An investigation into the effectiveness of ELF protective clothing when exposed to RF fields between 65 MHz and 3 GHz

Protective garments are worn by electric power workers to shield the body against electromagnetic fields. This paper uses the finite-difference time-domain method to calculate SAR in the heterogeneous human voxel model NORMAN, clad in a protective suit and exposed to radio-frequency (RF) electromagnetic fields between 65 MHz and 3 GHz. The representation of the suit was produced for this work by the modelling and voxelization of a surface-rendered object, based on the dimensions of the male voxel phantom. The calculations showed that the peak-localized SAR in the head was higher than that calculated for a model without a protective suit for a number of exposure situations. These localized SAR values could be up to three times the values of those calculated for a model without a protective suit for a particular frequency. It is thought that the SAR hotspots in the head are caused by resonances in a cavity, which in this case is the conductive hood of the suit. This work shows that the increase in the peak-localized SAR in the head due to wearing the suit meant that, in certain situations, the ICNIRP and IEEE reference levels were no longer conservative. Therefore, it is important that power line workers exposed to RF fields wear the correct high-frequency protective suits with conducting visors.