GHT Limited provided MEP design services for this renovation and addition to the Laborers’ International Union of North America (LIUNA) headquarters near the White House. The building remained occupied during the 110,000 SF renovation and the construction of a 60,000 SF addition at the rear corner of the building. The finished facility features two levels of below-grade parking, nine floors of new office space and a custom built penthouse central plant which serves the entire facility. As part of the addition, a glass-enclosed steel staircase was built to connect the sixth through the ninth floors.
During the phased renovation, employees were temporarily moved to a swing space to minimize disruptions and to expedite construction. LIUNA occupies floors six through nine, allowing it to use floors two through five of the building as revenue-generating space available for lease.
The new central plant features two separate chilled water systems, gas fired boilers, evaporative condensing heat rejection, dedicated outside air supply (DOAS) with total heat recovery enthalpy wheel, and an exhaust air tunnel. The majority of this custom equipment was factory-fabricated and field-combined, which cut nearly six weeks from the schedule. By placing the new central plant above the ninth floor of the addition, the design team reclaimed what was the mechanical penthouse above the original building as usable space to extend the new ninth floor across the entirety of the updated building. The ninth floor now serves as a conference center offering breathtaking views of nearby landmarks. It features a new board room, and three multi-purpose rooms with demountable partitions.
The heating, ventilation and cooling, supported by the central plant was designed to be delivered through a Dedicated Outdoor Air System (DOAS) to VAV style terminal units. The plant’s air supply systems deliver dehumidified outside air to new 4-pipe DOAS VAV terminals throughout the building’s mix of private and open offices.
Electrical service to the building was also upgraded from 3,000a to 6,000a to serve the larger facility. A new remote disconnect room minimized the amount of destructive work required to accommodate the expanded footprint. Design was also challenged by an extremely tight electrical room, which required extensive coordination between GHT, the contractor, and the equipment vendors to fit and allow for proper clearance for the new electrical switch boards, panels and support equipment.