A vacuum test is used to check the watertightness of manholes, inspection chambers and small sections of drainage by sealing the structure and reducing the internal air pressure with a vacuum pump. Engineers monitor pressure recovery over a fixed period and compare the result against acceptance criteria under BS EN 1610 and BS EN 752. The method is particularly useful for new and reinstated chambers on adoption schemes with Thames Water and on commercial London sites where high standards of containment are required. Compared with water testing, the vacuum approach reduces water usage and avoids discharge into the public sewer. The work is carried out by qualified engineers using calibrated test equipment, and the resulting record forms part of the project handover documentation.
Vacuum test (drain)
Test using applied vacuum to check watertightness of manholes and inspection chambers.
