Group E-Atmospheres containing combustible metal dusts such as aluminum, magnesium, and their commercial alloys.į. Typical gases include acetone, ammonia, benzene, butane, ethanol, gasoline, methane, natural gas, naphtha, and propane.Į. Group D-Atmospheres containing a flammable gas, flammable liquid-produced vapor, or combustible liquid-produced vapor whose MESG is greater than 0.75 mm or MIC ration is greater than 0.80. Typical gases include ethyl either, ethylene, acetaldehyde, and cyclopropane.ĭ. Group C-Atmospheres containing a flammable gas, flammable liquid-produced vapor, or combustible liquid-produced vapor whose MESG is greater than 0.45 mm but less than or equal to 0.75 mm or MIC ratio is greater than 0.40 but less than or equal to 0.80. Typical gases include hydrogen, butadiene, ethylene oxide, propylene oxide, and acrolein.Ĭ.
Group B-Atmospheres containing a flammable gas, flammable liquid-produced vapor, or combustible liquid-produced vapor whose MESG is less than 0.45 mm or MIC ratio is less than 0.40.ĬATALOG 88 - FISHER VALVE & INSTRUMENT PRODUCT BULLETINS Group A-Atmospheres containing acetylene.ī. Groups A, B, C, and D are for gases (Class I only) while groups E, F, and G are for dusts and flyings (Class II or III).Ī. Group-The Group defines the type of hazardous material in the surrounding atmosphere. Division 2 indicates that the hazardous material has a low probability of producing an explosive or ignitable mixture and is present only during abnormal conditions for a short period of time.ģ. Division 1 indicates that the hazardous material has a high probability of producing an explosive or ignitable mixture due to it being present continuously, intermittently, or periodically or from the equipment itself under normal operating conditions.ī. Division-The Division defines the probability of the hazardous material being able to produce an explosive or ignitable mixture based upon its presence.Ī. Class III-Locations in which ignitable fibers may or may not be in sufficient quantities to produce explosive or ignitable mixtures.Ģ. Class II-Locations in which combustible dusts (either in suspension, intermittently, or periodically) may or may not be in sufficient quantities to produce explosive or ignitable mixtures.Ĭ. Class I-Locations in which flammable gases or vapors may or may not be in sufficient quantities to produce explosive or ignitable mixtures.ī. Class-The Class defines the general nature (or properties) of the hazardous material in the surrounding atmosphere which may or may not be in sufficient quantities.Ī. Hazardous locations per the Class/Division system are classified according to the Class, Division, and Group.ġ. However, the United States and Canada are trending more towards the Zone System. The Class/Division system is used predominately in the United States and Canada, whereas the rest of the world generally uses the Zone system. Currently there are two systems used to classify these hazardous areas the Class/Division system and the Zone system. Those areas where the possibility or risk of fire or explosion might occur due to an explosive atmosphere and/or mixture is often called a hazardous (or classified) location/area. When electrical equipment is used in, around, or near an atmosphere that has flammable gases or vapors, flammable liquids, combustible dusts, ignitable fibers or flyings, there is always a possibility or risk that a fire or explosion might occur. Contact your Emerson sales office for information on approvals not covered in this bulletin.Ĭontact your Emerson sales office for product specific hazardous area approval information or visit. Not all approvals are covered in this bulletin. The information provided in this bulletin is for educational purposes and should not be used in place of any other source or governing documents.
The intent of this document is to provide a broad overview of hazardous area classifications and the types of protection techniques involved. Hazardous Area Classifications and Protections File Info : application/pdf, 2191 Pages, 41.77MB Document Document catalog-fisher-valve-instrument-product-bulletins-catalog-88-en-202686 CATALOG 88 - FISHER VALVE & INSTRUMENT PRODUCT BULLETINS
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