Published September 2007
Sealing the Deal
By Rosalie E. Leposky (page 90)
A California contractor travels to a South Dakota hospital to perform a successful repair on a failing metal sump basin.
Last January, Paul Young of SGV Underground in Covina, Calif., took a call from far outside his normal service area. The caller was the maintenance administrator at Sanford USD Medical Center in Sioux Falls, S.D., who needed help to repair a failing metal sump basin and had found Young’s company through an Internet search.
Young, a licensed California contractor and a journeyman plumber, has managed SGV Underground since 1996. (His grandfather, Fred Young, founded the business in 1962.) The firm usually operates in the greater Los Angeles area and the San Gabriel Valley, with a population of about 14 million.
Working in a consulting role, Young supervised a hospital maintenance crew in repairing the sump basin. They sandblasted and manually cleaned its walls, filled cracks and holes with special mortar, covered the walls and base with a stainless-steel mesh skeleton, and applied a final epoxy sealer. The basin was then returned to service.
Restoring the old
Today, sump basins are made of fiberglass or polyurethane, or sometimes concrete, but 35 to 40 years ago, 12-gauge steel was the material of choice. Buildings all across North America have such sumps.
“Over time these metal sump basins or pits become rusty,” Young explains. “They corrode and leak. Sump basins are installed with a crane at an early stage in a building’s construction, before the walls go up and doorways are created. Typically, they are four or five feet in diameter and about eight feet deep. Buildings are built out around them. They are a challenge to repair. They often leak for years. Water builds up behind them in the soil that wants to leak back into the pit, causing additional corrosion.”
That was the problem confronting Sanford USD Medical Center (formerly called Sioux Valley Hospital USD Medical Center), a 500-bed facility affiliated with the University of South Dakota, serving about 211,000 residents. The failing sump pit was in an older section of the hospital.
The hospital maintenance manager had searched the Internet and found a story about SGV Underground in an e-newsletter on the web site of Perma-Liner Industries Inc., in Largo, Fla. “The story was on our relining of a steel sump at a bank in Santa Ana, Calif.,” says Young.” We’ve been doing this work for about six years and have done about 100 of these jobs.”
Protective coating
Young uses products sold primarily to create a protective coating inside manholes where bricks and concrete are under constant assault from sewer gas. Young believes his is the only company repairing sumps in this manner. He says the coatings should last at least 15 to 20 years.
Young and the hospital’s representatives discussed bringing in an entire SGV Underground crew to repair the sump. “In the end,” he says, “they accepted a consulting contract and flew me to Sioux Falls in April to supervise members of the hospital maintenance staff.”
Maintenance supervisor Kenny Middlend and maintenance workers Mike Turgeon and Kevin Olinger worked with Young. All were trained in confined-space work and had their own personal protective equipment. They provided a paper confined-space entry suit for Young to wear.
When Young arrived, he found “as expected, a rotted metal sump pit. The metal was corroded and thin and in bad condition.” The jobsite had been set up according to his instructions. The hospital crew had emptied the sump pit and removed its top to create additional work space.
“They also locked and tagged out its sewage flow to prevent any wandering gas from entering the sump while we worked,” Young says. “For added protection, the workers ran ventilation blowers provided by the hospital.”
Few hitches
Young flew in on a Sunday, started work Monday morning, and flew home on Wednesday. “We started each day about 8 a.m. and finished by mid- afternoon,” he says.
“The only problem we had was some groundwater that ran into the sump during the coating process. Eventually, epoxy sealed the leak.” Here is how the repair proceeded:
Day One. The crew sandblasted of all the internal metal surfaces — walls, base, and the inside of the lid. Then they manually cleaned the surfaces with electric mechanical grinders.
Next, they filled all cracks, deep holes, and perforations, covering weak spots in the metal walls and base with Perma-Mortar V/O, a polymer-modified, fiber-reinforced, silica-fume enhanced repair material for concrete or masonry. No mortar was applied to the inside of the top, as that portion does not hold water, is not structural, and was in good condition.
Over the mortar they attached a stainless-steel mesh skeleton to the metal walls and base, using stainless-steel screws. Then they troweled additional Perma-Mortar V/O over the mesh to cover it completely, and left the material to dry hard overnight.
Day Two. Over the mortar along the sump’s base and walls, workers liberally applied three coats of 125 mil (1/8-inch) PermaPoxy, a rapid-curing, medium- viscosity modified epoxy resin, also from Perma-Liner. The material is designed to repair sanitary sewer surfaces, including manholes, sumps, wet wells, and pipelines.
Crew members applied the material with trowels, working around the floor and sides of the sump pit. They coated half of the pit’s bottom, let it dry, then coated the other half. The epoxy cures to an extremely hard surface, ensuring that water never again touches the pit’s metal surfaces. After Young left, the hospital crew also applied a protective epoxy coating to the inside of the lid.
The cost to the hospital, in addition to Young’s consulting fee, was about $3,000 for supplies and employee labor — significantly less than the cost of replacing the sump. That would have entailed cutting and digging out the rusted metal, and replacing it with concrete pumped into a mold and treated with a protective liner, at a cost of $45,000.
