316
Bioelectromagnetism
TABLE 7.8 Reference Levels in ICNIRP Guidelines for Local Exposure, Averaged over 6 Minutes, to
Electromagnetic Fields from 100 kHz to 300 GHz (Unperturbed rms Values)
Exposure
Scenario
Frequency Range
Incident E-Field
Strength; Einc (V/m)
Incident H-Field
Strength; Hinc (A/m)
Incident Power
Density; Sinc (W/m2)
Occupational
0.1–30 MHz
>30–400 MHz
0.7
1,504/fM
139
10.8/fM
0.36
NA
50
>400–2,000 MHz
>2–6 GHz
0.43
10.58fM
NA
0.43
0.0274fM
NA
0.86
0.29fM
200
>6 to <300 GHz
NA
NA
0.177
275fG
300 GHz
NA
NA
100
General public
0.1–30 MHz
>30–400 MHz
0.7
671/fM
62
4.9/fM
0.163
NA
10
>400–2000 MHz
0.43
4.72fM
0.43
0.0123fM
0.86
0.058fM
>2–6 GHz
NA
NA
40
>6 to <300 GHz
NA
NA
0.177
55fG
300 GHz
NA
NA
20
Source: Reproduced from ICNIRP, Health Physics 118:483–524, 2020.
Notes:
1. “NA” signifes “not applicable” and does not need to be taken into account when determining compliance.
2. fM is frequency in MHz; fG is frequency in GHz.
3. Sinc, Einc, and Hinc are to be averaged over 6 minutes, and where spatial averaging is specifed in Notes 6–7, over the relevant
projected body space. Temporal and spatial averaging of each of Einc and Hinc must be conducted by averaging over the
relevant square values.
4. For frequencies of 100 kHz to 30 MHz, regardless of the far-feld/near-feld zone distinctions, compliance is demon
strated if neither peak spatial Einc or peak spatial Hinc, over the projected whole-body space, exceeds the above reference
level values.
5. For frequencies of >30 MHz to 6 GHz: (a) within the far-feld zone, compliance is demonstrated if one of peak spatial Sinc,
Einc or Hinc, over the projected whole-body space, does not exceed the above reference level values (only one is required);
Seq may be substituted for Sinc; (b) within the radiative near-feld zone, compliance is demonstrated if either peak spatial
Sinc, or both peak spatial Einc and Hinc, over the projected whole-body space, does not exceed the above reference level
values; and (c) within the reactive near-feld zone: compliance is demonstrated if both Einc and Hinc do not exceed the
above reference level values; Sinc cannot be used to demonstrate compliance; for frequencies >2 GHz, reference levels
cannot be used to determine compliance, and so basic restrictions must be assessed.
6. For frequencies of >6 to 300 GHz: (a) within the far-feld zone, compliance is demonstrated if Sinc, averaged over a square
4 cm2 projected body sursface space, does not exceed the above reference level values; Seq may be substituted for Sinc; (b)
within the radiative near-feld zone, compliance is demonstrated if Sinc, averaged over a square 4 cm2 projected body
surface space, does not exceed the above reference level values; and (c) within the reactive near-feld zone reference levels
cannot be used to determine compliance, and so basic restrictions must be assessed.
7. For frequencies of >30 to 300 GHz, exposure averaged over a square 1 cm2 projected body surface space must not exceed
twice that of the square 4 cm2 restrictions.
Reference levels in Table 7.7 are averaged over a 30-minute interval and correspond to the whole-body
average basic restrictions. Table 7.8 (averaged over a 6-minute interval) and Table 7.9 (integrated over
intervals between 0 and 6 minutes) each relate to basic restrictions that are averaged over smaller body
regions.
In ICNIRP 2020 guideline, for frequencies from 100 kHz to 110 MHz, additional limb current (induced
current) reference levels have been set to account for efects of grounding near human body resonance
frequencies that might otherwise lead to reference levels underestimating exposures within tissue at
certain frequencies (averaged over 6 minutes; Table 7.10).
Regarding the contact currents for frequencies from 100 kHz to 110 MHz, unlike the low-frequency
case, only guidance is provided for the contact current. High levels of RF contact current can result in
nerve stimulation or pain (and potentially tissue damage or burn), depending on the frequency, and
this can be a particular concern near large RF transmitters, such as those near high power broadcasting
antennas.