Alternative Technology Assn Forums

1. 

   aburnett
   Member

   I'm about to pour a new slab for my sustainable renovation, and am using the opportunity to lay hydronic tubing for possible future use. If connected, it will be to evacuated tubes and tanks.

   I have two wildly different quotations for supply of tubing for an 80 sqm slab. One company is quoting a polyethylene pipe system (Multitherm PE-RT), and the other is quoting a (brand unknown) Polybutylene PB system at three times the cost.

   Can anyone give any indication of the difference in performance (temperature range etc) of polyethylene versus Polybutylene tubing?

   Thanks for all the useful responses in the past, Antony

   Posted Thursday 13 Nov 2008 @ 9:12:15 pm from IP #
2. 

   aburnett
   Member

   I got a response from a company in Melbourne thus: "... To our knowledge Polybutylene would never have been used here in Australia for hydronics, even the old black piping used years ago was a PERT. It needs to be an approved hydronic pipe which would be a PERT (polyethelene raised temperature) with an oxygen barrier. These hydronic pipes are pink or with Multitherm a pink/purple colour which distinguishes them from other piping." Antony

   Posted Friday 14 Nov 2008 @ 4:34:52 am from IP #
3. 

   ghostgum
   Member

   Our system uses PEX (Cross linked Polyethlene), I think it is Rehau Rautitan. Purple for hydronic system, black for hot and cold mains, green for rainwater.

   Posted Tuesday 18 Nov 2008 @ 5:57:49 am from IP #
4. 

   TonyT
   Member

   The link

   http://www.ata.org.au/forums/topic/3105#post-25255

   lists questions about the use of Polybutylene pipe for hydronic heating.

   Oxygen and (hot-) water will corrode steel hydronic wall-panel radiators.

   To reduce the oxygen permeability below 0.1gram per cubic metre, an oxygen barrier (e.g. a layer of EVOH or a layer of Aluminium) can be included when plastic pipe is manufactured.

   For pipe without an oxygen barrier, chemicals to prevent corrosion can be added to the water.

   For use with polybutylene pipe, Google shows that Fernox F1 and Sentinel X100 are two possible products.

   Q1. What are the active ingredients in these products and are they dangerous/poisonous ?

   Q2. Are these or alternative corrosion-inhibitor products available in Australia ?

   Posted Wednesday 21 Mar 2012 @ 10:11:48 am from IP #
5. 

   TonyT
   Member

   copied from
   http://www.ata.org.au/forums/topic/3186#post-25609

   s2s

   Tiemme Cobra PEX-Al-PEX pipe and Rehau PEX-Al-PEX are constructed from multiple-layers as you describe.
   http://www.enter-shop.com.au/catalogue/c72/c76/c166/c173/p914

   Do either of the Rehau
   pink-RauTitan-Pink or the
   red-RauTherm-S
   PEX barrier pipes that are being sold for hydronic heating include EVOH in a layer that is sandwiched between layers of PEX ?
   http://www.rehau.com.sg/files/Piping_Connection_and_System_Guidline_ANZ.pdf

   Ditto the Tiemme-CobraPEX barrier pipe
   http://www.enter-shop.com.au/catalogue/c72/c76/c166/c169/p939

   Neither website is clear as to the position of the EVOH layer within the pipe cross-section.
   I have been told that the EVOH is sprayed onto the surface at the outside diameter.

   Iplex K1 PEX pipe is sold to move gas and it includes a barrier layer of Aluminium, PEX-Al-PEX
   Iplex K2 PEX pipe is sold to move water and it does not include an oxygen barrier.

   Posted Saturday 24 Mar 2012 @ 8:28:38 am from IP #
6. 

   TonyT
   Member

   Brands of Cross-linked Poly-ethylene (PEX) pipe with an oxygen barrier (of Aluminium or EVOH) include:

   AusPEX
   Gerpex
   Giacomini
   Iplex
   Rehau
   Tiemme Cobra-PEX

   Gerpex sell threaded fittings that do not need an expensive crimping tool

   Posted Saturday 31 Mar 2012 @ 11:38:23 am from IP #
7. 

   sun2steam
   Member

   Thanks for sharing your research!

   Posted Saturday 31 Mar 2012 @ 1:41:08 pm from IP #

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