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Grenfell Tower fire

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Is this a choice of material issue if it was the external wall insulation that caused the fire to spread?

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I understand that it was clad with EPS EWI a year or so ago.  Looking at the photos it seems as if the vertical spread of fire was up the outside, most probably the EWI burning.  The major problem with cladding high rise building in this way is that it creates a spread of fire risk vertically up all the walls, and what's worse, it prevents people leaving easily, or firefighters gaining entry, as the molten, burning, EPS drips down all around the walls. 

 

A search of YouTube for "facade fires" will show some nasty ones, like this:

 

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If it was the insulation/cladding, then it really needs to be incombustible rather than just slow burning in my opinion.

I wonder how many tower blocks have this system installed in the UK.

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I remember looking into this a few years ago, when it was being discussed either on Ebuild or maybe the GBF, and concluding that there were some pretty dodgy assumptions being made about the fire risk.  There were some changes made to the design of EWI, following tests that the BRE performed, that were intended to delay the propagation rate of fire in cladding and provide protection over openings, to reduce the risk of dripping, burning, plastic preventing the use of entrances/exits.

 

As this building was only clad about a year ago, I would have hoped that it should be to the current standards.  It seems very clear from the photos and reports that the spread of fire was very rapid, it went from the fourth floor to the top floor in a matter of a few minutes.  I strongly suspect that the very dense smoke from the burning EWI may have been a significant cause of people being unable to escape.  The building seems to have had only a single internal lift/stair well, and there are reports that this filled with dense smoke in the early stages of the fire.

 

Edited to add:

 

Sadly it seems that there have been fire concerns about this building for some time: https://grenfellactiongroup.wordpress.com/2016/11/20/kctmo-playing-with-fire/

 

Quote from that blog, from November 2016:

Quote

It is our conviction that a serious fire in a tower block or similar high density residential property is the most likely reason that those who wield power at the KCTMO will be found out and brought to justice! The Grenfell Action Group believe that the KCTMO narrowly averted a major fire disaster at Grenfell Tower in 2013 when residents experienced a period of terrifying power surges that were subsequently found to have been caused by faulty wiring. We believe that our attempts to highlight the seriousness of this event were covered up by the KCTMO with the help of the RBKC Scrutiny Committee who refused to investigate the legitimate concerns of tenants and leaseholders.

We have blogged many times on the subject of fire safety at Grenfell Tower and we believe that these investigations will become part of damning evidence of the poor safety record of the KCTMO should a fire affect any other of their properties and cause the loss of life that we are predicting:

 

Edited by JSHarris

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Reports seem to say it started on the 4th floor.

 

So just what set light to it on the 4th floor?  There won't be anything external (wiring etc) to cause that. So was it started by a fire in a 4th floor flat?

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18 minutes ago, ProDave said:

 

 

So just what set light to it on the 4th floor?  There won't be anything external (wiring etc) to cause that.

The most common risk is a lit cigarette being thrown out of a window and landing on the top of  a section of damaged EWI below. There was a similar case recently with a cigarette landing on a balcony and starting a fire.

 

Once the fire gets into the EPS it spreads upward and horizontally under the surface of the render. Fire barriers at intermediate floor levels will do little to contain a fire like that.

Edited by Ian

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There are eyewitness reports that there was an appliance fire in a fourth floor flat, that may have been the cause: http://www.bbc.co.uk/news/av/uk-england-london-40270332/an-eyewitness-inside-the-tower-block-describes-the-scene-inside

 

He reports the fire starting in a kitchen, spreading out the kitchen window and then igniting the flammable wall cladding. 

 

This photo (from the BBC News site) shows the early stages of the fire, spreading up from the window on the fourth floor where it started:

 

_96481851_grenfellpa.jpg

Edited by JSHarris

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Been listening to the breakfast news coverage in the background, and I have yet to hear anything that I think gets above "inane". Piers Morgan declaring "it is extraordinary that in modern Britain .... xyz". No it isn't, Piers - design errors and mistakes get made. Various perambulations around the alleged dodginess of "stay put" fire protection policy (as recommended by the people who know in the official guidance documents after balancing the risks against general panic etc). Just waiting for an expert to tell them to shut up and stop scaring people just to fill space.

