Grenfell Tower fire

[Jeremy Harris]

There have already been suggestions made as to the product, and all we really know is what's on some of the taken down web sites of companies involved in the project.  None of those give a great deal of detail as to what the actual insulation core material was, but looking closer at the debris that fell off the building, it seems clear that the aluminium itself was burning, and that may well have contributed to the intense heat on the outside of the building, seen on some of the photos of the fire itself.

 

The combination of aluminium and flammable insulation is a well known fire risk, and one that was looked at closely after the Manchester air accident in 1985, as well as a few other aircraft ground fires.  When aluminium and a flammable material are in close proximity in a fire, two things happen.  The insulation allows the aluminium to reach its ignition point more quickly, by insulating one side of it, and the insulation itself provides the initial fuel source to allow the fire to develop.

 

I doubt that there is much, if any, "cross pollination" from the world of aircraft ground fire safety to the building industry.  If there was, then I think it's unlikely that the Australian high rise cladding fire from a couple of years ago, that involved the use of aluminium sandwich insulated panels, would have happened. 

Edited June 15, 2017 by JSHarris

[Guest Alphonsox]

The company responsible for the cladding are quoted on the BBC. (Harley Facades).

"At this time, we are not aware of any link between the fire and the exterior cladding to the tower." !

 

 

[Ian]

@JSHarris

its now being widely reported that the overcladding system comprised Reynobond aluminium rain screen (the version with a polyethylene core); a 50mm ventilation gap and Celotex FR 5000 insulation

[Jeremy Harris]

@Ian, Thanks, I think that, if true, then that would have been a lethal combination.  In particular, there has been wide publicity of the risks of having an air gap with flammable EWI, because it massively increases the oxygen supply, from chimney effect, and accelerates the vertical spread of fire.  However, there should have been fire barriers to reduce the risk of vertical spread, as this was identified as a problem several years ago.  Looking at the remains of the building, and the photos of the fire in it's relatively early stages, when it was confined to one corner, there is no indication at all of any fire barriers being effective.  If there had been, then I would have expected there to be some indication that the vertical spread was being restrained, with the fire spreading out horizontally below the fire barriers, but it looks like the initial fire just went straight up to the top of the building, relatively unrestrained.

 

Edited to add:

 

I've just found a good photo of the exterior of the building, before the fire, that shows the cladding, with the air gap between it and the EWI behind fairly visible, and no indication of any fire stops running across the clad areas at the corner:

 

Edited June 15, 2017 by JSHarris

[Jeremy Harris]

I've just found the plans for the renovation of Grenfell Tower, that give more detail on the materials used and the design of the building.  First off, it seems that the cladding was zinc composite panels, rather than aluminium, as widely reported, and so the fire risk from the cladding itself was lower.  However, zinc fires should not be tackled with water, as that can accelerate the fire.

 

 

The problem with the single, narrow staircase is apparent from this plan section of the building.  With the lifts automatically out of action in a fire, the escape route for several hundred residents, and the entry route for firefighters, must have been a nightmare:

 

 

Finally, here are the elevation drawings of the renovated tower block:

 

 

 

Finally, a video of the fire, around an hour after it started, that shows just how absolutely horrific it was.  Do not watch this if you're faint hearted, as it's pretty distressing:

 

https://www.pscp.tv/w/1RDGlZqozBDxL

 

 

Edited June 15, 2017 by JSHarris

[ADLIan]

Just a couple of comments;

 

In Scotland all thermal insulation in cladding systems in high rise (18+m) must be 'non-combustible'.

 

Celotex FR5000 - surface spread of flame 'Class O' which is not relevant or covered in the manufacturing standard for PUR/PIR insulation, BS EN 13165. In CE Mark, declaration of performance, for this product there is 'No Product Declaration' for reaction to fire to BS EN 13165/BS EN 13501-1 (fire test).

 

[Jeremy Harris]

Just now, ADLIan said:

Just a couple of comments;

 

In Scotland all thermal insulation in cladding systems in high rise (18+m) must be 'non-combustible'.

 

Celotex FR5000 - surface spread of flame 'Class O' which is not relevant or covered in the manufacturing standard for PUR/PIR insulation, BS EN 13165. In CE Mark, declaration of performance, for this product there is 'No Product Declaration' for reaction to fire to BS EN 13165/BS EN 13501-1 (fire test).

