On 24/06/2017 16:20, Andrew wrote:
On 23/06/2017 09:23, The Natural Philosopher wrote:
On 23/06/17 09:09, Martin Brown wrote:
On 22/06/2017 22:48, Andrew wrote:
On 21/06/2017 10:50, The Natural Philosopher wrote:
Te problem is inflammable decorative cladding applied over the
(fireproof) insulation

The insulation is not fireproof, it is fire resistant, but
even the technical notes say once the temperature exceeds
a certain value, then even the fire-resistant nature of
this type of celotex will be overwhelmed.

It will contribute to the available fuel load if there is enough hot
flame played on it

No, it wont.

Yes it DID !!. ITV news did a test at a proper test lab.

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*.

That is scary. If it was the right grade for that purpose it wouldn't do
that - I think they need to analyse these foam samples to see which fire
retardant chemistry (if any) has been used. Burning them just shows a
fail and as of last night they had seen 100% failure rate of both foams
and plastic core cladding. How did the fire safety standards get so bad?

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

There are multiple sorts about. I think the one most commonly on sale to
DIY users is a variant of FR5000 - the properly fire retardant one.

The wisdom apparently has been that provided it is a block between foil
to prevent access to oxygen it doesn't need to be very fire suppressed.
And to be fair if it is installed as cavity insulation in between two
fundamentally inert brick/breezeblock wall skins that is about true.

But install that same material against concrete with a cheap thin and
also flammable rain cladding on the outside and all bets are off.

Making it 60m high also allows it to make its own updraft and things
will always burn a lot better when there is forced air ventilation.

--
Regards,
Martin Brown