SteamyTea

Grenfell Tower fire

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The 6th combination (Rock wool and ACM with a limited combustibility filler) passed..

https://www.gov.uk/government/publications/advice-for-building-owners-large-scale-wall-system-test-6

https://www.gov.uk/government/publications/fire-test-report-dclg-bs-8414-test-no6

So overall its looking as expected. Rockwool is safer than PIR but some combinations of PIR and cladding are ok.

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Updated table.

 

CladdingF.jpg.d10bde265639e129d9409ca7fea50990.jpg

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There are some unusual looking results in there, that make me curious as to the validity of the pass/fail criteria. 

 

For example, it seems reasonable to assume that in the test with the ACM with fire retardant PE filler and PIR foam, that the major fuel source was outgassing of the PIR, especially given that there is a significant body of evidence that shows that PIR does provide a fuel source for vertical surface fires, even though the body of the foam tends to char and degrade, rather than burn through.

 

However, we then have a test with ACM with a limited combustibility filler and PIR foam that passed.

 

On the face of it, these two test results look odd.  If the major fuel source is not the PIR, but the ACM filler, then I would expect the limited combustibility filler to contribute more fuel than the fire retardant PE.  From the tests with mineral wool (which we know is virtually non-combustible, it seems that neither the fire retardant PE, nor the limited combustibility filler, were significant fuel sources.

 

These tests seem to raise more questions than they answer.  They do, however, indicate that buildings with mineral wool insulation are OK, as long as the cladding is fire retardant.

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16 hours ago, JSHarris said:

I would expect the limited combustibility filler to contribute more fuel than the fire retardant PE. 

 

I also thought that was odd but googling suggests "limited combustibility" materials are actually less flammable than "flame retardant" materials.

 

For example the reports refer to..

 

"ACM with a limited combustibility filler (category 1 in screening tests)"

"ACM with a fire retardant polyethylene filler (category 2 in screening tests)"

 

The lower the category the less dangerous. Category 0 is non-combustible 

 

 

 

 

 

 

 

 

 

 

 

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Interesting article on the BBC: http://www.bbc.com/news/uk-england-berkshire-41466281 that suggests that water from either vapour/steam released by the charring PIR, or from the firefighters, could have exacerbated this fire.

 

This fits reasonably well with some of the video evidence, that shows the fire burning fiercely just above the range of the firefighters water jets, and seeming to spread vertically above that area pretty vigorously.  Perhaps steam given off from below rose up in the updraft through the ventilation cavity increasing the intensity of the fire by reacting with the cladding and foil on the PIR?

 

Makes sense, but is far from proof that this may have happened. 

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Interesting theory. I'd query whether steam rising from lower areas would be able to get close enough to the already burning cladding to initiate the described reaction with the aluminium. Between expanding air/combustion products and updrafts, I suspect any such steam would at best be carried straight up, or more likely slightly away from the facade.

 

The idea of water that had already been absorbed into the PIR over time seems plausible - you can imagine it being vaporised and expelled due to the heat.

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I agree, I'm not 100% convinced, but I'm tempted to do a couple of experiments to see if there's a difference between "wet" PIR and "dry" PIR.  I've already got some PIR tests underway to see how the surface coating reacts with cement, and I'm tempted to do some blowtorch tests to see just how the stuff reacts to flame.  Might as well compare "wet" and "dry" whilst I'm at it, just out of curiosity.

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I seem to remember that in the initial reports it was mentioned that water and aluminium not mixing too well when there is a fire.

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4 minutes ago, SteamyTea said:

I seem to remember that in the initial reports it was mentioned that water and aluminium not mixing too well when there is a fire.

 

 

Yes, it's one reason why aircraft fires are always doused with fire retardant foam, other than the risk from fuel.  The water/heat/aluminium reaction is pretty violent, if the temperature is high enough, releasing significant amounts of hydrogen, from the aluminium + water = aluminium hydroxide + hydrogen reaction.  This reaction isn't easy to start, but can be self-sustaining if the conditions are right.  A high initial temperature is usually needed, plus a reducing atmosphere that decreases the rate at which aluminium oxide forms.  A fierce fire is likely to be reducing at it's core, where the temperatures may also be at their highest, so in theory the conditions seem about right.

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I see that the initial review by Dame Judith Hackitt has stated the blindingly obvious to anyone that has dealt with building regulations and building control in the past couple of decades: http://www.bbc.com/news/uk-42392138

 

Quote

Dame Judith told BBC Radio 4's Today programme that people had to "commit to making buildings safer" instead of "simply doing things at least cost".

