In message <[email protected]>, dated Fri, 24 Feb 2006, Robert A. Macy <[email protected]> writes >Don't know what ICNIRP Guidelines are,
http://www.icnirp.de/documents/emfgdl.pdf >but as I recall the >old Swedish MPRII rules were on the order of 200nT over the >band of 5Hz to 2000Hz and 20nT over the band of 2KHz to >400KHz. [From memory, so numbers could be off] Those are very small fields. The ICNIRP numbers are higher, and are still regarded as 'very conservative'. There are FCC limits in USA, which differ from the ICNIRP. > [sneep] > > >PS the meter was my own invention and had sensitivity of >1V per microTesla with flat response from 5Hz to over 1 >MHz. I was amazed how easy it was for the earth's 50uT to >get into that bandwidth with very small movements of the >meter. > >For an NDE application to replace noisy Hall Effect and GMR >sensors, I extended the range of the meter down to 0.001 >Hz. The circuits took all morning long to "turn on". > Hated that delay. But with a 2 minute time constant and >0.1% accuracy, what are you going to do? NDE? I'd be interested in more details of your meter, if possible. > >40 year SHORT course? hmm....all is relative, right? Vita brevis... > > >What is the reasoning behind the ICNIRP Guidelines at >around 1/4 earth's field? The URL above gives a lot of rationale. >Who is requiring the guidelines >be met? > There is a new specific European EMF Directive about exposure of workers to ElectroMagnetic Fields, but there is something that affects ALMOST EVERY electrical and electronic product in Europe. The control of 'radiation' to safe limits is an Essential requirement of the Low Voltage Directive. When it was written, people probably had only ionizing radiation (X-rays for TV tubes) in mind, but it is now held that non-ionizing radiation is included, and every product that has not had its magnetic (and/or electric) field emissions assessed has not satisfied the requirements of the Directive. There is a lot of activity in CENELEC TC106X and IEC TC106 on the preparation of Generic and other general standards, but progress is difficult because many people involved are relatively new to standards work and don't know the best way to do things. This work isn't widely known about. Just like for EMC, product committees should be writing EMF standards (giving detailed operating conditions for, and methods of, measurement) for their products, but only the household appliance committee has yet done this. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk 2006 is YMMVI- Your mileage may vary immoderately. John Woodgate - 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
