Major safety upgrade for vital tunnel

Major safety upgrade for vital tunnel
The Lyttelton Tunnel is used by more than 11,000 vehicles each day and provides a critical transport link for the South Island.

Fifty litres of water-per-second for each 30-metre zone will be ready to surge from sprinklers inside the Lyttelton Tunnel protecting people, critical infrastructure and business continuity when the tunnel’s deluge fire suppressant system is commissioned early in May.
Automatically triggered by heat sensors or through human intervention, a minimum of three zones, side-by-side, distribute a deluge of water effectively suppressing fire until emergency services arrive.
The deluge system is all part of a major $28m NZ Transport Agency upgrade to the tunnel; the first since the gateway between Christchurch, Lyttelton Port and the wider Canterbury region was opened in 1964.
Just on 2 kilometres in length, the Lyttelton Tunnel was New Zealand’s longest tunnel, before the recent development of Auckland’s 2.4 kilometre Water view Tunnel.
Used by more than 11,000 vehicles each day and providing a critical transport link for the South Island, the Lyttelton Tunnel is the most direct route for Port traffic, and economically vital for the South Island.
Critical for getting fuel supplies to Christchurch and beyond and for exporters to get their product to markets, on average, since the 2011 earthquake up to 600 tankers have travelled through the tunnel each month and up to 30 on some nights.
With the re-opening of Sumner Road in recent weeks, these dangerous goods carriers will now take the round trip from Lyttelton to Sumner and the city rather than having to take the tunnel with inevitable delays for other traffic.
Eight years ago it was identified that the tunnel had no fire suppressant system, presenting a risk to through-traffic, surrounding infrastructure and business continuity.
Following a competitive tender process, major New Zealand civil construction company McConnell Dowell was awarded the tunnel refurbishment project in May 2017, bringing with it substantial experience gained as lead contractor for Auckland’s Waterside Tunnel and its deluge system.
In addition to the installation and commissioning of the deluge fire suppression system and dedicated 1.5 megalitre water reservoir on land above the tunnel, the project’s scope included improvements to ventilation fan drives, and installation of a new Christchurch City Council (CCC) sewer pressure main to service Lyttelton Harbour.
A high-risk component of the project was the specialist removal of 2 kilometres of 200mm asbestos concrete pipe that ran through a fresh air duct within the tunnel, supplying the Lyttelton reservoir.
That pipe was replaced with a 300mm stainless steel pipe – almost doubling capacity -and combining it with the water deluge supply.
In total eighteen kilometres of pipe work went into the tunnel and all of that hand carried through a door no bigger than a bathroom door.
Some earthquake strengthening of portal buildings was also included as well as major upgrades to the tunnel’s communications, public address systems, and new CCTV systems.
The cameras are FLIR (Forward-Looking Infrared Radar) that sense motion movement, smoke, they can check stopped vehicles, people walking in the tunnel and vehicles in the wrong lane.
There is also a suite of pan-to, tilt, zoom cameras throughout the tunnel, enabling tunnel operators to look at anything in the tunnel.
Part of the deluge system includes a new pump house that will be situated next to the tunnel fan house.
As owner/operator of the tunnel and state highway, the Transport Agency (NZTA) contracted McConnell Dowell and within its contract included the upgrade of Christchurch City Council’s water main and the installation of a sewer pressure main.
Phil Terry had the role of Contractors Representative for McConnell Dowell – effectively the Project Manager – for what was really a multifaceted programme of work.
“Once we were awarded the project we had a programme that took us up to last September.
The original programme was 19 months, but there’s been some scope-creep and a few variations that have added time.
“The actual deluge system is now fully constructed and will be signed off early May – so it will end up being a 24-month project.”
Reflecting on the project’s success, Phil says that while the project was challenging, it was not so much the magnitude of the job, but its complexity.
The challenge is that you’re not dealing with one type of industry. You’re dealing with electronic control systems, electrical, the deluge system, water supply, and sewer supply—there is just a big list of disciplines.
“Normally a job of this size you would have 3 – 4 different sub contractors. We had about 27 different subcontractors with different skill sets that were required on this job.”
Phil says the project went very well considering the high profile, the high risk with traffic, floor loading, working in confined spaces and the constant exhaust fumes.
Despite the many and varied risks, there have been no ‘lost time injuries’, no ‘medical treatment injuries’ and no reportable incidences throughout the entire two years that the project has run its course.
Phil puts that down to the project being so risky that everything they did had to be so well managed and controlled. “It’s like walking on fire.
You make sure you’ve got all the right protection on before you go near it and most probably you’re safer than if you were walking down the street.
“We’ve gone to extreme measures to ensure that our employees are safe.”
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