Aspirated smoke detector systems are based on the application of nephelometers which enable the early detection of minuscule particles of smoke that hang in the air. This is made possible through the detection of scattered light from the combustion particles in the sample compartment. Aspirated means drawn in. It is exactly how the aspirated smoke detector systems operate. Smoke is drawn in to a chamber where the light scattered from particles will be detected and the alarm set. A fan is required to draw air into the sample chamber or compartment. VESDA is a brand of aspirated smoke detector systems and is available from IDTek. Early warnings of smoke ensure that buildings can be evacuated in time and that valuable equipment can be saved.