Wireless portable devices are now part of our daily habits and have almost become an extension of ourselves.
We frequently use our smartphone and carry it in our pocket, or we have a smartwatch on our wrist and we don't think that we are exposing parts of our body, in a prolonged manner, to electromagnetic fields generated by these objects which are always connected to some communication network.
Transmitting equipment that can be used in close contact with the body must be subjected to specific tests before being placed on the market: the evaluation of the human exposure to electromagnetic fields and the so-called SAR measurement.
What is SAR?
The HRH, acronym for Specific Absorption Rate it is defined as the amount of EM energy absorbed by the tissues of the human body per unit mass and is measured in W/Kg.
SAR tests, therefore, measure the percentage of electromagnetic energy absorbed by the human body when it is near a radio frequency magnetic field. The values thus obtained allow us to verify that the established limits of safe exposure to electromagnetic fields are respected.
Following the guidelines defined byInternational Committee for Non-Ionising Radiation Protection (ICNIRP), the European Union, the United States, Canada, Japan, Australia and others have approved harmonized standards that establish the maximum emission levels allowed to keep the absorption tolerance within certain safety thresholds.
By implementing these provisions, in the EU area the permitted SAR value is 2 W/Kg on 10 grams of tissue. The regulations of the United States and Canada impose more restrictive parameters, setting the limit at 1.6 W/Kg measured on 1 gram of tissue.
SAR tests in laboratories Sicom Testing
Sicom Testing performs SAR measurement of electrical, electronic and telecommunications equipment that can be used in the vicinity of the body.
This laboratory is specially equipped to measure the rate of specific absorption of electromagnetic energy by human tissues when exposed to EMC fields.
The equipment it has Sicom Testing allow you to perform SAR measurements of small objects, such as portable phones, or large devices.
All measurements can be applied to different sensitive parts of the human body such as the head, abdomen or wrist.
The SAR measurement is carried out using a machine composed of a robotic arm, an electric field probe and particular tanks, the shape of which reproduces the model of the human head and body. Inside the tanks there is a special liquid that allows the characteristics of human tissue to be simulated.
The device on which the tests are carried out is then positioned underneath the tanks in order to simulate its use near the head or body. The measurement takes place through a complex test procedure, at the end of which the value obtained from the measurements is compared with the limits established by the reference regulations.
Sicom Testing: experience, competence and continuous innovation
The lab Sicom Testing dedicated to this type of test and measurement, and created thanks to the collaboration of the Area Science Park Research Institute and the Friuli Venezia Giulia Region, since 2006 it has been a unique reality in the area and established nationally for its recognized skills in the field of checks on human exposure.
In this compound Sicom Testing has developed proven experience in measurement, calculation and simulation techniques for SAR measurement, verifying the compliance of various devices with the different standards in force.
The continuous evolution of the reference standards is accompanied by constant updating work, focused on the skills and preparation of the staff as well as on the laboratory instrumentation.
Sicom Testing offers a complete risk assessment service human exposure to electromagnetic fields and the SAR measurement of your products.
To request further information on this topic, write to info@sicomtesting.com
or call +39 0481 778931.
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HI,
I am really confused about choosing a smartphone with low SAR.
Head SAR: 0.279 W/Kg
Body SAR: 1,525 W/Kg
Are these values high or low?
Is a phone with a lower SAR value safer?
What should be the SAR for the head or lower body?
Thank you,
Racheli
Good morning,
to understand whether the SAR value of a radio device is sufficiently low, just remember that in Europe the permitted limit of the SAR value is 2 W/Kg on 10 grams of tissue, while in the United States and Canada the limit is 1, 6 W/Kg measured on 1 gram of fabric.
A device with a SAR value within these limits can be considered sufficiently safe.
Greetings from Sicom Testing
Good morning, can you kindly tell me how much the maximum threshold of the SAR value should be for a person weighing 100kg in order to compare the permitted limit of the SAR value in Europe of 2 W/Kg on 10 grams of tissue. Thank you
Good morning,
The SAR limit value does not change and does not depend on a person's body weight. The value is always 2 W/kg, taking into consideration the 10 grams in which there is maximum power absorption.
