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Solutions For Lateral Rehab
One contractor’s operating procedure
Mark Metcalfe, vice president of operations for Hoffman Southwest Corp., said all the company’s shops are equipped to service laterals by CIPP, pipebursting and excavation. Hoffman Southwest operates Roto Rooter franchises in California, Oregon, Arizona and Utah.
Metcalfe said on most service calls, a CCTV inspection is made after the line is opened. Video inspection usually confirms the cause of stoppage and whether the line is clean. If the line is damaged, inspection results can be used to identify repair options.
“Most customers,” Metcalfe said, “are receptive to inspection when its cost is included in the cleaning service. When there is a separate charge they normally are only receptive if they have had repeated backups. For lines that were full of roots, the old practice was to clean them once a year. The trend now is to rehab them.”
When a lateral is found to be damaged, have severe root problems or is an obvious source of I&I, the recommendation is rehabilitation.
Generally the first choice of rehabilitation is CIPP, pipebursting is second, and excavation last.
“Advantages of CIPP are that it can be done with little or no excavation and can rehabilitate the entire line without going into easement or public right-of-way,” Metcalfe explained. “With pipebursting, material is less expensive than CIPP, but it is more labor intensive and is more unfriendly to the landscape. Excavation generally is the last choice because the landscape damage is the most severe.”
Figuring in all factors, Metcalfe said costs for the three procedures are much the same, although repairs to surface damage after excavation can add to the cost when excavation is used.
“CIPP and pipebursting generally can be completed in one day versus excavation which may take several days including relandscaping,” said Metcalfe.
Signs of progress
Laterals continue to age and fail, but there is a greater recognition today of the serious problems they cause.
“Considering the cumulative effect of the infiltration from most laterals in a system, the failing laterals must be considered community problems,” observes George Kurz, P.E., DEE, senior technical leader, Barge Waggoner Sumner & Cannon Inc. “Therefore, reducing lateral infiltration and recapturing capacity of public sewers must be recognized as a community benefit.”
There is evidence that sewer system operators are beginning to understand that.