Completed in 1967 and maintained by the U.S. General Services Administration (GSA), the 32-story, 1.5 million-sq-ft Anthony J. Celebrezze Federal Building in Cleveland houses offices of the Defense Finance and Accounting Service, the Internal Revenue Service, the Equal Opportunity Employment Commission, the Coast Guard, the Department of Veterans Affairs, and the Department of Housing and Urban Development.
On each floor, four-pipe (hot- and cold-water supply and return) fan-coil units supply zoned heating and cooling to perimeter offices. The system allows some units to be in heating mode while others are in cooling mode. It also allows reheating of cold dehumidified air before it enters work spaces. Depending on room size, each office has four, six, or eight fan-coil units. Air-handling units located in the basement circulate conditioned air to central spaces throughout the building. Chilled water for the system comes from an off-site central chilling system operated by Cleveland Thermal Energy.
After 37 years, the original fan-coil units had outlived their usefulness. The only method of temperature control was changing fan speed (low, medium, or high), so employees often were either cold or hot. Drain pans on some units collected moisture, so indoor-air quality was a concern. And the need for constant maintenance and repair was disruptive for tenants and a financial burden for building management.
Architectural and design firm Westlake Reed Leskosky assessed the building's mechanical systems to determine how best to improve costs and tenant comfort.
“Because of the sheer volume of the units to be replaced — 4,640 — we specified a customized unit that would both simplify the renovation and create a comfortable, energy-efficient work space,” Mitch Lyles, PE, of Westlake Reed Leskosky said. “This included having the piping, controls, and insulation all in one box, as well as custom cabinetry.”
McQuay International designed new fan-coil units to accommodate a wide range of temperature preferences. Modulating valve control is included to provide more-even heat distribution and less temperature fluctuation through control of both delivered-air temperature and fan speed. A high-efficiency centrifugal-fan assembly helps minimize noise and vibration for increased occupant comfort. Multidirectional grilles let users direct airflow from the units toward windows during winter to minimize drafts; during summer, the grilles can be directed toward rooms for increased cooling comfort.
Filters can be replaced easily via a hinged door on the front of the units. Drain pans and coils are readily accessible for cleaning via a quick-snap panel.
Each fan-coil unit was factory-fitted with LonMark direct digital controls. Valves can be controlled and temperature set points adjusted with a hand-held device. Quick connects on sensors and relays simplify servicing and replacement. Communication wiring is run from controller to controller using a standard plug-in jack and Ethernet cable, making a continuous loop around the perimeter of the building. Technicians simply plugged in the units to the pre-wired system during installation. A future project will tie the units into a building-automation system.
McQuay designed the fan-coil units to be virtually “plug and play.” The new units fit the footprint of the original units exactly, even though the original units were not manufactured by McQuay.
With the building required to remain fully occupied and functional throughout the renovation, McQuay designed the fan-coil units for easy installation and efficient operation. Time-saving features included factory-installed and insulated horizontal piping (supply, return, and condensate) and a unique joining technology that allowed the units to be connected on site without soldering. Specially designed wheeled carts were provided to maneuver the units down halls and into place for installation.
While McQuay designed all 4,640 fan-coil units for quick and easy installation, the mechanical contracting firm, The Smith & Oby Co. of Walton Hills, Ohio, developed methods and materials that made installation nearly invisible to the building's 5,500 occupants. A 23-man crew, including pipe fitters, electricians, and laborers, worked 10-hr days, beginning at 6 p.m., four days a week every week for almost a year.
During installation, pipe-fitting technicians hung the new fan coils on existing steel racks with custom-made angle iron clips. Piping was connected from one unit to the next using a solderless coupling technology that not only reduced the risk of fire, but allowed the team to meet its quota of installing 30 fan coils a night.
“After the units were mounted in place, my guys simply slipped the pipe into the coupling, crimped each joint, placed insulation over the coupling, and the units were connected,” Jeff Klie, project manager for The Smith & Oby Co., said. “That saved us a lot of time and made us very efficient.”
Once the units were installed and connected, the crew started a 2-hr pressure test for leaks, broke for dinner, then installed the fan-coil covers.
“It was very much like a wheel — turning, turning, turning,” Klie said. “It was very repetitious, but also very efficient.”
As the new fan coils were installed, laborers carted away the old units, disassembled them, and separated the steel, brass, and copper into bins. The 664,000 lb of metal that was recycled earned the GSA a federal recycling award, Klie said.
Each morning, work did not end until spaces looked exactly as they did the evening before. Crews dismantled partitions, moved desks and other furniture, and even took digital photographs to ensure everything was put back in place.
“In the morning, it was just like we were never there,” Klie said. “There was only one item I had to replace throughout the entire project: a $14 clock that fell off a wall.”
The project was completed two months ahead of schedule and 32 percent under budget.
“You've heard of the perfect storm,” Klie said. “The Celebrezze project could have been one, but it became the perfect project instead.”
The key was close coordination between the GSA, The Smith & Oby Co., and McQuay.
“When you are able to get done two months ahead of schedule and under budget,” Klie said, “it speaks to the team effort.”
The assembly-line efficiency of the installation drew praise from the building's tenants.
“Coast Guard officials told us, ‘What you did was militaryesque,’” Klie said.
The project has been registered for certification under Version 2.0 of the Leadership in Energy and Environmental Design (LEED) for Existing Buildings Rating System.
Information courtesy of McQuay International.