In ceiling-mounted installations fans and filtration equipment are mounted at intervals overhead.This system has been installed by CTA in Norway's Hell Tunnel (Trondheim), Nygårdstunnel (Bergen) and Strømsåstunnel (Drammen).
The above illustration shows the principle of a ceiling-mounted installation.
Advantages of Ceiling-mounted compared to Bypass:
Lower construction cost
In the event of fire, exceptionally large heat and smoke evacuation capacity