Advisory Leaflet DWA-M 149-4E Conditions and Assessment of Drain and Sewer Systems Outside Buildings - Part 4: Detection of Bedding Defects and Cavities by Means of Geographical Techniques

The Advisory Leaflet makes recommendations and provides information on measuring techniques, by means of which bedding defects and cavities can be detected in the surrounding of earth-buried pipelines. It describes possible applications and application limits of the measurement methods ground-penetrating radar (GPR), geoelectricity as well as seismic technology. Additionally, research and development projects that make use of the measurement methods „acoustic inspection“ and „gamma-gamma probe“ are presented. For this purpose, relevant information is compiled for the most important areas of application when detecting bedding defects. The Advisory Leaflet lists areas of application that are based on practical experience. The Advisory Leaflet addresses all institutions planning, operating and supervising in the field of condition recording and evaluation of drainage systems as well as companies that are assigned with condition evaluation.