The assessment of the condition of drains and sewers, and of possible hazard potential due to damage, also demands the verification of tightness. Optical inspection (for this see ATV Advisory Leaflet M-143, Part 2 [1] can provide such information to a limited degree only. Thus visible damage does not always imply unsatisfactory tightness. On the other hand, leakage points, in particular in the area of pipe connections, are barely identifiable visibly. For the leak testing of newly produced or rehabilitated drains and sewers there are standardised regulations available.weiterlesen