Edit: I wrote this before reading the NYT article above, which says the exact same thing. Perhaps use this post as a companion to that article, lol. At least all of my research agrees with theirs!
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Here's the actual facade details for Grenfell Tower:
Big image because detail is important:
So a few things, the ACM (Aluminum Composite Material) panel installed was
Reynobond PE, which is the cheaper option from the Reynobond offerings. PE indicates
poly
ethylene core, which is combustible & does not meet fire standards. Had they used the more expensive fire retardant model
Reynobond FR with a mineral core, which is
fire
retardant/limited combustible, the tragedy may not have happened to the extent that it did. You should not be immediately afraid of buildings clad in aluminum composite panels, as many architects do spec the fire retardant option for towers in the US, as the non-fire retardant model is not supposed to be used on towers in the US. An example of this is ADD Inc's MassArt Tree House which utilizes
Alucobond Plus ACM panels.
Alucobond Plus is Alucobond's fire retardant mineral core composite offering.
There are other factors besides the ACM panels that contributed to the spread of the fire. If you notice on the plan & wall section details above, insulation was also added to the facade. This insulation was found to be Celotex FR5000 rigid polyisocyanurate ("PIR"), which proved to be quite combustible despite claims otherwise. The positioning of the insulation proved particularly deadly. Notice that along the columns, an air gap was left between the insulation & the original precast column structure. This air gap is a simple way to let water weep out, but it is highly dangerous in the event of a fire. As we all know, fires accelerate with air flow and travel up air shafts quickly. If you notice in the pictures & video of the building burning, the fire traveled straight up the columns as it flailed around and lit other parts of the facade on fire. Additionally, the detail does not indicate appropriate firestopping that should be shown at each floor for the insulation & panel arrangement.
As to if this could happen in the US, you can never say never;
Reynobond PE &
Alucobond are often submitted as VE items to save money instead of
Reynobond FR &
Alucobond Plus and architects must be very vigilant when reviewing the submittals from contractors; however, a tragedy of this scale is unlikely due to key US fire & building code regulations. NFPA requires automatic sprinkler systems in any new or substantially renovated building with more than 4 units (residential) or a certain number of square feet per a variety of building use groups. Sprinklers knock out about 90% of small apartment fires to begin with, but ultimately sprinklers are really life safety devices (providing a safe means of egress) and aren't directly intended to save the building, although they do in most cases. Additionally, per IBC Chapter 10, at least 2 means of egress are also required from any point in the building with a travel distance not to exceed a certain amount per the building use group. Grenfell Tower & so many other UK tower blocks shockingly only have a single staircase (see plan). Oddly, according to the planning documents, the renovation actually added rated fire walls between the units on the floor that the fire is thought to have broken out on (see plan).
Plan, note the SINGLE staircase!:
(The additional staircase you see being removed in the plan above was a dedicated one for that former office space only. It did not continue up the tower. The typical tower floors are all what you see in the new plan on the right.)
