Jun 1, 2012

Exposure of the Human Body to Professional and Domestic Induction Cooktops Compared to the Basic Restrictions

Andreas Christ, René Guldimann, Barbara Bühlmann, Marcel Zefferer, Jurriaan F. Bakker, Gerard C. van Rhoon, and Niels Kuster, Bioelectromagnetics, online ahead of print June 1, 2012

The product standard IEC 62233 requires that the incident magnetic field of induction
cooktops be measured at a distance of 300mm from the appliance. Because of the strong
field gradients in the immediate environment of the cooking zone, the user may be exposed
to comparatively high field strengths. We measured the incident magnetic field of 13
professional and 3 domestic induction cooktops at the distance specified by IEC 62233
and immediately at the appliance. While most measured cooktops comply with the exposure
limits for the general public at a distance of 300mm, the majority exceeds them at closer
distances, some of them even the occupational limits.

In order to quantify the user exposure, a numerical model of a generic induction cooking
zone was developed and scaled to the incident fields of the measured appliances. The induced
currents were simulated in different anatomical models of adults, pregnant women and children.

The scientific and technical impact of the study can be summarized as follows:

  • When operating the generic cooktop at incident field strength compliant with the measurement
    standards, the current density exceeds the basic restrictions (ICNIRP 1998) by up to 24 dB.
  • Brain tissue of young children can be overexposed by 6 dB. 
  • The exposure of the tissue of the central nervous system of the fetus can exceed the limits for the general public when the mother is exposed at occupational levels. 
  • In consequence, the product standard IEC 62233 does not sufficiently protect exposed persons according to the basic restrictions as defined by 1998 ICNIRP guidelines.
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