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Stormwater pipe inspection
James Lio
Civil Engineer,
George Town Council TAS, asks:
Currently I am looking into collecting stormwater asset information i.e. SW pipe deterioration around GTC (George Town Council) in Tasmania. Hiring and purchasing a SW inspection tool is nearly out of the question and employing subcontractors from Launceston to do the work is time consuming and expensive, especially to inspect minor blockages after a storm.
Have you faced similar issues and if so what methods did you implement to collect data on SW asset? My initial idea is to purchase a $120 dollar remote control car (waterproofed with silicon glue and duct tape) with a nylon rope tied to its back. Nylon rope will provide me with measurement and for retrieving the vehicle.
In addition, I am planning to employ a pan and tilt IP camera i.e. D-LINK/SWANN or even GOPRO hooked onto a LCD monitor in the car via HDMI. The vehicle will also be equipped with a simple LED torch. A small LCD HUD for the GOPRO will show the chainage.
Rick Jervis
Manager Parks & Assets
Leichhardt Municipal Council
LEICHHARDT NSW
CCTV is expensive anywhere, and is only justified for pipes that are identified as in poor condition. That is, a CCTV image of a good or fair pipe tells you very little for a great expense.
So I recommend that you do an initial inspection of each network link end first to get an indication of condition. You can do that with a small computer video camera on a pole with some LED lights passed through the sump grates, or down a manhole.
Or simpler still, a basic digital camera bolted on a pole, using the time-delay shutter. This quick inspection gives you information of the inlet and outlets at every node. Inlet and outlet pipe lengths are representative of the link pipe’s condition. Now you can develop a condition database and define which pipes you need to look into in more detail – the poor condition pipes and the unknowns. That makes your CCTV task much smaller.
Your remote control toy camera truck has been done before with success, but always use a light tether line to recover the toy when things fail.
Metal corrosion measurement tool
Marilyn Wickee,
City of Mandurah,
MANDURAH WA, asks:
Corrosion of light poles – with rusty poles, is there a metal corrosion measurement tool any of you use and can recommend?
We are hoping to measure the remaining thickness of true metal around the corrosion and then be able to assess the rate of corrosion and perhaps the structural integrity. I presume once we has established that the corrosion is serious, we’d either replace the poles or get a structural engineer in to access them?
Andrew Craig
Manager Strategic Assets
City of Tea Tree Gully SA
We use a TIME TT100 Ultrasonic thickness gauge for light pole condition assessment work. Then you can assess the extent of corrosion and decide if a specialist or replacement or repair is needed.
Luke Matthews
Senior Asset Inspector
City of Stirling
BALCATTA WA
The City of Stirling has purchased a metal thickness tester. I recommend that you ensure you have a probe that can measure down to one millimeter or finer. I think that six monthly testing of poles showing signs of corrosion would give you a deterioration rate.
Rene Baur
Manager Building Assets
Shire of Mundaring
MUNDARING WAau
There are commercial ‘pit depth’ measuring tools available, which can be used to measure the depth of corrosion on the poles. However, I would be careful whether in-house expertise is robust enough to make a judgement on how serious the effect of the corrosion is on the pole’s structural integrity. Call in a qualified person if there is anything more serious than surface rust.