Measurements

On behalf of the German Social Accident Insurance Institutions, the IFA measures electromagnetic fields at workplaces and evaluates the interference with active implants with respect to individuals. The measurements cover the entire frequency range of the fields, from static fields, through low-frequency to high-frequency fields.

Evaluation of non-sinusoidal or pulsed fields and checking of the observance of the exposure limit values constitute special cases of exposure evaluation. Special exposure evaluation methods are used in these cases (see below).

Checking of observance of the exposure limit values

Evaluation of non-sinusoidal and pulsed fieldspper action level be determined during evaluation of the exposure and measures for reduction of the exposure fail to have the desired success, the German Ordinance on the protection of workers against hazards presented by electromagnetic fields (EMFV) makes provision for checking of whether the normative internal body exposure limit values are observed. Since these values cannot be determined by measurement, numerical field simulation programmes and anatomical body models are employed.

Evaluation of non-sinusoidal and pulsed fields

In order for non-sinusoidal or pulsed fields to be evaluated, such as those arising on electric resistance welding equipment, the EMFV makes provision for use of the weighted peak method (WPM) or the time-domain assessment method (TDA) described in Research Report 457 (in German) concerning the evaluation of non-sinusoidal and pulsed fields. Case studies of application of the TDA are described in detail in DGUV Informative publication 203-038 (in German) concerning the assessment of magnetic fields of electric resistance welding equipment. An introduction to the WPM can be found in Chapter D.3.1.1 of the European Commission's guide.

IFA Project 5158 concerning the evaluation of pulsed magnetic fields (in German) analyses the two evaluation methods in detail, compares them and provides guidance for users. In the first quarter of 2020, a two-part article comparing methods for evaluating pulsed magnetic fields was published in the journal Sicher ist Sicher ( English translation of the article (PDF, 1.4 MB, non-accessible) ). Furthermore, a joint measurement project was conducted with Narda Safety Test Solutions GmbH in which selected magnetic fields were recorded by a number of measuring devices and their respective evaluations compared by means of WPM and TDA.

* Software: ZMT Zurich MedTechAG, "Sim4Life" [software], Zurich, Switzerland; body model: IT'IS Foundation, "Virtual Population Human Models", Zurich, Switzerland