical installations have been established and are governed by a variety of organizations throughout the world to ensure safe electrical systems in hazardous locations. The surface of a high pressure steam pipe may be above the autoignition temperature of some fuel-air mixtures. 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. Hazardous Area Classifications D103222X012 Product Bulletin 9.2:001 September 2019. Ex Zone. Powder Filling "q" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. Typical gas hazards are from hydrocarbon compounds, but hydrogen and ammonia are also common industrial gases that are flammable. Other ignition sources can also be present, like static electricity. This level of risk is represented by classifying the hazardous area as Zone 0, Zone 1 or Zone 2 (for gas, vapour and mist atmospheres) or Zone 21 or Zone 22 for dust atmospheres. You will find this equipment in paint factories, a warehouse or around a bag dump station. Choose the right method for Hazardous Area Classification! In instances of areas within the same facility classified separately, Class I, Zone 2 locations may abut, but not overlap, Class I, Division 2 locations. 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. For example, in the US by the Occupational Safety and Health Administration. Lets take a look at what defines each zone. Intrinsic safety -- This protection technique is permitted for equipment in the Class I, Zone 0 or Zone 1 locations for which it is approved. Determined to be none of the above. July 2020 And safety must be guaranteed in the case of two faults occurring independently of each other. The disadvantage of standards with example installations, is that a huge safety factor is incorporated and thus relative large hazardous area are defined. The value is represented is volume percentage of oxygen. (Hazardous Area Classification) . Gas a. July 2019 Equipment should be tested to ensure that it does not exceed 80%[according to whom?] Often an area classification plan view is provided to identify equipment ratings and installation techniques to be used for each classified area. National Electric Code 2020 edition National Fire Protection Association. A light switch may cause a small, harmless spark when switched on or off. January 2022 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). The NEC Zone system was created to harmonize with IEC classification system, and therefore reduce the complexity of management. It is good to be aware of the fact that the mixture of flammable gas with oxygen has an optimum point where the combustion is most severe and leads to the highest explosion pressure. A potential few examples of this are: The air space inside a tank of petrol Informational Note No. Division 1 and 2 Zone 0, 1 and 2 A (acetylene) IIC (acetylene & hydrogen) B (hydrogen) C (ethylene) IIB (ethylene) What are 'Dark Factories,' and Do They Really Exist? D8.1.3 Hazardous areas are subdivided into Zones 0,1 or 2, the definitions of each cate-gory being as follows: Zone 0 an area in which an explosive gas-air mixture is continuously present or present for long periods. All areas in the facility that are not Zone 0, Zone 1, or Zone 2 are considered unclassified. * Zone 1 a location in which explosive gas atmospheres are likely to occur during normal operation, or which is adjacent to a Zone 0 location. Area classification documentations are reviewed and updated to reflect process changes. An oversimplification of this example is shown in Table 1. 2: For Group IIIC combustible dusts or metal combustible fibers/flyings, there shall only be Zone 20 or 21 locations. 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. 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. Informational Note No. These generally give rise to areas classied as Zones 0, 1, and 2 respectively. Two possible classifications are described, in Section 18 (Zones), and Appendix J (Divisions). Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications! EN 16985 concerning spray cabins and powder coating cabins, EN 12779 related to extraction systems for hot sawdust and chips, EN 60079-10 series, 2020 version for gas and dust explosion hazard, NPR 7910 series for gas and dust explosion hazard based on EN 60079-10-1, 2015 version, EN 13617 for fuel dispensers at filling stations. Class I hazardous locations are identified by zones as follows: * Zone 0 a location in which explosive gas atmospheres are present continuously or for long periods of time. Area's are divided into zones. Beside sufficient fuel, also sufficient oxygen is needed for combustion of the mixture. Within a working area or installation an ignition can be created by many factors. NFPA 70 NEC establishes area classifications based on Classes, Divisions and Groups that when combined delineate the hazardous conditions of a specific area. Equipment marked as suitable for Group IIC is also suitable for IIB and IIA. A: No. It is an Americanized version of the International Electrochemical Commissions (IEC) Zone system which maintains the NEC wiring methods and protection techniques. In North America the suitability of equipment for the specific hazardous area must be tested by a Nationally Recognized Testing Laboratory, such as UL, FM Global, CSA Group, or Intertek (ETL). But beside electrical equipment also mechanical equipment must be Ex certified, e.g. For methane this is shown in the following figure. The minimum concentration of oxygen, necessary for the combustion to take place, is called the Limiting Oxygen Concentration. NEGATIVE PRESSURE 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. 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. Offshore Living Quarter 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. The process of determining the type and size of hazardous locations is called classification. Although every application is different, for the ease of monitoring and specification each hazardous area is classified as a particular level or zone. February 2022 August 2022 So for an explosion there must be enough fuel. No. 