Aspirating smoke detection (ASD) is a method of smoke detection where the air from
the protected area is actively drawn through a network of sampling pipes, passed
through a central detection unit and sampled for the presence of smoke.
Based on the forward light scatter principle, the unit directs a powerful semiconductor
laser through an aperture in a specially designed reflector. Any combustion products
present in the moving air sample scatter light on the reflector from where it is focused
on a single photo‑receiver.
There are seven main drivers or opportnities for ASD:
Where very early warning is required
Where high air flow (air conditioning) is present
Where environment is hostile (very cold, very hot, wet or dusty)
Where detection is to be covert (unseen)
Where building height will cause smoke stratification
Where coincidence detection is required for extinguishant release
Where access for maintenanve is impractile
