The Pentagon Renovation Program (PENREN) is among the largest facility renovation and modernization programs ever accomplished, spanning two decades of planning, design, and construction. Integrating complete structural and building systems renovation with information technology and security improvements, the Program's activities began with the building of the Pentagon Heating and Refrigeration Plant and basement renovations. Subsequently, the effort focused on the above-ground portion of the Pentagon and various support facilities and projects. Work took place in one wedge at a time—a wedge being a one–fifth slice of the building between the centers of two adjacent sides.
From 1991 to 2011—a turbulent time around the world–the nerve center of the nation's military power remained operational 24/7, during all phases of demolition and renovation. PENREN's successes with sustainable construction and delivering a quality product have provided safe, modern, efficient, and flexible spaces for the Department of Defense.