Hi Robert - I would refer you to UL's HAZLOC web page to learn more about standards requirements, and to NFPA No.: HLH-97, Electrical Installations in Hazardous Locations, to learn more about how hazardous areas are classified.
>What is the difference between a product that is certified to Class I >Division 1 versus Class I Division 2? I assume the product is listed to a UL standard, most likely UL1604. I make that assumption because the rating term "Division" is only used in the US. To understand the difference, you have to understand how hazardous areas are classified. In a nutshell, the Division refers to the frequency of the hazard - in Division 1 locations, the hazard is assumed to be present continuously under normal conditions. In Div. 2 locations, the hazard exists infrequently, under equipment failure or maintenance conditions. The Division 1 equipment takes more steps to eliminate the risk of a spark under failure. >>If I had a product that was certified to Division 2, what would be needed to >>make it pass Division 1 requirements? Evaluation to UL913 5th Edition (6th Edition pending). There is generally a HUGE difference in equipment designed for Div. 1 and Div. 2. It all comes down to the "protection method" employed. UL913 describes requirements for an intrinsically safe (2-fault) design. UL1604 describes requirments for non-incendive, non-sparking, or hermetically sealed devices. In theory, a 2-fault intrinsically safe design has no need for an enclosure; the electrical design has robust protective components that prevent ignition from a spark or arc or surface temp, even with the application of 2 (countable) faults. Classifying Hazards - a layman's guide: Hazards are first separated by Class, defining the type of hazard present. Class I - A location in which flammable gases or vapors are or may be present in the air in quantities sufficient to produce explosive or ignitable mixtures. This Class also includes flammable liquids; vapors are generally present near liquids, and atomized liquids can ignite with flame speeds that are for all intents an explosion. Class II - A location that is hazardous because of the presence of combustible dust. Class III - A location that is hazardous because of the presence of combustible fiber or flyings. The classes are further divided by conditions within the classes; in simplest terms, "normal" and "abnormal". This division is called the Division or Zone, depending on the system used (in the US, it is Division - under EX Directive, it is Zone). In both cases, the lower the number, the more likely the presence of the hazardous material is. Classes of hazards are also defined by groups of materials present. While there are literally hundreds of hazardous gases and materials, they can be grouped according to their explosive potential; similar flash points, minimum ignition temperatures, etc. Class III locations have no material groupings. Finally, equipment for use in hazardous areas must be marked with a temperature code, referring to the maximum surface temperature of the equipment under fault conditions. In short: Class = Type of hazard present Division or Zone = Condition of hazard present Group = physical properties of hazard present Temp Code = ignition temp of hazard present Doug Massey LXE, Inc. -----Original Message----- From: Loop, Robert [mailto:[email protected]] Sent: Thursday, March 15, 2001 11:13 AM To: [email protected] Subject: Class I Division 1 versus Class I Division 2 Hello Group, I need some education on Classified/Hazardous locations. What is the difference between a product that is certified to Class I Division 1 versus Class I Division 2? If I had a product that was certified to Division 2, what would be needed to make it pass Division 1 requirements? I apologize for my ignorance, there are simply too many standards out there and this is out of my league. Sincerely, Robert Loop Engineering Supervisor Wyle Laboratories Product Safety ph - (256) 837-4411 x313 fax- (256) 721-0144 e-mail: [email protected] ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: [email protected] Dave Heald [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall," ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: [email protected] Dave Heald [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
