The Museum built a special conservation laboratory to accommodate the large flag laid out flat. Museum visitors can observe the conservation process through a 50-foot (15.2-m)-long glass wall. A moveable bridge (gantry) gives the conservation team a working surface above the flag. The lab is equipped with its own heating, ventilation, and air conditioning system (HVAC) that keeps the air free of contaminants and maintains a steady, beneficial temperature and relative humidity. Low light levels are also maintained to minimize damage to the flag.  A movable bridge, or gantry, suspended about 3 to 4 inches (7-10 cm) above the flag permits easy access for examination and treatment. It can safely hold seven people at one time.  The tables and rolling tube are used to support and move the flag. The tables are modified stages topped with a chemical-resistant surface. The tube allows the flag to be moved or turned over safely.  To protect the flag in case of fire, the conservation lab is equipped with a special gaseous fire-extinguishing system.  The lab is equipped with its own heating, ventilation, and air-conditioning system (HVAC) that keeps the air free of contaminants and maintains a steady, beneficial temperature and relative humidity. The conservators must monitor this daily.  The support lab provides space and equipment for the conservation team to conduct tests, analyze findings, and document the work done on the flag.  Back to top Diagram of the Star-Spangled Banner conservation laboratory. National Museum of American History, Smithsonian Institution