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. Lasers are an area of NIR which have their own particular range of hazards and laser safety is dealt with on a set of dedicated web pages.
The non-ionising radiation part of the electromagnetic spectrum can be divided into three approximate regions, namely:
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.