What is Electromagnetic Radiation (EMR)? Sources, Values and Protection
What you should know before deciding on shielding: the types of fields, everyday sources, what dB attenuation values mean, and how shielding works.
Electromagnetic fields fall into three groups
We divide the fields we are exposed to in everyday life — and that can technically be shielded — into three groups:
- High-frequency (HF / RF) electromagnetic waves: Mobile base stations, 5G antennas, Wi-Fi routers, DECT cordless phones, Bluetooth devices, smart meters, baby monitors and radar. They reach the interior through walls, glass and the roof.
- Low-frequency (LF) alternating electric fields: Caused by building wiring, sockets, extension cords and mains voltage (50 Hz). Even when a device is switched off, a live cable still produces a field; the most critical area is the head of the bed.
- Low-frequency magnetic fields: Transformer stations, high-voltage lines, main riser cables and rail systems. They pass through ordinary materials; shielding them requires special alloys.
Where does the health debate stand?
In 2011 the International Agency for Research on Cancer (IARC), part of the World Health Organization, classified radiofrequency electromagnetic fields as "Group 2B — possibly carcinogenic to humans". While scientific research continues, many countries and expert bodies recommend the precautionary principle — reducing exposure by every technically reasonable means — especially for sleeping areas and spaces used by children. That is exactly what shielding products do: they measurably reduce exposure. This is a technical precaution, not a medical treatment.
What does a dB (decibel) attenuation value mean?
The effectiveness of shielding products is expressed in decibels (dB). The scale is logarithmic: every 10 dB means a tenfold reduction in power.
| Attenuation | Power passing through | Share blocked | Example product |
|---|---|---|---|
| 10 dB | 1/10 | 90% | — |
| 20 dB | 1/100 | 99% | NEW-DAYLITE net (23 dB) |
| 30 dB | 1/1,000 | 99.9% | RDF72 window film (33 dB) |
| 40 dB | 1/10,000 | 99.99% | NATURELL fabric (40 dB) |
| 50 dB | 1/100,000 | 99.999% | HSF54 paint, two coats (53 dB) |
| 100 dB+ | 1/10,000,000,000 | 99.99999999% | A300-HEMP fleece (123 dB) |
The attenuation values of all YSHIELD products are measured in accordance with ASTM D4935-10 and IEEE Std 299-2006 and documented with published reports up to 40 GHz (including 5G mmWave). Unless stated otherwise, values refer to 1 GHz.
How does shielding work?
A conductive or magnetically permeable layer reflects and/or absorbs the electromagnetic wave that strikes it. Carbon-based paints, metallised fabrics and foil-laminated membranes create a kind of Faraday cage effect installed in the interior. Two rules are critical:
- Continuity: There must be no gaps in the shielding surface — windows are closed off with film or net, joints with tape, and penetrations with the right details. The weakest point determines the performance of the whole system.
- Grounding: Conductive paint and groundable fabrics only shield low-frequency electric fields when they are grounded; grounding is also an electrical-safety requirement.
Which solution for which situation?
| Situation | Recommended solution |
|---|---|
| Base station on the building opposite, entering through the walls | Shielding paint + window film + grounding |
| I only want to protect the sleeping area | Canopy / shielding tent + base underlay |
| I'm a tenant and can't make permanent alterations | Fabric curtains, pop-up tent, bed textiles |
| New build / major renovation | Membranes, fleeces and meshes (100 dB+ structural solution) |
| Next to a transformer or high-voltage line | Magnetic field shielding — planned as a turn-key project |
| Wiring-borne fields at night | NA7 demand switch + NCV95 fleece at the bed head |
Frequently asked questions
Can shielding paint be painted over?
Yes. Shielding paint is an intermediate layer; it is finished with a water-based interior or exterior paint in any colour you like.
Can I use a phone inside a canopy?
Not recommended. Using an active transmitter inside a shielded volume keeps the signal trapped inside; leave the phone outside the canopy or switch it to flight mode.
Should I measure first?
It is recommended: a product chosen without knowing the source and intensity may fall short or cost more than necessary. With our measurement instruments you can assess the current situation yourself, or we can clarify the need together during the free site-survey stage of our turn-key projects.
Will the products cure my health problems?
No; shielding products are not medical products. What they do is measurably reduce the level of electromagnetic fields in your environment.
Get a recommendation for your situation
Tell us briefly about your space; we will suggest the most economical and effective shielding combination for you.