The consistency of visual sewer inspection data

  • In common with most infrastructure systems, sewers are often inspected visually. Currently, the results from these inspections inform decisions for significant investments regarding sewer rehabilitation or replacement. In practice, the quality of the data and its analysis are not questioned although psychological research indicates that, as a consequence of the use of subjective analysis of the collected images, errors are inevitable. This article assesses the quality of the analysis of visual sewer inspection data by analysing data reproducibility; three types of capabilities to subjectively assess data are distinguished: the recognition of defects, the description of defects according to a prescribed coding system and the interpretation of sewer inspection reports. The introduced uncertainty is studied using three types of data: inspector examination results of sewer inspection courses, data gathered in day-to-day practice, and the results of repetitive interpretation of the inspection results. After a thorough analysis of the data it can be concluded that for all cases visual sewer inspection data proved poorly reproducible. For the recognition of defects, it was found that the probability of a false positive is in the order of a few percent, the probability of a false negative is in the order of 25%.

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Metadaten
Author:J. Dirksen, F.H.L.R. Clemens, H. Korving, F. Cherqui, P. Le Gauffre, T. Ertl, H. Plihal, Karsten MüllerORCiD, C. T.M. Snaterse
DOI:https://doi.org/10.1080/15732479.2010.541265
Parent Title (English):Structure and Infrastructure Engineering
Publisher:Taylor & Francis
Place of publication:London
Document Type:Article
Language:English
Year of Completion:2013
Tag:reproducibility; sewer inspection; uncertainty
Volume:9
Issue:3
First Page:214
Last Page:228
Peer Review:Ja
Link:https://doi.org/10.1080/15732479.2010.541265
Zugriffsart:bezahl
Institutes:FH Aachen / Fachbereich Bauingenieurwesen
collections:Verlag / Taylor & Francis