Grenfell: Not One Failure, Many

Trying to navigate the appalling fire at Grenfell Tower is a horrible task. It’s difficult to be forensic about this, and this isn’t intended to be a forensic piece. We don’t know or sure what happened, and pre-empting it is never a good idea.

One thing I have noticed is that many commentators are looking for a magic bullet: a single thing wrong that caused this appalling piece of (quite probably) mass manslaughter. I think this is a little misguided, for this reason: Grenfell Tower can only have happened if there was a massive number of failures. A lot of focus is being given to the cladding, and with good reason (we’ll come to that). However, if this was just the cladding, the death toll should have been minimal (and quite possibly zero). All sorts of people have completely failed in their duties here, and I think it’s important to run through how.

There have already been some – in my view – misguided pieces that have rushed to judgement about how this happened. So I think it’s worthwhile is to look at how the regulations work, how buildings like this are supposed to work, and thereby make it easier to understand the evidence as it comes out. Fire is a horrible and primal force, but the language around it is technical. Terms like “non-combustible,” “fire-rated” and “Class 0 rated” sound like they are synonymous, when they are not. In addition, the ways of making a building fire-safe are not always intuitive.

To give an example: Jeremy Corbyn – for whom I have a lot of time – talked about the need for sprinklers in these building. I happen to agree with him that sprinklers are a good thing, in a belt-and-braces way, and there’s something to be said for installing them in tall residential buildings. However, the lack of sprinklers wasn’t the primary problem here, the building should have been safe without them, and by focusing on sprinklers you let other people off the hook.

Similarly, residents have referred to a series of worrying defects by the owners, such as fire extinguishers not being tested and power surges within the building. These are not good, to put it mildly. However if it transpires that none of these were primary issues in what happened, it doesn’t mean the owners are free of all responsibility. Fire safety is about structure, and layout, and wall specification, and all sorts of complex things that can only have been neglected for this to happen.

Fire safety is achieved by combining a number of factors. The regulations are split into five parts, which I’ve combined into four (My second part, Internal Fire Spread, is in fact two sections).

1. Means of Escape

This, essentially, is the big one. If a fire breaks out, it should be simple, safe and straightforward for people to exit the building. In an apartment building this means that there should be a central alarm system, which sensibly links the alarms in each property; each apartment should be fire-separated from other apartments, and from the shared corridors, which in turn are completely separated from the staircases; emergency lighting so people can find their way out; travel distances controlled, so nobody is ever too far from a place of safety. To get this to work needs a lot of detailed work on door widths, on fine-tuning the alarm systems, on providing fire-protected corridors and stairways, and (preferably) providing a choice of escapes.

Perhaps the most important thing to note is this: stairways are absolutely sacrosanct. No matter how much you’ve stuffed up everything else, the stairway being protected means that the fire is contained to a single floor and everybody else can get out. As Grenfell only had a single stair (a pretty abysmal arrangement that’s strongly discouraged these days), the safety of the stairway is absolutely critical. The fact that the stairwell was excluded from the recent refurbishment, and reportedly had gas pipes running through it, is enough to make anyone aghast. It’s known that there was a ruptured gas main, making this stomach-churningly critical.

As a final note – regardless of what happened to the cladding, the stairway was fully internal (See plans here). On the face of it, no matter how much the fire burned, it should have been safe to evacuate.

By definition, if anyone is killed or injured by fire, the Means of Escape element has failed. In this case, regardless of how the fire spread through the building, it’s clear that this failed completely. Nobody could get out. The emergency lighting, reportedly, didn’t work. The alarms did not warn residents. This is appalling; it’s also exactly the kind of thing that can easily fail with unscrupulous building owners, because the only thing that highlights their approach is… well, something like this. That’s why we need to be talking about oversight first and foremost.

2. Internal Fire Spread

This covers both linings and structure. The lining section is pretty straightforward; most parts of the building should be almost exclusively lined in substances that don’t aid fire spread (this is where “Class 0” terminology comes in), and it’s there to stop a room bursting into flames. The structure part is perhaps more important. Effectively, if one discrete part of a building (say an apartment) does go on fire, the boundary walls (”Compartment walls”) should be fire resistant – usually by at least one hour, but for a tall building this figure increases. This is a basic principle called compartmentation. In theory, the fire in one apartment should burn itself out without affecting anyone. At the very least, people should have ample time to evacuate the building by the time the fire spreads, and the fire brigade will generally have enough time to fight the fire before it breaches the compartment.

Many of the things about which Grenfell’s residents previously complained – power surges, for example – are extremely dangerous and could start a fire. That’s unforgivable in itself. However, fires can also be started by careless behaviour or bad luck. If the building’s compartmentation was working, that fire simply would not have spread beyond one apartment. Even if the apartment compartment failed, the fire should not have reached the stairs.

