On Sunday, 25 June 2017 11:55:55 UTC+1, Andrew wrote:
On 24/06/2017 21:05, tabbypurr wrote:
On Saturday, 24 June 2017 20:55:47 UTC+1, Mike Tomlinson wrote:
En el artÃ*culo , Andrew Andrew97d-
escribió:

First they exposed the foil surface to a 700 centigrade
source of heat (but no flame). The foil surface bubbled
but did not catch fire.

they they repeated the test exposing the cut surface
of the celotex core to the heat source.

It burst into flames *immediately*.

This was surprising, I always thought PIR just charred,
but that wasn't what I saw. Quite worrying.

Yes, that video clip was a real eye-opener. There'll be some worried
people in building control today.

I'm finding this all a bit odd. Surely anyone that knows anything about fire knows that no amount of
retardant stops plastics burning if sufficient external heat is applied,
and it's pretty obvious
that that's exactly what happens in a raging building fire. Ie any form
of plastic insulation
is going to go up if well flamed first. And thus the only sensible
insulation to use on a high rise
tower is anything non-combustible, ie it must be free of plastics.
PE or FR treated PE just don't cut it.

And that means rockwool slabs.

I think I read somewhere that 150 mm of celetex was being used.
This seems to be overkill, assuming that it tightly affixed to the
underlying concrete structure, which is practically impossible
because of the rough surface of the concrete, plus the corner
and intermediate columns that had a surface shape that rigid
board-style insulation is always going to be kludged.

SO it could well be that hot gases at 700+ centigrade shot up
both sides of the celotex boards.

Fibreglass or rockwool would be better on both those counts. OTOH it can trap water, so detailing matters.


NT