A quick and easy method for checking compliance of multi-frequency magnetic fields with ICNIRP's guidelines.
In many practical cases human exposure to extremely low frequency magnetic fields with many spectral components (multi-frequency fields) has to be examined in order to check compliance with ICNIRP's guidelines. Showing compliance, according to existing methods, requires sophisticated instruments and measurement procedures to assess some complex exposure metrics. Furthermore, even where the field levels are very low, there is no method to show compliance using broadband instruments, which are the most common and simple ones. In this paper, a new method is described where the frequencies emitted by the source are known and only simple broadband instruments are required. First, the spectral distribution of the field that maximizes exposure metrics is found. Then, an effective reference level for the broadband value of the field is estimated for this distribution. If the measured broadband value of the magnetic field is lower than this reference level, then compliance with ICNIRP's guidelines is readily shown. A case study for a magnetic field consisting of 50 Hz and 60 Hz components is presented. The worst-case spectral distribution contained 64% 50 Hz and 76.8% 60 Hz components, and the corresponding effective broadband reference level is 64 muT for general public exposure. The method is generally conservative in cases of incoherent fields and very conservative in cases of coherent fields. To that end, it is practically a quick and easy test to check if further measurements are needed or not. Application of this method is expected to save time, money, and resources.
Filippopoulos
George
G
Greek Atomic Energy Commission, Non Ionizing Radiation Office, P.O. Box 60092, 15310 Agia Paraskevi, Greece. filippop@eeae.gr
Karabetsos
Efthymios
E
D004574:Electromagnetic Fields / Q000009:adverse effects*; D004781:Environmental Exposure / Q000592:standards*; D019983:Guideline Adherence; D017408:Guidelines as Topic; D006801:Humans; D008280:Magnetics / Q000009:adverse effects*; D016273:Occupational Exposure / Q000592:standards; D011834:Radiation Monitoring / Q000592:standards