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Safety and Electromagnetic Field Guidelines

TABLE 7.9 Reference Levels in ICNIRP Guidelines for Local Exposure, Integrated over Intervals of between >0

and <6 Minutes, to Electromagnetic Fields from 100 kHz to 300 GHz (Unperturbed rms Values)

Exposure Scenario

Frequency Range

Incident Energy Density; Uinc (kJ/m²)

Occupational

100 kHz–400 MHz

>400–2,000 MHz

>2–6 GHz

>6 to <300 GHz

300 GHz

General public

100 kHz–400 MHz

>400 to 2,000 MHz

>2 to 6 GHz

>6 to <300 GHz

300 GHz

NA

0.29fM

0.86 × 0.36[0.05 + 0.95(t/360)0.5]

200 × 0.36[0.05 + 0.95(t/360)^0.5]

275fG

0.177 × 0.36[0.05 + 0.95(t/360)0.5]

100 × 0.36[0.05 + 0.95(t/360)^0.5]

NA

0.058fM

0.86 × 0.36[0.05 + 0.95(t/360)0.5]

40 × 0.36[0.05 + 0.95(t/360)^0.5]

55fG

0.177 × 0.36[0.05 + 0.95(t/360)0.5]

20 × 0.36[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. fM is frequency in MHz; fG is frequency in GHz; t is time interval in seconds, such that exposure from any pulse, group of

pulses, or subgroup of pulses in a train, as well as from the summation of exposures (including non-pulsed EMFs),

delivered in t seconds, must not exceed these reference level values.

3. Uinc is to be calculated over time t, and where spatial averaging is specifed in Notes 5–7, over the relevant projected body

space.

4. For frequencies of 100 kHz to 400 MHz, >0 to <6 minutes restrictions are not required and so reference levels have not

been set.

5. For frequencies of >400 MHz to 6 GHz: (a) within the far-feld zone: compliance is demonstrated if peak spatial Uinc, over

the projected whole-body space, does not exceed the above reference level values; Ueq may be substituted for Uinc; (b)

within the radiative near-feld zone, compliance is demonstrated if peak spatial Uinc, over the projected whole-body

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.

6. For frequencies of >6 GHz to 300 GHz: (a) within the far-feld or radiative near-feld zone, compliance is demonstrated

if Uinc, averaged over a square 4 cm² projected body surface space, does not exceed the above reference level values; (b)

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

275/fG

0.177 × 0.72[0.025 + 0.975(t/360)0.5] kJ/m2 for occupational and 55/fG

0.177 × 0.72[0.025 +0.975(t/360)0.5] kJ/m2 for gen­

eral public exposure.

7.8.2 IEEE Safety Standard

Te IEEE safety standard for RF electromagnetic felds (IEEE C95.1) was originally published in 1966

and recently revised in 2019 (IEEE, 2019).

Exposure limits are divided into DRL and ERL. DRL is limits expressed in terms of in situ electric

feld strength, SAR, epithelial power density, in the body and are considered to be basic restrictions of

ICNIRP. Te ERL is a limit indicated by the electric feld strength, magnetic feld strength, power den­

sity, current fowing in the limb, and contact current, which can be measured, and is considered to be

equivalent to the reference level of the ICNIRP guidelines.

For RF, the DRL is defned in terms of specifc absorption rate (SAR) and epithelial power density

for frequencies from 100 kHz to 6 GHz to protect against adverse heating (thermal efect). Like to the

ICNIRP RF guidelines, separate DRLs are defned for whole-body exposure (30 minutes averaging) and

local exposure (6 minutes averaging time, 10-g averaging mass) for “head and torso” and “limbs and

pinnae” for frequencies from 100 kHz to 6 GHz. For frequencies from 6 to 300 GHz, epithelial power

density DRL is defned at the body surface.

For RF, the ERL has been derived from the DRLs to provide a readily assessed quantity via measure­

ments or computation. ERLs are provided for both whole-body exposure (30-minute averaging time)