Radiation
Electromagnetic radiation spans an enormous range of wavelengths and frequencies and is generally divided into seven regions, in order of decreasing wavelength and increasing energy and frequency. The common designations are: radio waves, microwaves, infrared (IR), visible light, ultraviolet (UV), X-rays and gamma rays.
From a health and safety perspective, radiation is divided into two broad areas, namely non-ionising radiation (NIR) and ionising radiation. Ionising radiation carries more energy than non-ionising radiation.
Non-ionising radiation (NIR) is the term used to describe the part of the electromagnetic spectrum covering two main regions, namely optical radiation and electromagnetic fields (EMFs).
Optical radiation is another term for light, covering ultraviolet (UV) radiation, visible light, and infrared radiation. The greatest optical radiation risks to health are probably posed by UV radiation from the sun, exposure of the eyes to UV radiation and the misuse of powerful lasers.
Electromagnetic fields (EMFs) at different frequencies affect the human body in different ways, causing sensory and health effects but there are also persons who will be more susceptible to the effects from EMF exposure (if they are fitted with implants or pacemaker or if they are pregnant) and for those who work in close proximity to electro-explosive devices, explosive materials or flammable atmospheres. EMF´s include power frequencies, microwaves and radio frequencies and these can be produced in a number of light and heavy industrial processes including dielectric heating and welding, resistance welding (spot and seam welding), induction heating, induction soldering, magnetic particle inspection, magnetisers / demagnetisers, microwave heating/drying, RF plasma devices, industrial electrolysis, furnaces (arc and induction melting); medical processes involving the use of MRI equipment; in the transport sector, these include electrically-powered trains and trams (for overhead line equipment and third rail), Radar, air traffic control, weather and long range.
Ionising radiation occurs as either electromagnetic rays (such as X-rays and gamma rays) or particles (such as alpha and beta particles). It occurs naturally (e.g. radon gas) but can also be produced artificially. Ionising radiation has many uses in industry: energy production, manufacturing, medicine and research, however, it is important that the risks of ionising radiation are managed sensibly to protect those working with it and the public.