2. Initial progress
Once the fire had escaped from Flat 16, it spread rapidly up the east face of the tower. It then spread around the top of the building in both directions and down the sides until the advancing flame fronts converged on the west face near the south-west corner, enveloping the entire building in under three hours.
Three factors affected the progress
a. The principal reason why the flames spread so rapidly up, down and around the building was the presence of the aluminium composite material (ACM) rain screen panels with polyethylene cores, which acted as a source of fuel. The principal mechanism for the spread of the fire horizontally and downwards was the melting and dripping of burning polyethylene from the crown and from the spandrel and column panels, which ignited fires lower down the building. Those fires then travelled back up the building, thereby allowing the flame front to progress diagonally across each face of the tower.
b. The presence of polyisocyanurate (PIR) and phenolic foam insulation boards behind the ACM panels, and perhaps components of the window surrounds, contributed to the rate and extent of vertical flame spread.
c. The crown was primarily responsible for the spread of the fire horizontally, and the columns were a principal route of downwards fire spread.
3. Compliance with Building Regulations
There was compelling evidence that the external walls of the building failed to comply with the Building Regulations 2010. They did not adequately resist the spread of fire having regard to the height, use and position of the building. On the contrary, they actively promoted it. It will be necessary in Phase 2 to examine why those who were responsible for the design of the refurbishment considered that the tower would meet that essential requirement.
4. The second phase
Design and choice of materials will be a key theme of the second phase which starts in early 2020.
The report states that 'a number of aspects of the design of the refurbishment and the choice of materials will need to be examined.
The report goes on to say that the choice of 'ACM panels with a polyethylene core, the choice of combustible insulation and XPS window infill panels, a design which incorporated many vertical channels and the decision to incorporate an architectural crown composed of ACM fins, all of which made a major contribution to the extent of the fire, are just examples' of areas that need to be examined more thoroughly.