News Release 07-18
US Army Corps Of Engineers
August 02, 2007 Immediate

Sherrie Stewart
Telephone: (520) 584-1663
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Thinking Green:  Corps incorporates conservation into new construction on Davis-Monthan AFB

TUCSON, Ariz. -- Beginning with the design and continuing through the finished product, the Army Corps of Engineers incorporated “thinking green” into the new 49,000 square-foot structure near completion on Davis-Monthan Air Force Base in Tucson, Arizona.
  
Constructed by Au Authum Ki, Inc. of Glendale, Ariz., this almost $8.2 million operations building will be the new home of the 48th Combat Search and Rescue Squadron. Design with an emphasis on energy and water savings has been required in all government construction for a decade, but the latest technologies have increased the levels of both comfort and conservation in this new structure.

Energy conservation efforts for this project began with the design and construction of the walls. Standard, staggered course block construction was used for all exterior and some interior walls.

“The contractor filled every third cell of the exterior walls with concrete and steel rebar,” said Brian Childers, Corps Project Engineer at the Tucson Resident Office.

“Formed insulation pellets were poured into any remaining cells. This process created a nearly solid wall construction with an estimated insulation value of R7.”

Atop the walls, the metal roof included a three-inch underlayment of an environmentally-upgraded insulation called “polyisocyanurate.” According to the Polyisocyanurate Manufacturers Association (PIMA), recent developments made this widely-used insulation material compliant to new EPA standards of implementing hydrocarbon-based blowing agents which have zero Ozone Depletion Potential (ODP) and virtually no Global Warming Potential (GWP). Being almost 100 percent recyclable, moisture and heat resistant made this material preferable to the designers.
 
“That brings the insulation factor for the roof to R20,” said William C. Thames Jr., Corps mechanical engineer from the Mobile District office.
 
The Squadron Operations building was constructed with an emphasis on security. Along this vein, only a minimum of windows were installed. The windows were constructed of two panes of tempered glass with a one-half inch air gap between the panes. These stationary windows with exterior bronze tinting to optimize light and heat reflection were designed to enhance the comfort of personnel while conserving energy in this desert environment.
 
A dual cooling system made up of a chiller and evaporative cooler units was installed to provide optimum cooling under contrasting conditions.  Designed to supply energy efficient cooling to enclosed areas, the chiller consists of a tower that cools a contained water flow piped throughout the building over which fans blow recirculated air to cool enclosed areas.  An evaporative cooler was installed to cool the equipment bay due to the necessity for open bay doors in this area of the building. Outside air drawn in over water soaked pads and blown into the open bay adapted well to the cooling needs in this area of the building.

“Systems are computer-controlled through the [energy-management and control system],” said Alton Pitre, HVAC Engineer from the Corps’ Phoenix Area Office. “Over the past few years, the efficiency has increased drastically. Units like the Trane chiller in this building are inherently more energy efficient and the added computer technology improves the capacity for energy savings.”
 
Another area where designers addressed energy savings was lighting.
 
“Electronic ballasts were used on all fluorescent lights,” said Henry Battaglia, Corps Electrical Design Engineer of the Mobile District. “The older type electromagnetic ballasts use more energy and tend to decrease life on fluorescent tubes.”
 
In the equipment bay and other areas such as the aquatic equipment maintenance area, high pressure sodium lamps replaced the original hanging fluorescent fixtures. High pressure sodium (HPS) lamps, a member of the high intensity discharge lamp family, are the most efficient white light source commercially available today.  Developed and introduced in 1968 for industrial  and street light applications Due to their high efficiency and long life, today’s HPS lamps are also suitable for many interior uses.
    
Extreme importance was placed on eliminating any carcinogens and other harmful substances from the construction.
 
“No PCBs were used in this building,” said Mary Matsumura, Construction Representative for the project of the Tucson office. “The remotely-controlled thermostats contain no mercury and no asbestos in either insulation or flooring. In this way, the Corps ensured a safer environment for personnel through incorporating recent, more safety-conscious technologies.”

The Corps incorporated new landscaping and plumbing designs in order to address water conservation. The use of gravel ground cover required no irrigation for landscaping which saves water. In recent years the trend toward rock or desert landscaping indicated a move toward more water-conscious designs.
 
Another area where new technology improved water savings is in the bathrooms for the facility. Heat-sensors were installed to trigger automatic flushing devices on the toilets.

“The automatic flushing toilets are utilized in the design, but use minimal power,” said Battaglia. “The water savings were more substantial than the electrical usage.”
 
These toilets use only 1.1 gallons per flush as compared to a standard 3 gallon flush for older toilets. The heat sensors, also installed on the faucets, meter the use of water in the lavatories. Overall, these new plumbing technologies are estimated to conserve hundreds of gallons of water annually.

Through the Corps’ and contractor’s attention to so many environmentally sensitive and energy or water conservation areas, this new building met the silver standard for governmental construction. By implementing these technologies throughout the new facility, the 48th Squadron will soon enjoy a comfortable working environment.  In this way, the Corps exceeded the basic governmental construction standards, incorporated new, more efficient technologies, and ensured the building’s future functionality.

The Corps of Engineers contributes to the national defense mission by constructing projects on Army and Air Force installations worldwide that improve readiness and enhance the quality of life for military members and their families. Interested parties can learn more about the Los Angeles District at http://www.spl.usace.army.mil