But Cracks?

CCTV can be a great tool for inspecting pipe interiors for problems. At about 30 days after construction, gross problems can be seen such as tools left in the pipe, poor lateral connections, extreme over-deflection or collapsed pipe, and large cracks. At one year, sags, infiltration stains, and joint offsets are more evident. Since the maximum earth load on the pipe does not occur until about 3 to 12 months after construction, excessive deformation and cracks may not be detected for several months. CCTV has its issues, however. Untrained camera operators and video reviewers find problems that do not exist. This may lead to unnecessary removal and replacement. Case histories, from snail trails to wicking in hairline cracks, will be cited to illustrate that proper techniques, procedures, and reporting are important. The accuracy of the interpretation of CCTV systems heavily relies on the experience levels of operators and the quality of the acquired images. It can also depend on how well the pipe has been cleaned. Representatives from the clay pipe and concrete pipe industries will add their experiences to the paper and the presentation.