GAPS Inadequate material too small to halt fire spreading
"Rather, the Prohibition Order results from an oversight in regards to the installation of the horizontal cavity barriers
behind the cladding.
The reality is that a whole range of factors affect the fire performance of a facade, including design of cavity barriers
, fixings used and cavity width.
Ms Barwise added: "The combination of this highly combustible material and omissions of cavity barriers
amounts to a collection of catastrophic failures in construction safety."
The windows lacked fire resisting cavity barriers
and were surrounded by combustible material, meaning there was a "disproportionately high probability" of fire spreading to the cladding, she added.
It adds: "Where the ACM rain screen panels are missing, there is no evidence of cavity barriers
, a requirement designed to stop the vertical and horizontal spread of fire within the cavities." The report says there was concern about some fire doors, and adds: "One door has been cut back to the point where the fire-preventing qualities have been compromised and the door still does not close."
If the voids are not broken up with cavity barriers
, then extreme heat can quickly spread upwards through convection in the 'chimney effect', spreading the fire upwards far faster than if the voids were separated with fire-rated material at specified intervals.