From what I understand, it was the specific combination of PIR and ACM that was the issue, and that BRE tests with PIR and other cladding passed the requisite fire tests. However PIR and ACM was never tested in the arrangement as it was installed.
Apparently ACM passed as well, I imagine in conjunction with rockwool, for example.
It was probably cheaper to replace the PIR than it was to replace the ACM
Apologies, but I wanted to comment re Grenfell.
If you look at the BRE documents re green credentials/energy efficiency submitted as part of the planning application, they stipulated "rockwool or similar". I don't think the change to celotex was never officially amended, at least not in these documents.
They also originally stipulated some sort of community heating system, but this was later changed to gas boilers in individual flats. Interestingly, the "green" score fell below that required by RBKC,even with the rockwool spec', but RBKC waived it and said it wasn't practical to achieve the usually required score for Grenfell.
So many factors came into play that night, including crucially, the fact that there was a gap between the insulation and the original fabric of the building high I believe was related to the way the new windows had been installed. Essentially the gap (which had inadequate fire breaks)acted like a chimney, allowing the fire to spread very quickly up the outside of the building.I believe the window frames melted due to the intense heat.
The whole refurb' was a recipe for a disaster waiting to happen.
Seems like lessons weren't learned from the Lakanal House fire etc.
Having lived (briefly!) in a mid rise 60's council owned block, investigated, researched and complained about fire safety to the ALMO and experienced 4 small fires in the space of 6 months, including a deliberate arson attack, it's fair to say that even the basics of fire safety in many of these blocks aren't up to standard. I'm talking about fire doors, dry risers, automatic windows in stairwells,the fact that often nobody inspects the inside of flats inhabited by people who are at highest risk of fire, not even as part of Fire risk assessments, which usually only include the communal areas. Also communication cables running inside plywood boxing along the full length of corridors supplying individual flats, with no firebreaks.
The basis of the fire procedures in these blocks (that don't have building wide fire alarms, or sprinklers) is the compartmentation between individual flats and flats and communal areas, but it appears that owners, ALMO's and often the fire services refuse to acknowledge that rarely, if ever, is this intact.
