On the method of investigating human exposure to nonuniform magnetic field

Regarding compliance testing with existing guidelines on human exposure to ELF (extremely low frequency) magnetic fields, the nonuniformity of the fields has been one of the major concerns since guideline-level exposures are generally encountered in the direct vicinity of magnetic field sources Such as electric power facilities and electric appliances. According to the guidelines, when the measured maximum magnetic fields exceed the specified field level, induced currents inside human bodies are to be investigated to check their conformity. However, this calculation Still needs verification and requires massive computational resources, which are not readily applicable under practical exposure conditions. Therefore, a simple and relevant method of assessing nonuniform magnetic field exposure is highly desirable. In this paper, a method of obtaining an equivalent uniform magnetic field using a coefficient (the normalized induction factor) is investigated by a numerical calculation of induced current in anatomically correct human models. In addition, to assess the obtained coefficient easily, it simple method using a spherical model was proposed. (c) 2008 Wiley Periodicals, Inc.