Edit: more specifically I was interested in the following. In the relevant article it states:
>The most common forms of insulation cores for composite panels in use in the UK at the end of the 20th century, in order of decreasing probability of fire propagation, [4] were:
>polystyrene (EPS),
>polyurethane (PUR),
>polyisocyanurate (PIR),
>phenolic,
>mineral fibre.
And then:
>PIR, a variant of PUR having improved fire properties, is difficult to ignite and exhibits a pronounced charring which enables it to withstand fire for longer, but is ultimately combustible.
OK - so PIR "is ultimately combustible".
But then there is also the convection effect of cavities:
>If flames become confined or restricted by entering cavities within the external cladding system, they will become elongated as they seek oxygen and fuel to support the combustion process. This process can lead to flame extension of five to ten times that of the original flame lengths, regardless of the materials used to line the cavities.
So maybe what is needed is an sufficiently hot trigger - e.g. an exploding fridge or tumbler drier - and a PIR clad tower block like Grenfell Tower can become an inferno.
Unfortunately, it seems that all this was known and understood by the fire authorities in the UK and that they had been communicating it to government for years, but nothing was done.
Also relevant is the article referenced by Wikipedia:
http://www.probyn-miers.com/perspective/2016/02/fire-risks-f...
Edit: more specifically I was interested in the following. In the relevant article it states:
>The most common forms of insulation cores for composite panels in use in the UK at the end of the 20th century, in order of decreasing probability of fire propagation, [4] were:
>polystyrene (EPS),
>polyurethane (PUR),
>polyisocyanurate (PIR),
>phenolic,
>mineral fibre.
And then:
>PIR, a variant of PUR having improved fire properties, is difficult to ignite and exhibits a pronounced charring which enables it to withstand fire for longer, but is ultimately combustible.
OK - so PIR "is ultimately combustible".
But then there is also the convection effect of cavities:
>If flames become confined or restricted by entering cavities within the external cladding system, they will become elongated as they seek oxygen and fuel to support the combustion process. This process can lead to flame extension of five to ten times that of the original flame lengths, regardless of the materials used to line the cavities.
So maybe what is needed is an sufficiently hot trigger - e.g. an exploding fridge or tumbler drier - and a PIR clad tower block like Grenfell Tower can become an inferno.
Unfortunately, it seems that all this was known and understood by the fire authorities in the UK and that they had been communicating it to government for years, but nothing was done.