 

 

 

Worth looking at the video in the link above, as it shows the way the cladding burned fiercely, and that burning sections of it were raining down on the firefighters.  The bravery of the firefighters is just beyond belief.

[gravelld]

12 hours ago, JSHarris said:

Frankly the decision to use flammable cladding was the key factor that massively increased the fire risk, and which could not have been overcome without major structural redesign, and I suspect that would have been impossible, as it's almost certainly a building with a structural centre core, built around the stairwell and lift shafts.

 

Ok, so instead the question becomes why wasn't the retrofit done properly including major structural alterations (assume you're referring to the extra weight of less flammable insulation and also better fire access here), or (more expediently) why didn't they knock it down and start again?

 

Leaving the block in its 1970s state was not an option both for performance, fire safety reasons and all manner of other reasons, so I think it's irrelevant whether it would've gone up as quickly as it did if the retrofit hadn't occurred.

[gravelld]

1 hour ago, JSHarris said:

I doubt that there is much, if any, "cross pollination" from the world of aircraft ground fire safety to the building industry.  If there was, then I think it's unlikely that the Australian high rise cladding fire from a couple of years ago, that involved the use of aluminium sandwich insulated panels, would have happened. 

 

The construction industry could learn *a lot* from the aeronautics industries.

[Jeremy Harris]

1 minute ago, gravelld said:

 

Ok, so instead the question becomes why wasn't the retrofit done properly including major structural alterations (assume you're referring to the extra weight of less flammable insulation and also better fire access here), or (more expediently) why didn't they knock it down and start again?

 

Leaving the block in its 1970s state was not an option both for performance, fire safety reasons and all manner of other reasons, so I think it's irrelevant whether it would've gone up as quickly as it did if the retrofit hadn't occurred.

 

 

Not questions anyone not involved in the project can easily answer, I think.  I do know that demolition costs in London are astronomical, often a great deal more than construction costs, because of the very limited free space around tower blocks like this.  The MoD owned a few smaller blocks in London that were past their sell-by date, and the plan was to sell them to help pay for a new build in Bristol.  When the time came to sell them, after the new Bristol complex had been opened and the staff transferred, it was discovered that there would be very little gain from disposing of the old London buildings, largely because of the problems in either refurbishing them, or demolishing them and rebuilding.  Given that this is social housing, I suspect that money was very tight, and a refurbishment, without major structural internal work, may have been the only viable option.

[Jeremy Harris]

3 minutes ago, gravelld said:

 

The construction industry could learn *a lot* from the aeronautics industries.

 

 

Yes, they could.  One major benefit would be to somehow transfer the safety culture that is deeply ingrained within aerospace to the building industry.

[gravelld]

14 minutes ago, JSHarris said:

Not questions anyone not involved in the project can easily answer, I think.  I do know that demolition costs in London are astronomical, often a great deal more than construction costs, because of the very limited free space around tower blocks like this.  The MoD owned a few smaller blocks in London that were past their sell-by date, and the plan was to sell them to help pay for a new build in Bristol.  When the time came to sell them, after the new Bristol complex had been opened and the staff transferred, it was discovered that there would be very little gain from disposing of the old London buildings, largely because of the problems in either refurbishing them, or demolishing them and rebuilding.  Given that this is social housing, I suspect that money was very tight, and a refurbishment, without major structural internal work, may have been the only viable option.

 

You're right. I do get frustrated though how short term "costs" are used to justify not doing anything, or taking cheaper, less optimal options. It's not like the short term economics balances all the facts; what about the unknown unknowns, the intangible, the unmeasurable? It's not like the derived costs are in any way some sort of representative and true summation of the net cost of the activity.

 

Even the finest costing machine built, the stock exchange (I'm referring to the worldwide trade in securities rather than any particular exchange), is enormously flawed in costing short term (EMH etc). Why would an Excel hero do any better?

 

We see it throughout Government; I think it is myopic, short termist and just ends up with higher costs (not always tangible, financial or measurable) later on.

[Jeremy Harris]

Both our local and general election processes drive short term views. 

