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10/ 19/83 3910.3A <br /> 33. PERMISSIBLE EXPOSURE LIMITS (PEL's). The permissible exposure <br /> limits for RF/microwave radiation shown in Figure 3-1 shall apply to all <br /> occupants of controlled areas. There is no distinction between <br /> occupational and nonoccupational exposure in their application. <br /> NOTE: The PEL's were adopted from the American <br /> National Standards Institute, ANSI C95.1-1982 <br /> Standard. This standard is comprised of a <br /> series of radiofrequency protection guides which <br /> are defined as "the radiofrequency field strength <br /> or equivalent plane wave power density which <br /> should not be exceeded without (1) careful <br /> consideration of the reasons for doing so, (2) <br /> careful estimation of the increased energy <br /> deposition in the human body, and (3) careful <br /> consideration of the increased risk of unwanted <br /> biological effects." <br /> FIGURE 3-1. RF/MICROWAVE PEL's <br /> Mean Squared Mean Squared Equivalent <br /> Frequency Electric Field Magnetic Field Plane Wave <br /> Range Strength (E2) Strength (H2) Power Density (PD) <br /> (MHz) (V2/m2) (A2/m2) (mW/cm2) <br /> 0.3 3 400,000 2 .5 100 <br /> 3 30 4,000(900/f2)** 0.025(900/f2) 900/f2 <br /> 30 300 4,000 0.025 1.0 <br /> 300 1,500 4,000(f/300) 0.025(f/300) f/300 <br /> 1,500 100,000 20,000 0.125 5.0 <br /> a. For near field exposures where power density (PD) cannot be measured <br /> accurately, the only applicable PEL's are the mean squared electric (E) and <br /> magnetic (H) field strengths. Equivalent plane wave PD can be calculated from <br /> field strength measurements as follows : <br /> PD in mW/cm2 = E2/3770 (where E2 is in V2/m2) <br /> PD in mW/cm2 = 37.7 H2 (where H2 is in A2/m2) <br /> b. For pulsed and continuous wave (CW) fields, the PD and the squares of <br /> the field strengths (E2 and H2) are averaged over any 6-minute period. <br /> c. For fields consisting of multiple frequencies, the fraction of the <br /> PEL incurred within each frequency range should be determined and the sum of <br /> all fractions should not exceed unity. <br /> **f=frequency (MHz) <br /> Chap 3 <br /> Par 33 Page 25 <br />