Rules imposed by Europe
Mobile telephones use radio waves. That is why they fall under the European R&TTE directive 1999/5/EC (R&TTE stands for 'Radio and Telecommunications Terminal Equipment'). The producer must demonstrate that his products meet the minimum requirements of this directive that relate to safety, electromagnetic compatibility and efficient use of frequency spectrum.
The producer must test his products to be certain that they meet all criteria. The limit values and the measurement procedure are described in the European standard EN 50364 and are harmonised under the R&TTE directive. You can peruse this standard at the Belgian Institute for Standardisation.
The scientific basis for determining the limit values to protect the health against effects of electromagnetic radiation is the recommendations of the ICNIRP (International Commission on Non-Ionizing Radiation Protection). According to the ICNIRP the specific absorption rate (SAR) as a result of electromagnetic radiation with exposure of the head may be no higher than 2 W/kg average for six minutes for 10 gram tissue. The limit value also applies for mobile phones and serves to protect the head against thermal effects.
It is known that radio waves are absorbed by the body. That means that the electromagnetic energy of radio waves is converted into heat by the body. This is called the thermal effect. There is no risk of that because telecommunication and radio equipment must comply with the standards as described in the R&TTE directive.
Rules in Belgium
A special point of interest is the use of mobile phones by children. As of 1 March 2014, special rules apply in Belgium concerning the sale of mobile phones and the publicity for children.
From that day on, special rules also apply to inform the consumer about the SAR-value: you will find out more about this on this page (under the title “Where can I find the SAR value of a mobile phone?”).
What is an SAR value?
The measure used for the conversion of energy into heat is the Specific Absorption Rate (SAR), expressed in watt per kilogram (W/kg). In fact, the SAR value describes the speed at which the energy of radio waves is absorbed in the body.
The manufacturer must measure the SAR value for each model. Only wireless appliances with a low average power (lower than 20 mW) are exempt from SAR measurements (for example Bluetooth devices).
The measuring procedure is standardised and takes place as follows.
A mobile phone to be tested is fastened to the ear of a dummy head. The dummy head is filled with a liquid with the same electrical properties as human tissues. Measuring devices (probes) are fitted inside the dummy head that measure the distribution of the electrical field produced by the mobile phone. The SAR value is calculated based on these measurements.
Does the SAR value represent actual exposure?
All laboratories work in the same way because the standard very accurately describes the measuring procedure. This makes the measurement results reproducible and reliable within the margin of measuring uncertainty. But this does not necessarily mean that the SAR value resulting from the test corresponds with the actual exposure. In practice the transmission power is variable. A mobile phone automatically adapts its transmission power depending on the reception quality: better reception means a lower transmission power.
How one uses a mobile phone (with an earpiece, sending messages instead of calling) also has an influence on actual exposure, i.e. the actual SAR value. It can as a result be up to a thousand times lower than the SAR value established in the test.
Where can I find the SAR value of a mobile phone?
You will find the SAR value of a mobile phone or smartphone in the user manual, or on the manufacturer’s website. From the 1st of March 2014 it will be obligatory to state the SAR value of mobile phones at every point of sale. Therefore, from that moment on you will not only find the SAR value in the shop, but also in case of remote selling, through the Internet. This is arranged through the Royal Decree concerning the availability of consumer information on the specific absorption rate of mobile phones and concerning the advertising for mobile phones. You want to learn more? Take a look at our list of frequently asked questions.
The SAR of mobile phones available on the market is in the 0.2 – 1.6 W/kg range. The most common SAR values are in the region of 0.8 – 0.9 W/kg. You can find a summary of the SAR values on the website of the Mobile Manufacturers Forum and the German 'Bundesamt für Strahlenschutz', BFS. The figure shows you the distribution of the SAR values according to the list of BFS (2008).
Checking compliance with the above mentioned regulations is carried out by the FPS Economy, SMEs, Self-Employed and Energy and the FPS Health, Food Chain Safety and Environment.