Overpressure method – Hood test
As in the vacuum hood test the overpressure hood test is an overall leak test. A test set-up similar to the vacuum test is used. A vacuum chamber is used for the hood, which can be evacuated by a auxiliary pump and to which the leak detector is connected. The helium search gas which is escaping through leaks in the test object is indicated by the leak detector.
The use of a helium leak detector allows detection of extremely small leaks and is suitable for automatic leak detection in industrial equipment. The hood test can for example be used for examination of vessels, heat exchangers etc..