11500 C Street

Designing and constructing 11500 C Street to LEED standards helps lessen this 40,900 gross square foot, two-story commercial office building’s carbon footprint in Anchorage, Alaska. Energy savings is fundamentally important in Anchorage as temperatures average 10 degrees Fahrenheit in the winter and 60 degrees in the summer, yielding 10,570 annual heating degree days and zero cooling degree days. Window placement and use of overhangs become another energy saving design tool when responding to Anchorage’s extreme sun angles, which vary from 5.5 degrees in the winter to 52.5 degrees in the summer. Although electricity in South Central Alaska is not as expensive as it is in rural Alaska, Anchorage commercial building tenants still pay over 14 cents per kilowatt-hour; any reduction on electrical use positively impacts the life cycle cost of the building. Another initial cost being offset with long-term energy savings is the additional seismic requirements met by the structural frame. Seismic Zones 1-5 occur throughout Anchorage’s geographic footprint, with this project located in Zone 2 under seismic design category D. Large isolated spread footings support the main steel structure that, for both aesthetic and functional reasons. This all-steel structural frame, paired with a metal-panel building skin, provided the majority of the 32.33% recycled content in the Materials and Resource category. The use of certified wood achieved yet another credit. All doors and wood stair treads were sustainably harvested and certified by the Forest Stewardship Council (FSC). Inside this Class A office building, air quality and controllability of systems were prioritized to achieve tenant comfort, which translates to stable occupancy for the owner. Individual thermostats and lighting controls were installed in all offices. Daylighting sensors respond to natural light, while motion sensors use infrared technology to help conserve electricity. Dual flush toilets, high efficiency urinals and low-flow faucets and showers reduce building water use by 41.45 percent and provide cost savings for long-term operations. Low Volatile Organic Compound (VOC) paints, adhesives and sealants were used to prevent any harmful off-gassing, and smoking is not allowed within twenty-five feet of any entrance. The project yields 24.5 percent energy savings through the use of heat recovery, outside air cooling and a continuously insulated building envelope. Enhanced Commissioning upon construction completion required weekly meetings, where building systems installation and setup were highly documented to ensure that the correct sequence of operations were in place and could continue throughout the life of the building.