Assessing complex low frequency magnetic fields against the EU directive for worker protection

Abstract

The EU Directive 2013/35/EU requires that companies carry out a risk assessment for workers exposure to Electromagnetic fields (EMF). This paper describes how low frequency magnetic fields can be assessed against the directive. The exposure limit values are expressed as the induced electric field strength in the human body. The induced electric field cannot be measured, only calculated in computer simulations. Therefore the directive also gives action levels expressed in the magnetic field strength The magnetic fields in work places, such as welding, are often not sinusoidal. Complex signals can be assessed using weighting filters. If the action levels are exceeded, an assessment against the exposure limit values has to be done. This can be done by using computer simulations of the induced electric field strength in the body, which can be used to define a coupling factor between the source current and the induced electric field in the body. By using weighting filters and coupling factors the time and geometrical dependences can be treated separately, which considerably simplifies the assessment and makes it cost effective.