High Performing Buildings - Winter 2008 - (Page 44)

visible light transmission. Daylighting performance improved, and the glassto-ﬂoor ratio fell below typical sidelit solutions. The white single-ply rooﬁng further reduced daylighting glass areas by increasing reﬂected light into the clerestory areas of the classrooms on the north side. The underﬂoor air-distribution system reduced the ceiling cavity by 2 ft to 3 ft. This minimized high-end ﬁnishes on the exterior of the ceiling cavity spaces and eliminated several masonry courses. The underﬂoor strategy also eliminated scaffolding costs while easing the installation and coordination problems associated with overhead ductwork, plumbing, electrical, and control wiring. The single sloped ceiling improves reﬂectance back into the space and eliminated the roof monitor well cavity. Through the incorporation of an optimally sized daylighting strategy, the cooling peak loads are signiﬁcantly less and chiller capacity is reduced. By implementing indirect lighting, the ceiling cavity was reduced 6 in. to 8 in. The simpliﬁed construction framing of the roof assembly resulted in material and installation cost savings. Another innovative daylighting strategy used in the classrooms is an interior dropped sofﬁt that is situated to intentionally shade the projection R A I N W AT E R H A R V E S T I N G Both schools incorporate extensive rainwater harvesting that is used primarily for toilet and urinal ﬂushing. Reedy Fork uses a 45,000 gallon underground tank to save 750,000 gallons annually, 94% of the school’s nonpotable water demand. for toilet flushing at the middle school and high school and saves over 4 million gallons of potable water annually. Given that no city water is at the site, the bottom half of the tank is kept in reserve for firefighting. From the toilets, the waste water from both the high school and middle school is directed At Northern Guilford Middle School, the rainwato a plant-based treatment strategy that ter harvesting is only the beginning of a more cleanses 30,000 gallons of wastewater per day. holistic water cycle approach. The school’s The treatment plant, called a Living Machine® , sustainable cycle of water use is a unique uses a hybrid horizontal flow wetland (HFW) and feature and a lesson for the students in ecology. Rainwater is collected from the roof areas tidal flow wetland (TFW) system to treat up to 5 of the middle school and adjacent high school million gallons of water annually. The HFW is an outdoor surface treatment area that removes and stored in a centrally located 360,000 TSS (total suspended solids), BOD (biochemical gallon concrete cistern, the top of which also serves as a basketball court. The water stored oxygen demand) and denitrifies the wastewater. The TFW is also outdoors and is partially in the top half of the tank is used primarily underground. It consists of three cells that act in much the same way as a tidal wetland and is used to address nitrogen levels. The water that comes out of the Living Machine® is distributed to a subsurface irrigation system (that in itself requires 40% less water than conventional sprinkler systems) to irrigate ball fields at both the high school and middle school. The water strategy saves over 9 million gallons of water per year and, after borrowing the water twice, allows the water to seep into the aquifer below. Not only is 90% of the water demand at Northern Guilford met through this sustainable strategy, but more than 5.7 million gallons of water are exported to the adjacent high school. The environmentally sound, on-site treatment strategy costs less than other pretreatment strategies and helps to reduce the amount of nitrogen entering the watershed. It was pursued originally because no central sewer line existed within miles of the site and the cost of extending the city waste lines would have exceeded $4 million. 44 HIGH PERFORMING BUILDINGS Winter 2008

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High Performance Buildings - Winter 2008 Passing On the Gift: Heifer International Headquarters Head of the Class: University of Florida’s Rinker Hall How Far Can You Go? Pearl River Tower The Proof Is Performance: How Does 4 Times Square Measure Up? Lighting the Way: Two Guilford County Schools Montreal’s Retail Example: Mountain Equipment Co-op® (MEC)

High Performing Buildings - Winter 2008

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