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Air-Intake Filters Help Hospital Keep Airborne Debris From Cooling Towers

April 1, 2005
For 16 years, managing the cooling of several modern medical buildings next to Baptist Hospital East (BHE) of Louisville, Ky. the region's leading hospital

For 16 years, managing the cooling of several modern medical buildings next to Baptist Hospital East (BHE) of Louisville, Ky. — the region's leading hospital for oncology, cardiology, orthopedics, and neurosurgery — was difficult because of the maintenance challenges of two cooling towers.

During spring and summer, organic debris (insects, pine needles, cottonwood seeds, leaves, dirt, and other airborne matter) would enter the cooling towers, where it would mix with the cooling water and clog the fill material, resulting in reduced thermal efficiency. Debris also would collect in the basins, where it would decompose, resulting in sludge buildup that supported bacteria proliferation, plugged the basin strainers, and reduced cooling efficiency. On many occasions, debris would get through the basin strainers, resulting in the solenoid blowdown valves getting stuck in the open position, which triggered the automatic release of water-treatment chemicals and prematurely drained the treatment-chemical tanks, requiring BHE to call for emergency refills. Additionally, thousands of gallons of makeup water would be lost.

Although the cooling towers were equipped with water-filtration systems, they required weekly monitoring and cleaning. Over the course of a year, thousands of dollars were spent to keep the cooling towers operational and ecologically sound.


Seeking a way to prevent debris from entering the cooling towers, rather than manage it once it was drawn in, Properties Manager Gilbert Fister contacted Air Solution Co., a manufacturer of cooling-tower and chiller-coil air-intake-filter systems.

Mounted to the outside of intake openings, air-intake filters are designed to isolate airborne debris on the outside of cooling towers. The filters are made of a UV-resistant, non-electrostatic, vinyl-coated polyester medium that resists mold and mildew, never needs changing, and is easily cleaned using a brush, broom, or wet/dry vacuum.

Since the filters were installed in 1999, BHE has eliminated sludge buildup, not experienced strainer or blowdown-valve clogging, and reduced its chemical consumption by more than 50 percent and its makeup-water consumption by 35 percent. Further, BHE has not required unscheduled service because of system fouling, saving thousands of dollars in labor and service costs.

“We now only inspect our towers monthly and find little or no maintenance required vs. our inspecting them weekly … and nearly every time finding a need for some maintenance work,” Fister said.


BHE's cooling-tower-maintenance and water-treatment providers were contracted for scheduled service throughout the year based on “normal” operation. When the blowdown valves would stick in the open position and emergency service calls would be made, both companies would end up absorbing the added costs.

According to both companies, the air-intake filters have helped keep the cooling towers running optimally and have reduced maintenance-cycle time by nearly half. That means the towers are out of service for shorter periods of time during scheduled maintenance and both companies have greater flexibility to deploy their service teams where they are needed most and service more customers per day. Additionally, because they have virtually eliminated unscheduled maintenance, the air-intake filters have helped both the cooling-tower-maintenance and water-treatment companies to optimize the profitability of their respective service contracts.

Information and photograph courtesy of Air Solution Co.
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