Basic assumptions on fighting fires were rendered invalid at Grenfell

So, the fire at Grenfell rendered invalid all of the basic assumptions about fighting fires from the inside and telling residents of other flats to stay inside because they will be protected by compartmentation.

“The fire at Grenfell rendered invalid all of the basic assumptions about fighting fires from the inside and telling residents of other flats to stay inside because they will be protected by compartmentation.”

That meant there had to be an improvised approach to fighting the fire from the outside on the night but most of the building was always going to out of reach even for aerial appliances – the whole reason why the risk of external fires should be designed out in the first place.

Dr Lane’s report is one of six published on the first day of the first phase of the hearings following the commemorations over the last two weeks, and all of them pose some fundamental questions about different aspects of fire safety in high-rise buildings and the regulatory regime that lies behind it.

Even before we get to questions of liability and culpability, they are yet another reminder of just how complex this inquiry is going to be.

Jules Birch, award-winning blogger

Dr Lane’s Grenfell Inquiry report in detail

Cladding and compartmentation failures

Fire safety relies on “defence in depth” or multiple levels of safety, meaning not just compartmentation but a whole range of other levels such as provision of firefighting equipment, fire doors, smoke control, ventilation of the staircase, fire alarms and active and passive fire protection systems. But once the fire spread they began to fail one by one.

As Dr Lane puts it: “The building envelope created an intolerable risk on the night of the fire, resulting in extreme harm. It did not adequately resist the spread of fire over the walls having regard to the height and use of the building. The active and passive fire protection measures within the tower were then required to mitigate an extraordinary event and, as a result, the consequences were catastrophic.”

“The building envelope created an intolerable risk on the night of the fire.”

She concludes, based on test evidence supplied to the inquiry, that the construction materials forming the rainscreen cladding system “did not comply with the recommended fire performance set out in the statutory guidance of [Approved Document] B 2013 for a building of that height”.

But the problems went beyond just the cladding, with “multiple catastrophic fire-spread routes” created by the construction form and detailing, and the arrangement of materials used around the old and new windows increasing the likelihood that fire would spread from a flat to the cavities in the cladding system.

Attempts had been made to subdivide the cavities but both the horizontal and vertical fire stopping were installed incorrectly, and “no evidence has been provided that they were ever tested for performance in an ACP [aluminium composite panels] based rainscreen cladding system of the type installed at Grenfell Tower”.

The windows did not have fire resisting cavity barriers and “these unprotected openings themselves were surrounded by combustible material”, meaning that there was a disproportionately high probability of a fire starting near a window spreading to the cladding.

The arrangement and type of construction materials in the cladding system then stretched the rest of the fire safety system to breaking point with multiple internal fires, large amounts of smoke, an early need for external firefighting and a need to change the evacuation strategy.

She finds that the cladding system was “therefore non-compliant with the functional requirement of the building regulations” but all of that had severe knock-on effects for the firefighting operation with the fire brigade never told that there was a combustible cladding system.

“I have found no evidence yet that any member of the design team or the construction team ascertained the fire performance of the rainscreen cladding system materials, nor understood how the assembly performed in fire.”

In one of the most damning sections of the entire report she says: “I have found no evidence yet that any member of the design team or the construction team ascertained the fire performance of the rainscreen cladding system materials, nor understood how the assembly performed in fire. I have found no evidence that Building Control were either informed or understood how the assembly would perform in a fire.

"Further, I have found no evidence that the Tenant Management Organisation risk assessment recorded the fire performance of the rainscreen cladding system, nor have I found evidence that the London Fire Brigade risk assessment recorded the fire performance of the rainscreen cladding system.”

Stay put advice failure

Dr Lane says she is particularly concerned about the delay between 02:06, when a major incident was declared, and 02:47 when the advice was changed.

However, she points out that there is no requirement in the UK for automatic detection and alarm systems in high-rise buildings and no way to raise an all-out alarm in Grenfell Tower or to communicate with vulnerable residents.

As the report makes clear, Grenfell went through an extensive refurbishment between 2012 and 2016, including not just the cladding but also full internal refurbishment of the first three storeys, work on the building services on every floor and in every flat, replacement of all the fire doors and gas supply works.

The problems with the fire doors are now well known. The report says that the installed doors had different metal fittings and intumescent seals, which could have affected their performance and some were glazed and could have failed prematurely.

Dr Lane concludes that “all the flat entrance doors (from Level 4-23) were non-compliant with the fire test evidence relied on at the time of the installation” and that this non-compliance “would have contributed to the failure to prevent the spread of fire and hot smoke from the fire to the lobby.”

“There were further failures of the ventilation system that was meant to extract smoke from the lobbies and of the fire lift, with the fire brigade unable to take control.”

There were further failures of the ventilation system that was meant to extract smoke from the lobbies and of the fire lift, with the fire brigade unable to take control.

Grenfell also had a dry fire main rather than a wet one, making it non-compliant with design guidance at the time of the original construction and with current standards.

A wet main would have enabled a faster response to the original fire and enabled greater water pressure but it even they are not designed for the multiple hoses needed.

That non-compliance contributed to a failure to prevent the spread of fire and hot smoke from the flat to the lobby.

Conclusions

Overall, Dr Lane finds that “the number of non-compliances signify a culture of non-compliance at Grenfell Tower. I am particularly concerned about the maintenance regime of the active and passive fire protection measures. I note that multiple automatic systems such as the control of the fire lift and the smoke ventilation system, appear not to have operated as required.”

That and other issues such as the gas installation will be covered in Phase 2 of her report. In the meantime, though, she recommends action on:

• Cladding – she says the remains concerned that some “limited combustibility” materials may not be adequate and that full scale testing should be carried out of cladding systems including windows and fixtures and fittings that would help establish whether materials need to be non-combustible in high-rise buildings.
  She adds that: “I have found no evidence so far that there was any understanding by any member of the design team or construction team, nor by the approving authority, that the rainscreen cladding system was either combustible or in breach of the building regulations.”
• The testing and classification regime – she found “no relevant test evidence” for the cladding, fire doors not in compliance with test evidence provided and no evidence this was understood by professionals or fire safety managers.
  She adds that it is essential that there is proper understanding of test evidence and how it relates to performance. “This is a critical change which is needed throughout the design and construction industry”.
• Standards and regulations – how to treat ‘filler material’ in cladding systems will be a crucial issue for the inquiry and potentially for future liability but Dr Lane highlights a complex and confusing array of national and European standards and guidance.