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

Shook: Failures can occur whenever proper preparation and/or application procedures are not followed. We strive to eliminate field problems by requiring certification training with annual updates so applicators demonstrate proven performance standards. In rare instances when defects are discovered, an investigation is made to discover the cause then defects are corrected and reports issued to eliminate recurrence. Our company has provided solutions since 1976 without a single failure to correct defects. No matter how rare or costly.

Haessig: While no material failures have ever occurred or been documented, leakage related failures have occurred. The cause of these leakage related failures is most often associated with improper surface preparation, not following recommended installation instructions, specifically, the lack of use of the supplied expansion band lubricant. Remedies for leakage related failures are as simple as removal of the seal and performing any necessary surface preparation or repairs and reinstalling the seal and bands making sure to use the expansion band lubricant.

Kiest: During the development of the CIPMH liner system, we did experience failures due to ruptured inflation bladders. Although the installer must take precautions not to puncture the inflation bladder during insertion into the manhole, we have developed a very robust bladder, and today failures are not common.

Johnson: The only cataloged failures have been in corrosion applications, 125 to 150 mils, with the failure due to improper substrate preparation. All Sprayroq products are hydrophobic and will have an adverse reaction if applied to a substrate that does not meet the proper moisture threshold. The reaction is immediate with the primary reaction being a vigorous outgassing resulting in a scaly, “popcorn” looking foam. Operators are trained to stop and find out why the substrate is not dry enough, and the remedy is to remove the improperly applied SprayWall, recheck the stoppage of the moisture, and reapply on to the newly prepared substrate. SprayWall, our structural polyurethane, has never had a latent structural failure -- meaning, after proper ASTM design and proper application, no failure has ever been reported.

Warren: After curing, we use Elcometer testing for adhesion, ultrasonic testing to verify millage and Positestor testing, for pinholes.

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