Cabinet shielding inherent in standard equipment racks not designed to provide high-performance shielding

Information technology equipment is often housed in racks enclosed as cabinets that are either poorly designed as electromagnetic shields or have not been specifically designed to provide high-performance shielding. This study examines the shielding characteristics of a class of computer systems each housed in similar cabinet racks that were not designed to provide significant levels of shielding. At frequencies above a few hundred MHz, these cabinet racks can provide shielding sufficient to be important in compliance with regulatory EMC requirements on radiated emissions. At frequencies lower than a few hundred MHz, these cabinet racks do not reliably provide significant shielding. These conclusions are based on radiated emissions testing of equipment racks with and without doors and side panels.