Gordon Campbell: The lessons of the London tower block fire

Published: Thu 15 Jun 2017 10:55 AM
Gordon Campbell on the lessons of the London tower block fireFirst published on Werewolf

As details emerge of the deadly fire at Grenfell Towers in north Kensington, it has become clear that the tenants group at the tower block had repeatedly warned the authorities about the fire risk - the record of neglect on fire alarm batteries alone dates back to 2004. These warnings included concerns about the inadequate exit route for tenants and the equally inadequate access route for firefighters. According to news reports, some 20 fire engines attended the blaze yesterday. On the prior evidence, the access routes might well have struggled to cope with four to six.
The links below show how often those complaints and warnings were made by the Grenfell Action Group, and the inadequacy of the official response to them, prior to the fire. This warning issued by the tenants group in November 2016 seems particularly chilling:
It is a truly terrifying thought but the Grenfell Action Group firmly believe that only a catastrophic event will expose the ineptitude and incompetence of our landlord, the KCTMO [ie, the Kensington and Chelsea Tenant Management Organisation] and bring an end to the dangerous living conditions and neglect of health and safety legislation that they inflict upon their tenants and leaseholders. We believe that the KCTMO are an evil, unprincipled, mini-mafia who have no business to be charged with the responsibility of looking after the every day management of large scale social housing estates and that their sordid collusion with the [Kensington and Chelsea Royal Borough] Council is a recipe for a future major disaster.
Some of the tenants group’s other prior warnings and safety concerns can be traced here:
One of the other factors evident in yesterday’s fire – and this should be of interest to anyone in New Zealand living in a high rise apartment – is the speed with which the fire climbed the outer shell of the building once it had escaped from its original site, which is believed to have been located circa the fourth floor. Grenfell Towers had been renovated fairly recently. It is as yet unknown whether the fire risk issues to do with the external cladding were addressed at that time. It would seem not, given how quickly yesterday’s fire spread.
This 2016 document by the UK Probyn-Miers firm that specialises in architectural dispute resolution offers the clearest explanation I could find overnight of how external cladding can contribute to the speed with which fire can travel through high rise buildings. Probyn-Miers cite evidence from fires in the UK and from high rise building fires in Dubai. It begins its discussion of the mechanisms of how the fire spreads with these observations:
Ignition of composite panels, even those with combustible cores, is not usually instantaneous, but there are various core materials used and they have very different ignition properties. The early stages of fire development are relatively slow. It is only in well-developed fires that the combustible cores burn with savage intensity. However, polymeric core materials such as EPS [expanded polystyrene] and PUR [polyurethane] will burn at temperatures well below that of a fully developed fire and thus contribute to fire spread.
There is a risk in fire conditions that composite panels are attacked at the joints, or the panels suddenly delaminate and the metal facing falls away, thus exposing the combustible core which then intensifies and spreads the fire. The sudden increase in fire severity can accelerate the failure of the adjacent panels, so that if a fire does take hold, it can race up or through an entire facade of a building, causing a major hazard to occupants and a major property loss. Foam cores exposed through damage, fixings or penetrations will ignite sooner than intact panels. Aluminium has a much lower melting temperature than steel and aluminium facings will fail earlier.
Delaminated panels can fall off the building, raining down hot metal and burning foam insulation on the surrounding area, with risk of personal injury and of starting secondary fires. [In media photos yesterday firefighters at Grenfell Towers were shown using shields for protection against this falling debris.]
Probyn-Miers also quote from the UK Building Research BR 135 report (2013 edition) which details the mechanisms of how a fire once established, then proceeds to spread:
Following the initiation of a fire inside the building, if no intervention occurs, the fire may develop to flashover and break out from the room of origin through a window opening or doorway … Flames breaking out of a building from a post-flashover fire will typically extend 2m above the top of the opening prior to any involvement of the external face, and this is therefore independent of the material used to construct the outer face of the building envelope …
3.3 Interaction with the external envelope
It is at this stage of the fire scenario that the fire performance of the complete external cladding system, including any fire barriers, is critically important. Once flames begin to impinge upon the external fabric of the building, from either an internal or an external source, there is the potential for the external cladding system to become involved, and to contribute to the external fire spread up the building by the following routes.
3.3.1 Surface propagation
The reaction to fire characteristics of the materials used within the external cladding system will influence the rate of fire spread up the building envelope by way of the surface of the external cladding system.
3.3.2 Cavities
