On Sun, 24 Sep 2006 22:01:16 GMT, a particular chimpanzee named
"VisionSet" randomly hit the keyboard and
produced:

"jks" wrote in message
oups.com...

or use this spiral wrap from screwfix. It is silver bubble wrap and is
designed exactly for your purpose.

http://www.screwfix.com/app/sfd/cat/...62194&ts=16185

Equivalent to 33mm polystyrene!!!?!!?
That'll be UNexpanded polystyrene then.

I was sceptical too, but it appears to be correct. The R-value of
Alreflex (the nearest equivalent I could think of) with no cavity
either side is 0.15m2K/W; the R-value with cavity both sides is 1.56,
so the R-value with one side exposed must be 0.93. Multiply that
figure by the conductivity of polystyrene (0.037W/mK) and the
equivalent thickness is 34mm so they're not far off.
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
just how far from the pack have you strayed?"