Measurements of Radiofrequency (RF) Body Potential and Body Current in Personnel Aboard Two Classes of Navy Ships,
NAVAL AEROSPACE MEDICAL RESEARCH LAB PENSACOLA FL
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Recently revised radiofrequency RF exposure standards contain limits on the RF current induced in the bodies of irradiated personnel. Both current-to-ground and hand-contact current are limited, but heretofore no systematic shipboard measurement of these currents has been conducted. To provide the needed information, we measured irradiation-induced RF body currents in personnel aboard LDH-1 and PHM-1 classes of Navy ships. Both current-to- ground and hand-contact current were measured using specialized, prototype instruments. The Naval Sea Systems Command NAVSEA Burngun was also used to assess the indicated RF voltage on various metallic topside objects. Results showed that shipboard body currents are not small and can often exceed the draft Department of Defense Instruction DODI 6055.11 limit of 100 mA per limb for the high-frequency HF spectrum. We found that increased spacing between the feet and the deck decreased the RF current-to-ground in personnel. We also used a metallic, conductive glove to demonstrate the concept that RF burns to the hand can be prevented with the use of conductive gloves. Normally, insulating gloves have been used for this purpose, but such gloves are bulky and subject to aging and dielectric breakdown flashover. Conductive gloves, however, can be lightweight and are not subject to flashover because the RF current is capacitively coupled to the conductive glove over the large surface area of the wrist and hand. We recommend that measures be taken to reduce RF body currents in Navy shipboard personnel who are subject to HF irradiation.
- Radioactivity, Radioactive Wastes and Fission Products
- Radiofrequency Wave Propagation