Photo courtesy of Air Systems Engineering
A 265-ton hydraulic crane was used to lift new cooling units to the roof of TrueBlue's headquarters.

TrueBlue cooling towers
Air Systems Engineering

Structural engineer: PCS Structural Solutions
Mechanical, electrical design: Air Systems Engineering
Owner: TrueBlue Inc.

TrueBlue's headquarters is in the old Weyerhaeuser building built in 1910 in downtown Tacoma. The 184,000-square-foot office building houses more than 400 occupants.

The building's HVAC system had 1978-vintage cooling units nearing the end of their life. The system is a water-source heat pump with more than 190 heat pump units in the 12-story structure. A key part of the system is the cooling towers that reject the heat from the water loop.

TrueBlue budgeted for the replacement of the towers in 2011 and Air Systems Engineering began the design process in August 2011, with the tower replacement scheduled for Dec. 3. In addition, the tower support structure had failed so Air Systems had a new support frame prefabricated in its shop to minimize site construction and welding.

Using a 265-ton hydraulic crane provided by Magnum Crane was a major factor in the project, both in function and cost. Operations such as removing old parts, installing new components, and lifting tools and supplies were carefully coordinated to minimize crane down time. Two semi-trucks took three separate loads to the steel recycler and made seven trips with new tower parts from Air Systems' shop to the site.

Air Systems also created a complete safety and traffic mitigation plan, resulting in no time-loss accidents in nearly 863 hours worked by Air Systems and the subcontractors.

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