Case Study: TNL280 Deluge Nozzle
‘New M4’ Tunnel, Sydney, Australia
Project Description
The ‘New M4’ East (M4E) tunnel project is located in the inner west of Sydney, Australia. The M4E tunnel is a twin tube design of 3 lanes in both directions. Each tube is 3.4 miles (5.5 km) in length. Therefore, the project has approximately 6.8 miles (11 km) of tunnels in total. The tunnels are divided into 517 fire deluge zones along the entire length, including the covered entry & exit ramps. Each fire deluge zone is approximately 98 feet (30 meters) long. The tunnel is equipped with fibre optic detection that signals a central monitoring station. Each deluge zone is monitored by operators and manually activated. When the specifications for the project were being developed, the design brief called for “an extended coverage nozzle that could effectively deliver 0.25 gpm (10 mm/min) density”. No such product existed. In response to this requirement, the Reliable® model TNL280 nozzle was developed.
About the Reliable® TNL280 Nozzle
The Reliable® TNL280 pendent nozzle has been specifically designed to provide an extended coverage nozzle suitable for use in vehicle tunnels. Key to the design of the nozzle is a very large K-factor. The large nozzle coverage area typically results in lower installed costs by reducing the amount of material (pipe and hangers) and facilitates faster installation. By comparison, traditional tunnel nozzles — usually spaced at around 97 feet2 (9 m2)— are much more material and labor intensive. Other benefits of the very large K-factor are:
• TNL280 delivers large water droplets which are extremely effective at penetrating the fire plume of high challenge vehicle fires.
• TNL280 operates at very low pressure; typically between 7 to 20 psi (0.5 to 1.4 bar).
The TNL280 nozzle is a pendent nozzle that is used in the overhead position. Therefore, it less likely to suffer from a ‘shielded fire’ which can occur with different height vehicles. An overhead pendent layout, by design, directs water down toward the road and on top of the vehicles. Road tunnel environments can be extremely aggressive. To enhance the service life of the TNL280 nozzle, it is offered with an Electroless Nickel PTFE (ENT) finish, now with an anti-reflective black paint topcoat. See Reliable® Technical Bulletin 099 for complete information on the TNL280 nozzle.
About Deluge Systems
Deluge systems consist of water supply, a valve, a system of piping and nozzles that are open to atmosphere, and a means of detection and actuation. When the deluge valve is activated, water flows through all nozzles controlled by the valve. Unlike automatic sprinkler systems, where water flows only through individual sprinklers that have activated close to the heat source, deluge systems are designed to “surround and drown” an entire zone to prevent the spread of fire in hazardous environments.
Project Quick Facts
Client
Transurban and Transport for NSW
Consulting Engineer
Norman Disney Young (NDY)
Site Engineer
Jessica Keogh
Number of Deluge Systems
517
Tunnel Height
17.4 ft (5.3 m)
Unique Project Requirements
Design brief required an Extended Coverage Nozzle that could cover at least 17 ft x 17 ft (5.1 m x 5.1 m) delivering 0.25 gpm (10 mm/min) density.
No product on the market could deliver this – thus the Reliable® TNL280 was developed.
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