How are UV lamps used to disinfect the air?
Germicidal UV lamps can be used in ceiling fixtures suspended above the people in a room or within air ducts of recirculating systems. The first method is called Upper Air Irradiation. The fixtures are shielded on the bottom so that the radiation is directed only up toward the ceiling and out the sides. These fixtures are mounted at least 7ft. above the floor so that people will not bump into them or look directly at the lamps. The second method of air disinfection uses UV lamps placed inside the ventilation system ducts. If a ceiling is too low for an upper-air irradiation fixture, this type can be used. Also, because people are not exposed to the UV radiation, very high levels can be used inside the ducts.