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. Area which are not devided into Atex zones, are called non-hazardous area's. Whenever you are filling up your tank you are standing in a Zone 1 hazardous area. It may exist because of repair, maintenance operations, or leakage. The substance referred to by classhas a high probability of producing an explosive or ignitable mixture due to it being present continuously, intermittently, or periodically or fromthe equipment itself under normal operating conditions. Safe for the hazardous (classified) location. Much early equipment having Ex s protection was designed with encapsulation and this has now been incorporated into IEC 60079-18 [Ex m]. No hidden fees. area in which an explosive gas atmosphere is likely to occur occasionally in normal operation. April 2021 Zone 2 hazardous areas are typically storage areas but can also be process areas. What is an Explosion Protection Document? That is why the use of mobile phones on petrol forecourts are banned. Atmosphere containing carbonaceous dusts, Atmosphere containing combustible dust not included in Group E & F - such as. Group II is for explosive gases (Zone 0, 1 and 2) and Group III is for explosive dusts (Zone 20, 21 and 22). The Class/Division/Group system is based on Article 500 of the National Electrical Code (NEC) where. 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. 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. 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. As a guide for Zone 0, this can be defined as over 1000 hours/year or >10% of the time. 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. Methane has a LEL of 4,4 vol%. For dusts: Zone 20, Zone 21 and Zone 22. Temporary Refuge The Zone system has wider use in the chemical and petrochemical industries. Only emails and answers are saved in our archive. Note to paragraph (c)(3) 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 requirement. 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. NFPA 70 NEC Zone Classification System The Zone Classification System is offered as an alternative to the Class and Division system. November 2021 Zone 0/20: An area in which an explosive atmosphere is present continuously or for long periods or frequently. These would be then labeled with each of the individual methods. WATER TIGHTNESS . The NEMA enclosure rating or IP code may also be indicated, but it is usually independent of the Classified Area suitability. June 2019 If you want to promote your products or services in the Engineering ToolBox - please use Google Adwords. Many items of EEx rated equipment will employ more than one method of protection in different components of the apparatus. Sources of When comparing Divisions and Zones, Division 2 is equivalent to Zone 2, but Division 1 is equivalent to either Zone 0 or 1. SIGN UP FOR EMAILGet more great content in your inbox. Ambient Temperature (-20C to +40C if not marked) Establish Zone Based on "IEC 60079-10". Equipment is placed into protection level categories according to manufacture method and suitability for different situations. 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. 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. 7: For further information on application of electrical, Informational Note No. Zones compares to classes and divisions in the Class/Division system. How to perform Hazardous Area Classification? [12], International Electrotechnical Commission, Occupational Safety and Health Administration, National Electrical Manufacturers Association, "Hazardous Area Classification and Control of Ignition Sources", "Hazardous (Classified) Locations NEC Articles 500 through 517", https://en.wikipedia.org/w/index.php?title=Electrical_equipment_in_hazardous_areas&oldid=1134828101, ignitable concentrations of combustible dust can exist, under normal conditions, ignitable concentrations of combustible dust are unlikely to exist normally, ignitable fibers, or materials producing combustible flyings, are handled, manufactured or used, easily ignitable fibers are stored or handled. In Europe and the rest of the world - but also more and more in North America - the Zone system is used. But every hazardous area is different and each has specific requirements depending on the nature of the atmosphere and the elements that are present. The types of protection are subdivided into several sub classes, linked to EPL: ma and mb, px, py and pz, ia, ib and ic. . Upon detection, appropriate action is automatically taken, such as removing power, or providing notification. Sources
In electrical and safety engineering hazardous locations HazLoc pronounced hazlk are places where fire or explosion hazards may exist. Home About Us News Hazardous Environment Classifications: NEC vs IEC, Posted March 11, 2019 by springercontrols. The housing may be strong enough to contain and cool any combustion gases produced internally. A room with a propane gas installation will typically be classified with the. | For Gas/Vapor this would be Zone 0. 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 . The most standards and codes of practise for Hazardous Area Classification describe typical installations and work environments and their hazardous areas. Marking "EEx d" in Accordance with EN 50 0 14 and 50 018 . Refrigerated Container Hazardous area classification. 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. 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. Flour, wood/sawdust, plastic dust), IIC Conductive dusts (eg. 2: Where gas detection, Informational Note No. The temperature marking may not exceed the ignition temperature of the specific gas or vapor to be encountered. 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). Carbon monoxide, ether, hydrogen sulfide, . Class I: hazardous because flammable gases or vapors are present in the air in quantities sufficient to produce explosive or ignitable mixtures: . 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. 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. There are four zones in the IEC classification system: Zone 0: An area in which an explosive atmosphere is present continuously or for long periods. The American Petroleum Institute publishes analogous standards in RP500 andRP505. 