Electromagnetic and RF shielding

Electromagnetic and RF shielding builds rooms that block radio signals, either to keep sensitive work in or interference out. These Faraday cages are specified by attenuation in dB over a frequency range. Design starts with the attenuation target across the frequency range, then every seam, door and cable entry is detailed to hold it.

• dB attenuationHow RF rooms are specified
• Frequency rangeSpecified across the bands you need
• Shielded doors and filtersEvery penetration treated
• Tested on completionAttenuation verified by survey

What is RF shielding

RF shielding is the construction of rooms that block electromagnetic signals across a defined frequency range. The shielded room, often called a Faraday cage, either keeps sensitive emissions inside, or keeps outside interference away from delicate equipment. It is a core discipline of our shielding range.

Typical uses include EMC test laboratories, secure communications rooms, and rooms housing equipment that must neither emit nor receive stray signals. Performance is specified as attenuation in dB over a frequency range, agreed with the consultant before design begins.

Which RF specification do you need

Specify the frequencies and the attenuation first; the construction follows from those two numbers. Every element below must be treated, because the room performs only as well as its weakest penetration.

How RF shielded rooms are built

The room is lined with a conductive material, commonly copper or steel sheet, with seams sealed so the lining behaves as one continuous shell. Doors are purpose-built shielded doors with conductive gaskets; a standard door, however heavy, will not do. Ventilation passes through waveguide vents, and every power and signal line is filtered where it enters.

Coordination matters: the shield goes in before final finishes, and other trades must not drill the lining for fixings afterwards. Any penetration added later is treated and the room is re-tested.

The lining material is chosen for the frequency range and the attenuation target: copper suits most rooms, while steel is used where magnetic performance or mechanical strength also matters. Seams are overlapped and sealed, corners are treated as continuous joints, and the floor lining turns up at the walls so the shell has no breaks. Penetration panels group services together, which keeps the number of filtered entries low and the testing simple.

Where a room must stay usable during maintenance, a shielded lobby or double-door arrangement lets staff enter without opening the main envelope to the corridor.

Specify the frequencies first. A room that performs well at one band may not at another. Name the frequency range and the attenuation you need before the design starts.

Combining RF shielding with other ratings

The approach to a shielded room often needs its own protection: security doors rated to LPS 1175 guard the corridor outside, and fire rated steel doors provide fire separation where the building regulations require it. Inside the room, sound masking adds speech privacy where eavesdropping is also a concern. Our standards hub explains the rating systems behind these products.

Where RF shielding is used

Government and defence sites use shielded rooms for secure communications and sensitive work. Data centres shield rooms housing equipment that must be isolated from interference. Utilities and energy operators protect control and telemetry rooms.

What sets the cost and lead time for electromagnetic and rf shielding

Room size sets the lining scope, and the attenuation target sets the material and detailing: higher performance needs more careful seams and more penetrations treated. The number of doors, vents and filtered entries drives cost directly. Retrofitting an existing room takes longer than lining a new build, because services must be rerouted or sealed. No prices are given here because every room differs.

How to specify RF shielding

1. Define frequencies and attenuation. Agree the bands and the dB target.
2. Survey the space. Record construction, services and penetrations.
3. Design the envelope. Fix lining, doors, vents and filtered entries.
4. Install the lining. Build the continuous conductive shell.
5. Treat penetrations. Fit shielded doors, vents and filters.
6. Measure and prove. Verify attenuation through surveys and testing.

RF shielding FAQs