Occupational exposures to high frequency electromagnetic fields in the intermediate range ( >300 Hz–10 MHz)

Abstract

The aim of this study was to identify work situations with electromagnetic fields of 300 Hz-10 MHz and to characterize the occupational exposure. Work place investigations included descriptions of the work environment and physical measurements. We estimated electric (E) and magnetic (H) fields by spot measurements in air, by logged exposure data, and when possible, we recorded induced currents in limbs. The instruments used were Wandel and Golterman EFA-3, NARDA 8718, Holaday HI-3702. The exposure sources comprised five induction furnaces, seven induction heaters, one surface treatment equipment, four units of electronic article surveillance (EAS), and medical devices for surgery and muscle stimulation. The induction furnaces operated at 480 Hz-7 kHz, and the maximum values of logged data varied between 512-2,093 V/m (E field) and 10.5-87.3 A/m (H field). The induction heaters (3.8 kHz-1.25 MHz) also showed high maximum exposure values of both E and H fields. Three EAS units, an electromagnetic plate at a library, a luggage control unit, and an antitheft gate, showed E fields reaching 658-1,069 V/m. The H fields were comparatively lower, except for the antitheft gate (5 and 7.5 kHz) showing a maximum value of 27.2 A/m (recorded during repair). Induced currents of 5-13 mA were measured for the medical devices. The study improves the basis for an exposure assessment for epidemiological studies of long term effects of exposures to high frequency electromagnetic fields.

Measurements of intermediate-frequency electric and magnetic fields in households

“…Previous research on IF field emitting sources has tended to focus either on occupational sources (Aerts et al, 2014;Floderus et al, 2002;Joseph et al, 2012a;2012b;Liljestrand, 2003;Nelson and Ji, 1999; Van den Bossche et al, 2015;VMBG, 2003;Wilén, 2010) or on non-residential appliances such as electronic article surveillance (EAS) systems (Harris et al, 2000;Joseph et al, 2012c;Kang and Gandhi, 2003;Martínez-Búrdalo et al, 2010;Roivainen et al, 2014;Trulsson et al, 2007), smartboards, and touch screens (Van den Bossche et al, 2015). Research on residential IF sources, on the other hand, is limited.…”

Risk management of magnetic field from industrial induction heater - a case study

“…Measurements done by Floderus et al also concluded that spot measurements at the induction heater units were higher than those recorded by the worker held logging system, except for the brazing machine [15].…”

“…Their spot measurements at 0.5 m from the induction heater varied 0. 4-20.9µT as compared to 20µT in the current induction heater work station [15].…”

In situ exposure assessment of intermediate frequency fields of diverse devices

“…(3,4,6) and it was reported that the reference levels of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) (7,8) were exceeded for several of the investigated EAS systems. Also fields from fluorescent lights and energy saving bulbs (9,10) , domestic or professional induction cookers (6,11,12) , non-direction beacon (NDB) systems (13,14) , and electrosurgical units (6,15,16,17) exceeded the reference levels. Induction cookers can even exceed the ICNIRP basic restrictions by a factor of 16 (11) .…”

“…Induction cookers can even exceed the ICNIRP basic restrictions by a factor of 16 (11) . Floderus et al (6) investigated induction furnaces and heaters, surface treatment equipment, EAS, and medical devices for surgery and muscle stimulation. There is a lack of publications about the electromagnetic fields within less than 30 cm distance from fluorescent lamps (9) .…”