Technical Manual: Conduits through Embankment Dams (FEMA 484)

Conduits through Embankment DamsFigure 185.—The calibration hose of this pulled-in-place CIPP developed“fins.” These fins were considered to have an insignificant effect onhydraulic capacity for this particular conduit application and were notremoved.generally resists the adherence of sediment. See section 9.6 for guidance on cleaningof conduits.If the CIPP liner experiences some type of damage over the long term, the damageshould be assessed by trained personnel using man-entry or CCTV inspectionmethods as discussed in section 9.5. Repair of the CIPP lining after installation andcuring are completed is possible. Repair kits are available from the manufacturer.For an example of a project that utilized a CIPP liner see the case history for WillowCreek in appendix B.12.3 Spray liningSpray lining is a conduit renovation method that has been used since the 1920smainly for small diameter water mains (USACE, 2001d, p. 10). Spray lining typicallyinvolves the spraying of a cement mortar mixture or epoxy resin against the insidewalls of the existing conduit. Trowels that trail the rotating sprayer head smooth thesprayed cement mortar. Spray lining has been used to retard iron pipe corrosion andreduce the rate of deterioration of the existing walls of water mains.While this renovation method may have some limited applicability for low hazardembankment dams, it is not recommended for significant or high hazardembankment dams. The spray lining technique cannot ensure a long term watertightbarrier and has a limited life expectancy.330