Green Building Bible, Fourth Edition |
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Posted By: djhPlastic is less likely to leak than copper since there will be fewer joints in inaccessible places. It should be pressure tested before being hidden away. You could always run it inside a larger diameter pipe if you're particularly concerned (like electrical cable in conduit). I would run it in the insulation, since you'd need to insulate it otherwise.
Posted By: GreenPaddyJust consider mice. They are very fond of
Posted By: WillInAberdeenIf the pipes run parallel to the direction of the joists, it's convenient to run them between the joists, within the insulation layer but not too deep, so the residual heat losses end up in the room. I used pipe insulation as well as burying them in the wool insulation layer, as I felt the wool didn't "wrap around" the pipe very well.
But for pipes going perpendicular to the joists, I think it is easier to go underneath the joists, rather than thread through holes in the joists.
You can get metal pushfit fittings, which fit both copper and pastic pipe.
Mice just love to shred the standard clip-on polyethylene foam pipe insulation, must make for comfy nesting. I'm using some foil-covered rockwool pipe insulation in the hope that it's not so comfortable.
Posted By: Peter_in_HungaryPosted By: GreenPaddyJust consider mice. They are very fond of
all things organic - along with other bugs etc. I would be a bit nervous about putting sheeps wool as insulation between joists.
Re pipe work - have you considered alpex pipe?
Posted By: bardoThe alpex pip sounds interesting. Have you used it? What are the merits?
Posted By: Peter_in_HungaryPosted By: bardoThe alpex pip sounds interesting. Have you used it? What are the merits?
I have used alpex, I found it good, the 5 layer alpex has an O2 barrier, useful on closed systems. It is reasonably easy to install and can be got pre-insulated. The joints are either swaged (install all the pipework then hire the machine for a day) or bolt-up. The fittings tend to be more expensive than copper but you use a lot less of them and with a bit of planning you can avoid fittings in hidden places (like underfloor). Alpex pipe is good for drinking water as well as CH.
I have also installed a CH system using 6mm nylon microbore - very easy but benefits from a centrally placed boiler as each radiator had its dedicated supply and return from the manifolds. Although microbore seems to have gone out of fashion these days.
There are a couple of threads on here about using sheeps wool insulation under floor - probably worth a read if you haven't already done so.
Posted By: revorI would avoid any joints that eventually become inaccessible.
Posted By: bxmanIf it is a new build would the money not be better spent on more or better insulation .
Posted By: bxmanShould there be a need for central heating these days ?
Posted By: revorI would avoid any joints that eventually become inaccessible. Could be trouble in years to come. A lot will depend on your finished floor covering and whether you will in the future be able to lift it and gain access. Are you already committed to I joists? I used web based joists "posi joist" and they are just great to run pipes through.
I used plastic pipe under floor and connected to copper with brass compression fittings elsewhere for domestic supply. (Also had to comply with my insurance company as I had to agree to no hot work so no soldering and the crimping gear was too expensive) Compression joints are a great benefit if later you want to modify the plumbing.
Given the void under the joists I presume this will be ventilated to avoid damp issues in which case pipes will need to be well insulated.
I used alpex for underfloor heating and I would consider this for conventional CH system. It is easy to bend and retains the shape so you are not fighting it like you would do with barrier pipe. It also comes in very long coils mine were 360 m long so less wasteful. If you use it there are different diameters around the 15 mm size mine was 16 mm and if you want to connect up to 15 mm you will need conversion fittings. So be aware.
If you are planning on soil pipe or ducting to go under the floor they may need to go in when you fit the joists.
Have not used sheep's wool insulation but I looked at it and considered it to be too expensive. Also been horror stories about it getting moth eaten if it's not been manufactured properly.
Posted By: bardoI am interested in alpex however can't see the real merit over plastic especially given that we will need to adapt to fit onto copper pipes coming out the floor and into small radiators.
Posted By: Peter_in_HungaryPosted By: bardoI am interested in alpex however can't see the real merit over plastic especially given that we will need to adapt to fit onto copper pipes coming out the floor and into small radiators.
The alpex installation I did had the alpex pipe coming out of the floor and going straight to the radiators without conversion to copper. If the rad. is the normal height from the floor there are no problems, long(ish) horizontal runs in alpex can develop a sag over time and would be more vulnerable to knocks
I see you are using a plumber rather than DIY. IMO there is a lot of merit in going with what ever is in the middle of your plumbers comfort zone. If what your plumber is happy using is too far away from what you want - then better to get a different plumber!
Posted By: bardowhat is your experience in obtaining fittings for Alpex and or converting to 15mm?
Posted By: ealingbadgerCan I ask how you are holding the insulation up between the joists please?
Posted By: Peter_in_HungaryPosted By: bardowhat is your experience in obtaining fittings for Alpex and or converting to 15mm?
No problem - I just go to the shop and pick them off the shelf, same with the pipe, either bare or pre-insulated. But remember I am in Hungary and even so I live next to a small(ish) town of 16,000 population and have a choice of 3 shops selling the parts. I can't imagine that there is a problem getting the fittings in the UK e.g. Amazon UK list the items just for one example including radiator fittings to connect alpex directly to the rads.
Posted By: goodevansconsequences. Whatever you use, keep it as far in to thermal envelope as poss. Try hard to avoid running wet
Posted By: bardoThis looks a really interesting solution for the hot water system. Thanks for sharing. Re cold water I wonder about PEX for drinking water and the possibility of aluminium leaching. Did you look into this at all?
Posted By: goodevansAluminium shouldn't ever come into contact with the water, and I'm not aware (nor did I look into) any issues with PEX or other plastic for cold water supply, nor for that matter brass, copper, flux and solder.
The plumber was not keen on the idea of plastic pipes - but after this job he admitted, reluctantly, that he would do the same for his house.
Unlike other well known pipe systems these pipes are malleable. You can bend them with a 100mm radius without kinking by hand, probably tighter by either an external spring or a internal silicon rod. When bent they stay put, have reasonable stiffness and can be "bent straight" for tidy installs.
The manifold above is the 1 inch version - it is also available in a 3/4 inch version which I should have used given the rest of the plumbing is 22mm. the smaller manifold has the pipes spaced at 36mm centrers as opposed to 50mm that is shown in the photo. 4 port and 3 port manifolds can be linked together in a line or above each other or a combination. The plastic clips came supplied in two depths/offset to aid stacking one above the other.
I was able to lay all the ground floor pipes in the insulation under the slab without the help of a profesional! (the insulation was 3 layers of 75mm eps with H&C above the bottom layer and the heat pump feed/return above the second layer - all under slab pipes in conduit to give a small chance of replacement in the future and the pipe channels cut with a "U" shaped hot knife. Below is a photo of the pipes coming out of the ground slab with enough length to get to the future 1st floor manifold, and in the background some of the pipes coming out where sinks are located as well as the UFH manifold.
http:///newforum/extensions/InlineImages/image.php?AttachmentID=7492" >
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