What's that valve?
They may look like Ninja Turtle hideouts (and perhaps they are when we're not looking), but what are these mysterious little trap doors in the pavement?
We walk past them every day but it’s likely we are focused on our destination rather than what’s happening at our feet.
The city is filled with City West Water’s ‘panel markers’ along our footpaths; valves, hydrants, manholes… and that’s just the beginning! Within the City West Water precinct (Melbourne’s CBD and western suburbs) there are almost 5,000 kilometres of drinking water pipes with 40,000 valves, as well as 4,000 kilometres of sewer pipes with just under 325,000 connections.
Believe it or not, the first water valve was installed in 1840, and the most recent installed only just this month. On top of this, there are over 30,000 water hydrants and 96,000 sewer manholes for ready access during an emergency or a fault.
But what do all the panel markers mean and how are they identified? It's time we lifted the lid, so to speak, on these iconic panels dotted across Melbourne’s pavements.
Before you read on, it’s important to note that it is not only illegal, but dangerous to enter any manholes without authorization, so they should only be accessed by the professionals: City West Water maintenance staff who have the knowledge, training and access permits. If you see a broken panel or a panel that just doesn’t look right, this could be a hazard so please contact City West Water as soon as possible.
These two panels are a dynamic duo.
On the left is a valve cover, with its quaint geometric design. This cover is opened using a big ‘key’ which is connected to the valve below.
A maintenance worker can open and close the valve by using the valve key. A valve is what turns the water main below on and off, like a tap. When we get a burst water main, the first thing our maintenance staff will do is turn off the main via the valve. There are valves throughout the network.
Take a look, as it is highly likely there will be one in your street. A court might only have one valve but a street might have two valves, one at each end to enable shutting down the main so maintenance workers can undertake repairs.
The cover on the right is a water access point for a ground level hydrant.
I bet you’ve walked over one of these today.
Maybe many! These moon-like panels offer not just a break in our regular pathway walk, but a discussion topic on whether they should still be referred to as ‘manholes’ in 2018. Perhaps ‘peopleholes’ is a better term in today’s environment?
This familiar circular panel to the left is a sewer cover. Featuring a grid-like pattern – embossed to avoid slipping - the hole is opened using a uniquely shaped access point cover key.
Beneath these ‘concrete lids’ is a cave of wires, pipework and a sewer, anywhere between 1 to 20 metres deep. To open one of these requires strength – sometimes they are almost concreted in – and a special key to open it. Needless to say, it’s a two-person job!
Maintenance workers can lift the lid off and lower sewer jetting equipment into the sewer, normally to clear a blockage or clean fats, tree roots etc. from the pipes. However in some instances workers may be lowered into the sewer via a larger access cover to a manhole or an excavation to carry out repairs to the sewer.
For safety reasons this access involves use of specialised equipment such as harnesses, gas detectors and more. They may also lower a remotely operated CCTV camera to carry out an inspection of the pipe before and after completing pipe cleaning or repair.
These two panels are a dynamic duo.
This could be a secret map. There definitely is a secret key to open these panels!
The spray paint markers are artistically created by surveyors highlighting the pipework underground.
They highlight the three panels: Two water valves and one property service valve, located in the middle.
Multiple valves provide flexibility to supply water from either direction and minimise the impact to businesses or residents in the event of needing to shut down the water pipes to undertake a repair.
This is an above ground fire hydrant called a Pillar Ball Hydrant.
The old PB hydrants were installed above ground like this one and painted red so that it was visible to a fire brigade.
The new hydrants are installed below ground to avoid vehicles accidentally damaging these and causing the sometimes spectacular water fountain effect– all hydrants are marked by a blue reflector located in the middle of the road which is visible at night.
You can typically find a fire hydrant every 50-90 metres in the CBD and in residential areas they can be found at 120-200 metres spacings.
This is an ‘L Type’ fire hydrant.
The cover or lid can be removed to reveal an above ground connection to the water pipe for firefighting equipment.
These hydrants are installed in areas that are non-trafficable or in rural/grassed areas where a below-ground hydrant may be difficult for the fire fighters to locate.
If the white section was a yellow colour this would indicate the water pipe is greater than 225mm in diameter.
The valves are painted these colours to alert the maintenance workers that if they have to visit the valve again, they are aware that our customers have previously experienced at least three water interruptions in the last 12 months.