There are no compulsory international safety standards for the exposure to electromagnetic fields. Instead, various international limit guidelines, which have been developed on different bases, are implemented in each country into its national recommendations or legally binding regulations. Here, the EMF limit values can refer either as so-called reference limits to the fields emitted by electrical devices, characterized by frequency and field strength or flux density, or as basic restrictions to the (usually) measured variables induced in the human body, such as SAR or current density. When applying the limit values, a distinction should therefore be made between reference limits and basic restrictions. The basic restrictions are normally not accessible with a measuring instrument, in contrast to the reference limits, but can only be checked by numerical simulations or measurement phantoms. In our research projects, we pursue the evaluation of exposure situations with the aid of both metrological and simulative approaches.
In order to evaluate exposures due to new technologies, for example, we set up measurement systems which are customized to the technology and the application. For measurements on electric vehicles or power grids, we use a fully battery-operated measuring system to record magnetic fields in the time range up to 400 kHz. With the help of the recorded signals, complex analyses can be carried out and checked for compliance with different reference limits (e.g. general public and occupational health and safety). If the reference limits are exceeded, the signals can also be used to check the basic restrictions using numerical simulations.
We also use exposure simulations to assess electrical accidents, for example to understand the current path in the human body and to determine the risk of ventricular fibrillation. With the help of these numerical calculation methods, many accident scenarios can be evaluated under real conditions without endangering human health.
Thanks to our interdisciplinary team and our versatile methods, we are able to carry out a complete risk analysis for various technologies, also for people with cardiac implants.
Kai Jagielski, Pia Schneeweiß, Ralph Kühn, Günter Wermeester