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Non-Ionising Radiation

Non-ionising radiation (NIR) is the term given to the part of the electromagnetic spectrum where there is insufficient quantum energy to cause ionisations in living matter.

The non-ionising radiation part of the electromagnetic spectrum can be divided into three approximate regions, namely:

visual radiations

Slow time-varying fields: alternatively referred to as static magnetic, static electric, and ultra-low frequency fields (i.e. ELF, VF, VLF, LF). Frequencies are generally accepted to be below 10 kHz and with wavelengths ranging from 103m to infinity.

Radio-frequency fields: includes radiofrequency (RF) and microwave (MW) radiation. RF banding is between 10 kHz to 1 GHz frequency, wavelengths approximately 103m down to 10-2m. Microwave banding is between 1 GHz and 100GHz frequency, wavelengths approximately 10-2m down to 10-4m.

Both slow time-varying fields and radio-frequency fields fall into the category of electromagnetic fields (EMFs) for the purposes of health and safety legislation.

Optical radiations: range from infra-red through visible light to ultra-violet. Conventionally, wavelengths rather than frequencies are used to define optical radiation band. The bands represent comparatively only a very small part of the electromagnetic spectrum. Infrared radiations range from approximately 10-4m to 7x10-7m, the visible light spectrum ranges from 7x10-7m at the red end to 4x10-7m at the blue end. Ultraviolet radiation is sub-banded into UVA, UVB and UVC and ranges from 4x10-7m to approximately 10-7m.

Below wavelengths of approximately 10-8m i.e. at and beyond the limit of UVC radiation, radiations have sufficient energy to become ionising.

The most important information for those working with non-ionising radiations are Hazards associated with the use of non-ionising radiations and Essential actions for work with non-ionising radiations. Please ensure that you read through both these documents before commencing any work with or in areas where there is Non-Ionising Radiation.