Some municipalities use a method called vacuum testing to identify potential leaks in their newly constructed manholes and pipes. Leaks can be caused by honeycombed concrete, deflected joints, and poor installation of boots. Sometimes precast units can be cracked by heavy equipment during the installation and backfilling process. Municipalities can implement vacuum testing to ensure that the taxpayer is not footing the bill for a system that will fail and require costly repairs down the line.

Technicians identify leaks in new structures by coating the inside with soapy water. Next, they perform a vacuum test with special equipment that extracts all the air and causes bubbles to appear in the leaking areas. After leaks are identified via vacuum testing, professional leak seal contractors can seal them with polyurethane grout using the process outlined below:

1. Drill a small injection hole near the leak location.
2. Flush the hole with water to clear out any debris.
3. Insert a port into the drill hole.
4. Install a Zerk fitting in the port and connect your injection gun.
5. Inject water into the cracks/voids to make sure the moisture activated grout will react.
6. Inject a moisture activated polyurethane grout such as Spetec PUR F400 or Spetec PUR GT500.
7. After the grout cures, the technicians apply the vacuum test again to determine if the leaks have been repaired.

Leak seal contractors should encourage local municipalities and specifiers to require vacuum testing on structures after they are backfilled. If you’d like assistance in making a presentation on this subject, call us today at 404-618-0438.

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