LF Shielding Materials (EMC)
Shielding of Electrical Alternating FieldsThe principle of shielding electrical alternating (AC) fields is based on the deduction of these fields to earth. For this purpose, electrically conductive materials are required, which are applied to the radiating surfaces and which then have to be earthed (grounded) by means of appropriate materials.
Without earthing, these shieldings do not work!
There are conductive, breathable and solvent-free paints available for applying to walls, ceilings and floors (in shell state), which can be overpapered or overpainted after earthing.
There are also conductive nonwoven fleeces available, made of carbon-coated polyester for applications under the bed, under carpets or under wood covering.
In principle, all RF (HF) shielding materials with a metallic conducting surface are also suitable for shielding electrical alternating fields.
Shielding of Magnetic Alternating Fields
Magnetic alternating fields penetrate almost every material (including lead!), but there are also some metal alloys, such als MU metal or an amorphous cobalt alloy, which can be used as "shielding materials" for magnetic alternating fields in the form of plates and foils. This kind of shielding is based on the fact that the magnetic field lines are short-circuited by the materia in the vicinity of the field source and thus can no more spread into the room.
Smaller field sources are preferably encapsulated with this material, if necessary also in a plurality of layers, while, for example, electrical lines in or behind walls have to be covered over a large area with these materials. Subsequent magnetic field measurements are urgently required to control the effectiveness of the shielding measures.
These magnetic field shielding materials have their price and the shielding of a whold room can this be costly! The shielding of a whole house under a high-voltage powerline or nearby an electric railway by means of these materials is unrealistic!