 

In the interim report, she wrote: "It has become clear that the whole system of regulation, covering what is written down and the way in which it is enacted in practice, is not fit for purpose, leaving room for those who want to take shortcuts to do so.

 

"There is plenty of good practice, but it is not difficult to see how those who are inclined to take shortcuts can do so."

 

The quality assurance of both people and materials was "seriously lacking," she added, and she criticised "complex" systems for making guidance harder to follow.

 

"Rather than [complex regulations] giving people everything the need to know, it makes it quite difficult for people to penetrate that complexity to truly understand what they need to do," Dame Judith told the BBC.

 

"There is clearly an opportunity to make that much simpler and to guide people to the right answer, rather than presenting them with all that information."

 

 

Her interim report can be read here: https://www.gov.uk/government/publications/independent-review-of-building-regulations-and-fire-safety-interim-report

 

Quote

Change control and quality assurance are poor throughout the process.

What is initially designed is not what is being built, and quality assurance of materials and people is seriously lacking. I have been shocked by some of the practices I have heard about and I am convinced of the need for a new intelligent system of regulation and enforcement for high-rise and complex buildings which will encourage everyone to do the right thing and will hold to account those who try to cut corners

 

Edited by JSHarris

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On 02/10/2017 at 17:16, JSHarris said:

Interesting article on the BBC: http://www.bbc.com/news/uk-england-berkshire-41466281 that suggests that water from either vapour/steam released by the charring PIR, or from the firefighters, could have exacerbated this fire.

 

This fits reasonably well with some of the video evidence, that shows the fire burning fiercely just above the range of the firefighters water jets, and seeming to spread vertically above that area pretty vigorously.  Perhaps steam given off from below rose up in the updraft through the ventilation cavity increasing the intensity of the fire by reacting with the cladding and foil on the PIR?

 

Makes sense, but is far from proof that this may have happened. 

 

Having burnt some PIR by mistake I do seem to recall it giving off what looked like steam.

 

Steam would be a very effective transmission medium to heat things up, or perhaps as a catalyst (wrong word) for facilitating the speeding up of other reactions.

 

One difficulty is that if she shifts from rules based regulation to something else then the regulators will have more complicated and nebulous decisions to make.

 

Ferdinand

 

Edited by Ferdinand

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I hope that what comes out of this are regulations that are more specific, approval processes for both materials and people that cannot be fudged and fiddled the way they are at the moment and an enforcement system that is actually fit for purpose.

 

Currently anyone who knows how to game the system can do so with near-impunity, as had been shown time and time again with the compliance failings by major construction companies that get regularly highlighted on new developments, and I strongly suspect that's just the tip of the iceberg, as many of the compliance failings will be hidden from the final customer. 

 

One clear problem in my view is that big builders can buy their own inspectors, so there is a very clear problem with a clash of interests.  Any building inspection company that makes life too challenging for a construction company, by insisting they follow the regulations is likely to lose business to other building inspection companies that take a more relaxed view, in order to make sure they win future contracts.

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I see nothing good here for the self builder.

 

All I foresee is more regulations, more inspections and I fear more items that will require some professional sign off.

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Building regs that are not ambiguous, not open to interpretation and fit for purpose ( non flammable, simples )

 

We have had many on here where one inspector in one part of the country says one thing and another elsewhere says different.

Edited by joe90

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The interim report says this:

 

Quote

The Building Regulations 2010 are clear about the outcomes to be achieved but not about where responsibilities lie.

 

and then goes on to say:

 

Quote

There is widespread confusion about what constitutes the regulations and what is guidance.

The guidance on ways to meet the Building Regulations, set out in the Approved Documents, are frequently referred to as ‘the regulations’.

 

Quote

The Approved Documents are not produced in a user-friendly format.

The current format of covering each requirement (fire safety, thermal insulation, noise abatement, etc.) in separate sections leads to multiple, separate specifications for overlapping or common elements of a building, with no easy means for these to be integrated into a single, compliant specification

 

Quote

Key definitions are unclear; for example, ‘high rise’, ‘persons carrying out the work’, ‘limited combustibility’ and ‘material alteration’, leaving too much open to interpretation

 

I don't think I'd disagree with those statements at all.  There are many times when I've reverted to looking at the letter of the underlying law, rather than the guidance in the Approved Documents, and have gone on to make the case that compliance with the law is all that matters, not rigid compliance to the suggested methods of compliance in the Approved Documents.

