Federal Signal 3T22
The Federal Signal 3T22 was an outdoor warning siren made by Federal Signal Corporation (formerly Federal Sign and Signal Corporation) from 1955 through the early 1990s. It has a very recognizable design, having a ten-port rotor (chopper) on the bottom with ten cones (horns) and a 12-port one on top with twelve cones.
History
The Federal Signal 3T22 was designed as dual purpose siren for both civil defense signals and fire alert signals in 1955. Similar to the model 2T22, but with the addition of solenoid operated damper plates on each air intake which when engaged would restrict air flow and mute one end of the siren at a time, producing an alternating hi-lo signal, or both end at the same time creating a pulsed signal in addition to the standard attack wail and steady alert signals. Production ceased in 1990.
Design
The 3T22 came in 10/12 port ratio. It had ten ports and cones on the bottom and twelve ports and cones on the top. It also had a smaller cone on top to reduce rain and other water-related substances such as snow from getting inside. It had two solenoid boxes, one on top, and one on the bottom. There were also two air intake spots: also one on the top and bottom. The siren had a small stand with three legs so it could be mounted on a pole or roof.