 

1 hour ago, JSHarris said:

Sadly it seems that there have been fire concerns about this building for some time: https://grenfellactiongroup.wordpress.com/2016/11/20/kctmo-playing-with-fire/

 

Probably (and I am sure everyone here will) treat that blog with a degree of caution. It has a Green Ink feel, and they are given to startling jumps.

 

eg Before the para Jeremy quotes, it says:

 

Quote

We believe that the KCTMO have ensured their ongoing survival by the use of proxy votes at their Annual General Meeting that see them returned with a mandate of 98% in favour of the continuation of their inept and highly dangerous management of our homes. It is no coincidence that the 98% is the same figure that is returned by the infamous Kim Jong-un of North Korea who claims mass popularity while reputedly enslaving the general population and starving the majority of his people to death.

 

Or this piece where the refusual to temporarily unfence a fenced-off of a tree (presumably for protection etc) causes them to make comparisons to various genocides. 

 

One of the possible moments of levity in this business will be when media doesn't check properly and reports the Green Ink stuff as news.

 

(Add: I have seen mention of an alleged "exploding fridge".)

 

Ferdinand

Edited by Ferdinand

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I have seen mention of an "appliance fire" presumably where the fire happened (if this is indeed what happened) they opened the window, or the fire burst the glass?

 

P.S wood fibre external cladding does not ignite and spread like this.

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Whilst I'd agree about the bias in that blog, it does seem a little prescient that the author of it wrote this sentence:

Quote

It is our conviction that a serious fire in a tower block or similar high density residential property is the most likely reason that those who wield power at the KCTMO will be found out and brought to justice!

 

Edited, in light of new information to remove an innocent companies name.

 

I don't think it needs a detailed analysis to prove, beyond any reasonable doubt, there there are significant spread-of-fire risks from fitting flammable external wall insulation to high rise buildings; there have been enough cases of facade fires to prove this.  The photos that have been published show pretty clearly that the spread of the fire was up the outside of the building, not the inside.  Fires that spread from inside tend to show on the outside with smoke and flames coming out of windows; this fire shows the flames spreading over the outside walls.

 

To balance this risk, and put it into perspective with regard to domestic properties, I don't believe that EPS/XPS EWI is really a problem with houses up to two or three storeys high.  All the evidence available seems to show that facade fires like this almost always occur on tall buildings, where the intense heat can penetrate through parts of the structure and any fire breaks within the insulation itself.  From the photos of Grenfell Tower, it seems that the aluminium cladding outside the insulation was actually burning as well, which gives an indication of the sort of temperatures generated around the outside of the building.  Sadly, there are also eye witness reports that the firefighters were unable to access the dry riser - if they turn out to be true then it would have made things a lot worse, as they would have found it very hard to try and fight the fire from inside, I'd guess.

 

 

Edited by JSHarris
corrected typos and new information

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3 minutes ago, JSHarris said:

also find it interesting that Knauf have acted very quickly to take down all references to the insulation on the outside of this building from their website.  It was there earlier this morning and now it's been deleted (but it is still cached in a couple of places and easily found).

 

On the basis that Knauf have removed the references, one can infer that it was their insulation used. Are we able to determine from that, what sort of insulation it was?

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Edited, in light of new information to remove an innocent companies name (article quote removed).

 

There are other articles that state that the insulation was covered with aluminium architectural cladding, which I would guess was also intended to be a fire barrier.  If the insulation was foam (and I think this is extremely likely - the mass would need to be low, because it's going on a 24 storey building) then it would have been treated with fire retardant, but no fire retardant will work on flammable foam if it gets exposed to high temperatures, the retardant can only really reduce the chance of the foam igniting accidentally.

 

 

Edited by JSHarris
New information

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I have read that it was a PE based insulant, although probably just Interweb speculation.

 

Is this a failure of design or procurement - should the insulant have been flame retardant and some dodgy panels have been fitted, or is it allowed to not be?

 

I can see Knauf might get a lot more work out of this when they start tearing down all the retrofits.

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1 hour ago, JSHarris said:

All the evidence available seems to show that facade fires like this almost always occur on tall buildings, where the intense heat can penetrate through parts of the structure and any fire breaks within the insulation itself.  From the photos of Grenfell Tower, it seems that the aluminium cladding outside the insulation was actually burning as well, which gives an indication of the sort of temperatures generated around the outside of the building. 

