SAR Rating
What is SAR?
SAR stands for Specific Absorption Rate, which is a measure of how much radio frequency (RF) energy is absorbed by your body when using an electronic device like a mobile phone. In the EU, SAR limits are governed by the European Committee for Electrotechnical Standardisation (CENELEC).
Any mobile device with a SAR up to 2 Watt per kilogram (W/kg) for head and body and up to 4 W/kg for limbs, averaged over 10 grams of tissue, is considered safe for consumer use (for the limits current laws still quote this Council Recommendation, page 6, table 1).
There is a lot of research out there about the effects of exposure to radio frequency, but many remain inconclusive. If you would like to research more, consult the World Health Organization.
How is it calculated?
SAR is calculated for three areas: the head and the rest of the body. During testing, the phone’s radio is set to its highest transmission level for each frequency.
- For the head rating, the phone is placed directly next to the head to simulate actual calling behavior.
- For the body rating, the phone is positioned 0.5 cm away from the body.
- For the limb rating, the phone is placed directly next to limbs to stimulate normal handling of the phone, including skin contact.
In summer 2017 the new RED legislation (Radio Equipment Directive) has come into force; mostly replacing the (older) R&TTE Directive. In this new directive and the standards related to it, a new way of measuring SAR for mobile phones is required.
For old measurements at the head, the lab applied a multiplying factor on the old measurement to comply with the new standard. For the body measurement, the separation distance used in the test is now 0.5 cm.
In other words, the new legislation changed the numbers for phones first tested before 2017 not because of any hardware changes, but because of the new testing methodologies. The information published here is according to the latest testing methodologies.
SAR rating of the Fairphones
|
Localised SAR head (W/kg @10g) |
Localised SAR trunk/body (W/kg @10g) |
Localised SAR limbs (W/kg @10g) |
||
|---|---|---|---|---|
| Limit | 2 W/kg | 2 W/kg | 4 W/kg | |
| Fairphone | 5 | 0.402 W/kg | 0.847 W/kg | 0.847 W/kg |
| 4 | 0.467 W/kg | 0.867 W/kg | 0.867 W/kg | |
| 3(+) | 0.388/0.411 W/kg | 1.405 W/kg | 2.537 W/kg | |
| 2* | 0.65 W/kg | 1.1 W/kg | -** | |
* Those are the measurements according to the latest legislation.
** Measurements for limbs weren't mandatory to publish when the Fairphone 2 came out. It is still within the legal limits.
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