Sellen, ZGF, WSP F+K and the mechanical and electrical contractors— brought in early to assist with design—are all sharing the risk related to the holdback. "We are all on the hook, responsible for performance, which is new to us," says Tom Boysen, project executive for University Mechanical Contractors Inc., Mukilteo, Wash.

Separate from the fee holdback, Sellen plans to share any leftover contingency funds with ZGF and the main subcontractors. In turn, ZGF will share any leftovers with other consultants, proportional to the risk they assumed during the competition.

Abatement and demolition of half of the existing warehouse started in July 2010. Pile-driving for the new building started in January 2011. Originally set for July, the completion date was pushed to September because of unforeseen site conditions, tenant improvements and $1.3 million in additions to scope, including rainwater harvesting, a geothermal system, upgraded lighting, a building management system and other "betterments."

The current total design-build contract cost is $73.6 million, which includes demolition of the rest of the warehouse. The total project cost, including management and inspection, is $75.2 million. The construction cost is $293 per sq ft, which includes the build-out. The cost is about average for prime office space in the region, says GSA.

In addition to the energy-use requirement, all ARRA-funded federal buildings must comply with the Dec. 1, 2008, Guiding Principles for Sustainable New Construction and Major Renovations.

The team plans to supersede the minimum goals. This includes a LEED Gold rather than a LEED Silver rating from the U.S. Green Building Council's Leadership in Energy and Environmental Design program. Based on energy modeling, the team predicts the building will use 20,300 Btu per sq ft per year, which is 40% below ASHRAE 90.1-2007's energy-performance benchmark. If all goes according to plan, the structure will be in the top 1% of energy-efficient buildings in the U.S., says ZGF.

Federal Center South has a cornucopia of features to minimize energy use, including a high-performance facade, optimum orientation and dimensions for daylighting and passive solar heating, and high-efficiency lighting that uses 0.7 watts per sq ft. In addition, the building has an overhead, water-based chilled-beam system of pipes for cooling. It also has a phase-change thermal storage tank—like ice storage—coupled with a ground-loop heat exchanger to capture and reuse otherwise wasted thermal energy.

GSA, Sellen, ZGF and WSP F&K are working out specifics for the measurement, validation and fine-tuning period, which begins in September. One issue they must agree on is how energy-use data ought to be assessed, says ZGF's Stine.

Energy models are based on assumptions about weather, occupancy hours and how the building is going to be used by individual occupants, who may violate assumptions made in the model, explains Stine. For example, the model assumes there will be no electrical-plug loads from individual space heaters or refrigerators.

In reality, while the building operators have been trained in all the systems, "there are variables that we don't control," says Stine. "If [the occupants] operate the building outside the assumptions or if the weather is different, the benchmarks need to be adjusted."

"Operational energy performance is difficult to achieve, despite best efforts," agrees WSP F+K's Corney.

He adds, "GSA has done a good job of setting up a process to transform the market. Any public- or private-sector owner looking at performance should look at this method."

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