Benchmark of different assessment methods for non-sinusoidal magnetic field exposure in the context of European Directive 2013/35/EU

Abstract

For the assessment of non-sinusoidal magnetic fields the European EMF Directive 2013/35/EU specified the Weighted Peak Method in Time Domain (WPM-TD) as the reference method. However, also other scientifically validated methods are allowed, provided that they lead to approximately equivalent and comparable results. In the non-binding guide for practical implementation of 2013/35/EU three methods alternative to the WPM-TD are described, i.e. the Weighted Peak Method in Frequency Domain (WPM-FD), the Multiple Frequency Rule (MFR), and an alternative Time Domain Assessment Method (TDAM). In this paper the results of a benchmark comparison of these assessment methods, based on 12 different time domain signals of magnetic induction, measured close to real devices and nine additional generic waveforms, are presented. The results demonstrated that assessments obtained with WPM-TD and WPM-FD can be considered approximately equivalent (maximum deviation 3.4 dB). The MFR systematically overestimates exposure, due to its inherently conservative definitions. In contrast, the TDAM significantly and systematically underestimates exposure up to a factor of 22 (26.8 dB) for the considered waveforms. The main reasons for this exposure underestimation by the TDAM are the introduction of an inappropriate time averaging, and the fact that the characteristic time parameter τp,min, describing the minimum duration of all field changes dB/dt of the waveform is derived independently from the extent of the field change in the definitions of the TDAM. Consequently, we recommend not to use the TDAM as presently published in the non-binding guide to 2013/35/EU, as its application would be in contradiction with the underlying aim of 2013/35/EU, i.e. a harmonised level of occupational safety with respect to exposure to electromagnetic fields.

Uncertainty quantification in the assessment of human exposure to pulsed or multi-frequency fields

“…All results are normalized by the EI obtained with the WPM in time domain (i.e. the most stable method according to the literature (Keller 2017, Schmid et al 2019) for the first value of the parameters (e.g. EI obtained with τ = 100 ms in the case of trapezoidal pulse).…”

“…Each standard and guideline addresses this problem differently proposing solutions that depends on the shape of the waveform (ICNIRP 2003, 2010, Bailey et al 2019. The literature includes several papers using these methods to analyze specific exposure scenarios (Lodato et al 2012, Andreuccetti et al 2013, Fiocchi et al 2015, Canova et al 2016, Paffi et al 2016, Tang et al 2022 and other papers pointing out issues and performances of these methods (De Santis et al 2013, Schmid and Hirtl 2016, Keller 2017, Schmid et al 2019. Most of these methods move the problem from the time domain to the frequency domain by means of the Fourier decomposition of the waveform.…”

“…The analysis shows that the WPM is the approach more closely related to the underlying concepts of electrostimulation and the results obtained are very reliable, especially when applied in the time domain. Schmid et al (2019) In the literature, to the best of the author's knowledge, there is no study trying to evaluate the uncertainty propagation of any of the available methods. For this reason, in this paper the analysis of the uncertainty associated to the methods used to assess a pulsed or a multi-frequency field is considered.…”

“…Results will be presented as 95% confidence interval plots. It must be stressed that the method used for the uncertainty quantification is very general and it can be applied to all methods for the assessment of pulsed or multi-frequency fields, however, in this paper we take into account only the weighted peak method proposed by the ICNIRP because it is recognized to be the most suitable and less conservative among all methods (Schmid and Hirtl 2016, Keller 2017, Schmid et al 2019. The WPM can be applied both in time domain and frequency domain.…”

Nonsinusoidal in situ electric field caused by magnetic deactivator device for EAS labels—assessment of field strength inside a detailed anatomical hand model

“…Several different basic methods for the assessment of nonsinusoidal fields have been proposed in recent years (IEEE C95.6-20022002, ICNIRP 2003, and some of these assessment methods were analysed and compared in publications by two different research groups (De Santis et al 2013, Schmid et al 2019a. EU (2013) declares the so-called weighted peak method (WPM) in the time domain (WPM-TD) to be the preferred method because it avoids the overestimation of exposure which may occur using methods that neglect phase relationships of different spectral components, e.g.…”