Originally Published EMDM May/June 2005
Technology News
Novel Panel Design Enhances Shielding Performance |
| Corus development manager Sara Price holds a MagnaShield panel, a thin alternative to conventional shielding materials. |
Modular steel panels designed to protect people and equipment from electromagnetic (EM) fields feature a patent-pending design that ensures a high level of shielding integrity, even at the joints between the panels. Developed by international metals company Corus (London, UK) and Cogent Power (Newport, Wales, UK), a producer of electrical steel, MagnaShield systems were recently installed at magnetic resonance imaging (MRI) suites in two UK hospitals.
Directive 2004/40/EC sets minimum requirements to protect workers from EM fields. Published in May 2004, the directive must be transposed by member states by April 2008. MagnaShield can go a long way toward helping firms to achieve compliance, says Corus.
Initial testing shows MagnaShield to be effective at dc or common power frequencies of 50–60 Hz. The panels can be used to completely encase EMI sources in buildings or rooms. In applications such as MRI equipment, however, shielding may be limited to the wall that adjoins public areas. Panels were recently installed in the MRI suites at Birmingham Heartlands and Redditch hospitals. They provide protection well above the recommended minimum levels suggested by the National Radiological Protection Board, according to Corus. In addition, installation was accomplished quickly.
“The panels are designed for ease of construction,” says Ian King, managing director of Euro EMC, which installs EM shielding. MagnaShield panels are about 3 mm thick, whereas conventional shielding steel is 12–16 mm thick. “That makes installation simpler,” says King.
King also applauds the joint system. “A poorly designed shield concentrates the magnetic field into an adjacent room. It just causes a new problem in a different location,” he says. “The overlapping panels from MagnaShield completely prevent this. Although this is a more expensive material than conventional steel, it is a more cost-effective overall shielding solution,” King explains.
New applications for the material are emerging constantly, notes Sara Price, MagnaShield development manager. “For example, we recently assisted in the design of a transducer for an electric wheelchair,” she says. “Both external and internal EMI and magnetic fields were proving problematic. The Magna-Shield material has helped the manufacturer to increase the unit’s effectiveness.”
Copyright ©2005 European Medical Device Manufacturer
