To reduce/attenuate Magnetic field emanations a highly permeable shield is installed, the radiated field then flows easier in the shield barrier compared to 'free air', this is known as magnetic reluctance.
The greatest threat is power frequencies, most buildings have some field contamination of 50/60Hz field but certain apparatus such as Sub-station transformers, high current feeder cables, LV switch rooms/panels can give off significant radiated energy.
The tolerable levels are in parts, (1) Public exposure (2) EMC effects on other apparatus (3) long term exposure or residency.
- System 8000 'high-perm' modular stand-alone system
- EEG Rooms
- Building shielding (sub-stations/LV switchgear room & panels)
- Shielded cable containment for feeder runs, bus bars and risers
- TEM (Transmission Electron-Microscopy) Faraday cages with guaranteed maximum perturbation levels (Quasi-DC and power frequencies)