24th June 2012
By Alasdair Philips – powerwatch.org.uk
Study shows that using induction cookers can often exceed European and UK EMF exposure guidelines!
A very alarming new study [1] by a leading test laboratory which tested a number of modern induction cooking hobs reports that most hobs/rings exceeded even the high 1998 ICNIRP maximum exposure levels (currently the UK and European maximum exposure levels) when a person was standing close to the cooker.
What the authors say:
“The maximum current density in the tissue of the user significantly exceeds the basic [1998 ICNIRP] restrictions for the general public, reaching the occupational level. The exposure of the brains of young children reaches the order of magnitude of the limits for the general public.”
“For a worst-case cooktop compliant with the measurement standards**, the current density exceeds the 1998 ICNIRP basic restrictions by up to a factor of 16-fold.”
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“The brain tissue of young children can be over-exposed by 6 dB or a factor of 2. The exposure of the tissue of the central nervous system of the foetus can exceed the limits for the general public if the mother is exposed at occupational levels.
This demonstrates that the methodology for testing induction cooktops contradicts the basic [ICNIRP EMF] exposure restrictions.”
** The induction cookers passed the required CENELEC tests which assumes that your body is never closer to the front of the cooker top than 30 cm (about 1 foot). Cooking at arm’s length!
What is an Induction Cooker?
In our Powerwatch Handbook (Piatkus, 2006, now out of print) we stated:
“Hobs with magnetic induction plates work on a different heating principle from traditional cookers. Although such hobs are electrically efficient, high EMFs are generated by the cooker on purpose, and these EMFs induce currents to flow in the metal pans which cause them to heat up. The top of the cooker stays relatively cool and is mostly heated by contact with the hot pan.”
“Some magnetic induction hobs use mains frequency fields but most now use low radio frequency signals which induce currents in the pan (and people standing nearby!) more easily. As very high EMFs are generated on purpose and these extend into the user, we cannot recommend this way of cooking.”
Most modern ones now use low-frequency RF energy (20 to 100 kHz) to induce currents in the pan in order to heat it up. They are very energy efficient, but they do expose nearby people to high electromagnetic fields.
While most 13 of the 16 measured cooktops complied with the public exposure limits at the 300 mm distance specified by the International Electrotechnical Commission (standard IEC 62233), the majority (13 of the 16) exceeded them at closer distances, 7 of them reaching or exceeding the occupational limits.
It has been know for some time that induction cookers were reaching or passing the ICNIRP limits. This important paper from a highly regarded institution gives us some hard data that proves the point. This paper has taken almost a year from original submission to early on-line publication.
At present the European Commission guidance is still base on the 1998 ICNIRP values. So confirmation of worries about exposure from induction cookers adds to the list of guidance breakers. Some seats in electric trains exceed the 100 microtesla 50 Hz guidance and some Electronic Article Surveillance (EAS) shop security systems (like supermarkets and large stores use at their doorways) also exceed ICNIRP 1998 public exposure guidance levels. Details of the ICNIRP 2010 changes [2] will follow in a separate news article.
The graph below shows the enormous increases in exposure levels that ICNIRP guidelines now allow.
These increases are not justifies by evidence of plenty of science at these frequencies showing no biological effects – in fact the opposite is true in the relatively few modern studies that have been published.
These changes go against the whole rationale of the Precautionary Principle, the 2009 European Parliament Reis Resolution and the 2011 Council of Europe resolution on EMF exposures and human health- which state that we should take precautionary action on EMF when there is evidence of possible harm but the science is not conclusive. ICNIRP have done the opposite by reducing the need for precaution until a case for harm is proven, despite the evidence of serious long-term harm from some low level exposures at these frequencies.
What Powerwatch says:
We believe that induction hobs, if used at all, should be used with great caution and that pregnant women (including those trying to become pregnant) and children should keep out of the kitchen while induction cookers are in use.
Article References
- Christ A, Guldimann R, Buhlmann B, Zefferer M, Bakker JF, van Rhoon GC, Kuster N. Exposure of the Human Body to Professional and Domestic Induction Cooktops Compared to the Basic Restrictions, Bioelectromagnetics. 2012 Jun 1. PubMed
- ICNIRP, Guidelines for limiting exposure to time varying electric and magnetic fields (1 HZ-100 kHz), Health Physics 99(6):818-836; 2010. Download the Guidelines
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