Cavities may be incorporated within an external cladding system, or may be formed by the delamination or differential movement of the system in a fire. If flames become confined or restricted by entering cavities within the external cladding system, they will become elongated as they seek oxygen and fuel to support the combustion process. This process can lead to flame extension of five to ten times that of the original flame lengths, regardless of the materials used to line the cavities….
As a result, such established fires can “jump” above any compartmentalised fire safety sections of a tall building, and re-enter at a higher point, thus creating a situation where firefighters can be faced with several simultaneous fires. As Probyn-Miers indicate in the section of their report on the history of building materials, with particular respect to composite panels and their related fire risk:
Composite panels were developed as a means of providing a cheap, lightweight, weathertight, insulated building envelope, rapidly erected over the interior structure. Composite panels generally consist of internal and external metal facing sheets, bonded to a core of various alternative insulation materials. The facings are typically aluminium or steel, with coatings for weather-resistance externally and decoration and hygiene internally.
The most common forms of insulation cores for composite panels in use in the UK at the end of the 20th century, in order of decreasing probability of fire propagation, [4] were:
•polystyrene (EPS),
•polyurethane (PUR),
•polyisocyanurate (PIR),
•mineral fibre.
Probyn-Miers then discuss each of these ingredients in turn. For example:
EPS will initially soften and shrink away from a small flame, but will then melt and burn. The voids created by melting admit oxygen, which intensifies the fire. Molten flaming droplets can spread the fire. All the material between the metal facings is likely to be consumed, leading to loss of structural stability. At the outset of the fire, development is fairly slow and contained. In a well-established fire, the material will contribute to the fire development. Delamination and collapse may be sudden. EPS was recognised as the worst of the plastic foams in fire conditions.
Probyn-Miers go on to offer a useful discussion of the potential role in a fire situation of the other materials it has listed. Its conclusions indicate that – as with earthquake prevention – the risks of fire will probably be balanced against the costs involved.
Can anything be done about the worldwide legacy of buildings with combustible cored composite panels? Unless something radical is done, such as national retro-fitting subsidy schemes, it seems inevitable that there will be further fires involving aluminium-faced polyethylene core panels. Nightmare scenarios include multiple-fatality building-engulfing fires as in China, or given the proximity of towers in some districts, the ignition of neighbouring buildings’ cladding from an external cladding fire, or disintegrated burning panels igniting the roofs of lower buildings adjacent.
It is difficult to envisage owners voluntarily stripping off entire existing aluminium composite panel facades and replacing them with Fire Code-compliant cladding panels, as the cost would be prohibitive. Partial replacement with barrier bands of fire resistant panels has been suggested to stop fires spreading, but given the flame heights at the Tamweel, Torch and The Address, such barrier bands would have to be substantially large. The works necessary to provide these barriers would involve much of the scaffolding and associated costs of full replacement.
At Grenfell Tower, such factors seem to have led the authorities to hope that the worst would never happen. They were choosing, as the Grenfell Tenants Action Group pointed out prior to the fire, to play Russian roulette with the lives of their tenants. At the very least – in the light of the Grenfell tragedy – it will now behoove any body corporate or tenants group or hotel management in any high rise building in this country to become better acquainted with the role of composite panels, the composition of the insulation cores and the extent of external cladding in their particular building.
Similarly, such groups may need to update the practice drills of the emergency exit routes for tenants, and the adequacy of access for firefighting services. One of the tragic aspects of the Grenfell Tower fire is that tenants had reportedly been advised to retreat to their rooms in the event of fire - and not take the risk of descending the sole narrow, twisting stairwell in the dark. Anyone who took that advice appears to have lost their lives.
From the Grenfell Tenants Action Group links, it is also clear that (a) the sole exit was allowed by management to be cluttered with rubbish and that (b) the narrow roadway access for fire vehicles was routinely clogged by other vehicles using the site. Points also worth checking in local high rises.
Song for Theresa
It seems every boomer on the planet has been weighing in on the 50th anniversary of Sgt Pepper – and the drug does appears to be finally wearing off, given the prevalence of the “Oh it wasn’t so great/Revolver was better” verdicts. Personally, John Lennon’s “Rain” and Paul McCartney’s Little Richardesque screamer “I’m Down” were pretty much where it began and ended for me with these guys – and the latter song came to mind recently as a soundtrack for Theresa May’s, terrible, no good, very bad experiences of late. “You tell lies thinking I can't see…” Indeed. “You can't cry 'cause you're laughing at me”. Sure. Here’s the live version of “I’m Down” from the Beatles’ 1965 Shea Stadium finale:
Around about the same time in Lima, Peru, Los Saicos were throwing down a solid claim as the godfathers of 70s punk rock. Or the culmination of early 60s surf/garage punk… a hat tip to Jon Spencer for spreading the word about them.

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