Narrow 25-Foot-Wide High Rise Puts the Squeeze on HVAC Engineers & Contractors
Sandwiched between two buildings on a tiny Midtown Manhattan site, the ACI challenged a blue ribbon HVAC team led by consulting engineering firm, Ove Arup and Partners, New York; mechanical contractor, Center Sheet Metal, New York; and indoor air quality equipment manufacturer, Dectron Internationale, Roswell, Ga.
Raimund Abraham, an architect at Atelier Raimund Abraham and a professor at New York's Cooper Union School of Architecture, designed the building for planner/developer, Bundes lmmobilien Geselischaft (BIG), Vienna, a wholly-owned subsidiary of the Ministry of Economic Affairs of the Republic of Austria. Construction consultant, Hanscomb Inc., New York, acted as BIG's domestic representative.
While a building with merely 33,000 square feet might appear like a cakewalk for an international consulting engineering firm, the project was one of the most difficult for Ove Arup, a firm with past work that includes New York-based John F. Kennedy International Airport's new billion-dollar Terminal #4, the Sydney Opera House, in Sydney, Australia, and other high profile projects. "Considering that all the trades had to be jammed into this building's small space, the tolerance for error of 1/16th of an inch in most cases, resulted in a very, very difficult project," said Steve Walker, associate and ACI project leader at Ove Arup.
The equipment installation required the same awareness of tight tolerances. Just to get two of Dectron's dehumidifying heat pumps into their sub-cellar location, Center Sheet Metal had to rig them down the elevator shaft with less than one-inch clearance on all sides. "It took us two days to lower those units approximately 30 feet," recalls Salvatore Scavo, senior project manager at Center Sheet Metal. "I've been in this business over 35 years and that was one of the most difficult equipment moves I've ever seen."
With such close tolerances, Ove Arup and the project's general contractor, Barney Skanska, New York, helped contractors differentiate between their respective disciplines by creating coordination drawings with color-coding of the mechanical, electrical, plumbing and other services.
And if the site's constraints weren't enough to mandate custom manufactured indoor air quality equipment, the building's mixed use of residential apartments, atrium, theater, art gallery, library, and offices guaranteed it. Manufactured according to the specifications of Ove Arup, three Dectron Internationale Dry-O-TronÂ® dehumidifying heat pumps with economizer modes are used to dehumidify, cool, and heat the lobby, atrium, art gallery and theater areas. When humidity is needed, duct-mounted humidifiers by Nortec Industries, Ogdensburg, NY, are activated.
The units use modulating hot gas-reheat control to ensure strict museum requirements of a two-degree temperature differential are met. This temperature control, as well as equally stringent dehumidification requirements, is critical since the gallery will showcase touring fine art expositions from around the world.
Temperature and humidity set points will be monitored and controlled through a building automation system manufactured by Andover Controls Corp., Andover, Mass., and installed by temperature control contractor, T.M. Bier Associates, Glen Clove, New York.
Two of the heat pumps fit snugly in the structure's sub-cellar. The third however, is an unusually shaped 104 (L) X 72 (W)-inch unit that's only 24 inches high so that its ceiling-hung location offers ample space underneath for a mandatory restroom on the theater's mezzanine level. Because only a wall separates the unit and the 100-seat theater it supplies, quiet operating compressors and fans plus sound attenuating innovations were built-in at the factory. The unit fits its ceiling location within an inch on all sides. In the event the unit needs service up and above routine filter changes, it will need to be lowered and removed from its tight niche.
Because equipment failure is not an option, one reason Ove Arup specified Dectron is because all equipment is first performance tested in its factory-based $250,000 environmental laboratory. Dectron pre-tested all the units under environmental conditions and guaranteed trouble-free start-ups.
"Usually a critical dimension refers to the leeway of getting a unit through a doorway or some other opening to its destination," explained Robert Senia, president of manufacturer's representative firm, SRS Enterprises, New York. In the case of the ACI, critical dimension was plus or minus one inch and it refers specifically to the equipment's actual installation, which is very, very unusual."
An example of the ongoing communication throughout the project between Ove Arup's design team and Dectron is illustrated with the installation of the outside air damper inside ductwork instead of on the exterior of the unit, which would have decreased serviceability.
While the first two floors have custom-made equipment, the upper floors each use one ceiling-mounted heat pump manufactured by the Thermoplus division of Dectron Internationale. They supply air through metal duct and have one return air plenum. "Ideally we would have liked one large unit that supplied each floor, but the supplies and returns would have taken too much space," added Rebecca Welch, project mechanical engineer, Ove Arup.
Center Sheet Metal's work didn't end with heat pumps however. The 20year-old firm had to install a two-cell, 21 0 gpm. Baltimore Air Coil, Baltimore, Md., cooling tower on the roof that's pipe looped to all the building's heat pumps. Additionally, the building's hot water needs are handled with five HydroTherm, Westfield, Mass., 272,000 BTU/mbh boilers. Center also handled the installation of a complex smoke purge system that adheres to New York's stringent fire codes.
While the millions of visitors to the Austrian Cultural Center will subliminally enjoy superb indoor air quality, few will realize the painstaking measures taken by manufacturers, engineers and contractors to design and make the equipment fit.
For more information, contact Dectron Inc., 995 Mansell Road, Suite B, Roswell, GA 30076
Publication date: 05/14/2001