The FDA221 series of detectors are a very early warning dual wavelength (blue and infrared) smoke detectors designed to protect small business-critical environments up to 500 m². The detector works by continually drawing air into sampling holes in a pipe network. The air is passed into a uniquely designed detection chamber where light scattering technology detects the presence of very small amounts of smoke. The FDA221 detectors can communicate directly on the FDnet/C-NET loops (with an optional FDCC221S communication interface), so there is no need for separate relay or network connections.