I was wondering if these type of fire propagation tests are still of any relevance.
Nowadays most electronic designs have been built with compliant (be it UL or VDE or any other reputable test house) and wiring is HAR or better. Enclosures are most standard -off-the-shelf- types with a decent flammability marking. Isolating material is purchased for the purpose and decently marked. I must add that my experience is mostly in professional (low power <1500 VA) equipment (60950 / 61010), so I may be biased, but in 20 years of testing I still have to find an example where a fire could be started in a "fire enclosure" (or outside) using a single fault simulation, or a situation where a fire could propagate. Any overheated component/wiring/pcb produced (toxic?) smell/smoke only. I had some exploding capacitors, and semiconductors (DIL packages), and that was it. I'd like to hear any decent argument or example (yes!) on when a fire test had (recently) shown to be necessary ( had a fail result) where this was not expected based on the applied components ratings. I do not think that many wood enclosures are used, and paper has long been ruled out in electronics. Is this flammability issue (at least the equipment test) not something slowly becoming obsolete ? Regards, Ing. Gert Gremmen Approvals manager ------------------------------------------------------------------------------------ + ce marking of electrical/electronic equipment + Independent Consultancy Services + Compliance Testing and Design for CE marking according to EC-directives: - Electro Magnetic Compatibility 2004/108/EC - Electrical Safety 2006/95/EC - Medical Devices 93/42/EC - Radio & Telecommunication Terminal Equipment 99/5/EC + Improvement of Product Quality and Reliability testing + Education Web: www.cetest.nl (English) Phone : +31 10 415 24 26 ------------------------------------------------------------------- This e-mail and any attachments thereto may contain information that is confidential and/or protected by intellectual property rights and are intended for the sole use of the recipient(s) named above. Any use of the information contained herein (including, but not limited to, total or partial reproduction, communication or distribution in any form) by persons other than the designated recipient(s) is prohibited. If you have received this e-mail in error, please notify the sender either by telephone or by e-mail and delete the material from any computer. Thank you for your co-operation. From: Richard Nute [mailto:[email protected]] Sent: Saturday 21 May 2016 19:16 To: [email protected] Subject: Re: [PSES] fire safety test methods for different country standards Hi Scott: “In general, the users and testing houses are referring to the rating of UL yellow card rather than the actual test on individual final designed pcb. Should we use it to object their normal practice. How often is it successful?” Testing in place is a once-per-product-model (and board design) test. Passing the test will depend on how much copper clads the epoxy versus exposed epoxy. Only boards with lots of copper are likely to pass. So, it is an “iffy” test and the outcome cannot be predicted with certainty. As a general rule, use a board with ratings prescribed by the standard. Where you must use a rating not prescribed by the standard, or you are using a non-rated board, and if the board design uses lots of copper, then testing the completed board in its end-product orientation may pass the flammability test. Rich - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) 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]>
