What caused the Grenfell fire? Here’s what we know

Never again. Image: EPA/Neil Hall.

The Grenfell Tower fire resulted in the greatest loss of life from a fire in Britain since World War II. A year on, we know that the fire’s rapid spread was at least partly due to the cladding that enveloped the building. Although a public inquiry is ongoing, and we’re still waiting for the full results of forensic evidence, there is no doubt that changes are needed to prevent this catastrophe from happening again.

This includes new regulation for high-rise buildings and the use of flammable materials in their construction. In addition, experts and researchers in fire safety need to work more closely with the government and construction companies. More immediately, for buildings similar to Grenfell, that were built according to old regulations, simple and immediate actions should take place now. Evacuation routes, sprinklers and fire retardant materials need to be installed as quickly as possible.

Construction problems

Grenfell Tower was built in 1974 and contained 120 flats, housing between 400 and 600 people. It was like a small vertical village. In 2016, the building was refurbished at a cost of £8.6m; this was when the cladding was introduced.

From the first media reports on the morning of 14 June 2017, engineers and scientists raised concerns over how quickly the fire spread, especially on the outside of the building.

It seemed that the fire was unable to be contained within a compartment. The concept of compartmentation in fire engineering is widely used in constructing buildings. By adding fire barriers, often fire resistant doors, fires are supposed to stop spreading quickly and so allow time for evacuation and treatment. But at Grenfell this did not happen: the fire quickly found access to the outer side of the building. Something had gone horribly wrong and the fire safety advice to residents to stay inside has since come under scrutiny.

The flammable cladding was instrumental in the fire spreading so quickly. Image: Flickr/ChiralJohn/creative commons.

Immediately, the focus was put on the new exterior skin (cladding). This not only contained flammable materials (polyethylene insulation covered by thin aluminium sheets that buckle in high temperatures and expose the internal material to flames), but was also installed onto the existing incombustible reinforced-concrete structure, in a way that left a gap between the facade and the building’s structure. This enabled what is known as the “chimney effect”. Put simply, the gap between the facade and the structural skeleton of the building meant that the fire sought oxygen and quickly travelled vertically, while burning more of the flammable skin.

It seems that the facade system, even if it was designed according to some regulations, did not perform properly. Such a catastrophic failure can never be the result of one single factor but rather was a chain of unforeseen events happening all at the same time.

Making sure it doesn’t happen again

Materials are still being fire-tested and several blocks remain evacuated. But although changes to building regulations are likely, these changes have yet to happened. This is partly because of the sheer complexity of the issue.

But some of the regulations that need to be implemented are clear. For a start, each type of building should be designed or refurbished with the appropriate regulation. So for example, all buildings that are higher than five stories ought to be provided with alternative evacuation routes such as more (or external) staircases, be equipped with sprinklers, and only be allowed to use fire-retardant materials, such as cementitious boards, ceramics, or glass facades.


Buildings like Grenfell should further be equipped with more sophisticated early warning systems that can detect the smoke and fire early enough. Not only could these systems set the alarm on and activate the sprinklers, but they could also restrict the fire within an area by making the building “active”. This could include automatically closing windows and self-controlled ventilation systems and elevators.

Another major positive change for tall residential buildings, would be the increasing use of performance-based fire resistance design. This is when each particular building is designed so that it performs under certain safety and strength criteria, allowing engineers to fully understand how the building will respond thermally and structurally to a fire incident.

Currently in the UK, for some buildings a general prescriptive-based approach is followed, which simply states how a building is to be constructed. The problem with prescriptive guidelines is that engineers ignore the actual response of the building and the effect of real fires, making the level of safety and robustness an unknown. Although this might be more costly in time and expense, when you have so many people living in one building it is necessary.

Each building design is also a different entity with its own limitations. So each building should be treated accordingly.

Collaboration and communication

Forensic evidence is still being collected and preserved. Once all the evidence is in, researchers and investigators will be able to review the causes and reasons why the fire spread in more detail. But right now we still do not have a deep enough understanding of the flammability of the facade systems, or the toxicity of the materials used.

Once we do, collaboration between academic researchers and companies producing cladding and other construction materials will be key. This is the only way of ensuring that products are developed to meet or exceed rigorous safety standards when put under pressure. This will be crucial for giving housing residents and the public greater confidence. Better communication between building regulators, local authorities, manufacturers, developers, and designers is also important.

The ConversationWe must start rehabilitating tall residential buildings as soon as possible, before another disaster occurs. And out of this tragedy must come long lasting changes to the design of buildings, the construction materials used, and the way they are applied.

Konstantinos Daniel Tsavdaridis, Associate Professor of Structural Engineering, University of Leeds.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

The media scumbag’s route of choice: A personal history of London’s C2 bus

A C2 bus at Parliament Hill. Image: David Howard/Wikimedia Commons.

