On the south side of Colorado Springs, Colo., at the Fort Carson Army post, two sustainable construction projects are taking shape. The first project involves the design and construction of six Company Operations Facility (COF) buildings. Totaling approximately 400,000 square feet and costing $57 million, the COFs will house company administrative and storage operations for unit personnel and their equipment. The six buildings will accommodate 32 separate army companies ranging in size from 100 to 150 soldiers per company. The second project features the design and construction of six Tactical Equipment Maintenance Facility (TEMF) buildings to maintain and repair military vehicles and tactical equipment. The TEMFs, totaling approximately 220,000 square feet and costing $55 million, are companion buildings to COFs and are located in close proximity to them.

These facilities are being built for Fort Carson by the U.S. Army Corps of Engineers (USACE) as part of a new Heavy Brigade Combat Team (BCT-H) complex under the Base Realignment and Closure (BRAC) program. The BCT-H complex will serve as the new home for more than 3,000 soldiers from the Army’s 4th Infantry Division relocating from Fort Hood, Texas, after they return from a tour in the Middle East.

In addition to the USACE, the project teams also include Fort Carson personnel, M.A. Mortenson as the design-build contractor, RK Mechanical and AMI Mechanical, Riviera Electric, and the Minneapolis office of LEO A DALY, an international architecture, planning, engineering, interior design and program management firm.

The two projects feature a number of sustainable design elements designed to meet Leadership in Energy and Environmental Design (LEED) Silver certification requirements as set forth by the U. S. Green Building Council (USGBC). The project team utilized numerous strategies to improve the site, manage runoff, reduce energy consumption and water use, maximize indoor air quality, and minimize the impact of the buildings on the environment.

Preparing the Groundwork

The USACE carried out the site selection, master planning and site design of the BCT-H Complex, including roads, storm water management and utility infrastructure. To achieve its sustainability goals, the Corps assumed responsibility for achieving nine LEED points through site development and design.

As such, the Corps’ designers undertook several initiatives during the planning phase to meet LEED Silver certification for the overall project, and for each building. The projects are located on a former brown field site used for many years to incinerate excess munitions propellant. Tests were conducted to determine the extent of contamination and remediation activities that took place over a period of several years to clean up the site and allow for this eventual development.

The COF and TEMF buildings comprise what have formerly been known in the Army as motor pools. As such, much of the area around the buildings is required to be hard paved to accommodate military and personal vehicles. The Corps investigated green pavements that would allow infiltration and filtering of precipitation, but found them incapable of withstanding the extreme loading conditions of today’s tactical military vehicles. Consequently, a concrete pavement was required. To effectively manage the increase in runoff, the Corps developed two separate drainage areas that feed into detention basins to reduce peak flows and improve the storm water quality. As a result, peak flow for the 162-acre site was reduced from 338 cubic feet per second to 106 cubic feet per second.

Additional sustainable site measures were used to achieve LEED points, including: using drought tolerant native plants and grasses for site restoration, preferred parking spots dedicated for carpoolers and low-emitting or fuel efficient vehicles, multiple bus stops within a quarter mile of the site, community connectivity through close access to residential, work and community facilities, and encouragement of bicycling by providing secure bike racks and shower facilities at the COFs and TEMFs.

Energy Conservation

The project team used an integrated and comprehensive design approach to maximize energy conservation within the constraints of the total project budget. Specifically, the team focused on three major areas:

• Energy-saving mechanical systems
• Energy-efficient lighting fixtures and controls
• Enhanced building envelope performance

To quantify the results of these strategies, the team relied extensively on energy modeling. An energy model was developed for each building using Trane Trace software with numerous inputs such as building envelope materials and insulation values, project location, elevation and orientation, hours of operation, and detailed lighting, HVAC and system controls data. These models were then compared against a standard baseline model to calculate improvement in energy cost savings. Based on the modeling results, a number of design strategies were chosen to achieve a minimum of 30 percent savings over the ASHRAE 90.1-2004 standard base model.

The LEED points awarded by the USGBC for increased energy savings over the base model vary from six points at 28 percent savings, seven points at 31.5 percent and eight points at 35 percent savings. The energy savings for the different COF and TEMF buildings range from 30.5 percent to 36.6 percent.

“The most effective way to achieve energy savings is through the selection of proper mechanical equipment,” said Phil Vogel, LEO A DALY’s project manager.

