Radiofrequency field exposure standard
Standards are based on a careful review of the research into the health effects of exposure to radiofrequency radiation, including margins for safety.
Standard NZS 2772.1:1999
New Zealand standard NZS 2772.1:1999, 'Radiofrequency fields — Maximum exposure levels — 3 kHz to 300 GHz', recommends limits for controlling exposures to radiofrequency fields.
It sets out limits for exposure to the radiofrequency radiation produced by all types of radio transmitters, for people exposed at work and for the general public.
The limits are based on a careful review of the research into the health effects of exposure to radiofrequency radiation, and include wide margins for safety.
NZS 2772.1:1999 — Standards New Zealandexternal link
A second standard, AS/NZS 2772.2:2016, 'Radiofrequency fields — Part 2: Principles and methods of measurement and computation – 3 kHz to 300 GHz', describes how compliance with the limits should be assessed.
NZS 2772.1:1999 sets basic restrictions on the rate at which radiofrequency power is absorbed in the body. This is measured as the specific absorption rate. It is measured in watts per kilogram (W/kg).
Under NZS 2772.1:1999, for exposures of the public, the specific absorption rate averaged over the whole body must be less than 0.08 W/kg. When using a transmitter close to the body (for example, a cellphone), localised increases up to 2 W/kg over any 10 g of body tissue are allowed.
The limits for the general public are stricter than for occupational exposures. Public exposures are set at levels more than 50 times lower than the recognised threshold for established health effects.
For some transmitters (for example, AM radio transmitters), there is a second basic restriction on the current density induced in the body.
As the specific absorption rate is difficult to measure, NZS 2772.1:1999 also prescribes reference levels in terms of more easily measured quantities:
- electric and magnetic field strengths
- power flux density.
Compliance with the reference levels ensures compliance with the basic restrictions. In most situations, they can be effectively regarded as 'exposure limits'. (Although this term is not used as such in the standard.)
NZS 2772.1:1999 was adopted in April 1999. The limits in the standard are based on guidelines published in 1998 by the International Commission on Non-Ionizing Radiation Protection (ICNIRP).
The commission is an international scientific body. The World Health Organization has recognised it for its independence and expertise in this area.
Its guidelines have formed the basis for many other international and national exposure standards. They are based on consideration of all relevant health research data, from both long and short term exposures, and without presupposing any particular type of health effect.
Reviews of the research by other health bodies around the world support the commission's conclusions.
Research into non-ionising radiation
Following reviews of more recent research, the commission published revised guidelines in March 2020. The underlying basis of the new guidelines is the same as in 1998, but with:
- refinements in the limits at frequencies above 6 GHz
- small changes to help in the practical application of the limits.
The guidelines and accompanying explanatory material are available on the commission's website.
RF EMF Guidelines 2020 — International Commission on Non-Ionizing Radiation Protectionexternal link
The 2020 guidelines have been incorporated into the Australian Radiation Protection and Nuclear Safety Agency Standard for Limiting Exposure to Radiofrequency Fields — 100 kHz to 300 GHz (RPS S-1).
The commission considers that the 1998 guidelines are still protective for current commercial applications of radiofrequency fields. But they recommended that countries adopt the new guidelines to make sure protection for potential new applications.
The Ministry of Health has reviewed the 2020 guidelines and RPS S-1 and advises that compliance with either would provide at least equivalent protection to that offered by NZS 2772.1:1999.