 

One interesting point made is that private building control companies have NO power of enforcement, yet LABC do.  That alone is a curious situation that encourages larger construction companies to use private building control companies, knowing full well that they cannot enforce any action over any non-compliance they pick up................

Edited by JSHarris

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5 hours ago, ProDave said:

I see nothing good here for the self builder.

 

All I foresee is more regulations, more inspections and I fear more items that will require some professional sign off.

 

Indeed. From a self build perspective, the inevitable  outcome of a tightening of enforcement can only make using  "unusual" methods of construction even more difficult, or likely impossible. Which many on this forum are doing. 

 

Building control, in whatever form it exists will simply become more risk averse. Why put your name to something unusual, when you dont need to. 

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I think I have mentioned before that for every rule we have that says you must do something, there is at least one other that says you can't do it.

 

Maybe some good will come out of it as it will clear up some confusion.

 

I am an optimist by nature.

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I don't think we'll see a change to the Building Regulations, as they are fine as they are, in the main.

 

The problem areas are that the Approved Documents are not properly understood; not everyone realises that they are not the regulations and they are not legally binding directions or instructions, and also that the inspection regime can be inflexible and less than competent on occasion.  If inspectors stuck to inspecting for compliance with the Building Regulations themselves, rather than a few being obsessed with the Approved Documents, then things would be a great deal easier for self-builders looking to use new methods of construction.

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Small article in today's Times. It say that Celotex have ....

 

...'admitted that there were "differences" between the safety experiment conducted at the Building Research Establishment test laboratory and the way the outcome of that test was reported'

 

'A spokesman said: These differences were carried through into our marketing of RS5000'

 

'BRE said in a statement that "anomalies" had been discovered in the testing process and "the test results have been withdrawn"

 

Note: I believe they are referring to tests carried out at the BRE before Celotex marketed RS5000 as suitable for high rise buildings not the recent test carried out at the request of the government. I've not yet seen the statement by the BRE.

Edited by Temp

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New article in The Times today says that investigators have not been able to find any record of independent tests on the combination used on Grenfell tower, either in the UK or abroad. This combo was used on 299 similar high- rise buildings.

 

"Somehow or other, those materials have got onto 300 buildings without any tests being done or test results being produced."

 

Related... "A 95 year old man is being treated in hospital because of stress after being asked ( told?) to contribute to the cost of removing unsafe cladding from the block of flats where he lives."

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1 hour ago, Temp said:

New article in The Times today says that investigators have not been able to find any record of independent tests on the combination used on Grenfell tower, either in the UK or abroad. This combo was used on 299 similar high- rise buildings.

 

"Somehow or other, those materials have got onto 300 buildings without any tests being done or test results being produced."

 

Related... "A 95 year old man is being treated in hospital because of stress after being asked ( told?) to contribute to the cost of removing unsafe cladding from the block of flats where he lives."

 

 

When I was digging around for data shortly after the fire, I found many, many examples where materials, including those used on Grenfell, had been approved with no testing at all, just a desktop study.  The problem with the latter is that some of the extrapolated data is so far removed from an initial test result on a different material as to be useless, yet this doesn't seem to be picked up by people like BBA at all.  As long as they get a fee and are given a compliance pack that looks OK on the outside, they issue a certificate, it seems.

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Posted (edited)

BBC R4 PM reporting the "cladding" rainscreen panels used -- Reynobond PE -- were certified below the minimum 'B' fire rating required by the ADs. Some of the panels -- the riveted config -- scored C, and others -- the cassette system -- scored E.

 

http://www.bbc.co.uk/news/uk-43558186

Edited by richi
link finally; expand

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The report on the fire has been published.

 

A summary here https://www.standard.co.uk/news/london/grenfell-tower-report-how-the-fire-began-on-the-fourth-floor-and-spread-throughout-the-block-a3814831.html (and probably many other places as well)

 

The key things for me.

 

Fire started by a fridge / freezer

 

The kitchen window in that flat was open (to let the smoke out?) so it's fire rating was irellevant.

 

Sprinklers would only have helped if in the kitchen where the fire started.

 

The front doors to the flats did not have self closers and at least part pf the spread of fire was doors left open

 

No fire breaks in the cladding (I think we knew that)

 

 

 

 

 
 

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