Large-diameter pipeline inspection can be a costly and difficult undertaking and, as such, is often overlooked. These inspections are increasing necessary as the nation's infrastructure continues to age and deteriorate. Pipe failures in these large-diameter pipes are usually catastropic. The failure is typically sudden and unexpected and often involves major construction. As a proactive measure, a utility in the mid-Atlantic became concerned that some of their major interceptors were reaching the end of their design lives and required inspection. These interceptors are subject to significant sulfide attack during the warmer summer months. In addition, these interceptors lie beneath a major four-lane thoroughfare. The utility wanted to determine the existing structural condition of these interceptors, examine constructability issues, and decide if they should rehabilitate the existing interceptors or if they should replace the existing interceptors. This decision would be based on the findings of the structural assessment and constructability. This paper examines the approach in determining the structural condition of large diameter interceptors (20" to 66") with difficult access. Traditional cleaning and inline closed-circuit televising (CCTV) would be difficult and extremely costly. Therefore, zoom camera technology was selected. Zoom camera technology normally consists of an ultra high-powered zoom lens camera for rapid inventory and screening of collection system deficiencies. The work was completed successfully and the necessary data were obtained. Decisions regarding future work on the interceptors became much clearer as a result of this cost-effective and efficient investigative assessment.
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