ID Number		1756
Study Type		Engineering & Physics
Model		IEEE Standards for human exposure to electromagnetic energy.
Details		Revised 2005 version of the standard - the Committee agreed that a biologically based rationale, such as that use by ICNIRP, is more appropriate than the purely dosimetry based rationale in IEEE C95.1-1999. In addition, the IEEE C95.1-2005 standard provided rationale showing that a local limit of 10 W/kg in 10 grams is protective against potentially adverse effects in the human central nervous system. For these reasons, the local limits were revised upward in IEEE C95.1-2005 to 2 W/kg in 10 grams (with 4 W/kg allowed in extremities and the pinnae) for action level (general public exposure) and 10 W/kg (with 20 W/kg allowed in extremities) for the controlled environment (occupational exposure). Previously, different approaches were used to derive local SAR exposure limits in the ICNIRP guidelines vs the IEEE C95.1-1991 standard. In the case of ICNIRP, the basis for local SAR is studies mainly in rabbits showing ~100 W/kg as the threshold for cataract formation. A safety factor of 50x is applied as well as a tissue averaging volume of ~10 grams (to approximate the human eye) resulting in a 2 W/kg local limit. In contrast, the 1982, 1991 and 1999 IEEE C95.1 standards initially extrapolated localized RF exposure limits from whole body values based upon rodent work stoppage at ~4 W/kg (whole body). A safety factor of 50x was then applied to give a general public limit of 0.08 W/kg (whole body), and from that a 20x peak-to-average ratio based on dosimetry data available in the late 1970s was added to give a local RF exposure limit of 1.6 W/kg (per 1 gram tissue, per 30 minutes). Maximal permissible exposure limits for far-field (base station and radio tower) exposures are frequency dependent, and for power density equivalent values in the range of 400-2000 MHz - for the general public = frequency (in MHz) divided by 200 = limit value (W/m2). For occupational exposure = frequency (in MHz) divided by 30 = limit value (W/m2).
Findings		Not Applicable to Bioeffects
Status		Completed With Publication
Principal Investigator		IEEE ICES
Funding Agency		(vacant)
Country		UNITED STATES
References		IEEE ICES Committee, IEEE C95.1 Standard, (2005) :- IEEE ICES Committee, IEEE C95.1 Standard., (1992) :(76 pages)- IEEE, IEEE Standard 1654-2009, (2009) :- ITU, ITU-T Recommendations K-Series Supplement 4., (2018) https://www.itu.int/ITU-T/recommendations/rec.aspx?rec=13792:1-54 IEEE, et al. Institute of Electrical and Electronics Engineers (IEEE), International Electrotechnical Commission (IEC)., (2020) https://ieeexplore.ieee.org/document/9237217:- IEEE, et al. Institute of Electrical and Electronics Engineers (IEEE)., (2020) Part 1528: Human Models, Instrumentation, and Procedures (Frequency Range of 4 MHz to 10 GHz). :- IEEE, IEEE 1528.7-2020., (2021) doi: 10.1109/IEEESTD.2021.9319817.:1-90 IEEE, Institute of Electrical and Electronics Engineers, IEEE C95.3-2021., (2021) :- IEEE, Institute of Electrical and Electronics Engineers (IEEE), IEEE Std 2889-2021. , (2021) ISBN 978-1-5044-8015-4:1-152 IEEE, Institute of Electrical and Electronics Engineers (IEEE), IEEE PC95.7. , (2022) :1-139
Comments		One significant assumption in current RF exposure standards is a nominal 1 °C increase for whole body and ALL local tissue temperature increases. The 1 °C limit was originally written into WHO EHC #137, and seems to have been adopted by the current human exposure standards (ICNIRP 1998 specifically recommends RF induced tissues not exceed a 1 oC temperature rise, and both ICNIRP and IEEE C95.1 local SAR limits are extrapolated from the 4 W/kg whole body data in rodents and monkeys that corresponds to ~1 oC core body temperature increase). There is limited evidence that the 1 °C temperature increase represents a true localized thermal threshold, and is almost certainly conservative for most (if not all) tissues . From WHO EHC #137, this 1 °C increase is very loosely correlated with observable endpoints in animal models as "... rises in tissue or body temperature of about 1 °C or more ... although an equivalent 4 W/kg exposure in humans for 15-20 minutes may increase core temperature no more than 0.2-0.5 °C & which is quite acceptable in healthy people". Further, different tissues will presumably have a range of thermal thresholds that may also vary with time, perfusion, and other factors