Construction crews are in the process of removing harmful chemical compounds from the ground underneath Needham and Webb Elementary schools using a depressurization system.
Indianapolis-based sub-contractor All Points Considered arrived at the school grounds earlier this month to start construction. Environmental consultant EnviroForensics, also of Indianapolis, designed the system, and Franklin schools will pay an estimated $469,179, said Jeff Sewell, Franklin schools’ operations director.
EnviroForensics previously conducted tests before spring break that showed levels of the compounds PCE and TCE were higher than normal. Those compounds can cause harmful health effects in high enough concentrations.
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The process of extracting them from beneath the ground involves connecting pipes through the building, with the pipes starting under the ground and continuing upwards through the roof, Sewell said.
Fans above the roof connected to each pipe will suck the gaseous contaminants up from beneath the ground. The fans, facing upward, will then clear the vapors through the air, at which point they will no longer be dangerous, Sewell said.
The vapors break down when they are exposed to sunlight, according to a diagram of the process created by EnviroForensics.
The system also decreases pressure created by the compounds underneath the ground, ensuring they don’t make it into the air inside the school building.
Construction crews will cover the entire footprint of both buildings, not just the areas EnviroForensics tested before, to ensure all the compounds are removed from the ground, he said.
“Concentrations have moved around over time, they’re in some of the same areas but not always. We would not take any chances with that. We need to make sure the entire footprint is covered for both buildings,” Sewell said.
The construction part of the project should be complete by July 17. The process of the fan removing the compounds will continue even when school begins, but will operate on its own, Sewell said.
Tests in March for PCE and TCE showed some sub-slab areas at Webb Elementary School with TCE levels of 225, 242, and 849 micrograms per cubic meter. The acceptable limit set by the Indiana Department of Environmental Management is 70 micrograms per cubic meter. Further rounds of tests showed decreased levels of the compound, with May 5 tests showing no areas registering more than 50 micrograms per cubic meter and most with less than 10.7 micrograms.
Even with the decrease, Franklin schools are installing the system to remove the compounds in order to create long-term assurance that the compounds will no longer be present beneath the ground and will not infiltrate the air inside the schools, Sewell said.
Construction workers are currently installing the pipes. Once they finish, they will install the fans and electrical work. While workers wait for the parts, the pipes are capped off and resealed in order to prevent any possible leaks, he said.
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What;Depressurization system to remove harmful compounds PCE and TCE found underground.
Where;Needham and Webb Elementary Schools.
When;Construction crews arrived last week, expected completion on July 17.
How;Fans in pipes that run from under the ground to above the roof will remove the compounds from the ground beneath the schools.
Why;PCE and TCE can cause harmful health effects in large concentrations.
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