CALC-003

Exceedance ratios

Calculation · Cited by CLM-0010

What this is

This is the project's own arithmetic, published in full so it can be checked rather than taken on trust. It is not a source. Every input it uses is cited to a record, and the conclusion it reaches only carries as far as those inputs do.

Feeds CLM-0010.

Inputs. Design peaks from CLM-0001 (230 W/m2), CLM-0002 (240 W/m2) and CLM-0003 (245 W/m2). Reference levels from CLM-0008: 10 W/m2 general public, 50 W/m2 occupational, both averaged over 30 min and the whole body. Validity of the comparison from CALC-002.

General public, 10 W/m2:
  230 / 10 = 23.0 x
  240 / 10 = 24.0 x
  245 / 10 = 24.5 x

Occupational, 50 W/m2:
  230 / 50 = 4.6 x
  240 / 50 = 4.8 x
  245 / 50 = 4.9 x

Result. At the rectenna centre the design exceeds the general public reference level by about 23 to 24.5 times, and the occupational level by about 4.6 to 4.9 times.

What this does and does not establish. A reference level is a screening threshold. ICNIRP permits compliance to be demonstrated instead against the basic restrictions, which for the general public is a whole-body average SAR of 0.08 W/kg over 30 minutes. Exceeding a reference level shifts the burden to that fuller assessment; it does not by itself establish non-compliance, and it certainly does not establish harm.

So the honest finding is not "SBSP is unsafe". It is this: the published UK design sits more than an order of magnitude above the public screening threshold at the beam centre, the documents do not mention that threshold or any other exposure standard, and the safety statement they do make rests on a comparison with sunlight rather than on a radio-frequency assessment. Whether a compliant case can be made is an open question, and it is one the programme has to answer rather than assert.

Not yet calculated, and worth doing. The radial beam profile, so the distance from the centre at which the intensity falls to 10 W/m2 can be stated. That distance is the implied public exclusion radius, and comparing it with the stated rectenna dimensions would show whether the exclusion zone fits inside the site boundary. If it does not, the land requirement in every published cost model is understated. That calculation needs a beam profile from a source, which none of the five documents reviewed provides.

Cite this

energyaperture.com/calc/calc-003

CALC-003. The working above, not a source document.