London’s C2 bus route, which runs from Parliament Hill, by Hampstead Heath, down to Conduit Street, just off Regent Street, is one of the bus routes recently earmarked for the chop. It has oft been noted that, of all the routes recently pencilled in for cancellation after a consultation late last year, it was the one most likely to survive, for the simple reason that it links liberal suburban north London with BBC Broadcasting House and Soho; it’s thus the route most likely to be used by people who can convince someone to let them report on its imminent demise.

So it would come as no surprise that former Guardian editor Alan Rusbridger took to the Camden New Journal when the consultation began, arguing that it would be a disservice to the local community to discontinue a route where you can always get a seat – seemingly missing the point that the fact you can always get a seat is not a great sign of the route’s usefulness.

It wasn’t always that way. When I left university in 2000, and moved from accommodation near college to up to a rented shared house in N6, the C2 was my bus. I commuted to Soho for sixteen years: for more than a decade from flats around the Swain’s Lane roundabout, and for five years from Kentish Town. While my place of work bounced around from Golden Square to Lexington Street to Great Marlborough, it was always the most convenient way to get to, and from, work; especially given the difference between bus and tube prices.

So when it comes to the C2 I’ve seen it, I’ve done it, and bought the bus pass. And by bus pass, I mean those little paper ones that still existed at the beginning of this century. Not just before contactless, but before Oyster cards.

More importantly, it was before London buses operated a single zone. There was an outer zone, and an inner zone, with different prices. To travel from one zone to another cost £1.30, meaning an all cash commute was £2.60, whereas a paper bus pass was £2.00. That made it worth your while to divert to an early opening newsagents on your way to the bus stop (GK, in my case), even if you only got two buses a day.

It’s a measure of how greatly London’s buses have improved over the last twenty years, since first brought under control of the mayoralty, that pretty much everything about this anecdotage, including the prices, seems faintly mad. But there’s more: back when I started getting that bus down to Stop N, literally at the very end of the route, the C2 used single decker buses with a single door. It’s an appalling design for use in a crowded city, which meant most of any journey was, for most passengers, spent fighting your way up and down the middle of the bus to find a seat, and then back again to get off; or – and this was more likely – fighting your way up the bus to get into standing space the driver insisted was there, before fighting your way, etc.

Such buses – and in my former life in the English Midlands I went to school on one of these buses every day – are perfectly functional where bus stops are infrequent and buses rarely standing room only. But running through Camden Town at rush hour, they’re wholly unfit for purpose.

A Citypacer. Image: RXUYDC/Wikimedia Commons.

It could have been worse. I didn’t know this at the time, but a few years before the C2 route had been run using Optare City Pacers. Those are, let us be frank, not really buses at all, but minibuses. That’s something the reveals the C2’s origins, as a hopper route to the west end largely intended for the daytime use of Gospel Oak’s pensioners in the years immediately before bus privatisation. (The C11 has a similar origin, taking the same constituency from Archway to England’s Lane.)

Once responsibility for London Buses was moved to the newly established mayoralty, things improved dramatically. Under Ken Livingstone it went double decker in 2005, and 24 hour in 2007. Under Boris Johnson it was extended from its once, and future, terminus of Conduit Street to Victoria Station, swallowing up the cancelled sections of the 8 bus; this extension was quietly disposed of a few years later, once it was clear no one would notice. (I did.)


In those years I must have taken a C2 the best part of ten thousand times; but for all the years when I wouldn’t have been able to live without the C2, times have reduced its utility, and not just for me. I’m now a 214 sort of guy: these days the top chunk of the C2 route is duplicated exactly by that other bus, which starts up in Highgate Village and, once it gets to Swain’s Lane, follows the same path until the fork of Kentish Town Road and Royal College Street, opposite the long defunct South Kentish Town tube station.

From a few hundred metres below that point, at Camden Gardens, stop C, the 88 starts. That duplicates the rest of the C2’s route, with the exception of the run down Albany Street and onto Great Portland, for much of which the C2 is the only bus.

So the C2, old friend that it is, is pretty redundant in the age of the hopper fare, which allows you to change buses without paying a second fare. That’s even more true now the C2’s otherwise un-serviced stops are being giving over to a re-routed 88, which will pick up the C2’s most northern leg, by not finishing at Camden Gardens anymore and instead going all the way to Parliament Hill Fields. Which will be nice for it.

All this, however, ignores the best reason for getting rid of the C2 (or rather for merging it with the 88, which is what’s actually happening): that first character. The letter. Who wants a bus route with a letter in front of it when even half the night buses don’t have the N anymore? It’s relic of the route’s aforementioned origins as a ‘Camdenhopper’.

That C is twenty five years past its own utility. It’s just untidy. City Metric hates that sort of thing. Get rid.