An Evaluation of the Failure Modes and Condition Assessment Technologies for Small Diameter Ductile Iron Pipes

摘要

According to the Water Research Foundation, over 700 water main breaks occur daily in the United States, leading to huge losses in the distribution of potable water. A 2012 study by Utah State University indicated that ductile iron pipe (DIP) represents a considerable share of the potable water market (28% of pipeline network) in the United States. Among the various diameter classes of DIP. small diameter DIPs (pipes with nominal diameter less than or equal to 12 in.) exhibit the greatest failure rate, owing to thinner pipe walls and larger slenderness ratios. An understanding of the failure modes and mechanisms in small DIPs, and the condition assessment (CA) techniques suitable for detecting flaws and estimating the remaining service life of such pipes, would enable water utilities to identify pipes that are likely to fail, facilitating timely repair and replacement decisions. A qualitative research approach, which included a survey of North American water utilities was selected for this study. This study contributes to the body of knowledge and practice by: (1) identifying the predominant failure modes in small diameter DIPs, and (2) evaluating CA technologies currently used by North American water utilities based on their cost, ease of implementation, and suitability for detecting flaws in small diameter DIPs.