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May 2, 2013

Eagle of Merit Award • Specialty Construction

Photo courtesy of NW Wind & Solar [enlarge]
Solar panels extend up to 20 feet from the roof edge of Bullitt Center.

The Bullitt Center

NW Wind & Solar

General contractor: Schuchart Corp.

Architect: Miller Hull Partnership

Engineer: DCI Engineers

Owner: The Bullitt Foundation

ABC members: Star Rentals; Tradesmen International

The Bullitt Center is the greenest commercial building in the world due, in part, to the work of NW Wind & Solar. This challenging project earned the company the first-ever Eagle of Merit Award given to a subcontractor. NW Wind & Solar also won in the Specialty Construction category.

The Bullitt Foundation, which owns the building on the edge of Capitol Hill, has for years devoted its resources to protecting and restoring the Pacific Northwest environment.

The Bullitt Center will be certified a Living Building — the world’s most strenuous benchmark for sustainability — by the International Living Building Institute. This means that it must be self-sufficient for energy and water for at least 12 continuous months and meet rigorous standards for green materials and for the quality of its indoor environment.

NW Wind & Solar created and installed the “brains” of this remarkable building — its massive 14,300-square-foot photovoltaic roof that is expected to produce an estimated 230,000 kilowatt-hours of electricity a year, plenty to cover its needs.

The roof is comprised of 475 SunPower 425-watt solar modules (with a 244-kilowatt/DC system rating) that extend via cantilevers 20 feet beyond the roof’s edge. The additional space was needed to provide for the proper number of photovoltaic cells. The design also required a detailed safety and fall protection plan since the extended cells needed to be installed six stories over the sidewalk.

A project like this had never been built before, and it meant that NW Wind & Solar would have to solve the problem of longer-than-usual solar racking rails for installing the panels. Typical rails for solar projects are less than 6 feet in length, but this photovoltaic roof was going to need rails at least 10 feet long. The company was able to find 10.5-foot rails that allowed the solar panels to be installed lengthwise and parallel on the racking rail.

The next challenge involved determining how to attach the racking rails to the steel superstructure. Because components expand and contract with heat, racking attachments could not be static or else the connections would not line up, so the construction team came up with the idea of saddles with machine bolts that provide the necessary flexibility.

The Bullitt Center’s grand opening was, appropriately, on Earth Day this year. Said Denis Hayes, president of the Bullitt Foundation, “You can be exceedingly environmental without eating granola and living in a yurt. This is a highly productive building.”

One of the major safety challenges in this project was that the solar array extends up to 20 feet beyond the building’s walls at six stories high. That along with the complex nature of the roof structure and superstructure required a highly detailed, site-specific safety plan and fall protection work plan. There were no time-loss injuries in the 3,119 labor hours worked on this job.

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