American Industrial Hygiene Conference and Exposition, May 9-15, 1998, Atlanta, Georgia. Fairfax, VA: American Industrial Hygiene Association, 1998 May; :37-38
In recent years, with the increased use of cellular phones and pagers and the steady expansion of AM/FM/TV stations, there has arisen concern about numerous safety and health issues for workers near or on towers. Both ground and aerial tower workers can and do receive exposure to microwave and radio frequency (RF) fields in the megahertz to gigahertz region, which can result in either induced body or contact currents. In addition, they are subject to burns, electrical shock, falls, and ergonomic hazards, and suffer from the lack of meaningful and well-characterized protective clothing to reduce RF exposure. Workers receive their highest exposure when they are close to RF sources, e.g., antenna tower climbers and maintenance workers. However, existing methods (such as electric and magnetic field strength measurements), may provide misleading exposure evaluations under these work conditions, To answer questions about some of these concerns, NIOSH is presently performing a three-component feasibility study to determine the usefulness of measuring induced body and contact currents in RF tower workers, evaluating calibration factors associated with field strength meters typically used by the communication industries, and collecting exposure data for the direction (polarization) of electric and magnetic fields. For induced body current methodology, the results to date indicate accurate readings, good frequency response, acceptable temperature dependence of readings, and minimal electromagnetic interference levels. Initial results demonstrate that body current measurements are needed to obtain reliable exposure assessments near RF broadcast towers, and that such measurements are feasible with the new technique. Contact current measurements are helpful in exposure evaluations but are difficult because of the lack of standardized calibration and measurement procedures. Field strength meters can have large calibration errors if calibration has been established at or near the frequencies of the RF sources being surveyed. In addition, worker exposures can be underestimated if field direction is not measured. At the present time, little work has been performed on issues related to RF protective clothing, RF burns, ergonomic hazards, or fall protection equipment.
Electronic-devices; Electronic-equipment; Exposure-assessment; Exposure-levels; Electromagnetic-fields; Magnetic-fields; Communication-systems; Communication-workers; Electrical-transmission; Radio-waves; Radiofrequency-radiation; Employee-exposure; Maintenance-workers; Electromagnetic-wave-transmission; Body-temperature
American Industrial Hygiene Conference and Exposition, May 9-15, 1998, Atlanta, Georgia