在许多实际情况下,必须检查人体暴露于具有许多频谱分量的极低频磁场(多频率场),以检查是否符合ICNIRP指南。显示合规性,根据现有的方法,需要复杂的仪器和测量程序来评估一些复杂的暴露指标。此外,即使在现场水平很低的地方,没有使用宽带仪器显示合规性的方法,这些是最常见和最简单的。在本文中,描述了一种新的方法,其中源发出的频率是已知的,只需要简单的宽带仪器。首先,找到最大化曝光度量的场的光谱分布。然后,为该分布估计了该字段的宽带值的有效参考水平。如果测量的磁场宽带值低于该参考水平,然后很容易显示符合ICNIRP的准则。给出了由50Hz和60Hz分量组成的磁场的案例研究。最坏情况下的频谱分布包含64%的50Hz和76.8%的60Hz分量,相应的有效宽带参考水平为64mut,用于一般公众暴露。该方法在非相干场的情况下通常是保守的,而在相干场的情况下是非常保守的。为此,这实际上是一个快速和容易的测试,以检查是否需要进一步的测量。该方法的应用有望节省时间,钱,和资源。
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.