Pentagon Renovations Wedges 2–5

Located in Arlington, Virginia, the Pentagon is the headquarters of the United States Department of Defense. Completed in 1943, the facility has expanded significantly over the years, but despite numerous additions and modifications, the Department of Defense had made no major renovations to the structure for over 60 years.

Southland Engineering was awarded a multi-year renovation project for Wedges 2 through 5. The scope included mechanical designs for the more than six million square foot facility.

Approach & Innovations

The low floor-to-ceiling height of the building presented a unique challenge as any system relying on air delivery throughout ducts would be difficult to fit. The design team proposed the use of fan-powered induction units (FPIUs) along with chilled water-cooling coils and an air valve to supply a constant volume of conditioned outdoor air.

Utilizing the system allowed Southland Engineering to meet environmental, energy consumption, and indoor and outdoor ventilation requirements. The use of chilled water piping completely transformed the facility by saving a considerable amount of above-ceiling space and reducing the required amount of mechanical ductwork by almost half. Overall, the design maximizes the use of daylighting, decreases utility costs, and increases indoor air quality and ventilation effectiveness. These combined benefits create an ideal working environment that intensifies overall employee productivity and office morale.

The use of the chilled water piping also created the perfect opportunity to recommend the use of a propress system. By doing so, Southland Engineering was able to eliminate the need for open flames during the construction phase, as well as minimize future piping leaks.


Client: Pentagon Renovation Office

Location: Arlington, Virginia

LEED: Certified

Square Footage: 4,300,000