This mission critical project created new data center space by adding a second floor and air handler penthouses to an existing building on an active operations center campus. The 48,600 square-foot, state-of-the-art data center features air handler-fed underfloor cooling (a regional first for a data center), 36-inch raised access floor, and infrastructure to support 156 watts/square foot of in-place critical load. Another unique item to the project was a unique UPS electrical architecture, which allows the owner to maintain uptime performance while conducting facilities maintenance. The new facility also required the addition of a 32,000-square-foot, cast-in-place, two-story central plant building with 3,750 tons of chilled water capacity, seven service entrance sections, chilled and condenser water storage, 60,000 gallons of underground diesel fuel storage, seven 2,000 kW generators and nine 750 kVA UPS modules. The facility was constructed in just eleven months.