Sealing 'duct work' with polyurethane grout...
Andy Derenski, PE, LEED AP
Technical Chemical Grouting Solutions | Senior Sales and Business Development Leader | Registered Professional Engineer | LEED Accredited Professional | Construction & Infrastructure
I didn't think duct work sealing was an application for polyurethane grout, but that is exactly what GWS did for a church in Knoxville this summer. The church was built in the 1970s and has a round sanctuary. The return air is collected near the center of the sanctuary space and routed down (below grade) and back into the air handling unit located in the adjacent basement. The return 'duct work' is actually corrugated metal pipe - the same type of pipe used in storm sewers and culverts. At this site, the ground water table is higher than the return air pipe, and water has been infiltrating into the CMP at the joints and other locations. The system had a sump pump added to deal with the standing water in the pipe, but it couldn't always keep up. With standing water in the return air stream, the building humidity was much higher than it should have been and caused problems with the air quality, the finishes of the space, and some of the musical instruments.
The CMP was approximately 15' below the finished floor of the sanctuary. Accessing the pipe required shutting down the air handler in the basement of the church, then climbing in through an access door and dropping down into the CMP. This access proved a major challenge for other repair methods that the church had explored, but the URETEK polyurethane grout process requires minimal tools and equipment at the point of treatment.
In one day, GWS treated the 36" and 60" corrugated metal pipes that comprise the return air system. The church has reported major improvements in both the infiltration and the performance of the HVAC system.
#groundworkssolutions #uretek
T.Luckey Sons specialty contractor
7yYes my company T Luckey Sons has been doing this for over 30 years now , plus much more check out our web www.tluckey.com , I would have chose a different product , but hope it holds up for them .
2nd Generation Owner at Regional Foundation & Crawlspace Repair
7yHydrophobic foam has been for helpful us in voidfill applications. Our PolyLevel product has been provided very consistent results in saturated soils. But I cannot say that it's ideal for pipe sealing in itself.
In moisture-rich environments, using a plural component polyurethane will not address the I&I. It will only fill voids or compact soils within the annulus. Johnnie is correct when offering a total seal, the industry standard is to inject with a water-reactive polymer.
Operations
7yI like the idea of sealing with a poly, but be sure to use a poly that's equally reactive in water, as well as it's absence. All too often I see improperly done injections that don't cure because the poly hasn't got enough water to kick off and start to cure. In a recent test a saw a poly product that didn't cure after 30 days in the Arizona sun. When the injection ports were removed the poly was still liquid. Rhino has an injection poly that's designed to be equally reactive with or without water. That specific failure type is what made us enlist a crew of chemists to create that poly.