Greetings from Sicom Testing
Is there a way to measure the SAR of a phone at home?
Good morning,
SAR tests can only be performed in specialized laboratories.
Generally the SAR value of a phone is reported in the product user manual.
Greetings from Sicom Testing
Hi, I would like to know if the American limits are more restrictive, i.e. safer, than the European ones. Best regards
Good morning,
there are some differences in the way of conducting the measurements which do not allow a precise direct comparison of the results.
However, the American basic limit is more restrictive than the European one, being 1.6 W/kg versus 2.0 W/kg.
Greetings from Sicom Testing
Good morning
Why is the SAR standardized on a quantity of liquid of 1g and 10g why not 1Kg or 80Kg… ..etc.?
Thank you in advance
Best regards
Good morning,
the area of the body that is affected by the electromagnetic fields produced by consumer equipment is typically quite concentrated. The measurements are taken on a rather large area, for example the entire head or an area of the body as large as the bust, but of all the measurements that are taken we look for the part that receives the most power.
For technical reasons the resolution of this evaluation does not refer to a point but to a small volume. This volume in European standards was set as 10 g of tissue, while in US standards (developed later) it was defined as 1 g of tissue.
It's a bit like the resolution of a television: in the US case it is a slightly higher resolution, but this does not change the meaning of the image we are seeing, because in any case the measurement is expressed in power/volume involved, it changes the sharpness of the image a little.
In all cases, the complete image covers a larger part of the body.
Greetings from Sicom Testing
Good morning.
Does compliance (or failure) by an electronic device with the expected SAR limits have an impact on the CE certification of the product itself?
Thanks for the reply
Good morning,
certainly the product that exceeds the expected SAR limits cannot be placed on the market.
Greetings from Sicom Testing
Good morning.
Sorry for the question, I didn't actually understand the difference between the European and American measurements.
For example, my phone has much lower values with the American measurement but with the European one very high values.
Consequently I actually wonder why and whether it could actually create problems given that it has such high values in Europe?
Thank you
Good morning,
There are various technical details why the European measurement of SAR is different from the American one.
If the product has values within the imposed limits it can be considered safe.
Greetings from Sicom Testing
Hi, I have several questions,
-I bought a Samsung phone with 1.6 Sar in Body with European Union measurements. Does it have any negative effects?
-Can the casing infer and create more waves?
-In airplane mode is the Sar reduced to 0?
-Are SAR tests at maximum power? Bluetooth, call, mobile data etc.?
Good morning,
– the maximum European limit of the SAR value is 2 W/Kg, so the value 1.6 is within the limits;
– the casing generally has no effect on the creation of electromagnetic waves;
– airplane mode does not guarantee that all wireless functions will be disabled. However, the electrosmog produced by the mobile phone, tablet or other instruments in this operating regime is very low and the consequent exposure to electromagnetic waves is to be considered negligible;
– in the laboratory, SAR tests are performed on devices operating at maximum power.
Greetings from Sicom Testing
Good morning,
1- with 5G frequencies at 27.5 GHz, will the carrier frequency of the electromagnetic fields of cell phones also vary where, to date, exposure is calculated between 100 kHz and 10 GHz?
Thank you
Good morning.
Human exposure to electromagnetic fields from mobile phones is assessed through SAR measurements. In the case of portable devices operating in the 27.5 GHz frequency, if at the time of the evaluation no systems approved for the measurement of SAR at these frequencies are available on the market, other measurement techniques available for human exposure will be used. The limits for human exposure of the population have long been defined also for those frequencies, both for the general public and for workers.
Greetings from Sicom Testing
Hello, 1. What SAR indicators should I use when buying a phone (US or EU)??? 2. Why do some phones have no sar values in the technical specifications, but only indicate that they are EU certified??? 3. Why does the same sar have different sar values for US and EU measurements?
Good morning.
1. The SAR limit for the United States is 1.6 W/kg based on a mass of one gram of human tissue, while the SAR limit for Europe is 2 W/kg based on a mass of 10 g of tissue human. SAR measurements are made in two modes, head and body: head refers to when the product is used close to the ear, body refers to all other cases in which the product is used close to the body.
