Ahtna Engineering Services LLC (AES) replaced four large HVAC packaged units on the roof of the main terminal building at PDX that supplied heating and cooling to the FAA TRACON Facility on the third floor of the airport terminal. Our scope of work included engineering design of new equipment mounts and seismic evaluations, demolition of four existing units, installation of four new units, new power supply, installation and programming of new controls, cleaning of existing ductwork and air distribution system, and test and balancing. We used a large crane (total reach of boom: 275 feet) on the active airfield (terminal aircraft ramps) twice to hoist down demolished equipment, and to hoist up new equipment to the rooftop of the main terminal building. AES oversaw structural design work and seismic evaluation for setting and mounting the large packaged air conditioners on the rooftop of the main Portland International Airport Terminal Building. The 100% design effort included evaluation of alignment/locations and load calculations of these large (12.5-ton and 20-ton units) packaged units on roof structures, and design of seismic mounts/footings to meet new seismic load requirements. We completed the design work in three phases. The design package was reviewed and approved by the FAA, Port of Portland, and City of Portland. AES provided innovative tower designs to reduce fall hazards and liability associated with roof-mounted antennas. The design utilized existing infrastructure where possible to reduce construction costs. We provided corporate engineering packages including specifications, drawings, structural and electrical calculations, risk mitigation plans, and cost estimates for site preparation work. Ahtna removed two existing rooftop 12.5-ton HVAC packaged units with new ductwork (Phase I), and two existing 25-ton HVAC packaged units with new ductwork. We then installed two new 12.5-ton and two new 25-ton units, as well as new controls. Power was connected to new units, new thermostat controls (low voltage) were installed to new units, and we wired new smoke detectors in ducting to thermostat control.
Federal Aviation Administration