What Is Necessary For Manhole Rehabilitation Success? Correct Application, Use Of Manhole Rehab Technologies

By Gerhard “Gerry” P. Muenchmeyer, P.E., NASSCO Technical Director | October 2011, Vol. 66 No. 10

When specifying a coating or a lining, it is important to implement post installation inspection and testing as well as performing inspections during or just before the maintenance period expires. Coatings and linings, when properly applied, will protect the host structure from further deterioration provided no defects exist that allow corrosive elements to penetrate behind the applied coating. If defects occur, the host structure will continue to corrode and in some cases the deterioration process accelerates significantly.

In applications, it is not uncommon to experience some minor defect formation in the installed product where a pin-hole remained undetected or coating was applied thinner than required. If the defect remains unrepaired it will, over time, continue to spread towards total product failure.

Maintenance inspection of coatings and linings is very important. A defect left unrepaired will spread and fail. A defect, repaired in a timely manner, will ensure that the product will perform for its expected life.

After completion, when should your installed product be re-inspected to verify that no potential defects will occur that will affect long-term performance of the product?

Shook: It is best to perform tests immediately upon completion. Follow up inspections should be made during routine maintenance of the manholes and following major storm events or similar harsh events which impact the sewer system.

Haessig: The recommended acceptance test is a live water test during or after installation of the seal.

Kiest: Inspection can occur at any time. We have inspected liners that have been in use for more than five years, and they show no change from the time of installation.

Johnson: Adhesion testing should be done four-to-six hours after application which is the time needed to reach complete cure. Sprayroq products cure similar to concrete, outside to inside.

Warren: One to five years. Our product has passed the California Redner test, CIGMAT in Houston, by the European IKT test and the Department of the Navy testing.

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