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. Zone 1 is an area in which an explosive atmosphere is likely to occur occasionally in normal operation. The Hazardous Area Classification presents in this guide is based on the following items as reference: API: API RP 505 Recommended Practice for Classification of Locations for Electrical. 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. Group define the type of hazardous material and (partly) the location of the surrounding atmosphere. WHEN YOU NEED THEM. 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 . September 2018 - 1 2 (Class 1, . Dn 1 - a Ce e . Identifying Zone 0, Zone 1, and Zone 2 Hazardous Areas. 5: For further information on ventilation, see NFPA 30-2018, Informational Note No. IEC 60079-10.1 Classification of areas - Explosive gas atmospheres. In the US, the independent National Fire Protection Association (NFPA) publishes several relevant standards, and they are often adopted by government agencies. 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. Some of our calculators and applications let you save application data to your local computer. Ex s is a coding referenced in IEC 60079-0. 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. Offshore Workshop Container July 2021 0. Electric equipment depending on the protection techniques described by paragraph (g)(3)(i) of this section may not be suitable for use at temperatures lower than -20 C (-4 F) unless they are approved for use at lower temperatures. the inside of tank truck or the interior of a dust filter). 3: For further information on the classification of, Informational Note No. 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. You will find these zones at the manifold of a tank truck or the interior of a silo. >> NEC: Class II, Division 1, Group F. | IEC: Zone 20, Group IIC. 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. So the flammable range of a substance is the concentration of gases and vapors in air between the Lower Explosion Limit and the Upper Explosion Limit. . Table 1. Increased safety "e" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. Area Classification. The zone classification for gases is divided into three zones, namely Zone 0, Zone 1 and Zone 2 and for dusts Zone 20, Zone 21 and Zone 22. Ignitable concentrations of flammable gases or vapors which are present continuously or for long periods of time. . This article is not a substitute for review of current applicable government regulations, industry standards, or other standards specific to your business and/or activities and should not be construed as legal advice or opinion. When the concentration of methane is beneath the LEL, an explosion cannot occur, even when an ignition source is present. 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. Which Standards to use for Hazardous Area Classification. Ignitable concentrations of flammable gases or vapors which are not likely to occur under normal operating conditions and do so only for a short period of time. All equipment in Division 1 areas must have an approval label, but certain materials, such as rigid metallic conduit, does not have a specific label indicating the Cl./Div.1 suitability and their listing as approved method of installation in the NEC serves as the permission. Division II Comprising of Area Same as Zone 2. Cookies are only used in the browser to improve user experience. THE PRODUCTS YOU NEED, These generally give rise to areas classied as Zones 0, 1, and 2 respectively. Informational Note No. We will go deeper into ignition assessments in another blog. NFPA 70 NEC uses the familiar Class/Division system and has added an Americanized version of the International Electrochemical Commissions (IEC) IEC Zone system which maintains the NEC wiring methods and protection techniques. of 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. | For Dust this would be Zone 22. Zone 1 - Explosive atmospheres are likely to occur. 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. Comparisons between the two systems are not easily accomplished. 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. Type of protection "n" is further subdivided into nA, nC, and nR. Drop Test 1.1.2 This recommended practice provides information on specific flammable gases and vapors, flammable liquids . Comments. Temperature Control Exception No. Use this hazardous area guide to NFPA 70 location classes, divisions & groups to understand potentially dangerous situations at a glance. 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 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). Equipment in this category is intended for use in Zone 0 areas (gases) or Zone 20 (dusts), and must ensure a very high level of protection (i.e. hazardous areas as the following: An area where a potential hazard (e.g., a fire, an explosion, etc.) 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. 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). less than 0.45 mm or MIC ratio is less than 0.40. MCC Shelter See below for further details: Division system sample marking coal and charcoal), Group G Nonconductive dusts (eg. 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.) Flammable liquids with a high flash point are less hazardous than liquids This rapid expansion of volume is caused by the combustion of a fuel, like e.g. Oil Immersion "o" -- This protection technique is permitted for equipment in the Class I, Zone 1 locations for which it is approved. The key difference between Divisions and Zones relate to terminations. So yes, it is important to choose the right model and always wonder what am I assessing?. >> NEC: Class I, Division 2, Group D. | IEC: Zone 2, Group II. Google use cookies for serving our ads and handling visitor statistics. This concentration is substance specific and lies normally somewhere between the LEL and UEL. December 2013, All Documentation requirements likewise vary. Dry Container 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. Substances characterization Consequences . 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. Recommendat ions. This paper will discuss and review the current approaches and solutions of dealing with these HSE concerns, especially with the involvement of hazardous and potentially flammable and explosive chemicals.