Expansion on 5m run between Tees

Discussion in 'Plumbers' Talk' started by Jimbo, Jul 5, 2020.

  1. Jimbo

    Jimbo Screwfix Select

    Heating pipes in concrete channels around perimeter, 22m copper. Pipes are in 9mm Armaflex foam insulation, bends are pulled and generally allowance provided for expansion.

    But, on one section there is about 5m between tees to radiators in the straight line. Following 1mm per meter that concerns me about stress on the tails (22x15x22mm tees, tails are vertical 220mm at one end and horizontal at the other).

    To make things worse one of the tee's is right on the end of a pulled bend, i.e. at the point of maximum deflection.

    Any ideas? 'Plumbing sticks' for the tails maybe? Could use those for the horizontal part of the tails at one end of the section and normal copper for the vertical maybe.

    Maybe it's better to put an expansion joint like this in the middle.
     
    Last edited: Jul 5, 2020
  2. Jimbo

    Jimbo Screwfix Select

    Apparently the steel bellow expansion joints don't last forever and should be accessible.

    I've decided to use telescopic tails from our hosts on the radiator in question, keeping the piping below ground conventional and allowing for movement there instead.
     
  3. The Teach

    The Teach Screwfix Select

    Expansion is always a consideration,doubt your scenario needs any extra measures. The water in the pipes are temperature controlled,with all the insulation expansion at where it is critical is very mininal.

    TT
     
  4. Jimbo

    Jimbo Screwfix Select

    @The Teach thanks, reason I have concern here is because there is a further 4m of straight run prior to the first tee, where it's clipped around a corner (so not much if any give). So total expansion in this section approx 9mm and on radiator is right at the end of the section.
     
  5. andy48

    andy48 Screwfix Select

    Can you not put a squared of "U" shape of pipe in, say, the middle of each pipe run, so that expansion and contraction is taken up at that point. Needs to be clipped in a way to allow for movement, and "U" would need to be horizontal to avoid airlocks.
     
  6. Jimbo

    Jimbo Screwfix Select

    @andy48 thanks, that was a thought but the pipes are in cast concrete channels. So doing so would mean a lot of cutting out.
     

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