Renovation and upgrades of approximately 47,000 square feet of office and support areas at Federal Aviation Administration Air Route Traffic Control Centers in Atlanta, Georgia and in Ohio. Work included replacing live mechanical systems, DSR equipment and curtain walls while air traffic operations remained active, installing a new curtain wall and elevator, interior demolition and rebuild, and architectural, HVAC, masonry, security and IT improvements. Systems were upgraded using redundant infrastructure and carefully sequenced changeovers to avoid disruption in these high-security facilities.