 

Are you saying the temps are higher in a higher rise building?

 

Why? Because there's more building or material to burn?

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Just now, gravelld said:

 

Are you saying the temps are higher in a higher rise building?

 

Why? Because there's more building or material to burn?

Presumably because flames and heat go up - and up - and up and by the time it's half way it's quite literally a self feeding inferno. One thing that interests me was comments that the apartments have 1 hours protection against fire - and how in our house the focus is on 30mins for steel etc. 

 

30mins for a story 3 metres above the ground and 1 hour for something tens of metres up seems out of proportion... 

 

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Edited, in light of new information to remove an innocent companies name.

 

When I looked at this some time ago (around the time of that AECB link that @PeterStarck gave) I found a fair bit of evidence on fire testing that had been undertaken, by the German authorities and by the BRE.  The testing was aimed at assessing the effectiveness of fire stops, particularly over openings, as some of the facade fires had allowed dripping, burning material to pour down as a sort of curtain of flame over openings. 

 

The temperatures can get very high in a cladding fire, they work a bit like chimney fires, in that air flows in at breaches in the fire stop layers lower down and gets funnelled up between the exterior sheathing (aluminium in this case, I think) and the original outside wall of the building.  The photos of the early stages of the fire show this, with what look to be very high temperatures on the outside of the building, yet with the inside of the building still relatively unaffected by the fire, but almost certainly filling rapidly with smoke from outside (several witness accounts seem to support this).  All the photos show the facade of the building burning very fiercely, above the ignition point on the fourth floor, with the fire spreading around the outside of the building.

 

I would hazard a guess that the fire safety advice, to stay indoors, because the flats had a 90 minute fire resistance, may well have been outdated, and perhaps did not take into account the new external wall insulation.  Clearly there was a significant external fire ingress risk through the windows and balconies, and I wonder whether that had been allowed for when the tenants were advised to stay indoors?  I'm sure this will all be thoroughly investigated, but it wouldn't surprise me at all to find that the risk of fire entering a flat though a outside opening hadn't been examined since the building was clad.

Edited by JSHarris
new information

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1 hour ago, ProDave said:

P.S wood fibre external cladding does not ignite and spread like this.

Seems to back you up:

 

 

I think the second one is wood fibre isn't it? My russian ain't very good.

 

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Quite interesting tweets and retweets on John Band's Twitter Feed, @johnb68

 

John is a sensible, cynical, Ozzie journalist. He usually does the necessary digging.

 

 

Seems that the actual cladding company did a pre-pack bankruptcy soon afterwards:

http://www.constructionenquirer.com/2015/09/14/cladding-firm-harley-curtain-wall-pre-packed/

 

F

 

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Structurally, I suspect that there would have been problems with using something like wood fibre or mineral fibre as the insulation, because that would add a fair bit of mass to the outside of the building, and may well have been just too heavy for the existing structure to take.  I'm guessing here, but think that the choice of a lightweight exterior sheathing, aluminium it seems in this case, may also have been because of a need to keep the cladding mass down.  

 

Edited, in light of new information to remove an innocent companies name.

Edited by JSHarris
New information

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Are you saying the PUR / PIR foam is just as flamable?  for some reason I thought it was only EPS / XPS that was the danger?

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Both PIR and PUR can burn, depending on the exact make up.  Here's a test of PIR:

 

 

Generally, fire resistant PIR performs better than this, as far as I can tell from a quick look around, but it seems clear that fire resistance can vary a lot, within the same generic product description.

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2 hours ago, ProDave said:

On the basis that Knauf have removed the references, one can infer that it was their insulation used. Are we able to determine from that, what sort of insulation it was?

 

Knauf have clarified that it was an "industry news" story on their website, and they were *not* the supplier.

 

        

The perils of using other people's news to pad out your website !

Edited by Ferdinand

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Bad news indeed for Knauf, as the links to their news story on this refurbishment are all over the place, leading many, including me, to conclude that Knauf supplied the insulation.  I'll edit the references to Knauf out of earlier posts, and suggest others do the same.

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