The National Agricultural Library building requires repairs to its envelope, focusing on air infiltration and shaft sealing work. The project involves sealing intake housing, existing pedestrian doors, and utility air shafts, as well as replacing coiling doors with insulated, airtight doors. The contractor will be responsible for field verification and design adjustments if dimensions differ from the drawings. The building will remain occupied during construction, and the contractor must work around the occupants. The project duration is estimated to be 90 days. • The contractor must seal all gaps and penetrations along the perimeter of the walls on multiple floors. • The contractor must replace existing coiling doors with insulated, airtight coiling doors. • The contractor must provide a phasing plan for evaluation. • The contractor must work around the building occupants and adhere to the specified working hours.