Limits of Human Exposure to Radiofrequency Electromagnetic Fields in the Frequency Range from 3 KHZ to 300 GHZ - Safety Code 6

1. Introduction

Recent developments in the electronics industry have led to the widespread use of radiofrequency (RF) devices in various areas, including telecommunication, radio and television broadcasting, radar, industrial processing, medical applications and consumer products. Electromagnetic fields extend over large areas when generated for communication, broadcasting and radar devices, but generally spread only over small areas when used in industrial, medical and consumer devices. Reflection and scattering of electromagnetic waves and simultaneous RF emissions by more than one source frequently result in a complex condition known as "multi-path" propagation and spatially non-uniform fields.

Studies of possible hazards to human health from exposure to RF electromagnetic fields showthat there is a need for controls. Exposure to RF energy in excess of the limits given in this Safety Code may cause adverse health effects. The type and extent of effects depends not only on the strength of the field and the exposure duration, but also on various other factors such as the frequency, type of modulation, polarization, and distance from the source.

The exposure limits were established from a review of experiments conducted over the last 30 years on biological organisms, including humans, animals and cell systems(1,2,3). The limits recommended in this Code have been set at least a factor of 10 lower than the threshold where potentially harmful effects begin, as judged by a consensus of the scientific community(4,5). Biological effects of RF fields at levels too low to produce significant heating have also been reviewed(3,6). These effects are not well established, nor are their implications for human health sufficiently well understood. Thus, they cannot provide a basis for making recommendation towards the restriction of human exposures to such low-intensity RF fields.

SI units are used throughout this document unless specified otherwise. A glossary of definitions is provided in Appendix VIII.

1.1 Purposes of the Code

The purposes of this Code are:

1. to specify maximum levels and durations of exposure to RF fields of frequencies between 3 kHz and 300 GHz in order to prevent human health effects;
2. to specify maximum allowableRF contact and induced body currents to prevent the physical perception of RF fields to the general public and RF shock or burns to RF and microwave exposed workers;
3. to recommend general procedures for ensuring that exposure of the general public and of personnel working in the vicinity of RF and microwave devices is not greater than the levels specified in this Code; and
4. to recommend working conditions that will lead to high standards of safety for all personnel engaged in the manufacture, operation and maintenance of RF devices.