John, for EMC (and safety) most of the labs do not want to provide details as to what the failures were. One lab that does both safety and EMC, happened to mention that the 90% rule applied to safety as well as EMC, but would no discuss details, nor do they want me to mention their name. It points out we need to do a better job in the development stage of products..
On EMC I can provide a little better detail as one of the labs found my comments about failure rates interesting and stared tracking the rates. I mentioned it as part of a general conversation about a experience at a EMC lab back when the CE mark first started. I had taken 3 products to a lab to have them generate the EMC reports for Europe. They did the radiated emissions first. As the products had been previously tested to FCC Class A they did not have issues with radiated emissions. Then we went to the RF susceptibility tests. About half way through the first units test the technician stopped the tests and started playing with his equipment. He seemed flustered so I ask what was up. He said that there had to be something wrong with the equipment. I ask him why he through that and he said they had never had a product pass that far in to the testing on the first trip to the lab. So I told him I would have been surprised it it had failed. I got a weird look from him, so he went in and talked to others, came back out and finished the tests. All three products passed with no changes, so I broke their streak. After that I always asked the person running the tests what percentage they felt passed on the first trip. They were just guessing but gave very low numbers. I have used a number of different labs and they all responded about the same. The information from John is a little old, so by now he likely would have more significant numbers. Here is what John Barnes gave me to use in my presentation on EMC: I've (John Barnes) been doing an informal study of dBi's first-try pass rates for over 3 years now, and it is still incomplete. But having electromagnetic-compatibility (EMC)/ electromagnetic interference (EMI)/ electrostatic discharge (ESD) tested over 360 products since February 2002, my gut feel is that: About 5 to 10% of the 323 products brought to us for official testing passed with no changes. * About 45-50% passed with only minor changes-- and we completed the testing on the first try, within our budgetary estimate. * About 45-50% passed after major changes, which sometimes took 6+ months to complete. Changes to printed circuit boards are especially painful and costly! I would guess the same percentages are probably true for safety such as 45 - 50 % had minor issues. Jim [email protected] On Tue, May 10, 2016 at 3:58 PM, John Woodgate <[email protected]> wrote: > Re your last paragraph. Is it possible to categorize that 90% into, e.g. > trivial, documentation only, significant, serious? This is all to support > the 'Design it in!' movement, which potentially saves the industry > megabucks annually. > > > > With best wishes OOO – Own Opinions Only www.jmwa.demon.co.uk > > J M Woodgate and Associates Rayleigh England > > > > *From:* Jim Bacher [mailto:[email protected]] > *Sent:* Tuesday, May 10, 2016 3:30 AM > *To:* [email protected] > *Subject:* [PSES] Meet some of the list admins at the PSES Symposium next > week > > > > The following emc-pstc list admins will be at the IEEE PSES Symposium on > Product Compliance Engineering May 16-18 in Anaheim California: > > > > Rich Nute (former admin) > > Dan Roman > > Jim Bacher > > > If you are in the LA area or are attending the symposium, look us up. > > The tentative program schedule has been posted for this year's product > compliance symposium at http://2016.psessymposium.org . There are a > couple good tracks for someone getting stated in compliance (in addition to > the other tracks), which are Compliance 101 and the EMC and Wireless Track. > > I am the track chair for the EMC and Wireless Track at the symposium. The > track has good information in it for those starting to do transmitter > certifications along with starting in EMC. > > You may not know this, but 90% of all products fail on their first trip > to the EMC lab (safety labs as well). The bulk of the products I was > involved with passed with margin on their first trip to the lab. I am > doing a presentation on what I looked for in design reviews that > accomplished that. > > > Jim > > [email protected] > > - > ---------------------------------------------------------------- > > This message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. 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) <http://www.ieee-pses.org/list.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]> > - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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]>
