Value chain · CLM-1169
In plain terms
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.
The claim as recorded
ICNIRP 2020's whole-body reference levels at 2.45 and 5.8 GHz are the >2-300 GHz row of Table 5, "Reference levels for exposure, averaged over 30 min and the whole body": incident power density 50 W/m2 occupational and 10 W/m2 general public, with the E- and H-field columns "NA" above 2 GHz, "averaged over 30 min, over the whole-body space"; they "correspond to the whole-body average basic restrictions" of 0.4 and 0.08 W/kg, which come from a 4 W/kg threshold "for an increase in body core temperature of 1" C with "A reduction factor of 10" for occupational exposure and "a reduction factor of 50" for the general public; above 2 GHz compliance in the far field or radiative near field is shown by Sinc alone, while "within the reactive near-field zone, reference levels cannot be used to determine compliance, and so basic restrictions must be assessed"; the values are the 1998 values retained.
Evidence behind this: T1-the normative instrument quoted for its own requirement (METHOD.md rule: a normative instrument quoted for its own requirement is T1); the values, averaging conditions and derivation are the guideline's words at the page.
Scope and limits
NO LIMIT IN THE GUIDELINE IS SPECIFIC TO 2.45 OR 5.8 GHz ("5.8 GHz" absent from 43 pages; "2.45" three times, in appendix discussion of rabbit-eye heating and microwave hearing and in a reference title, never as a limit); the values are the >2 GHz band's. The 30-min whole-body level is one of two that must both be met; the 6-min local level (CLM-1170) is separate and higher. The guideline is ICNIRP's; national limits (the register's SRC-138 and the IEEE standards it reports) may differ in adoption if not in value.
What it assumes
A ground rectenna site is far-field or radiative near-field exposure for a person at ground level (the reactive near-field rule is for the antenna's immediate vicinity).
Where it comes from
PDF 14 / printed 495: "Reference levels for exposure, averaged over 30 min and the whole body, to electromagnetic fields from 100 kHz to 300 GHz (unperturbed rms values)" (normalised); ">2 - 300 GHz" rows "300 GHz NA NA 50" (occupational) and "300 GHz NA NA 10" (general public) (normalised; crop read); note 3 "Sinc, Einc, and Hinc are to be averaged over 30 min, over the whole-body space" (raw); note 6 "within the far-field zone:compliance isdemonstratedifSinc does notexceed the above reference level values; Seq may be substituted for Sinc" (normalised, page spacing), "within the radiative near-field zone, compliance is demonstrated if Sinc does not exceed the above reference level values" (raw), "within the reactive near-field zone, reference levels cannot be used to determine compliance, and so basic restrictions must be assessed" (raw). PDF 13 / printed 494: "Table 5 reference levels are averaged over a 30-min interval, and correspond to the whole-body average basic restrictions" (normalised); "provide an equivalent level of protection to the basic restrictions for worst-case exposure scenarios" (normalised); "in most exposure scenarios the reference levels will be more conservative than the corresponding basic restrictions" (normalised). PDF 10 / printed 491, Table 2 (crop read): "Occupational 100 kHz to 6 GHz 0.4 10 20 NA"; "General public 100 kHz to 6 GHz 0.08 2 4 NA" (normalised); "Whole-body average SAR is to be averaged over 30 min" (raw). PDF 10-11 / printed 491-492: "as the exposure level corresponding to the operational adverse health effect threshold for an increase in body core temperature of 1" C (normalised); "A reduction factor of 10 was applied to this threshold for occupational exposure to account for scientific uncertainty, as well as differences in thermal physiology across the population and variability in environmental conditions and physical activity levels" (normalised); "Thus the basic restriction for occupational exposure becomes a whole-body average SAR of 0.4 W kg" -1 (normalised); "a reduction factor of 50 was applied for the general public, making the whole-body average SAR restriction for the general public 0.08 W kg" -1 (normalised). PDF 32 / printed 513: "these guidelines retain the ICNIRP (1998) reference levels for whole-body exposure conditions" (normalised). Recomputed: 4 / 10 = 0.4; 4 / 50 = 0.08; 50 / 10 = 5.
Basis: W/m2 incident power density, unperturbed rms, averaged over 30 min and the whole-body space; W/kg whole-body average SAR over 30 min
Cite this
energyaperture.com/c/clm-1169
CLM-1169, Energy Aperture, as of 2020-05.
Connected records
Other published records linked to this one. A list, not a judgement.
- Also from SRC-137
- CLM-1170In the 2020 international guidelines, besides the half-hour whole-body limit there is a six-minute limit on the hottest spot on the body...CLM-1171In the 2020 international guidelines, the lower public limit exists because the public includes children, the sick and the unaware, and...CLM-1454The 2020 international limit for public exposure, 10 watts per square metre, is about 19 to 42 times lower than the beam strengths at which...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...