Why do FCC and ICNIRP limits differ?

Question

Why are U.S. and European EMF limits different numbers?

Answer

They are built on the same thermal basis but use different units, averaging masses and frequency breakpoints. The FCC expresses public RF limits in mW/cm² and averages SAR over 1 gram of tissue; ICNIRP expresses reference levels in W/m² and averages local SAR over 10 grams, so a phone's published SAR differs between regions without any difference in the device. Some countries then add precautionary layers on top — Switzerland's installation limit values are roughly a tenth of ICNIRP's reference levels in field-strength terms — which is a policy choice, not a different reading of the science.

Related records

• FCC Maximum Permissible Exposure (47 CFR 1.1310)

  Legally binding U.S. exposure limits for radiofrequency transmitters from 300 kHz to 100 GHz, adopted from NCRP and ANSI/IEEE recommendations in 1996 and reaffirmed in 2019.

  Standards & frameworks

• ICNIRP 2020 RF guidelines (100 kHz–300 GHz)

  International guidelines that most countries outside the U.S. adopt into law, covering 5G, Wi-Fi, Bluetooth, mobile phones and base stations.

  Standards & frameworks

• Reference level vs basic restriction

  ICNIRP's two-tier structure: basic restrictions are the dosimetric limits that matter biologically; reference levels are the externally measurable proxies derived from them.

  Glossary

Sources

1. fcc-1310 47 CFR § 1.1310 — Radiofrequency radiation exposure limits — U.S. Government Publishing Office (eCFR). regulation, link checked 2026-08-12.
2. icnirp-2020 Guidelines for Limiting Exposure to Electromagnetic Fields (100 kHz to 300 GHz) — International Commission on Non-Ionizing Radiation Protection, 2020. guideline, link checked 2026-08-12.
3. ch-onir Ordinance relating to Protection from Non-Ionising Radiation (ONIR / NISV, SR 814.710) — Swiss Confederation, 2000. regulation, link checked 2026-08-12.