Vacuum box testing is used to examine small and specific areas for defects, flaws, leaks or other imperfections. A vacuum box test can be used anywhere where a pressure differential can be created across the examination area. Commonly vacuum box tests is used in piping systems, pressure vessels, storage tanks, tank bottom floor, ships, oil rigs bottom plates and tank shell to bottom plate knuckle. The test is performed by coating the examination area with soapy water before placing the vacuum box. A vacuum pump creates a vacuum in the box; soap bubbles reveal leaks or weld defects locations.