Magnetic field shielding 
A magnetic field (an invisible force that acts on ferromagnetic material) can be generated by a permanent magnet (material that has its own field) or an electromagnet that requires an electric current to flow to create the field. Our interest lies with the latter.
Direct Current (DC) magnetic fields associated with MRI scanners are of particular relevance to the Healthcare sector to ensure that:
- MRI scanners remain unaffected from any nearby moving ferrous mass such as a lift or a vehicle passing by adjacent to the MRI room
- Medical equipment in an adjacent area can function without interference
- A safe environment is created for those fitted with electronic implants e.g. a pacemaker
This applies equally for a new build as for an existing facility upgrading to a more powerful MRI scanner.
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| Magnetic field shielding – underside of an MRI room |
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Low frequency alternating current electromagnetic fields (EMF) associated with power distribution (50/60Hz) sub-stations, transformers, power lines etc also pose potential problems and the ability to control the strength of these magnetic field to within pre-set limits, has implications for:
- Commercial facilities - ensuring office equipment functions properly and critical processes e.g. data processing can take place without risk. This need applies equally to company owned buildings as to landlords where a tenant may have similar demands.
- Industrial premises - the need for ‘clean’ test areas as well as ensuring office equipment functions correctly.
- Apartment blocks - ensuring there is no interference to domestic electronic equipment has important implications for the occupiers. A health dimension may also be a consideration.
EEP can assist designers or building owners and users by:
- Providing an input at the preliminary design phase
- Proposing remedial actions for existing installations
- Undertaking EMF surveys or pre-installation studies on EMF effects
- Designing and installing an appropriate solution
For more information see FAQ ‘Magnetic Field Shielding’.
Modelling (sic) Magnetic Shielding
Prior to commencing the design of the physical installation, EEP can plot the magnetic lines of force to verify that where the magnetic field strength is stipulated for a given area or room, then this will be achieved. By understanding the field shape, EEP is able to optimise the shield’s design.
3T MRI Scanner – magnetic field pattern at the shielding edge
Also see ‘The EEP supporting package – Advisory and Consultancy Service’.
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