UL's web site will have information about what standards they use for hazardous location product certifications, and they'll also have a list of what companies they have issued UL certifications to for hazardous location product categories, but I doubt there'll be any general information about equipment design rules, classifications of hazardous locations, etc. (Don't know about FM's website, though.) I've never had to design or test products for use in hazardous locations (thank goodness!), but my impression is that if you are a manufacturer, you really really want to make sure everything is done right, marked right, tested right, etc. etc. because electrical inspectors scrutinize everything a lot more closely, and if something bad does happen at the site it's more likely to be catastrophic (explosion, fire, release of chemicals, etc.) and there's just a lot more product liability to worry about. -Camille Good Portland, Oregon
"Barker, Neil" <[email protected]> wrote: Chris, What you are referring to is Hazardous Area equipment, or otherwise Electrical Equipment for use in Potentially Explosive Atmospheres. Exia refers to the classification of the protection; Ex for Explosive atmospheres, ia denotes intrinsic safety. You can readily find more information by searching the websites of UL or FM under Hazardous Area. For Australia, you would be best to seek an IECEx scheme certification. The relevant standards are in the IEC 60079 series. You could use one of the US based approvals bodies, such as UL, FM, SGS or Intertek, or you could seek certification in Australia with a body such as Simtars or TestSafe. Intrinsic safety does not involve a great deal of testing, but a considerable amount of assessment of equipment design. It is vitally important to have a good understanding of the principles of intrinsic safety before you start designing such equipment. The main aspect is that of limiting voltage, current or energy under fault conditions, with two countable faults in the case of ia certification. Circuits inevitably acquire additional components to provide the protection, typically extra resistors, clamp diodes, overvoltage protection devices, fuses and so on. Separation of circuits is also generally greater than would be required in normal environments. All of these factors serve to make your circuits occupy a bit more real estate than you may be used to. There are some useful reference books on the subject, such as "Intrinsically Safe Instrumentation: a guide" by Robin Garside; ISBN 0 9516848 1 7; published by Hexagon Technology Limited, Aylesbury, Buckinghamshire, UK. Best regards Neil R. Barker CEng MIEE FSEE MIEEE Manager Compliance Engineering e2v technologies (uk) ltd 106 Waterhouse Lane Chelmsford Essex CM1 2QU UK Tel: (+44) 1245 453616 Fax: (+44) 1245 453410 Mob: (+44) 7801 723735 From: Chris Maxwell [mailto:[email protected]] Sent: 08 December 2005 14:21 To: [email protected] Subject: Zone 1 Exia area (Explosion protection) Happy holidays list dwellers. Thanks for a job well done and Best wishes to Rich Nute as well. He has now officially become a member of TLGTABATR (The Last Generation To Actually Be Able To Retire) Now who's going to keep me in line? Anyway we have a customer in Australia asking if we have a product that is rated for Zone 1 Exia (maybe a typo...could that be "Exit"). They have explained that this rating deals with mine atmospheres where there could possibly be mixtures of explosive gases. We have never tested products for such a condition. Can anybody tell me what standard this rating is based on? Furthermore, does anybody know who performs such testing and what it entails?\ Thanks, Chris Maxwell, Design Engineer | Compliance Engineer Email: <mailto:[email protected]> [email protected], Desk Phone: 315-266-5128 Engineering Department Fax: 315-797-8024 NetTest (New York) Inc. 6 Rhoads Drive, Building 4, Utica, NY USA Web: <http://www.nettest.com/> www.nettest.com, Phone: 315-797-4449 NetTest, a Member of the Anritsu Group - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html L! ist rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
