Grenfell fire spread and cladding issues explored

Grenfell fire spread and cladding issues explored

THE INQUIRY into the fire in June 2017 saw experts note that flames spread in ‘just over 10 minutes’ to the outside of the tower, and that cladding issues ‘have been known for decades’.

Earlier this year, the inquiry began looking at the ‘factual narrative’ of the events, with expert witnesses describing the various safety failures in the tower and a ‘culture of non compliance’. After the inquiry resumed once more, a fire station manager stated that ‘vital’ plans for the tower were not able to be found in the lobby of the buildingIt then heard from 999 operators that due to a policy not to recontact callers, residents were not told to evacuate when policy changed.

In September, one of the fire commanders stated that ‘the building let us all down’, before London Fire Brigade (LFB) commissioner Dany Cotton admitted that she had no knowledge of cladding risks despite an LFB presentation created only a year before the fire. Now, Shropshire Star and BT.com have reported on the latest hearings at the inquiry, with the first coming from expert witness Professor Jose Torero in relation to the fire’s spread.

His statement said that the fire, which began in a fourth floor flat, ‘breached the uPVC window fittings and ignited one of the flammable components of the external cladding’, taking ‘just over 10 minutes’ to get to the outside and at that point ‘compromising’ the stay put policy. The passage of fire to the outside ‘probably happened’ before 1.05am, which was ‘about 11 minutes’ after the start of the fire, with a video compilation played showing the spread up the east side of the tower.

Professor Torero’s statement added: ‘Analysis indicates that a relatively minor, localised fire, compromised the uPVC window fittings and ignited one of the flammable components of the cladding by direct flame/plume impingement. From this point forward, the stay-put strategy was compromised and evacuation of occupants was an option to consider.’

He added that such a kitchen fire was ‘inevitable and perfectly forseeable’ in a high rise like Grenfell, and should have been contained, commenting that ‘fires are common events, but fires that create significant damage are rare events. The building is required to respond and deliver… so that a fire of this nature does not progress beyond a kitchen’.

Inquiry counsel Kate Grange QC asked whether ‘in the event of any fire starting near a window at Grenfell Tower, there was disproportionately high probability of fire spread to the cladding system?’, to which Professor Torero replied ‘absolutely’. He added that there was evidence that Grenfell’s compartmentation had failed by 1.05am, and had ‘clearly failed’ by 1.08am, and it ‘would have been obvious’ to firefighters by 1.11am that something was burning on the building’s exterior.

When compartmentation is breached, this ‘invalidates the stay-put policy’, and on being asked by Ms Grange whether he would agree that ‘once compartmentation is breached, evacuation is necessary to secure the fire safety of those in the building’, he stated in the affirmative, as well as to the question as to whether ‘it is the only viable option at that point’. LFB did not change the stay put advice until 2.47am, with fire spread ‘inevitable’ up the façade once established, he added.

Separately, Professor Luke Bisby concluded that the ‘primary cause’ of the ‘rapid and extensive’ fire spread was the presence of polyethylene (PE) filled panels, stating that the dangers of this flammable material ‘have been known for decades’. On exposure to heat, PE will ‘melt and drip – possibly flowing whilst burning or generating flaming droplets’, with evidence of its reaction to fire written about in publications from the 1970s.

He added that he would be surprised if fire safety professionals ‘were aware of the specific papers’, but noted: ‘The general principle that a thermoplastic will melt and drip and burn quite vigorously is very clearly highlighted in any of the reference texts that one would expect a competent fire safety professional to have at least skimmed if not know quite well.’

Inquiry counsel Richard Millett QC suggested that there had been evidence since 1988 of ‘the dangers of thermoplastic materials from a safety perspective’, to which Professor Bisby agreed. Mr Millett also asked whether that meant any flame ‘emanating from the window set could get up through that crack and melt or burn’ the exposed PE, to which Professor Bisby also agreed. He added his view that the fire spread through a hole in the window or through materials to the sides.

The witness also stated that he agreed it was ‘likely’ that any fire near the window would ‘break out of the window and into the cladding’, saying: ‘In my opinion, the primary cause of rapid and extensive vertical and horizontal external fire spread was the presence of polyethylene-filled ACM rainscreen cassettes in the building’s refurbishment cladding system and in the architectural crown detail.’