more on RF burn hazards

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

I'm looking for a report by S.J. Rogers (USAFSAM-TR-81-28) called 
"Radio-Frequency Burn Hazards in the MF/HF Band", and I'll report when I 
find it.  But, in the mean time, there's an interesting report at:


http://www.brooks.af.mil/AFRL/HED/hedr/reports/bioeffects/3-1-4-4.htm

which discusses shock and burn hazards from RF.  Lots of interesting data. 
(The table of contents for the whole report containing the part above is 
at: http://www.brooks.af.mil/AFRL/HED/hedr/reports/bioeffects/87-3con.htm )


There were some studies by Gandhi and Chatterjee (in 1982) that did some 
modeling and then measurements for threshold perception and let-go.  They 
mention that sensation changes from tingling to internal heat at around 
100-200 kHz.  Perception threshold linearly runs from 0.4 mA at 10 kHz to 
14 mA at 150 kHz, and then to 100 mA at 20 Mhz.  Let go is 6.4mA to 85mA to 
200 mA. (those are currents through the muscle/skin)..

They then worked out what E field corresponds to that for a metal roof, a 
50' fence, a car, and a forklift...
for 10-100 kHz, perception threshold was 250,160,80,20 V/m for the objects 
respectively. Let go fields were 1050, 850, 550, 110 V/m.

These are pretty low fields... the Efield program can calculate the 
expected field given topload voltage, etc. (I'd use a working number for 
max topload voltage of 500 kV, or, perhaps 30 kV per cm smallest radius of 
the topload) Something made with, for instance, 4" dryer duct would be 150 
kV (5 cm radius...)


The above report also cites some stuff from Guy and Chou more relevant to 
TCs because they were worried about LF and MF signals including signals at 
23 kHz and 146 KHz   They found that fields as low as 97 V/m could induce 
currents in the body, and the highest absorption would be at the ankles and 
would have a Specific Absorption Rate (SAR)of 8 W/kg (the maximum allowed 
by the ANSI standard, providing whole body averaged SAR is <0.4W/kg, and 
averaged over 6 minutes (0.1 hour).  The real problems were with people in 
contact with a vehicle (standing outside and touching the vehicle).

Fascinating stuff...


OSHA's site also has some interesting stuff..
http://www.osha-slc.gov/SLTC/radiofrequencyradiation/rfpresentation/healtheffects/mainpage1.html