Airborne radioactivity area
A room, enclosure, or area in which airborne radioactive materials, composed wholly or partly of licensed material, exist. It exists in concentrations that (1) Exceed the derived air concentration limits or (2) Would result in an individual present in the area without respiratory protection exceeding, during the hours the individual is present in the area, 0.6 percent of the annual limit on intake or 12 derived air concentration-hours.