Fläkt Woods Fans İnstalled As The Main Ventilation For The Hindhead Tunnel

The main ventilation for the cross passage sections of the twin bore A3 Hindhead project has been supplied by Fläkt Woods.

They installed a ventilation in the form of 43 of their 1120mm diameter JMTS horizontally mounted smoke vent category: 250 degrees C for 2 hour type jetfans to be mounted within the road tunnels, as well as 34 JM type axial fans.

The project has completed the dual carriageway link between London and Portsmouth and removed a major source of congestion, particularly around the A3/A287 traffic signal controlled crossroads. A new road is 4 miles (6.5km) long and includes the 1.2miles (1.8km) twin bored tunnels under the Devil's Punch Bowl Site of Special Scientific Interest.

It is, in fact, Britain’s most ambitious tunnelling project since the Channel Tunnel. It’s actually a pair of record-breaking, 1.3 mile, 70mph road tunnels — one north bound, one south bound — underneath one of southern England’s prettiest beauty spots.

Ventilation in tunnels is required for normal and emergency operation. During normal operation, its purpose is to provide a clean air environment and to maintain reasonable temperatures during congested conditions. During emergency operation, ventilation is needed to influence the flow of smoke and combustion products so as to create a safer environment for tunnel users to escape and for emergency services to intervene.