Montpelier, VT, U.S.A. — (METERING.COM) — January 30, 2013 – Vermont has become the latest U.S. state to investigate the radio frequency effects of smart meters, finding, like other studies, that the actual exposure levels are only a fraction of the maximum permissible exposures (MPE) set by the FCC.
But while several previous studies, such as the recent review from Texas, have been based on the published literature, the Vermont study is based on RF measurements of meters that have been deployed in the state. In total measurements were made at no less than 37 different locations in two different service territories, including 18 residential sites, six banks of smart meters (four of which were on residences), two data collection points, one isolated meter and 14 general environmental measurement sites – and they included meters from both Elster and Itron (in the Green Mountain Power and Burlington Electric Department service areas respectively).
Among the findings are that the instantaneous peak value of the RF field, during the pulses, may be as high as 3.9% of the MPE at a distance of one foot. However, when adjusted for duty cycle and spatial averaging, the resulting maximum value of potential exposure at one foot directly in front of the meter represents about 0.068% or less of the time averaged/spatial averaged exposure limit.
Further, the smart meter emissions decrease sharply with increasing distance from the meter being equivalent to about 0.0013% of the exposure limit (time averaged and spatial averaged) at 10 feet from the meter (equivalent to 3.8 million times less than the actual hazard threshold).
For these meters the maximum duty cycles were in the 3-4% range, which is comparable to duty cycles found in earlier studies.
The report notes that the FCC MPE values were derived with the inclusion of a safety factor of 50 below the actual threshold of hazard from prolonged exposure. When the above estimated RF field exposures for the meters at the closest distance of one foot are considered in this light, this means that the most conservative estimates of potential exposure range between approximately 75,000 and 156,000 times less than the hazard threshold (according to the meter type).
The report continues: “Using the highest indicated results from the measurements performed in this study, potential exposure of individuals to the RF fields associated with the currently deployed smart meters in the GMP and BED service territories is small when compared to the limits set by the FCC.It is concluded that any potential exposure to the investigated smart meters will comply with the FCC exposure rules by a wide margin.”
The report, An Evaluation of Radio Frequency Fields Produced by Smart Meters Deployed in Vermont, was prepared for the Vermont Department of Public Service by Richard Tell Associates.