Wi-Fi, phones and power lines: understanding EMF exposure

Whether it be from the sun or from our phones and other devices, we are all exposed to electromagnetic radiation in some shape or form. With the dramatic growth in the number of connected devices over the last two decades, do we need to be concerned? We talk to the experts to learn about exposure rates, exposure limits and much more.

The science of EMF Electromagnetic fields (EMF) are generated by many of the technologies we use every day, including power lines, household appliances, mobile phones and Wi-Fi devices. While scientific evidence indicates that the low-level, non-ionizing radiation produced by these technologies is unlikely to harm human health, ongoing research continues to monitor potential long-term effects.

Consistent testing and measurement are important to ensure devices operate within established safety limits. International standards provide common methods for assessing electromagnetic fields, helping regulators, manufacturers and consumers have confidence that products are safe and perform as intended.

Science based limits and assessment methods Organizations such as the IEEE Standards Association and the International Commission on Non-Ionizing Radiation Protection (ICNIRP) develop science-based exposure limits. One of these limits refers to a specific absorption rate (SAR), a measure of the rate at which EMF is absorbed by the human body when exposed to EMF above 100 kHz. They are designed to protect people from adverse health effects and come with very large safety margins. They can also be used by regulatory authorities as part of their requirements.

Jafar Keshvari is Chair of IEEE International Committee on Electromagnetic Safety (ICES) and leader of the joint IEC and IEEE working group that develops exposure assessment standards for wireless communication devices, such as smart phones tables and wearables. He explains that assessing EMF compliance requires considering many factors including the level of power transmitted, the distance from the source and combined exposure from multiple sources. In busy offices or on public transport, hundreds of phones, watches and tablets may operate simultaneously. As these devices adjust transmission power and use multiple frequency bands, assessing exposure becomes more complex, he said. Internationally agreed testing methods are essential to assess compliance with applicable exposure limits and produce results that can be trusted and compared worldwide .

Why standards for testing matter

This is where international standards play a critical role. IEC and IEEE experts work together to develop agreed methods that enable manufacturers, testing laboratories and regulators to assess human exposure to electromagnetic fields consistently. These standards help ensure that products are evaluated in the same way, regardless of where they are designed, manufactured or sold.

One of the key standards used by regulators, manufacturers and testing labs globally is the recently updated IEC/IEEE 62209-1528. It is an important standard because it specifies how to position and operate devices during testing and measure the rate at which their energy is absorbed by the body, says Keshvari. It also ensures that results are consistent so is essential for checking compliance with regulatory requirements.

Another example is IEC/IEEE 63184, which provides procedures for assessing human exposure associated with wireless power transfer systems below 30 MHz, including wireless charging technologies. The standard covers measurements of SAR, internal electric fields and currents induced within the body, as well as contact currents that can occur when people touch conductive objects in electromagnetic fields. It also describes measurement and computational modelling techniques that help ensure wireless charging systems can be used safely by the public.

These and many other standards are developed within the IEC Technical Committee 106 (TC106), providing a common global foundation for assessing human exposure to electric, magnetic and electromagnetic fields. They help manufacturers, laboratories and regulators evaluate compliance with applicable exposure limits using reliable, internationally agreed methods.

Sami Gabriel, Vice Chair of IEC TC 106 said the limits are already established, but they are of little value unless everyone is measuring in the same or equivalent way.

What we are doing with these is trying to find the universal ruler that everyone works to. They can measure different things, but all in the same way .

Which is no simple task given the speed at which the technology, market and regulatory requirements are evolving. They also need to consider the vast number of different scenarios that need to be tested to ensure every possible use is covered, such as where it is placed on the body or when different applications are activated.

The standards are never truly ready because they are based on the current information, says Gabriel. Which is why we are in regular contact with regulators so we can ensure the standard remains relevant.

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