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

Abstract

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.