Impulse Ventilation fans (also known as Jet fans) are typically installed within enclosed carparks where sufficient access to the open air is not possible. Generally the carparks they are installed in have low ceiling heights or significant beam obstructions, which do not lend themselves to a typical ducted ventilation system. Jet fan housings are generally installed directly onto the car park ceiling. The jet fans provide air at a velocity to provide momentum to produce air movement towards an exhaust point. The jet fans are located in strategic positions within the car park, and usually in the centre of a drive lane, to push air towards the exhaust points.
Jet fans can adversely affect the operation/effectiveness of installed fire safety systems, which is why it’s important you are up to date with the latest standard requirements of AS1670.1 and AS1668. VESDA systems having been successfully installed in car parks for general fire detection, and having been integrated with smoke management systems in numerous applications are suitable to provide this alarm signal for timely jet fan shutdown.
Each car park design and jet fan system layout is different which may result in different airflow patterns. Specific analysis for each cark park design must be undertaken. Please see attached some additional information for best practice with pipework designs for VESDA’s being used in car parks.