 

In central government this is a constant running battle, with the Civil Service trying hard to make sure that taxpayers get the best value for money and their elected bosses in government trying to thwart them by changing things to give a short term cost saving, even if that means increased spending in the long term, because their eye is always on re-election.    I had weekly meetings with my minister for around a year or so, and they were always acrimonious, to the point where I lost my temper and swore at him once, much to the horror of his PPS (plus it was a career limiting act on my part, but I don't regret it at all).

Edited June 15, 2017 by JSHarris

[ADLIan]

Had to go north of the border but insulation confirmed as celotex RS5000. No Performance Declared for fire performance.

 

The Herald (Scotland)

Edited June 15, 2017 by ADLIan
spelling of border !!

[Jeremy Harris]

Thanks @ADLIan, that confirms part of what seems to be on the plans, but conflicts with part of it, too.  The plans say the outer cladding is zinc, yet there are several reports that it is composite aluminium.  Given that there is a significant cost difference between zinc and aluminium, with aluminium generally being cheaper and lighter (which may have had an impact of the cost of fixings) I wonder if the plans were amended at some point to change the cladding material from the less flammable zinc that was specified, to the more flammable aluminium composite?

 

Looking at the fire, it has all the hallmarks of a burning aluminium fire, so I'm inclined to think that there was a switch from the originally specified zinc to aluminium.  If this is the case, I wonder if the change to the fire rating was taken into account?

 

I think the simple answer is that, even it it was, then there were some very serious errors of judgement by whoever made this decision.  The original design with the zinc cladding and air gap over the EWI was bloody awful, but changing that outer skin to aluminium composite seems downright criminal.  This is not a view with the benefit of hindsight; the high fire risk of having an air gap over flammable EWI has been well understood for many years.

[jack]

It will be interesting to see whether aluminium was used to replace the approved zinc without approval.

[MikeSharp01]

1 hour ago, JSHarris said:

Yes, they could.  One major benefit would be to somehow transfer the safety culture that is deeply ingrained within aerospace to the building industry.

My experience of the large scale construction sector is that HSE is handled, in the big picture very well, sign in / out, correct PPE, risk assessments, designated walkways the whole bang shoot. Its only when you get down to the actual work that people start to cut corners to get things done and speed is put ahead of user safety; poor material selection, voids not correctly filled, flashing omitted, intumescents poorly applied, tools left in high speed air ducts, etc. Essentially perhaps the culture, as you say @JSHarris, does not reach the operational end of the chain well even though the management are waggling their handles with a passion.  

[jfb]

Am i missing something but what is the point of a layer of insulation with a great ventilated void behind it? Doesn't it rather negate the benefit of the insulation?

[jack]

6 minutes ago, jfb said:

Am i missing something but what is the point of a layer of insulation with a great ventilated void behind it? Doesn't it rather negate the benefit of the insulation?

 

The void is on the outside of the insulation: wall->insulation->gap->cladding

[Barney12]

Sorry to drag this topic off a little but it's a local story (linked to an animal charity I have huge admiration for) linked to fire and smoke alarms.

I also have to put my cards on the table and say I generally like dogs MUCH more than humans (Sorry).

 

http://www.devonlive.com/dog-from-devon-receives-animals-george-cross-after-saving-family-from-house-fire/story-30389816-detail/story.html

 

A little cheer in the world seems much needed at the moment.

 

[AliG]

I have read somewhere today that over one million buildings globally may have similar cladding.

 

Certainly you see it often on offices, hotels, hospital etc as well as residential blocks.

 

I have read through the thread to try and clarify if there is actually a regulation in place that might have stopped this or if the regulations were not followed and I am still not sure.

 

Is the use of fire stops in such a cladding system considered good practice or is there a regulation that would enforce it? Similarly is the use of non combustible material recommended or is there a regulation to enforce it? I note someone said that this is the regulation Scotland for high rises.

 

Sadly I think that if we look at the body of safety regulations we have we would probably find that many of them were only introduced after the loss of life and few have been proactively introduced without bad things happening to highlight the issue.

 

One thing I do not understand is why the building did not seem to have a connected fire alarm system. Unlike sprinklers this would be a relatively easy and cheap installation. When we had our kitchen updated recently which required a building warrant due to some structural work we had to upgrade the whole alarm system in the house to connect the smoke and heat detectors to it. This was not the rule when the house was built but BC insisted that we had to meet current standards after the work was done. Why would this not apply here?

