The District 161 Board of Education is considering information about the suspected causes and potential solutions to humidity issues at Flossmoor Hill and Western Avenue schools.

A third-party report outlined progress in a plan to address humid air condensing on chilling pipes, which has caused significant damage to the facilities. The district has been trying to solve the problem for several years, but because the humidity and moisture are seasonal issues, efforts cannot be tested until the humid days of July and August return. 

On behalf of the district and Wold Architecture and Engineering, engineering and architecture firm Farnsworth Group conducted a series of inspections and tests to identify the source of the problem and recommend repairs. Jeff Boyer, a mechanical engineer and commissioning agent from Farnsworth Group, presented the information at the Oct. 14 board of education meeting.

Boyer reported that problems stem from HVAC upgrades implemented in 2020 at both schools. Due to inadequate insulation on curves in the pipes carrying cold water to cool the buildings, condensation drips on the ceiling tiles and classrooms below. 

“What we found is that the building was operating at negative pressure,” Boyer said. “So the building is exhausting more air than is being brought in to the space.”

Boyer explained that this negative pressure was causing hot, humid air to enter the schools as the building’s air equalized. The moist air then gets caught between the roof and the ceiling. Without kids in the building to warm up the space below the classrooms, the air conditioning system does not run long enough to dehumidify the air above the ceilings. 

Boyer and his team suspect that the humid air is entering the buildings through the bathroom exhaust fans, which vent to the roof. Boyer said that some of these fans only run intermittently, and others might not be functioning at all.

Potential solutions include equalizing the negative pressure and replacing the bathroom vents with new units that close automated dampers when not exhausting air. The humidity at Western Avenue, which has not been as severe, is suspected to have a similar cause and solution. More intensive remedies are also being considered, including heating the air slightly to keep the blowers running longer.

Farnsworth Group plans to complete additional tests, including a whole-building pressure test at Flossmoor Hills, before submitting final recommendations. The board will hear the results of those efforts and consider the costs of the solutions at a future board meeting.