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Bioelectromagnetism
7.8 Guidelines for Radiofrequency Electromagnetic Fields
In ICNIRP’s defnition, RF electromagnetic feld is used to describe the frequency range from 100 kHz
to 300 GHz. Due to the gradual increase of the use of RF-operated devices such as mobile phone, Wi-Fi,
Bluetooth, radar, smart meters, medical equipment, etc., exposure levels of RF felds have increased
gradually around us. Understanding of health, biological, and environmental efects of electromag
netic feld in the frequency range up to 300 GHz is now advancing rapidly. In 2020, ICNIRP published
a guideline in the frequency range from 100 kHz to 300 GHz (ICNIRP, 2020). Tis guideline protects
against adverse health efects relating to exposure RF feld including from 5G technologies.
7.8.1 ICNIRP Guidelines
Te ICNIRP guidelines for low RF electromagnetic felds were originally established in 1998 and revised
in 2020 (ICNIRP, 2020).
7.8.1.1 Basic Restriction
Te basic restrictions expressed as SAR for frequencies from 100 kHz to 300 GHz are provided in
Table 7.5 to prevent whole-body heat stress and excessive localized tissue heating. In the frequency range
between 100 kHz and 10 MHz, the basic restrictions on the induced electric feld related to nerve stimula
tion in Table 7.2 are additionally applied. Te following provides an overview of basic restrictions in the
ICNIRP guideline (ICNIRP, 2020).
Whole-body average SAR (100 kHz-300 GHz): For frequencies from 100 kHz to 300 GHz, the whole-
body average SAR limit averaged over the entire body mass and a 30-minute interval was set for an
increase in body core temperature of 1°C.
Local SAR (100 kHz to 6 GHz): For local exposure of the Head and Torso for 100 kHz to 6 GHz, SAR
limit averaged over a 10-g cubic mass and 6-minute interval was set for the local temperature rise of 5°C
or 2°C depending on the tissue type. For the local exposure for the Limb (100 kHz to 6 GHz), SAR limit
averaged over a 10-g cubic mass and 6-minute interval, for the Limbs of a 5°C rise in local temperature.
Local SAR (400 MHz to 6 GHz): In addition, for frequencies from 400 MHz to 6 GHz, ICNIRP sets
an additional limit expressed as SAR for exposure intervals of <6 minutes, as a function of time, to
ensure that the cumulative energy permitted by the 6-minute average local SAR basic restriction is not
absorbed by tissues too rapidly in Table 7.6.
TABLE 7.6 Basic Restrictions in ICNIRP Guidelines for Electromagnetic Field Exposure from 100 kHz to
300 GHz, for Integrating Intervals >0 to <6 Minutes
Exposure
Scenario
Frequency Range
Local Head/Torso
(kJ/kg)
Local Limb
SA (kJ/ kg)
Local Uab
(kJ/m2)
Occupational
100 kHz to 400 MHz
>400 MHz to 6 GHz
>6 to 300 GHz
NA
3.6[0.05 + 0.95(t/360)0.5]
NA
NA
7.2[0.025 + 0.975(t/360)0.5]
NA
NA
NA
36[0.05 + 0.95(t/360)0.5]
General public
100 kHz to 400 MHz
>400 MHz to 6 GHz
>6 to 300 GHz
NA
0.72[0.025 + 0.95(t/360)0.5]
NA
NA
1.44[0.025 + 0.975(t/360)0.5]
NA
NA
NA
7.2[0.05 + 0.95(t/360)0.5]
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. t is time in seconds, and restrictions must be satisfed for all values of t between >0 and <360 s, regardless of the temporal
characteristics of the exposure itself.
3. Local SA is to be averaged over a 10-g cubic mass.
4. Local Uab is to be averaged over a square 4-cm2 surface area of the body. Above 30 GHz, an additional constraint is
imposed, such that exposure averaged over a square 1-cm2 surface area of the body is restricted to 72[0.025 + 0.975(t/360)0.5]
for occupational and 14.4[0.025 + 0.975 (t/360)0.5] for general public exposure.
5. Exposure from any pulse, group of pulses, or subgroup.