[Inefficiency of electrical pollution-shielding mats. 1: low frequency range].
Despite of the fact that environmental electric and magnetic fields are magnitudes below the existing limits, fear from electromagnetic pollution increase and so does business with fear by offering more or less plausible products with partly excessively high prices . Based on numerical simulation the claims of manufacturers on the efficiency of electromagnetic shielding mats were tested. It is pretended that electric fields can be shielded to 98% and more, and transferred to earth by earth cables (if attached). It could be shown that in general such products do not fulfil the justified expectations of customers, but in contrary even cause the opposite. To connect the mats with earth potential by an attached cable might increase the beliefs on a protective effect, however, this is not capable to enhance the shielding effect but in most cases this causes even the contrary by partly considerably increasing electric field exposure. The electric conductivity of the used shielding mats plays a neglectable role and cannot explain the considerable price differences. The investigation demonstrates that in spite of references made to expert's opinions manufacturer's claims about the shielding efficiency are misleading and fooling clients about the real situation.
Leitgeb
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Institut für Krankenhaustechnik mit Europaprüfstelle für Medizinprodukte, Technische Universität Graz. Leitgeb@bmt.tu-graz.ac.at
Cech
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D003198:Computer Simulation; D004560:Electricity; D004574:Electromagnetic Fields; D019544:Equipment Failure Analysis; D008962:Models, Theoretical; D011829:Radiation Dosage; D011835:Radiation Protection / Q000295:instrumentation*; D011874:Radiometry / Q000379:methods*