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7.6 ICNIRP EXPOSURE GUIDELINES

The scientific principles described above are embodied in recommendations published by ICNIRP and in related standards developed by IEEE and national authorities. ICNIRP’s 2020 guidelines cover frequencies from 100 kHz to 300 GHz and are intended to protect against established adverse health effects of short- and long-duration, continuous, intermittent, and pulsed RF exposure.

This section provides only the biological link between evidence and restrictions. Chapter 6 introduced the dosimetric and external assessment quantities, while Chapter 9 examines the numerical limits, averaging rules, standards, and jurisdictional requirements in detail.

7.6.1 Scientific Basis

The ICNIRP recommendations are based on systematic evaluation of laboratory, animal, human, epidemiological, dosimetric, and thermal evidence. Findings are assessed for study quality, consistency, reproducibility, biological plausibility, and relevance to human health. Restrictions are derived from substantiated adverse effects. Depending on the evidence, an adverse-health-effect threshold or a conservative operational threshold is selected, and reduction factors are then applied to derive the basic restrictions.

Within the RF range, the established effects that determine the restrictions are electrostimulation at the lower frequencies and excessive whole-body or localized heating. The restrictions are expressed through dosimetric quantities linked to those mechanisms, while reference levels provide conservative quantities for practical assessment.

Table 7.1 and Table 7.2 summarize the principal quantities used in the ICNIRP framework for basic restrictions and reference levels.

Table 7.1. Principal physical quantities used in RF basic restrictions.

Quantity

Symbol

Unit

Induced electric field

Eind

volt per meter (V m⁻¹)

Specific absorption rate

SAR

watt per kilogram (W kg⁻¹)

Specific energy absorption

SA

joule per kilogram (J kg⁻¹)

Absorbed power density

Sab

watt per square meter (W m⁻²)

Absorbed energy density

Uab

joule per square meter (J m⁻²)

Table 7.2. Principal physical quantities used in RF reference levels.

Quantity

Symbol

Unit

Incident electric-field strength

Einc

volt per meter (V m⁻¹)

Incident magnetic-field strength

Hinc

ampere per meter (A m⁻¹)

Incident power density

Sinc

watt per square meter (W m⁻²)

Plane-wave-equivalent incident power density

Seq

watt per square meter (W m⁻²)

Incident energy density

Uinc

joule per square meter (J m⁻²)

Plane-wave-equivalent incident energy density

Ueq

joule per square meter (J m⁻²)

Current in the limbs

IL

ampere (A)