Satisfactory ductile foil material, ranging from 0.002 to 0.01 in thick, is available in various permeability ranges. It is necessary in some cases to provide shielding of bus bars or high current carrying conductors. R.F.I.Industries can design and supply shielding ducts or shadow shielding in plant rooms using high permeability steel or mu-metal materials. Without magnetic shielding, much of today's sophisticated electronic gear would be larger, less efficient and in some magnetic environments, impossible to function at all. As components are made more sensitive and packaging more dense, susceptibility to electromagnetic interaction increases dramatically even in the best engineered layouts.
Electromagnetic interference can originate from various sources.
These could include permanent magnets or electromagnets, coil components such as transformers, solenoids and reactors, AC or DC motors and generators, and cables carrying large DC or AC current at power frequencies. In many cases, even the normal earth's magnetic field can affect proper functioning. A survey of magnetic fields or extra low frequency fields measures the strength of magnetic fields in an area to more clearly define the source and strengths of the interference, and to determine parameters to provide a solution where necessary. A high permeability shield placed around a VDU is very effective against magnetic fields which emanate from power cables and power distribution boards. Cable duct or cable trays can be shielded to reduce the interference from magnetic fields.