Putting safety first, the Brihanmumbai Municipal Corporation’s (BMC) is all set to install Saccardo nozzles based system inside the two tunnels of the 29.2-km coastal road to improve ventilation and air flow.
The BMC officials said that the coastal road has two tunnels of 2.07 km each and these high-end Saccardo nozzles will be installed in both the tunnels enabling an advanced ventilation system, emergency escape routes and a safe room for the underground tunnel.
Saccardo nozzles also known as Saccardo ejectors or impulse nozzles supply external air into a tunnel by fans situated in a fan chamber outside the tunnel, officials said adding that in the event of a fire, the fans in the Saccardo system are not affected and hence there is a lower maintenance cost.
Suprabha Marathe, Chief Engineer of the coastal road project, said: "This is the first time in the country such a system will be installed in road transport tunnels. The system consists of typical fans with a diameter of 2 m each and a total of 6 fans for both the tunnels with 3 for each tunnel. A special construction will be carried out from inside the tunnels as well as on the top and a 'Saccardo Nozzle' system will be installed there. There is continuous air circulation with the system, hence the system will help in throwing out the smoke coming out of the vehicles passing through the tunnels."
The civic officials stated that these Saccardo nozzles introduce an air jet into a tunnel, at a high velocity. This air jet imparts most of its momentum to the tunnel air, and hence helps to drive the tunnel air in a particular direction. Saccardo nozzles supply external air into the tunnels through the fans situated in a fan chamber at the mouth of the two tunnels.
She added, "The fans installed rotate at a high speed of 1800 rounds per minute. The Saccardo nozzle system has a lifespan of 50 years and will not be affected by the fire. In case of any untoward incident, if the vehicle catches fire this will not affect the nozzles and the smoke generated from it will also be thrown out by this system. This will prevent smoke from accumulating in the tunnel and make it easier to plan for emergencies."
Among other benefits, the nozzle system will also have minimal disruption during maintenance work and traffic will not have to be diverted. “In most cases, it gets suffocating inside the tunnel because of the release of carbon monoxide from vehicles. The nozzle system will help control pollution. Among other benefits, the traffic will not be diverted during maintenance work," an official said.
