Thanks to today's technology and all parties involved, this pyramid's design and construction didn't require thousands of slaves working for years on end. However, if the design created by E.M. Kado and Associates (Sacramento, CA) did enhance the city's skyline, it also challenged project team members.
Escalating Interests"It steps in as it goes up," recalls Dean Schouweiler, the engineering manager with Airco Mechanical, Inc. (Sacramento), a design-build (D-B) contractor responsible for the project. "So the challenge was getting the air to all the different floors," in addition to the usual requirements of energy efficiency and meeting ASHRAE 62-89 recommendations.
The difference in each ascending floor's area led to a two-pronged ventilation attack. A basement system and two shaft risers served the lower six floors. Schouweiler reports that another air-handling unit on the roof served the top four floors.
A low-temperature system based on 45?F was designed, with outside and return air directed to a large acoustical plenum. Two 421-ton centrifugal chillers from The Trane Company (La Crosse, WI), fans from Greenheck (Schofield, WI), air handlers from Temptrol (Okarche, OK), and pumps from Bell & Gossett (Morton Grove, IL) helped round out the arsenal of equipment.
Throughout, the hvac system also employs several types of Ruskin (Kansas City) dampers. Several serve to help prevent flame spread or smoke migration in case of fire, which is especially important given the building's four-story atrium.
A 3- to 15-sec "controlled closure" feature protects the rest of the hvac system from instantaneous pressure shocks that can sometimes occur in emergency circumstances. Other dampers measure and control airflow for its specific segment of the system. Information is also reported back to the building automation system from Automated Logic (Kennesaw, GA).
Norman Wright Mechanical Equipment Co. (Sacramento) helped complete the design, installation, and commissioning of the hvac and life-safety system.
Closing The DealIt took three years from design to occupation, but Schouweiler reports that the "controls and low-temperature double-duct system have worked well."
There were also problems particular to the unusual design.
"It required quite a plumbing job," says Schouweiler. "There's also 11 roofs you have to drain."
However, on the hvac side, Schouweiler says the unique setup has been matched only by unqualified satisfaction. "The building has 400,000 sq ft, but we've had fewer complaints on this building than any other."ES