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.
NZS 2772.1:1999 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.
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.
Both standards can be purchased from Standards New Zealand.
Limits under NZS 2772.1:1999
NZS 2772.1:1999 sets basic restrictions on the amount of radiofrequency power absorbed in the body. This is measured as the specific absorption rate (SAR) – the rate at which radiofrequency radiation is absorbed in the body, measured in watts per kilogram (W/kg).
Under NZS 2772.1:1999, for exposures of the public the SAR 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 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 SAR is difficult to measure, NZS 2772.1:1999 also prescribes reference levels in terms of the more easily measured electric and magnetic field strengths, and power flux density.
Compliance with the reference levels ensures compliance with the basic restrictions, and in most situations they can be effectively regarded as ‘exposure limits’ (although this term is not used as such in the Standard).
Basis for NZS 2772.1:1999
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).
ICNIRP is an international scientific body which has been recognised by the World Health Organization for its independence and expertise in this area. Their 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 effect.
Following reviews of more recent research, ICNIRP reaffirmed the validity of their exposure guidelines in 2009, and again in 2017. Reviews of the research by other health bodies around the world (see, for example, the reports listed near the bottom of Research into non-ionising radiation) support ICNIRP’s conclusions.
ICNIRP published revised guidelines in March 2020. The underlying basis of the new guidelines is the same as in 1998, but there are refinements in the limits at frequencies above 6 GHz, and a few other small changes that help in the practical application of the limits. The guidelines and accompanying explanatory material, are available on the ICNIRP website. The ICNIRP 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).
ICNIRP considers that the 1998 guidelines are still protective for current commercial applications of radiofrequency fields, but recommended that countries adopt the new guidelines in order to ensure protection for potential new applications. The Ministry has reviewed the ICNIRP 2020 Guidelines, and RPS S-1, and advises that compliance with either would provide protection at least equivalent to that offered by NZS 2772.1:1999.