Over the years, the building underwent several renovations, during which the ventilation system was carefully preserved. This 1987 memo, which once hung in the machine room on the first floor of Building 7, reminded maintenance personnel to treat the old vents gently
The complicated ventilation system in Building 7 was designed specifically to protect researchers from the disease agents they studied. Air pressure was controlled so that the laboratories were kept under high pressure, and the “hoods” in which researchers worked with infectious organisms had vents which provided the only outlet. Air would therefore flow only from the room into the hoods, and never the other way. Air entering the hoods was then propelled through metal grids heated to high temperatures to kill any infectious organisms present before being released to the outside of the building. The building was also called the “Memorial Building” in honor of the many NIH researchers who died while investigating diseases.