SRC-137

ICNIRP Guidelines for Limiting Exposure to Electromagnetic Fields (100 kHz to 300 GHz), 2020.

Commissioned by ICNIRP. Who paid for a study is recorded because it bears on how its conclusions should be read, not because it makes them wrong.

Published claims resting on this source

• CLM-1169 Under the 2020 international guidelines, which keep the 1998 values, for a microwave beam at either SBSP frequency the public may be exposed to ten watts per square metre and trained workers to fifty, averaged over half an hour and over the whole body; both come from the absorbed power that raises core temperature by one degree, divided by fifty and by ten, and close in to the antenna the power-density number stops being usable at all.
• CLM-1170 In the 2020 international guidelines, besides the half-hour whole-body limit there is a six-minute limit on the hottest spot on the body, 40 watts per square metre for the public and 200 for workers at these frequencies, and a rule for bursts shorter than six minutes that lets a single brief pulse carry at most about 720 joules per square metre for the public.
• CLM-1171 In the 2020 international guidelines, the lower public limit exists because the public includes children, the sick and the unaware, and anyone pregnant counts as public even at work; you may show compliance by either the external field number or the absorbed-power number, and need not show both; and ICNIRP admits that its public limits between 1 and 4 GHz, which include 10 W/m2 at 2.45 GHz, can over-expose a small child by up to 40 per cent, and has chosen not to lower them.
• CLM-1454 The 2020 international limit for public exposure, 10 watts per square metre, is about 19 to 42 times lower than the beam strengths at which one theory says the beam might start to focus itself in the upper atmosphere (42 times uses a 2008 estimate, 19 times uses measured conditions), and 23 times lower than the 230 that a 2019 CASSIOPeiA paper gives as a typical peak. Those atmospheric figures are estimates, not hard limits. A 2026 international radio report that takes CASSIOPeiA as its example says the beam can be designed to fall below the public limit at the edge of the receiving site, with a safety zone over the beam's footprint; it gives no figure for the beam's strength at that edge, and a diagram in it shows the receiving site taking 245 watts per square metre.
• CLM-1467 (low confidence) Keeping people out of the area where the beam is strong is a plausible way for a strong beam to meet the 2020 international limit for public exposure, and international exposure guidance accepts limiting access as a way to comply. Other designs have worked this out: a 2013 Japanese review plans a no-entry area 3.5 kilometres across, and a 2007 international study sizes a 4-kilometre receiver this way. A 1977 US study set aside 204 square kilometres for one receiving site, without saying in its cost table what fixed that size, and costed buying and preparing that land. A 2026 international radio report that takes CASSIOPeiA as its example says the beam can be designed to fall below the public limit at the edge of the receiving site, with a safety zone matching the beam's footprint, about 3.5 to 6.5 by 7 to 13 kilometres in the UK. A diagram in it shows the receiving site taking 245 watts per square metre, but the report gives no figure for the beam's strength at the edge and no cost for the zone. A 2021 UK cost model for a CASSIOPeiA design includes the land for the receiving site but names no safety zone.

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