On Sat, 02 Aug 2008 13:13:51 +0100, Steve wrote:

Hi

I'm going to be using quite a bit of (22mm and 15mm) plastic barrier
pipe for central heating and wondered if anyone can advise on the
following.

Q1. I used a coil of Speedfit a few years ago and it was a bu**er to
work with because it was so springy and wanted to return to its coiled
shape. Are coils of other makes any better in this respect (I have
Hep2O and Equator in mind)?

The JG Speedfit pipe is made using PEX which is a lot less flexible than
Hep2O whcih is made using PB there is at least one other manufacturer that
uses PB (PolyPlumb IIRC?).

The difference is very marked. The 15mm PB stuff will nicely follow a
300mm radius without too much work.




Q2. Presumably the different makes have slightly different internal
diameters. I calculate that if an internal diameter increases, for
example, from 11mm to 13mm then the internal cross-sectional area
increases nearly 40% (area being proportional to diameter squared).
This would give a significant reduction in resistance. Are any of the
available barrier pipes of significantly greater internal diameters than
their competitors?

You must use the same manufacturer for the end supports as for the pipe.
IME the PB pipes use stainless steel supports which offer less resistance
than the plastic ones from JG (and others).

I've not had an issue with the flow resistance of plastic pipe relative to
Cu.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
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