The integral leaktest with helium pressure in the volume around the tubes and atmospheric pressure in the tubes

This test requires long waiting times and is used only, when other methods are not possible and when the safety conditions allow a higher testgas pressure in the volume around the tubes. The test is carried out by measuring the helium concentration in the volume of the tubes. The value of the leakrate must be calculated. The procedure of this test, the calculation of the waiting time as well as the leakrate are described.