Exposure Criteria for Pulsed RFMW Radiation

DOE-HDBK-1092-2004

10.8.4.2.2

EXPOSURE CRITERIA FOR PULSED RFMW RADIATION

The basic considerations for peak-power exposure limits are consistent with ANSI/IEEE C95.1

(1999) as follows:

1. For more than five pulses in the averaging time and for pulse durations exceeding 100

milliseconds, normal time averaging applies and the time-averaged power densities

should not exceed the Maximum Permissible Exposure (MPE) given in Table 10-1 for

controlled and Table 10-2 for uncontrolled environments, per IEEE/ANSI C95.1 (1999).

2. For intermittent pulse sources with no more than five pulses during the averaging time,

the peak power density for any of the pulses should not exceed the limit given by the

following equation.

This limits the specific absorption (SA) of each pulse to SA=28.8 joules/kg (whole-body

or spatial average), or SA=144 joules/kg for 5 pulses.

For intermittent pulse sources with no more than five pulses during the averaging time,

the single-pulse SA of < 28.8 joules/kg, though higher than the threshold for auditory

effect (clicking), is three orders of magnitude lower than the SAs that produce RF-

induced unconsciousness.

3. Maximum E field for any of the pulses should be no more than 100 kV/m. This peak E-

field limit is prescribed to eliminate the possibility of air breakdown or spark discharges,

which occur at 2,900 V/m. A large safety factor is applied to account for local field

enhancements where nominally lower fields may result in arcing discharges.

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