High Performing Buildings - Spring 2008 - (Page 8) Form and Function The 200,000 Seattle City Hall houses offices of the mayor, city council and related departments, the council chambers, media studios and archive, retail and ft2 gallery spaces, and venues for public gathering. With views of Puget Sound and the Olympic Mountains, the building rises from the top of a hill between 4th and 5th avenues and overlooks the civic plaza, built in the footprint of the old building. The phased design allowed the existing municipal building to remain on the site while the new building was under construction less than 10 ft away. P E R C E P T I O N S A N D E VA L U AT I O N S The dedication of Seattle City Hall’s civic plaza, marking the completion of the second and final phase of the building’s construction, was met with controversy regarding the new building’s energy consumption. Energy use was found to be higher than originally predicted for this new symbol of the city’s pursuit of sustainable design. The local press took up the story, setting off a flurry of criticism and rebuttal. In the end, the data may have been gathered prematurely or may not have been suitable for the conclusions drawn. However, everyone involved learned valuable lessons from this experience. A new study is now underway (expected for release later this year), but the city is being careful not to release information until the report is complete. Initial Data Initial energy data, gathered from 2003 through 2005, for Seattle City Hall shows a total annual use of 87,231 Btu/ft2 at an annual cost of $234,517. This is all the data that is currently available until the city’s report is complete. 41% Natural Gas (35,765 Btu/ft2 per year) 59% Electricity (51,466 Btu/ft2 per year) 25% Air Conditioning/Fans/Pumps 16% Lighting 10% Plug Load 2% 6% Elevators Special Use (Security, Television Station, Water Features) Influences The collection period was the first two years of the new building’s operation. During this time part of the lower levels, the entire plaza and the western extensions of the building were still under construction. The building was still in its shakedown period with many operational issues unresolved. These included construction problems with the underfloor air-distribution system, such as faulty diffusers and leaks at shaft connections and between zones. Additionally, in response to user complaints, the DDC system had been reprogrammed and temperature setpoints reset without consideration of the intended operation or building systems as a whole. New technology involved in sustainable design often requires new operations and maintenance procedures, and a more complete understanding of the design parameters of the building. Sustainable design can also change how occupants experience the building. Lower footcandle indirect lighting, for example, while improving energy conservation and glare, creates a different interior ambiance and requires supplemental task lighting which was not initially purchased by the city. Additionally, an underfloor air-distribution system requires users to understand a little about its operation. Not surprisingly, when feedback was solicited from the city’s staff in an initial survey during this period, staff found the building only marginally better than its predecessor. Comparing Old and New When the energy data from the new Seattle City Hall was released, it was seen by some as proof that the city’s visible push towards sustainability was ill-founded. The local press took up the story and declared that the new building, using a full 18% more energy than the old municipal building, was an “energy hog.” A direct comparison of the old and new city hall is difficult to make because of the significant differences between the two buildings. Their programs were quite different. The municipal building, adapted from a design originally developed for a motel in Texas, had few public spaces and no civic stature. This is one reason the building was replaced. In addition to conditioning large spaces, the new city hall is open for extended hours on weekends and outside of the normal workday. The building’s post 9/11 security measures require more cooling and a large separate uninterruptible power supply. Furthermore, the current building codes require significantly more HVAC than the old building with as much as three to five times the amount of fresh air intake. The data for the old municipal building contained significant shortcomings that exaggerated the differences between the two. The municipal building was partially empty during the data collection period: lights were off on three floors. The municipal building was also heated by a steam plant shared with the adjacent public safety building which was not included in its overall energy calculation. Quantifying Success The collection of building performance data is a complex exercise that considers many disparate factors. When the data is gathered, its timing relative to the building’s construction, the final adjustments required and their continued maintenance can affect the data considerably. At Seattle City Hall, the initial energy report was useful for the finetuning of initial problems and for user awareness. The city’s new energy study will allow for further improvements of the building’s operation. Just as sustainability considers more than reduction in a building’s energy bills, quantifying the success of a building is more than quantifying its energy performance. Building program size and the way in which it is used must, in the case of a civic building, be factored in along with its value to the community. Seattle is proud of its new city hall and committed to sustainability and environmental stewardship. The building is well used and its environmentally conscious features contribute to an overall building that is sustainable. According to this data, the energy use is higher than predicted. However, the information is not indicative of the optimum performance of the building as designed. Several reasons exist for this. 8 HIGH PERFORMING BUILDINGS Spring 2008
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