PolyFoam Solutions worked closely with Charlie Lerman, Alchemy-Spetec's Director of Technical Services for the Leak Seal Division. Together, they devised a plan to seal the large leaks using Spetec PUR F400. Spetec PUR F400 is a solvent and phthalate-free, water-reactive, hydrophobic, closed-cell, low viscosity, shrink-free, flexible, one-component polyurethane injection resin designed to stop water leaks. It is also certified to NSF/ANSI/CAN 61 (approved for contact with drinking water).
The crew drilled four holes around the lower manhole joint and then installed injection ports. As they pumped the polyurethane grout into the ports, it began to travel around the joint, sealing the leaks. Once the grout had traveled as far as it could from one port, the technician moved on to the next port until the entire joint had been sealed watertight. They used oakum to temporarily seal some of the larger leaks until the grout had time to cure. The upper joint only required 3 port injections due to the speed at which the grout traveled.
The crew only took about 3 hours to completely seal all of the leaks and return the manhole to service. There was no way the leaks could have been left un-repaired due to the water treatment cost and the potential damage the erosion would have caused. Replacing the manhole would have easily cost three or more times the price of grouting. In this case, the community wins as many tax dollars are being saved.