2. When the equipment is within the European limit indicated above, the product is considered safe according to European regulations and can be placed on the European market.
The SAR values obtained under different conditions of use are additional information.
3. Because the value refers to different quantities of exposed mass, furthermore in some cases there are small technical differences in the execution of the test.
Greetings from Sicom Testing
Hi, I was wondering if there was a variation of SAR on a mobile phone with Wi-Fi or mobile data enabled and without Wi-Fi/Mobile data? And can there be a correlation between smartphone battery capacity and SAR?
Thank you.
Best regards
Good morning,
The SAR measurement is used to verify that a product complies with health requirements for users. This is done taking into account all the radio interfaces present.
The exposure of each individual user is different and depends on many variables. First of all the distance at which the product is used. Secondly, the services that are activated may perhaps have an influence, but only if the product is kept in contact with or close to the body.
Battery consumption is not suitable as an indicator of SAR because it depends on many factors: a running application or an active GPS receiver can increase consumption without any implications for exposure.
However, even if we measured the consumption of the radio transmitter alone, this would not be significant for evaluating the SAR since the characteristics and position of the antenna in the product considerably influence the exposure value.
Greetings from Sicom Testing
Good evening, I would like to ask for information regarding the SAR value of a smartphone for which only the USA SAR Level is known
Head: 0.28 W/kg
Body: 0.76 W/kg
Simultaneous Transmission: 0.92 W/kg
Hotspot SAR: 0.70 W/kg
Is there a way to calculate or understand what the values are in EU SAR?
Good morning,
there is no way to derive the European SAR values from the US ones, the measurement must be carried out by applying the method provided by the European standard.
Lacking the European SAR value, the product probably needs to be fully certified for the European market, covering all aspects required for use of the spectrum, electromagnetic compatibility and safety.
Greetings from Sicom Testing
Thanks for the previous reply. I have another question: I imagine the SAR values referring to the head refer to the use of the cell phone during a phone call. But I wonder if for the SAR values referring to the body the values are those always measured during a call (which, in reference to the body, would in my opinion be of little significance) or during the normal activity of a mobile phone connected to the internet (receiving messages, WhatsApp , notifications, etc.). Thank you
Good morning,
SAR is measured with the transmitter operating at maximum power and under all operating conditions. The indicated value is the largest of those measured. We proceed in this way both in the case of the head and the body.
In real use, the actual transmitted power depends on the distance from the base station, the noise present on the radio channel and the information content that must be transferred. The data flow can also be variable in the case of voice calls.
Then there are applications in which the equipment transmits a few packets of information per day and we wondered whether it was correct to indicate the SAR of the worst operating condition even if in the specific case it would never have been used.
Both the European and American FCC commissions concluded that the SAR of the worst operating condition should still be indicated.
Greetings from Sicom Testing
Good evening, I have 3 questions to ask:
1-I read that a terminal that uses the radio module more efficiently, despite having a higher maximum SAR value, could produce fewer electromagnetic emissions than one that uses it less efficiently. So if SAR isn't enough to evaluate the "security" of a smartphone, what else can you look at?
2-Also, are the American and European tests done at the same distance from the source?
3-If you use the phone more for messages or videos, is it better to only compare smartphones for body SAR or head SAR (since a low head SAR does not always equate to a low body SAR)?
Thank you
Good morning,
1 – The safety of a smartphone is guaranteed by the fact that it is within the pre-established SAR limits. A product that exceeds these limits must not be placed on the market. A product that is within the limits can be placed on the market and should be considered safe. The attempt to make further distinctions or classifications takes us onto rather treacherous terrain.
2 – The American and European tests are done at the same distance. However, there are technical differences in testing which lead to non-identical results in the two cases.
3 – The “head” SAR represents the situations in which the smartphone is used against the ear. The “body” SAR represents cases in which the smartphone is used in contact with the body or hand.
Greetings from Sicom Testing
HI! The question arose: according to the SAR formula, it is necessary to know the density of human tissues. If the SAR device uses this data, what parameters is it setting for tissue density? Or is the density of human tissue not very different between different people?
