I get the idea that we a missing the whole point of this discussion. Should we as Professional Safety Engineers and Product designers consider the safety implications of EMC emissions ?
The answer is a definite Yes. We have a clear duty of care and responsibility to consider all implications of our products being used in there intended application. Even if the consideration on EMC emissions and safety is "Do not be silly." We still have to at least consider it. It has been stated that CISPR22 and CFR Title 47 Part 15b is only concerned with interfering with radio transmissions. This is true and why the enforcement falls under the Federal Communications Commission. But not all products fall under this remit and could quite happily be emitting large EM fields and comply with all current US legislation. Take for example the line surge equipment you use to test immunity to EN61000-4-5, exempt from the Part 15B under section 15.29 as "A digital device used exclusively as industrial, commercial, or medical test equipment." And clearly not medical equipment. Yet when operated can produce a magnetic field that will interfere with the operation of old style pacemakers. Should you consider this when addressing the safe design of the product, or blindly state you meet all applicable EMC regulations for this product. With my unit the manufacturers have considered this and clearly state in the user manual that people with pacemakers should not operate or be be near the equipment when it is use. Two lines in the manual is not very big much against the risk the of killing someone. In Europe for CE we have no choice. The LVD state quite clearly that testing to a standard alone is insufficient to demonstrate compliance. You to consider foreseeable use and misuse, and you have to perform a risk assessment on your equipment. Taking it down to the standard level IEC60950 3rd Edition, section 0.2.7 states you must consider the effect of rf radiation on service and user personnel. Another example, you build a IPC cabinet for to be built into a production line, again exempt from CISPR 22, yet when it it running, causes interference on the control circuitry of a nearby Robotic arm. In the US immunity testing is not required, so who is liable. A susceptible Arm or noisy IPC cabinet. Being that every was fine until the cabinet was installed, you can see the blame would be pointed. Simply put, if EMC emissions from one of your products caused someone's death, because you did not consider it important. Could you sleep at night ? Ken Javor wrote: > In my experience it is EXTREMELY unlikely that personal electronics > could have disturbed ADF heading indication. The ADF sensor is an > electrostatically shielded loop which is mounted typically on the > belly of a transport class aircraft, well away from any > passenger-conveyed intense sources of magnetic fields. The loop is > very insensitive and requires quite a bit of magnetic field to respond > and is completely insensitive to electric fields altogether. Further, > no one would use ADF to line up an approach on a runway. > > ---------- > From: Cortland Richmond <cortland.richm...@alcatel.com> > To: Mike Hopkins <mhopk...@thermokeytek.com> > Cc: cherryclo...@aol.com, emc-p...@majordomo.ieee.org > Subject: Re: EMC-related safety issues > Date: Wed, Jan 2, 2002, 5:26 PM > > > > If they meant "radio compass," that is a different can of > monkeys. The radio compass was traditionally the indicator > for the ADF set , pointing to the ground station, and was > usually mounted so as to revolve in front of a scale which > rotated with the aircraft's' magnetic heading. A noisy > switching power supply could well interfere with a > low-frequency receiver. But (in MY opinion) the Guide does > not say enough about what actually happened. > > > Cortland > (My thoughts, not Alcatel's!) > > > > Mike Hopkins wrote: > > As already stated, the incident of the DC-10 has > for years been used as an example of personal > electronics (laptops) interfering with avionics. > The only version I've ever heard (and the only one > that makes sense) had to do with interference to > an ILS receiver operating somewhere between 108MHz > and 118MHz. I for one, don't believe in laptop > computers interfering with a compass -- UNLESS -- > the people reporting the story (and writing the > guide?) used a "compass" as a way to relate to the > general population that a laptop caused > interference with an instrument that kept the > airplane headed in the right direction -- probably > assuming that most people would not be able to > relate to an ILS or NAV receiver, but everyone > knows what a compass is..... I remember the > magazine article, which also reported on an > electronically controlled wheelchair going out of > control when an EMT keyed a mobile two-way radio > in a nearby ambulance. (I might add, I've since > heard several variations on that story as well -- > wheelchair went over a cliff, wheelchair went > around in circles, wheelchair dumped patient and > took of by itself; radio was a walkie-talkie, > radio was CB, etc.... You get the idea.) There was > also a video being circulated of a Connie Chung > news broadcast relating similar horror stories of > the effects of EMC. We used to have a copy here, > but I haven't seen it in years -- probably dumped > when we moved.....My 2 cents worth......Mike > HopkinsThermo KeyTek > > ------------------------------------------- This message is > from the IEEE EMC Society Product Safety Technical Committee > emc-pstc discussion list. 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