| 摘要 |
A method of detecting the presence of a leak in a barrier, e.g. a floor membrane 16 of a building or the wall of an underground a pipeline 61, comprises creating a pressure differential across the barrier, e.g. by introducing superambient air at a plurality of spaced points into the region 14 beneath the building or by creating a vacuum within a sealed section 63 of the pipeline, and detecting the presence of toxic or noxious soil gases G on the lower pressure side of the barrier (i.e. in region 15 or in the sealed section 63) within a limited period of time from the creation of the pressure differential. <IMAGE> |
