Thoughts on Grenfell Tower

I have been following news about the Grenfell Tower disaster fairly carefully. My work as a surveyor has involved residential tower blocks from time to time. I managed several private blocks in London early in my career and looked at the potential refurbishment of Mill View in Toxteth when I was leading a regeneration partnership between Gleeson Homes and Liverpool City Council. The last major report that I did at Arup was for Leeds City Council, advising them how to allocate over £40 million across their 107 tower block estate to most effectively reduce fuel poverty and to cut carbon emissions. This included recommendations for over-cladding a relatively small number of solid-walled blocks constructed from large pre-cast concrete panels, the most thermally inefficient buildings in their portfolio. The Council had already over-clad quite a number of blocks over the years, some of which have more recently been reported in the press to have potential problems in relation to combustible cladding. Our report was very high level and we did not recommend any particular system but, had we been asked, we would have been cautious. My colleagues in Arup Fire had already become very concerned about issues of specification and workmanship on new build residential blocks. 

Dr. Barbara Lane leads Arup Fire and has been an expert witness to the Grenfell inquiry. I read the summary of her report online: it was powerful and damning. I looked at others too. There were different types of flammable foam used in the infill panels around new windows, as well as fixed to the outside of the building. There were gaps around some windows and the gap sealant was flammable polyurethane foam, although there appeared to be gaps where it had not been installed at all. The fire barrier strips intended to prevent flame from spreading up the building behind the rain screen were badly fitted from the evidence of sample inspections: some were at right angles to their correct positions or had ineffective expanding foam fire barriers (not flammable, of course), rendered useless by being fitted against the concrete rather than facing outwards. The rain screen cladding that conceals the insulation is in sizeable panels, which go on quite rapidly and soon cover up mistakes. Daily inspections by supervising professionals are needed in this type of critical work and my experience is that this no longer happens on most jobs because of the cost. It is no longer usual to employ a clerk of works for such duties but instead to rely on occasional inspections by the design team. The errors are usually as a result of ineptitude or haste in my experience, rather than anything more venal. 

Once the fire took hold there was a vertical route behind the rain screen cladding, which acted as a flue to spread the fire up the building very rapidly. The temperature was sufficient for the aluminium cladding to ignite, accelerated by the thin layer of foam at its core. Barbara Lane’s assessment was that by 1:30, about 40 minutes into the fire, the stay in place strategy was redundant and the building should have been evacuated. Easier said than done, as the fire service testimonies have shown. The fire service response is criticised in Arup's report and the evidence of individual officers to the Grenfell public inquiry suggests a lack of training and equipment. The unprecedented rapidity and scale of the fire soon overwhelmed the fire officers attending. Nevertheless, despite appalling conditions in the single staircase that was the sole means of escape, more residents escaped or were rescued than might have been expected, given the scale and speed of the blaze. There were also numerous other issues around:

• under-performing fire doors
• disconnected door closers
• gaps around services pipes and wires entering the flats
• gas heating to individual flats (strongly advised against after Ronan Point)
• the smoke evacuation system's failing to work in the (single) stairwell.

Andrew O’Hagan’s 15,000 word article in The London Review of Books provided a very interesting alternative analysis to the main press and broadcast coverage. His view is that the media decided early on to pursue a story of an uncaring, cost-cutting, developer-centric Tory council that has long disregarded the welfare of its poorest residents. It has been inept and lacklustre in responding to the disaster. Media coverage has not revised this narrative, despite the emergence of a more complex reality. The Council had invested in the tower block and although the cladding specification and related choices of materials have proved disastrously unsuitable, the architects followed an established approach, which was believed to compliant with the Building Regulations and codes of practice. The Council has provided extensive funding for the dispossessed residents and its staff have worked hard to help them from the outset. It is clear, however, that the Council hopelessly mismanaged the public relations challenge of such a catastrophic incident and should have sought expert help from the outset.

This has been a terrible disaster and it is remarkable that, apart from the serious fire at Lakanal House in 2009, which the Government failed to act upon, we have not had more problems with tower blocks. I was surprised to discover in Liverpool in 2005 that many councils had routinely not taken out gas supplies or strengthened wall to slab connections in blocks directly at the same risk of disproportionate collapse as Ronan Point 37 years earlier, despite clear advice. For me some of the most significant points to emerge from the investigation of what went wrong at Grenfell are the dangerous extent to which we have become dependent on flammable foamed plastics for insulation and gap filling. Plastic windows also burn more readily than timber windows and perhaps new materials such as Accova, a chemically treated and hardened softwood highly resistant to decay, might provide more resilient solutions. The importance of fire doors, fire alarms, fire stopping around building services where they pass through walls and floors and properly protected escape routes are fundamental essentials to protect residents and must be maintained and tested regularly.