AWWA ACE65429

The repair of a cast iron water main presents an opportunity to install a sacrificial anode,which can reduce the rate of corrosion and thus potentially delay the occurrence of futurefailures within the anode's zone of influence. While the additional cost of the anode issmall, is it a good economic investment? Using the spatial location of failures, clusteranalysis identifies zones of active corrosion defined as four or more failures, each nomore than 20m from its nearest neighbor within the cluster. Within these clusters, afailure is considered to have occurred within a cathodically protected zone if the failureoccurred within 20 m. of a previously installed anode. Otherwise, the failure isconsidered to have occurred within a zone that is not protected. Survival analysis showsthat the times to failure within cathodically protected zones are longer than the times tofailure in an unprotected zone. An economic analysis shows that the incremental costs ofsacrificial anodes indeed result in an economic benefit based on the deferral of futurefailures and their associated costs alone. The subsequent delay in replacement of the mainrepresents a further economic benefit. Includes 6 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

06/01/2007

Number of Pages:

59

File Size:

1 file , 1.1 MB