Measuring multifrequency magnetic fields for exposure assessment based on induced body currents.
Appl Occup Environ Hyg 1995 Jul; 10(7):628-634
A study was conducted on the use of multifrequency magnetic field measurements in determinations of exposure limits for magnetic fields in the subradio frequency (subRF) range. The basis for the calculation of multifrequency exposure limits using previously established limits for magnetic fields with a single subRF frequency was described. Limits on induced current were demonstrated to be equivalent to placing restrictions on the derivative of the magnetic field. Two methods were presented for measuring the magnetic field derivative in multifrequency environments using commercially available equipment. These methods involved the calculation of the derivative from a measurement of the frequency spectrum obtained from instruments which measured components of the time dependent magnetic field expanded as a Fourier series, or application of a correction factor to the readout of a gaussmeter with a linear frequency response.
NIOSH-Author; Magnetic-fields; Electromagnetic-radiation; Biophysics; Permissible-limits; Mathematical-models; Exposure-limits
Applied Occupational and Environmental Hygiene