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Best Practice Guide |
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Commercial Office Buildings |
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Case StudyNatural Resources Defense CouncilProperty Name: Robert Redford Building Website: NRDC main www.nrdc.org and Green Offices page www.nrdc.org/cities/building/foffice
When it was time for the Natural Resources Defense Council to relocate its Southern California office, staff decided to invest in a real-life demonstration of sustainable design. Lead architect Elizabeth Moule, Moule & Polyzoides Architects and Urbanists, choose to renovate a 1917 building in Santa Monica, locating the office in a densely populated urban center that is easy to reach by walking, biking, or riding public transit. Named after the actor and environmentalist Robert Redford, the NRDC Southern California Headquarters features innovations in energy and water use efficiency. With the ocean only 100 yards away, the building takes advantage of ample breezes to provide cooling and ventilation. Windows are thoughtfully placed and fully operable, with additional clerestories and rooftop vents that allow heat to rise and escape from the interior spaces. To lower indoor temperatures and reduce urban heat island effect, the rooftop is coated with a liquid rubber polymeric membrane, also referred to as a "cool roof." The cool roof has a 95 percent emissitivity rating, meaning that almost all solar radiation is reflected. Air conditioning is provided by a high-efficiency, multi-staged, low-velocity displacement system that directs cool air only where it is needed. Heat is provided via radiators connected to the building's tankless, on-demand hot water system. Each office has a personal thermostat that lets staff adjust heating and cooling according to individual preference. However, when someone opens a window, automatic sensors shut off any climate control equipment in operation.
To protect indoor air quality, CO2 sensors provide an early warning whenever more ventilation is needed. A warning light reminds staff to open windows, allowing fresh air to circulate. Routine buildings operations are similarly accounted for in the design; for example, the copy room has negative pressure to flush toxins out of the building.
The design consciously capitalizes on the natural light provided through windows, light wells, interior clerestories, and architectural glass. These openings provide staff with outside views and access to outdoor terraces. High efficiency T8 and T5 fluorescent fixtures with electronic dimmable ballasts supplement the daylighting design, and are controlled by both occupancy and photo-sensors. Even the LED exit signs were chosen to reflect NRDC's values. By reducing the artificial lighting system and air conditioning system, NRDC has been able to lower utility costs by about 44 percent over comparable buildings built to meet California's strict Title 24 energy standards. This has helped NRDC meet is goals for net-zero carbon dioxide emissions and 100 percent renewable energy. A 7.5 kW photovoltaic system on the rooftop provides 20 percent of the building's energy need; the rest is purchased through renewable energy credits for wind generation.
NRDC's achievements in energy efficiency are only outmatched by their innovations in water use efficiency. Rainwater is collected in two 1000-gallon cisterns. One is used for watering garden plants around the ground level as well as on rooftop terraces. The other cistern is used, along with a separate graywater collection system, for flushing toilets. Bathrooms are equipped with low-flow fixtures: dual flush toilets, low-flow faucets and showerheads, and waterless urinals. The dishwasher in the staff kitchen is a low-water-use model. All together, these features reduce consumption of potable water by 60 percent. This $5.1 million project was financed through funds raised in a capital campaign. Because of their achievement, NRDC was awarded LEED-NC Platinum certification (Version 2.0) -- the third building in the country to receive this green building distinction. |