The Shielding performance of EMC chambers, Shield Rooms, Bunkers, Cat A compartments in Ships are largely dependent on the quality of Shielded Door. These require shielding test/performance verification prior to supply at the manufacturer premises or at the end customer site after installation. BNN undertakes onsite shielding effectiveness measurements on Shielded doors based on Standard IEEE 299:2006. Frequency spots and test locations are specified in the standard, however additional points can be included.