SAR – Specific Absorption Rate
The Australian safety standard for electromagnetic emissions (EME) is set by the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) and regulated by the Australian Communications and Media Authority (ACMA).
These requirements are set out in the Radio Communications Act 1992 and the Radiocommunications (Electromagnetic Radiation – Human Exposure) Standard 2003.
These regulations cover all common radio services including AM and FM radio, police, fire and ambulance services, mobile phones and mobile phone base stations. These regulations are based on careful analysis of all related national and international scientific literature.
Australia’s standard is consistent with 40 other countires around the world including: France, Germany, Japan, Singapore, New Zealand, South Africa and the United Kingdom.
Before each mobile model can be sold in Australia the manufacturer must test the phone using an international testing procedure and provide the test results to the ACMA.
This procedure tests phones in normally held positions, such as next to the ear when making phone calls, because this is when a phone is likely to be working at the highest level. These tests are done at the maximum power of the phone.
You can check to see if your phone has passed these tests by looking for the A-tick stamped on the phone (usually under the battery). The A-tick on phones indicates that they operate below the Australian safety limit when tested using the agreed test procedure.
What is SAR and what is it used for?
SAR (Specific Absorption Rate) is a unit of measurement used in the standard and it measures the amount of radio frequency energy absorbed by the body when using a mobile phone.
It is expressed in watts per kilogram. The safety limit in Australia is based on the International Commission on Non-Ionizing Radiation Protection (ICNIRP) limit which is 2.0 watts per kilogram averaged over ten grams.
The safety limit for exposure to mobile phone emissions is set by determining the lowest level of exposure known to cause health hazards and then adding a safety margin.
Because mobile phones are used close to the hand and head, safety limits are also set to prevent possible localised hotspots. Independent standard setting agencies review the extensive research literature on acute exposures in animals and worst-case estimates whic leads to very large safety margins.
During manufacture the maximum power output of phones is regularly tested.
How is SAR measured?
SAR is measured using an internationally-harmonised standard.
Mobile phones are tested using a phantom head that is based on the dimensions of a large adult male head to ensure worst-case measurements. The phantom head is filled with liquid that simulates human head tissue and SAR values are measured with the phone at maximum power and placed in a number of positions to simulate normal use.
This also includes tests with the antenna in or out and at the different frequencies the model of phone can operate at. A probe inside the liquid measures the electric field strength inside the phantom head and shows the maximum SAR value for the model of mobile phone. The test procedure including the testing of phone accessories can take up to two weeks.
In Australia and overseas, only mobile phones that have maximum SAR values below the safety limit can be sold.
Does a lower SAR mean a phone is safer?
No. Although mobile phones sold in Australia may vary slightly in their measured exposure levels at maximum power output, they are regarded as equally safe because they are all below the safety limit. The limit also includes a large additional safety margin to ensure mobile phones are safe.
Furthermore, the test method is designed to find the maximum SAR value for each phone, which does not necessarily reflect the exposure in every-day use. In order to improve battery life and available call time, mobile phones constantly adapt to the minimum power required to make a quality call depending on reception and how close they are to the nearest base station. This is called adaptive power control.
Generally the closer you are to a base station, the lower the output of the phone.
There are many ways to find SAR information for mobile phones. We have listed some easy tips below:
- Check the phone handbook or user manual; look under “safety” or “specifications”;
- Search the manufacturer’s website for your phone model and SAR; it is usually listed under “safety” or “product specifications”;
- Use a web search engine like Google to search for your phone model and SAR;
- Contact the manufacturer and ask for the SAR information;
- Contact the mobile dealer or your network provider;
- Check the Mobile Manufacturers Forum website
- If you need further assistance please email [email protected]
Please note – as with all external links on the AMTA website, AMTA is unable to verify the information provided, and therefore is unable to guarantee the accuracy of information contained on external pages. These links are provided as a useful services to consumers.