Gregg, As an EMC engineer and a member of the IEC committee that wrote the 2nd edition of IEC 60601-1-2, I find your "challenge" interesting. First, I have to say I was not impressed with the referenced article. Facts were played a little bit too loose for my preferences. That said, I strongly believe that EMI is an inseparable portion of product safety. You mention that "EMC interferes" and I agree. When it interferes with a wheelchair controller and drives the patient into traffic or causes an infusion pump to triple the drug delivery rate, it can kill. I don't believe I have enough product safety experience to say if those same failures could have been caused by single component faults, but I suspect that a real world examination of the product has a significant possibility of missing the single component that was effected. I can say from 15 years or so experience that it takes much less than a microwave oven to cause medically critical control electronics to misbehave. Regards, Brent DeWitt Datex-Ohmeda Louisville, CO
From: [email protected] [mailto:[email protected]]On Behalf Of Gregg Kervill Sent: Tuesday, February 11, 2003 12:14 PM To: 'Richard Hughes'; 'drcuthbert'; [email protected] Subject: RE: EMC-Related Functional Safety I fully agree with Richard Hughes – it is an interesting article but those of us who have conducted “Flight Safety” work will find it VERY weak is its content and treatment. Whilst EMC interferes (unless you are sitting in a microwave oven) - it is Product Safety (or the lack thereof) that kills! Furthermore I challenge anyone to demonstrate that the EMC related fatalities could not have been caused by a single components failure. Best regards Gregg From: [email protected] [mailto:[email protected]]On Behalf Of Richard Hughes Sent: Tuesday, February 11, 2003 11:01 AM To: 'drcuthbert'; [email protected] Subject: RE: EMC-Related Functional Safety Dave, As you say, an interesting article. Note however that it states in regard to the LVD that: "The Low Voltage Directive (LVD) Although the LVD (73/23/EEC, modified by 93/68/EEC) is generally reckoned to cover functional safety, there are no words in its text that specifically mention it - never mind EMC-related functional safety" While this is accurate as far as it goes (and remembering that the Safety Objectives of the LVD were published in 1973), it could give people a false impression. The February 2001 version of the Commission publication "GUIDELINES ON THE APPLICATION OF COUNCIL DIRECTIVE 73/23/EEC" states: "The Commission interpret that all electromagnetic aspects relating to safety including functional safety are covered by the LVD." Many of you will be aware that a revision to the LVD is underway. At the present state of discussions the draft "essential requirements" are far more detailed than the old "safety objectives" and certainly include this issue. Of course, what the final text will be is not known with certainty at this time. Regards, Richard Hughes Personal opinions only, of course. -----Original Message----- From: drcuthbert [ mailto:[email protected]] Sent: 10 February 2003 19:27 To: [email protected] Subject: EMC-Related Functional Safety
