Human Body Impedance and Threshold Currents for Perception and Pain for Contact Hazard Analysis in the VLF-MF Band

The body impedance and threshold currents needed to produce sensations of perception and pain have been measured for 367 human subjects for the frequency range 10 kHz to 3 MHz. A sufficient number of subjects (197 male and 170 female subjects of ages between 18 and 70 years) were utilized in the study to make valid statistical predictions for the general adult population. Various types of contact with metallic electrodes were used to simulate the situation where a human being would be in contact with a large metallic object (car, van, school bus, etc.) in an electromagnetic field in the VLF to MF band. Based on these measurements, it is speculated that the body impedance of a human being is inversely proportional to the body dimensions and the threshold current for perception is directly proportional to the square of the body dimensions. Predictions are made, based on scaling, for the corresponding threshold values for ten-year-old children. The average measured impedance and threshold current values are used to calculate threshold electric fields required to produce sensations of perception and pain in humans in contact with these vehicles. It is concluded from these calculations that many situations can exist in which the present ANSI (American National Standards Institute) recommended standard of 632 V/m for the frequency band 0.3-3 MHz is too high.