SDP-2 Hochiki Duct Detector Housing including Short PipeThe SDP 2 is a duct probe housing allowing a standard photoelectric smoke detection device, either a conventional detector or an analogue sensor, to be mounted on the outside of an air duct for the purpose of monitoring the air within the duct. Using an aspirating technique, the air within the duct is drawn vai a pipe into the duct probe's housing. This allows constant sampling with a standard. LPCB approved smoke detector, which makes smoke detection