An electromagnetic Field (EMF) is produced whenever a piece of electrical or electronic equipment (i.e. TV, food mixer, computer mobile phone etc.) is used.
EMFs are static electric, static magnetic and time-varying electric, magnetic and electromagnetic (radio wave) fields with frequencies up to 300 GHz.
EMFs are present in virtually all workplaces and if they are of high enough intensity, an employer may need to take action to ensure employees are protected from any adverse effects.
- There are three types of field that are considered potentially harmful:
- Magnetic field – low frequency – typically generated by transformers, large electric motors, industrial processes, railway environments, power stations and electric power distribution networks
- Electric field – low to mid frequencies – typically anywhere close to high voltage systems such as electrical power distribution networks (eg. HV power lines), electrically powered railways (typically 25kV), industrial processing equipment.
- EM fields. – mid to high frequencies – typically RF radiation from transmitters (broadcast transmitters, base stations, radar equipment), scanners and RF induction heating.
ELF – extremely low frequency. Applies to frequencies below 100Hz. The 50/60Hz mains power supply is a source of such fields. No conclusive evidence has been published to show that these fields affect humans, however there are limits embodied in the regulations.
MRI – Magnetic Resonance Imaging scanners use high power fields in the 10s of Megahertz, plus powerful static magnetic fields.