Good morning.
It is not the density that is important, but the electromagnetic characteristics. These are defined in the standards, vary with frequency and there are some differences between European and US standards.
Greetings from Sicom Testing
I inadvertently left my cell phone turned on between 70 and 90 cm from my body.
The question is: how much do SAR values affect the body at similar distances? And how much does the WiFi to which the phone was connected affect the SAR value?
Thank you.
Good morning,
The SAR value decreases rapidly with distance from the body. A few centimeters make a big difference. At the distances you indicate the exposure is negligible.
Greetings from Sicom Testing
Hi, I'm looking at smartphone models taking into account the low SAR level. I don't know whether to prioritize it being lower than the head or the body. For the body, we take advantage of the distance, but if cell phone use is minority in terms of calls and I use headphones. Is it no longer convenient for me if the SAR is low in the body, especially?
Good morning Anna,
generally low SAR values equate to greater safety. Laboratory tests are performed on devices operating at maximum power and the results are the maximum values found in the worst case. In normal use of the device it is always advisable to use the speakerphone and headset, therefore a low SAR value for the body should be taken into consideration.
Greetings from Sicom Testing
Good morning. Cell phone SAR values usually refer to the exposure of the person's head (ear) during the phone call. I find no correspondence, in the tables I find online, between these values and those referring to body exposure. The latter, on average, are much higher than the former. How are they measured? Does anything change in the detection system? Thank you
Good morning,
The SAR measurement relative to the body is carried out on all sides of the product by placing it close to a flat surface. The SAR measurement relating to the head is carried out by placing the product close to a head-shaped surface, pointing the speaker towards the ear.
A higher SAR measurement relative to the body than to the head is obtained if the emission occurs mainly towards the back of the phone and if the antenna is positioned so as not to come close to the cheek during use near the ear.
Greetings from Sicom Testing
What difference does it make measuring 1 gram or 10 grams?
Good morning,
according to the European standard the SAR value is expressed as an average value on a cube corresponding to 10 g of tissue. The (ideal) cube is placed in the area of maximum exposure. The SAR value is expressed in Watts of power per kilogram of tissue.
According to the US standard the value is expressed on a cube of only 1 g of fabric. The value thus measured is greater than the European one because the average is made on a volume which is a subset of the European one and which contains the maximum peak of exposure.
Greetings from Sicom Testing
Is the SAR value the energy generated by the RF fields? entonces 1.73 w/kg that emits X telephone is the calorific energy generated by RF absorbed by the body?
Good morning,
The SAR value expresses the measurement of the percentage of electromagnetic energy absorbed by the human body when it is exposed to the action of a radio frequency electromagnetic field. The value 1.73 W/Kg refers to the amount of energy absorbed by the body per unit mass.
Greetings from Sicom Testing
Good morning. I have a question. Based on the criteria for measuring the sar of the same smartphone, shouldn't the corresponding US value always be higher than the EU one?
Good morning,
Yes, this is typically the case, however the broadcast bands are different in the two geographic areas, so there may be unexpected results.
Greetings from Sicom Testing
In the case of 5G?
Are there specific studies?
Thank you.
Good morning,
For 5G, SAR measurement occurs in the same way as for other devices that transmit radio waves, and the same limits must be respected (independent of the technology used).
Best regards
Sicom Test
Hi, if I use my cell phone only with wi-fi and turn on airplane mode, the SAR value will be much lower than if I used it with data
Good morning.
Airplane mode does not guarantee that all wireless functions will be disabled. However, the electrosmog produced by the mobile phone, tablet or other instruments in this operating regime is very low and the consequent exposure to electromagnetic waves is considered negligible.
Greetings from Sicom Testing
Good afternoon, I would like to know if the SAR of a terminal is lowered by wearing warm clothes (I am referring to the SAR of the body). Thank you
Good morning,
It is possible that the SAR level of a device may be lowered if you wear clothing. In general, the SAR value depends on the distance between the body and the radio transmitting device.
