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By Nancy B. Solomon, AIA

The facility consists of eight residential wings, one administrative wing, and a two-story connecting spine containing various communal functions. Cooling throughout the facility depends on the careful orchestration of various elements, including concrete structural systems for thermal mass, generous floor-to-ceiling heights, well-conceived window designs and placements, high-performance glazing, and appropriate shading devices.

 

Boulder Community Foothills Hospital, Boulder, Colorado Boulder Associates and Oz Architecture minimized the amount of water needed for exterior use, in large part by specifying plantings that are native to Colorado (above) and other semiarid regions. Photography: © Sergio Ballivian Photography

The team did not eschew all mechanical systems: The building, for example, is heated with a two-pipe hydronic baseboard system and has a minimal ducted mechanical ventilation system to meet basic health standards. Feeding building geometries, solar angles, actual daily temperatures, and other data into a thermal modeling program, the mechanical engineers painstakingly demonstrated, room-by-room, that the temperature would not exceed the WAC threshold. Both the client and design team clearly had faith in their strategies, as the construction-document phase was 90 percent complete, early site work had begun, and key components were being bid out when the natural ventilation exemption was finally granted by the Washington Department of Social and Health Services.

According to Carl R. Tully, AIA, senior associate at NBBJ, the additional up-front costs associated with the design and construction of this passive cooling system are partly offset by the reduction in mechanical equipment. He estimates that the remaining costs will be paid back by operational savings in eight to 10 years. Scheduled for completion in January 2005, the 170,000-square-foot, 240-bed skilled nursing facility is aiming for LEED certification at the silver level.