 

 

Edited June 15, 2017 by AliG

[Jeremy Harris]

12 minutes ago, Barney12 said:

Sorry to drag this topic off a little but it's a local story (linked to an animal charity I have huge admiration for) linked to fire and smoke alarms.

I also have to put my cards on the table and say I generally like dogs MUCH more than humans (Sorry).

 

http://www.devonlive.com/dog-from-devon-receives-animals-george-cross-after-saving-family-from-house-fire/story-30389816-detail/story.html

 

A little cheer in the world seems much needed at the moment.

 

 

Great story, and a very useful point about fire and smoke alarms, particularly as there seem to be quite a few stories circulating that the alarms in Grenfell Tower may not have been linked and that they failed to go off on some floors.

 

I've been caught out be an alarm with a flat battery once, the battery must have gone flat whilst we were on holiday and had stopped giving the flat battery beep by the time we returned.  It was months later when I decided to check it, as it hadn't gone off after we'd burned some toast.  It was only then that I realised we'd had no functioning smoke alarm for several months, a pretty scary experience.

 

Mains powered, with lithium battery back up, linked alarms have to be the way to go.

[Jeremy Harris]

1 minute ago, AliG said:

I have read somewhere today that over one million buildings globally may have similar cladding.

 

Certainly you see it often on offices, hotels, hospital etc as well as residential blocks.

 

I have read through the thread to try and clarify if there is actually a regulation in place that might have stopped this or if the regulations were not followed and I am still not sure.

 

Is the use of fire stops in such a cladding system considered good practice or is there a regulation that would enforce it? Similarly is the use of non combustible material recommended or is there a regulation to enforce it? I note someone said that this is the regulation Scotland for high rises.

 

Sadly I think that if we look at the body of safety regulations we have we would probably find that many of them were only introduced after the loss of life and few have been proactively introduced without bad things happening to highlight the issue.

 

 

The BRE have done a fair bit of work in trying to evaluate the risk from EWI, and also the effectiveness of fire stops, but mainly those above openings.  There are a lot of BRE fire test videos on YouTube, I believe, and I'm sure that I remember seeing some that demonstrated how effective fire stops could be.

 

As far as I can see, this hasn't made it into the regs, they still seem focussed on surface spread of fire.  I believe that we have a problem with the length of time between new methods of construction coming to market and them being catered for in building regs, but I'm not sure this is wholly a building regs issue.  There should have been a fire risk assessment of the completed building that covered far more than just compliance with building regs, I believe.  From what I can recall of the last commercial build I was involved with, there was an overall risk assessment that included things like the interior furnishings, the high volume of IT equipment and cabling in the building, as well as the basic building regs fire safety stuff.

[PeterW]

So..... where does ICF clad with timber fit into this ..??

 

Would the standard construct of ICF with an outer ventilation gap and then timber cladding create exactly the same scenario...?? It would create a chimney effect that  would be similar to what has been seen here

 

A lot of the aluminum cladding panels are only clad with 1mm aluminum at best and it is the core material that becomes the issue - plastic honeycomb is flammable and as soon as this is compromised the the panels will delaminate. 

 

 

[Jeremy Harris]

4 minutes ago, PeterW said:

So..... where does ICF clad with timber fit into this ..??

 

Would the standard construct of ICF with an outer ventilation gap and then timber cladding create exactly the same scenario...?? It would create a chimney effect that  would be similar to what has been seen here

 

A lot of the aluminum cladding panels are only clad with 1mm aluminum at best and it is the core material that becomes the issue - plastic honeycomb is flammable and as soon as this is compromised the the panels will delaminate. 

 

 

 

On a tall building, where fire could enter the insulation layer from either the base, or via an opening, then I'd say it was every bit as dangerous as all the other facade fires that have been reported.  On a lower building, where there would be far less chimney effect, then I think the risk would be a great deal lower.

 

It really all comes down to the whole fire risk assessment of the individual building, as there are ways to mitigate the risk that even flammable cladding may pose on tall buildings (external, roof top, cascade sprinklers, for example).

 

Using thin aluminium composite cladding only really poses a risk when there is a flammable material close to it, as it takes sustained high temperature, plus a lot of oxygen, to get aluminium to burn.  However, once it is burning it burns very fiercely, as anyone who's made aluminium accelerated thermite will testify (and no, I'm not going to give the recipe for making it here.........).