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blue plastic water mains - Reliability

  • 13-09-2018 11:06pm
    #1
    Registered Users Posts: 8,781 ✭✭✭ Carawaystick


    I was looking at the new watermain installation work going on in North St, Swords today.
    Looked like 60-80cm diameter, 1.5-2cm thick walls and similar plastic to the gas mains

    Once the main is installed, should it be as unlikely to burst as gas mains( or in the similar ballpark)
    Or as it will be shallower, be subject to some ground movements?


Comments

  • Registered Users Posts: 9,072 ✭✭✭ antoinolachtnai


    A 60cm water main is unlikely to ever freeze, because of the movement of water in it and because if the outer water were to freeze in some extraordinary situation, there would probably still be liquid water at the centre.

    I'd imagine the old pipes burst mainly because of corrosion but I don't know.

    These pipes should last a long time provided they are laid and joined correctly.


  • Moderators, Science, Health & Environment Moderators Posts: 17,077 Mod ✭✭✭✭ Sam Russell


    We had the water pipe feeding our road replaced a number of years ago. They reduced leakage to zero - actually zero - in the project.

    The method used was to feed a new blue plastic pipe inside the old cast iron one, and then make each connection. They also fitted new water meters at the same time which allowed them to track down leaks. This was many years before Irish Water.

    The plastic pipe is robust, flexible, and inside the old cast iron, is an excellent solution. This project was run by the DCC, and was never mentioned in the IW fiasco.

    This type of work should be carried out right across the DCC area, one section at a time each as a stand alone project, with an overall annual budget.


  • Registered Users Posts: 20,511 ✭✭✭✭ FreudianSlippers


    We should be putting in pipes that have built-in hydro-electric power generators.

    https://www.citylab.com/environment/2018/01/portlands-drinking-water-is-powering-the-grid/550721/


  • Registered Users Posts: 9,072 ✭✭✭ antoinolachtnai


    Why?


  • Registered Users Posts: 20,511 ✭✭✭✭ FreudianSlippers


    Why?
    Ok - so you know that cable that ends in a three-pronged plug attached to all your magic boxes? Well, once those three prongs get plugged into the wall they are connected to electricity which powers those devices.


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  • Registered Users Posts: 9,072 ✭✭✭ antoinolachtnai


    Ok - so you know that cable that ends in a three-pronged plug attached to all your magic boxes? Well, once those three prongs get plugged into the wall they are connected to electricity which powers those devices.

    Oh very entertaining.

    Where do you think this kinetic energy in the water actually comes from?

    What makes you think there is excess kinetic energy in the water supply in Dublin So that such a system would be beneficial?


  • Registered Users Posts: 20,511 ✭✭✭✭ FreudianSlippers


    Oh very entertaining.

    Where do you think this kinetic energy in the water actually comes from?

    What makes you think there is excess kinetic energy in the water supply in Dublin So that such a system would be beneficial?
    I see you prefer asking vague questions rather than making a coherent point.

    I believe most pipes are gravity-fed from reservoirs, creating the pressure in the pipes.


  • Registered Users Posts: 8,825 ✭✭✭ markpb


    We should be putting in pipes that have built-in hydro-electric power generators.

    https://www.citylab.com/environment/2018/01/portlands-drinking-water-is-powering-the-grid/550721/

    The article isn't very convincing. It's only viable with gravity-fed systems and has an annualised ROI of 0.67%. You could argue that it's not being done for economic reasons but that money could have been better spent on investing on pretty much any other green energy source.


  • Registered Users Posts: 9,072 ✭✭✭ antoinolachtnai


    I see you prefer asking vague questions rather than making a coherent point.

    I believe most pipes are gravity-fed from reservoirs, creating the pressure in the pipes.

    Covered in this thread from days of yore. https://www.boards.ie/vbulletin/showthread.php?t=2055083481

    Water for the most part needs to be pumped up a tower to provide the pressure required.

    Low water pressure is a real issue in the city and is one reason to fix the leaky pipes in the first place.

    Untreated water doesn't have a lot of kinetic energy either. There is damn-all fall in the Dublin area (maybe 210m elevation). Portland's water supply by contrast comes from a high lake (around 1000m elevation).


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