Greetings from Sicom Testing
Good morning,
It's not clear to me how head and body SAR data from phones can often be very discrepant. Lately, for example, I purchased a phone with a decidedly low head sar (0.27 w/kg) but the body sar is not the best (1.39 w/kg). I would expect that if a device features a low sar placed near the head, it would behave the same way for the body. Can it also be stated that the parameter sar head is more important from a risk point of view than sar body? Thanks for the attention.
Good morning,
There are technical differences in the SAR measurement methods between head and body, furthermore the position of the device in head tests is that typical of the telephone during a call, in this case the antenna is usually further away because it is at the back of the phone and most of the power is emitted in the opposite direction from the head; in measurements for the body the measurements are repeated with all 6 faces facing the body and the highest value is considered. Which of the two is the most important parameter depends on the use made of a device.
Best regards
Sicom Test
Greetings. I lived 60 meters from a cell tower for 21 years. What test would show whether a human or dog could suffer from the effects of said RF radiation?
Good morning,
Environmental field tests can be performed to verify that RF radiation is within regulatory limits. These tests are usually carried out by teams of specialized technicians equipped with adequate equipment.
Greetings from Sicom Testing
Can a person's SAR be “X” due to a phone's non-ionizing radiation emissions? In short, is it possible to know how a person absorbs radiation from an antenna?
Good morning Cristian,
thanks for contacting us.
The measurement of SAR and assessments of human exposure to electromagnetic fields in general have the purpose of determining how much radiation the human body absorbs when exposed to a specific electromagnetic field source, for example a mobile phone or base station.
Normally the SAR value is obtained by carrying out tests on a radio device in a laboratory. In the case of a base station, the tests relating to human exposure that can be carried out are those of electric fields.
Best regards
Sicom Staff
Good afternoon. What is the difference between head and body SAR? Why are the coefficients different in a phone: for the head-0.3, for the body-1.38?
Good morning.
The head SAR evaluates human exposure when the product is used against the ear, as occurs in traditional telephony.
Body SAR evaluates human exposure when the product is used close to the body, for example attached to a belt, held in a pocket or in the hand.
There are some technical differences in the two measures. For head SAR, only one face of the product is typically turned towards the head, while for body SAR the test is typically repeated on all faces of the product. The latter may be one of the causes of the difference in values obtained.
Greetings from Sicom Testing
With what data do I discover my SAR mobile phone?
Good morning,
the SAR value is expressed in units of Watts per kilogram (W/kg) and is reported in the product user manual.
Greetings from Sicom Testing
Good evening,
I would kindly like to have some information below:
– what type of liquid is used in the test tanks and in what sense does it allow the characteristics of human tissue to be simulated?
– how does the value of 2 W/kg per 10g relate to the other radio transmission threshold set (for now) at 6V/m?
– I remember that regarding the SAR parameter, we were talking about thermal related effects (in fact you reported a color thermography image) of raising the temperature on the skin interface in contact with a mobile phone. But are there also studies on the possible interrelationship with the cells of the deeper layers and not only on a thermal level?
I imagine that your systems also allow you to calculate SAR and effects generated by other devices in the microwave range (ovens etc.), am I right?
Thank you very much and see you soon
Alberto
Good morning,
– the liquid used in the test tanks simulates human tissue by having the same transmission and absorption properties of the electromagnetic field;
– the value of 2W/Kg per 10 g does not directly relate to the environmental limit of 6V/m;
– some medical studies state that a temperature increase greater than 1°C is not negligible. However, when the SAR measurement techniques were defined, the experts preferred a method based on the measurement of the electric field because it was more reliable and precise. Currently, human exposure to electromagnetic fields must be assessed for all electrical and electronic systems. The technique applied and the laboratory measurements to be carried out depend on how the equipment is used.
In the specific case of the microwave oven, the SAR measurement does not apply.
Greetings from Sicom Testing
Good evening,
when choosing a terminal, which measurement scale is more rigid or more reliable, the American one or the European one?
Thank you
Good morning,
The limits and various measurement parameters differ between American and European standards, so it is not possible to make a direct comparison between measurements that is valid for each terminal. In any case, if you want to place a product on the European market, it will have to be evaluated according to European standards, if you want to put it on the American market it will have to be evaluated according to American standards.
Greetings
Sicom Test