In this instance, compartmentation obviously failed catastrophically. The usual hateful shitrags (the M**l, The S*n) have started focusing on the guy whose fridge started the fire, but blaming him is pathetic. The fire should not have spread. Now, there’s a fair amount of evidence that, rather than the apartment walls failing, the fire spread externally. Which leads us to…

3 .External Fire Spread

It’s no good having compartments if the fire can jump the gap externally. There are rules about fire spread, which means that the area around compartment walls need to be treated carefully. There should be 1.5m between zones of unprotected wall around a compartment line. For a stairs (as mentioned before, keeping the stairs safe is critical), that gap widens to 4m – and for avoidance of doubt, any wall with a combustible surface cladding is not protected. If there are cavities or air gaps between cladding and the main wall, they need to be blocked at these lines with a fire-resisting material.

This means that the issue isn’t the cladding being “flammable”. Even if the cladding burns away in one zone, it shouldn’t spread to any other zone.

Extract from Approved Document B

For tall buildings, external fire spread becomes even more critical. I haven’t seen the following reported widely, but it seems crucial to me: there’s a requirement that cladding be of “limited combustibility” for buildings more than 18m high (Approved Doc B, Section 12.7).

Doc B appears to prohibit the use of combustible materials for high buildings

While “Limited combustibility” isn’t the same as “non-combustible,” the cladding really shouldn’t burn very much at all. This really doesn’t seem to have been the case, and doesn’t square with the contractor’s insistence that the cladding was installed in accordance with the building regulations.

(Here’s an important note: a lot of the early coverage noted that the cladding was “Class 0 rated.” This is one of the ways that fire safety gets a big complicated. Class 0 means that fire won’t spread along the surface of the material; it doesn’t mean it won’t catch fire. Something being Class 0 doesn’t mean it won’t burn.)

It’s so obvious that it’s almost tasteless to say it, but this seems to have failed appallingly.

4. Access For The Fire Brigade

This is partly about how close a fire engine can get to a building, but there’s another dimension.

Fire engines can’t run their ladders 50m up in the air. The fire brigade have to get into the building, via a safe route, and fight the fire from the inside. Their safe route is a firefighting stair, or in some cases a firefighting lift.

In many cases – and Grenfell Fire is one – the escape stair and the firefighting stair are the same thing, so people escape down and the fire brigade work their way up. In this case, the fire stair was completely inaccessible. This left the fire brigade with absolutely no way of fighting the fire at all. At most, they would have been able to access the first ten or twelve storeys with ladders. Anyone above that couldn’t be helped.

There’s also the question of how they fight the fire. There should be risers within the building – essentially, pipes full of water for the fire service to connect hoses to. This seems not to have been present either, meaning they simply had no water above a certain height.

So again, this element completely failed.


These are general headings. It’s impossible to precisely apportion blame at this point. Even if we assume that the new cladding was the main way that the fire spread, we don’t know if it failed because it wasn’t up to the task, or because it wasn’t detailed carefully, or wasn’t installed properly, or because a cheaper material was substituted… there’s no way of being sure right now. There are a number of parties (owner, architects, the builder) who will have questions to answer, and some of these people may yet be blameless.

What we do know is that if the problem was just that the cladding failed, there still should not have been a catastrophic loss of life. So there has been not just one failure, but a whole multitude of them. The likelihood is that a great many people have been negligent.

The local council state that the building was regularly inspected, but this is where the question becomes political. An “inspection” can mean anything. Fire safety is complicated and technical, and many of the measures used to keep a building safe will be hidden. It takes a lot of time – and therefore money – to thoroughly test the fire safety of a building. I’m not sure whether councils are sufficiently resourced to do this. Measures that really could save lives – we’re talking insitu testing of wall construction, or fire drills conducted by a third party – are so expensive to be out of reach. In the UK, approved Building Control Assessors do not have to be specialists in fire (Irish readers should note that Irish regulations are different, and Fire Safety Certificates are assessed by specialists as a separate process).

One would hope, at the very least, that this will lead to some serious prosecutions. It should also lead to an overhaul in how we assess fire. Over the coming days and weeks, no doubt we will hear of this being called a tragedy. It is, of course. But we should also be clear; this tragedy came about as the result of a series of deliberate actions or omissions. Everybody deserves to understand what they were.

About Mike Morris

A British / Irish architect who practiced in Ireland and Ontario, now working in the U.K.
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2 Responses to Grenfell: Not One Failure, Many

  1. Colm Moore says:

    You seem to have misspoken here: “the contractor’s insistence that the **fire** was installed in accordance with the building regulations” – I presume you mean cladding.

  2. Susan Pettie says:

    Thanks for this. Susan

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