Drying equipment stays in county courthouse

The drying process continues at the Flathead County Courthouse this week to remove all the moisture spread by a fire sprinkler set off as a result of a heating malfunction early Dec. 20.

Late last week, people overseeing the restoration process thought the drying equipment could possibly be removed from the building Tuesday, following three days of uninterrupted drying during the long holiday weekend.

But on Tuesday morning, Cameron Wride, project supervisor for Rainbow International Restoration and Cleaning, said the building isn’t fully dry.

It’s tough to predict exactly how long the drying process will take, Wride said. On Thursday he expects to again evaluate the building to determine if the fans, dehumidifiers and drying mats can be removed. He uses an infrared camera to check for moisture pockets in the building. Until those disappear, the drying work needs to continue, he said.

“When we first looked at it a week ago, realizing how thick the walls, floors and ceiling are in this building, we thought we needed about eight days of drying time,” Wride said.

Rainbow employees were setting up equipment to remove water within three hours of the 4:34 a.m. Dec. 20 report of the incident.

The drying process was aided by the three-day county office closure for Christmas, Wride said. The drying equipment could run at full speeds and the building’s temperature could be elevated while no one worked. Wride checked on the equipment every four hours during the holiday weekend. 

While the courthouse is open for business, some fans are turned off and speeds lowered on others because people are working in the building.

Wride is aware of the difficulties the cleanup effort poses for county employees.

“They’ve been displaced and had just got moved back into the building and this happened,” he said. “But we need to get it dry before we release it.”

A $2.7 million renovation effort of the 108-year-old courthouse has been under way since February. All of the offices just completed moving back into the building on Dec. 6.

CTA Architects Engineers, the architect for the courthouse renovation, provided the county with an explanation of what caused the building’s heat system to overheat last week.

The building got so hot it set off a fire sprinkler and temperatures exceeded the 165-degree rating of fuse links in the building’s heating and fire suppression system. Those fuses already have been replaced with links rated to withstand temperatures up to 180 degrees.

Nathan Ratz, a mechanical engineer with CTA, has recommended the links be upgraded again to 200-degree fusible links as an extra safety measure.

Ratz’s report states that when the air handling unit in the attic of the courthouse went into unoccupied mode the evening of Dec. 19, the supply fan shut off, which resulted in the discharge air temperature rising to about 180 degrees. The system is supposed to keep the discharge air temperature between 55 and 60 degrees.

It appears the steam valve was open during unoccupied mode, allowing heat to continuously be added to the air inside the air handling unit and the supply ducts, Ratz stated.

Eventually, the air in the supply duct on the third floor got hot enough to melt the fire damper links, which were supposed to be able to handle temperatures up to 165 degrees. The heat also closed the fire damper, which prevented the heat from transferring to the air in the duct below the third floor.

That caused the air temperature in the duct to rise and eventually the heat transferred through the duct into the chase and heated the ambient air in the chase to 155 degrees,  which melted the bulb in the sprinkler head and caused it to discharge, he wrote.

The controls and control components now in place at the courthouse are enough to allow for additional monitoring and control to keep the overheating situation from happening again, Ratz wrote.

CTA has recommended the county add a critical alarm to the control system so that if the discharge air temperature sensor rises to 120 degrees,  the control system would generate a critical alarm and a supply fan would start running to help dissipate the heat.

The steam valve also should be reset to a set point of 75 during unoccupied mode so the valve would open only if the discharge air sensor dropped below 75 degrees.

Reporter Shelley Ridenour may be reached at 758-4439 or sridenour@dailyinterlake.com.