[Strawbale] Sustainability of wood heat.

[Sherwood Botsford]

Shody Ryon wrote:
> What about poly tubing used for irrigation? It is made
> of HDPE, I think. It is flexible, but not so flexible
> in larger diameter. It might be a little pricey
> though, compared with PVC.
>
>   
Poly pipe has several points against is as a structural building system.

1.  It's way too flexible.  Remember it comes on a spool.  It's trivial 
to unroll even 1.5" ID pipe.
2.  It's strength goes down rapidly (and it's flexibility increases) 
with rising temperatures.  If you are using it for making swimming pool 
heaters or solar heating of any sort, you don't run it at mroe than 15 
psi at 170 F. That's 20% of the nominal rating for utility grade pipe.
3.  There is no cement system for joints.  Joints are insert fittings + 
hose clamps, or external compression ring fittings.

On the flip side, it's actually cheaper than PVC.