Measurement of electric- and magnetic-field strengths from industrial radio-frequency (6-38 MHz) plastic sealers.
Conover-DL; Murray-WE Jr.; Foley-ED; Lary-JM; Parr-W
Proceedings of the IEEE 1980 Oct; 68(1):17-20
Electric and magnetic field strength radiation from plastic sealers was measured and compared to personnel exposure standards. Measurements were made of sitting or standing stationary source operators at approximately 1 meter from the radio frequency (RF) source during a normal work pattern. A probe detector was placed 2 to 3 inches from the eyes, neck, chest, waist, gonads, knees, and ankles during the 1 to 3 seconds of measurement time. Adjacent operators continued normal tasks and the degree of field perturbations caused by them was unknown. The highest field strength readings were recorded and corrected for duty cycle. Most sealers operated at approximately 27 megahertz (MHz), had a duty cycle of 0.051 to 0.200, and operated at 5 kilowatts or less output power. No single location could characterize operator exposure, but it was clear that the upper torso received the highest electric and magnetic field strength exposure. Over 60 percent of the sealers exceeded 200 volts per meter and 29 percent exceeded 0.5 amps per meter when corrected for duty cycle. These measurements exceeded the recommended guidelines for electric and magnetic field strengths. The authors conclude that the near field measurements indicate significant magnetic field strength exposure of personnel. They recommend that the magnetic component of the RF field exposure not be neglected. The component can only be determined in near field measurements which are not standardly performed or considered in Federal regulations.
Electromagnetic-radiation; Radiation-exposure; Radio-waves; Nonionizing-radiation; Standards; Monitoring-system; Plastic-materials; Industrial-processes; Work-environment; Radiation-measurement
Proceedings of the IEEE