To that end, roof top units with a total enthalpy wheel heat recovery system were specified for each building. These units utilize warm exhaust air to preheat the incoming outside air, thus saving heating energy – an effective approach in the Colorado climate. Make-up air units with return air capability increase ventilation rates, while cooling pumps and supply and return air fans with variable frequency drives save energy during times of reduced load and provide enhanced flow and thermal comfort control. Low-NOx, low-mass, high-efficiency pulse boilers with modulated burners are used for heating, further minimizing energy consumption and emissions. Low-NOx water heaters were also specified.

In developing the building enclosures, the design-build team tried to balance the need for energy efficiency with functionality, durability and the desire to create attractive buildings that could be built within the constraints of Mortenson’s guaranteed maximum price.

“As architects, we continually strive to design buildings that not only meet programmatic and functional requirements, but also go beyond these basic needs to be appealing in the way they relate to their site, one another, and the greater context of the built and natural environment in which they are located,” said Vogel. “Designing for sustainability and LEED certification adds another level of complexity to that challenge.”

Load bearing, insulated precast concrete walls were selected as a primary element of the building enclosure early in the design process. The precast, in addition to being economical and durable, provided the design team flexibility in determining quantity, height and size of wall openings for both facility types, which in turn enabled greater use of daylighting. At the COFs, high clerestory windows with insulated translucent panels were incorporated to provide diffuse daylight along the central corridor and into the innermost areas of the facility. At the TEMFs, oversized openings in the walls are provided for overhead doors with the openings in-filled with translucent panels above the doors. Translucent skylights also bring natural light deep into the TEMF buildings, minimizing the need for artificial lights on bright days.

Additionally, photocells are used in both facilities to control lighting of the main corridors and vestibules and to control exterior lighting for dusk to dawn operation. Fluorescent light fixtures with T8 or compact fluorescent lamps (CFLs) are used in all areas of the building. Both facilities are also designed with occupancy and ambient daylight sensors. These lighting strategies are expected to save approximately 650,000 Kilowatt-Hours per year.

The COF buildings are designed with both flat and sloped roofs while the TEMF roofs are flat only. Sloped roofs are covered with long-lasting standing seam metal while flat roofs are covered with white TPO membrane to reduce roof heat-island effects. Roofs are insulated to R25 on COFs and R33 on TEMFs, helping to minimize heating and cooling costs. Other energy saving strategies include low-E insulating glass in thermally-broken aluminum frames, insulated exterior doors, and vestibules.

Combined, the energy saving strategies employed on these projects will yield an anticipated cost savings of more than $135,000 each year for the COFs and approximately $180,000 each year for the TEMFs.

Additional Steps

The project team also designed sustainable elements to reduce consumption. About 20 to 30 percent of potable water is conserved by eliminating exterior irrigation and by using waterless urinals and low flow plumbing fixtures. Water closets and lavatories are hardwired with automatic sensors that are programmed to manage water flow.

Integrated Approach

Close coordination from the onset of the project between the Army Corps of Engineers, Fort Carson personnel, and M.A. Mortenson's design-build team including LEO A DALY has been pivotal to the success of the design process and to achieving LEED goals for these facilities. With a tight budget, the team often had to balance the competing goals of holding down material and equipment costs while meeting the project’s sustainability requirements.

The project team worked collaboratively to tackle the challenges on each sustainable element of the project. Weekly team meetings were scheduled to evaluate design progress, including discussions on equipment selection and costs, energy-savings, and LEED credits associated with each design strategy. This integrated, tight-knit approach has been crucial to the project’s success to date.  

Facility Overview

Company Operations Facility And Tactical Equipment Maintenance Buildings

Location: Fort Carson, Colo.
Size: COFs (Six) - 400,000 Square Feet Total, TEMFs (Six) - 220,000 Square Feet Total
Cost: COFs - $57,000,000, TEMFs - $55,000,000
Scheduled For Occupancy: COFs – September 2008, TEMFs – October 2008 and February 2009
LEED: Silver Registered

Project Team

Owner: U.S. Army Corps of Engineers
Design-Build Contractor: M.A. Mortenson
Architect: LEO A DALY
Mechanical Contractor: RK Mechanical
Electical Contractor: Riviera Electric
Civil Engineer: PBS&J
Acoustic Design: Kvernstoen Kehl & Associates

Green Products

Roof-Top Unit: Aaon
Boiler: Fulton
Water Heater: State Commercial Water Heaters
Make Up Air Unit (TEMFs): Haakon
Make Up Air Unit (COFs): Reznor
Waterless Urinal: Falcon
Water Closet (Sensor Operated): Kohler
Lavatory (Sensor Operated): Sloan
Shower: Bricor  
Mechanical Equipment Controls: Wattmaster Controls, E3ms, And Long