Grenfell Tower fire

[Onoff]

33 minutes ago, JSHarris said:

 

 

It's also still misleading, as the melting point of zinc is a lot lower than the melting point of aluminium, 419 deg C for zinc, versus 660 deg C for aluminium.  Had the composite zinc cladding been used over PIR, with the PIR providing the fuel for the fire, then the cladding skins would have failed sooner, exposing the core to the fire earlier.

 

Is there an argument maybe that the zinc might have burned off quicker and thus fallen away quicker? 

[Jeremy Harris]

Just now, Onoff said:

 

Is there an argument maybe that the zinc might have burned off quicker and thus fallen away quicker? 

 

 

Could be, although whether or not it would have made a significant difference I'm not sure.  My guess is that, by the time the fire had become established on the outside, the outcome may well have been the same.  The zinc composite panels that were originally specified had the same rating as the aluminium composite panels, but as the ratings were pretty meaningless with regard to the way the entire system was designed and installed, there's no way, short of a proper full scale test, to be sure.

 

One (wholly unacceptable to the local residents. I'm sure) way to test the way this fire developed might be to deliberately start a fire low down on one of the undamaged areas of Grenfell Tower, and record carefully how it develops.  If evidence that swapping the zinc composite for aluminium composite was a contributory factor, then some of the surviving cladding could be swapped for the zinc composite so a direct comparison could be made.

 

I'm sure this won't happen, because of the trauma it would cause to the local residents seeing that block on fire again, apart from anything else, but it would be a very good way of collecting some first-rate evidence.

[ProDave]

What staggers me, is (according to someone from BRE that they interviewed on the news) they are just testing the outer rain screen on buildings for flamability and condemning the cladding on that test.  NOBODY seems to be testing the "system" i.e insulation, air gaps, fire stops and cladding to see if the system is safe or not.  Surely that is fundamentally what needs to be tested?  Or am I way off the mark?

 

If I was investigating I would want a mock up of the exact EWI and cladding system set up on a multi storey test building and set fire to. then repeat the tests with different claddings, different fire stops and different insulation.

[gravelld]

Yep... different weather conditions too.

[SteamyTea]

1 hour ago, ProDave said:

If I was investigating I would want a mock up of the exact EWI and cladding system set up on a multi storey test building and set fire to. then repeat the tests with different claddings, different fire stops and different insulation.

I am sure that will come, but at the moment they have to act fast and make sure places are safe, or not.

[Crofter]

With a bit more analysis I would expect that measures can be found to mitigate the danger without having to strip off all of this cladding. For example, in the immediate term, updated safety advice and perhaps evacuation of the upper storeys only of affected buildings. Then implement a robust inspection and maintenance program for alarm systems.

Longer term, it might be that adequate firestops around windows and every few floors of the facade is all that is needed. Major work to retrofit, but not quite as difficult or expensive as replacing entire EWI systems.

 

There is an understandable and justifiable lack of trust in the politicians and organisations involved, though, so to satisfy the general public that adequate steps are being taken there must be honesty and transparency. 

[Jeremy Harris]

There are already some fire risk reduction schemes used in other countries that have insulation clad buildings that could be adopted, but one major issue now is that the government have whipped up a frenzy of fear with their barking mad sample testing regime.  I'm pretty sure I know why they are doing the sample testing, it's almost certainly to just identify the type of thin core inside different panels, and establish whether it has fire retardant additives.  These tests aren't, strictly speaking, fire resistance tests at all, but rubbish reporting, and the lack of adequate government control, is making them sound as if they are.

 

Other countries have far greater EWI fire risks on some of their buildings than we do, and, as this problem has been around for well over a decade, solutions have been devised to make buildings safer.  The simple and easy solution is one borrowed from the oil and gas industry; the use of external, roof-mounted, deluge sprinklers, that pour water over the outside of the building.  These are relatively easy to install, not massively expensive and are able to quench an external wall fire if operated during the early stages.  Best of all, there is no real risk of damage from accidental operation of the sprinklers, so they can have a high-sensitivity trigger system, as false alarms don't really cause much of a problem.

 

Fire stops are an essential requirement, but the building regs are clear about the need for these already, so all that needs to happen is an enforcement of the regulations.

[Temp]

+1

 

I don't think they are attempting any sort of realistic test, just trying to confirm what been fitted. Google found that a burn test is one way to identify different plastics..

 
http://www.boedeker.com/burntest.htm

 

They probably don't trust the paperwork for a lot of projects. 

[Jeremy Harris]

I suspect they are wise to not trust the paperwork, as it seems that some of these cladding materials were never, ever fire tested, but were approved using a desk top study, something I find unbelievable.  How on earth we have allowed a system to develop where safety-critical materials aren't physically tested as a part of the approval process I don't know; it makes the multifoil approval fiasco look insignificant by comparison. 

 

I wonder how many other building materials have never actually been tested in order to gain approval certification?

[Temp]

Just seen this on the BBC web site..

 

http://www.bbc.co.uk/news/uk-40465399

 

Newsnight has obtained confidential reports that help explain how flammable material has become more common on tall buildings.

 

Combustible cladding has been permitted based on reports arguing fires involving combustible aluminium panels would behave similarly to ones with non-combustible ceramic tiles.

Developers use them to persuade inspectors to sign off buildings.

 

Exova, the company that produced the reports, refused to comment.

 

Continues

[Jeremy Harris]

That's simply unbelievable. 

 

How on earth could anyone assume that an aluminium composite panel would behave in a similar way to a ceramic tile?

 

More to the point, how on earth could any rational being accept that a compliance demonstration based on such an obviously flawed assumption was in any way reasonable?

 

The more information that seems to being revealed about the way product approvals have been undertaken, the more shocked I'm becoming.  I started from a position where I already suspected that a lot of approvals weren't worth the paper they were written on, so I shouldn't be surprised, but the extent to which this seems to have been going on is simply incredible.

 

 

[Temp]

On ‎6‎/‎14‎/‎2017 at 11:12, gravelld said:

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

 

The construction as I understand it was..

 

Inside - concrete - Celotex RS5000 - ventilated cavity - Reynobond (Aluminium/PE/Aluminium sandwich) - Outside

 

I think the PE is essentially just a filling to help with the stiffness of the panels. I think another make uses an aluminium honeycomb. It's on the outside of the ventilated cavity so it wasn't being used as insulation. 

 

The RS5000 is similar to their FR5000 product. It's possible there were also unventilated cavities between the concrete and Celotex.

 

[Temp]

http://www.independent.co.uk/news/uk/home-news/grenfell-tower-fire-cladding-building-combustible-flammable-still-approved-use-safety-rules-a7822521.html

 

Quote

Grenfell Tower fire: Combustible cladding used on building still approved for use.

Reynobond aluminium panelling still certified as 'safe' despite manufacturer Arconic removing product from market.

 

The cladding used on Grenfell Tower that may have aided the unprecedented spread of last month’s blaze is still approved for use by the building materials board, it has emerged. 

Reynobond aluminium panels are still certified by the British Board of Agrément (BBA) as “fit for their intended use provided they are installed, used and maintained as set out in this certification".

The cladding’s approval has not be withdrawn despite manufacturer Arconic removing the panelling from the market due to concerns over its fire safety.

Reynobond was first approved as “fit for purpose” in 2008 and is reviewed every three years, according to The Times. 

BBA said it would not review Reynobond again until 2020 “unless the information before us changes”.

Continues..
 

 

Edited July 4, 2017 by Temp

[Crofter]

Surely it's not the Reynobond itself that's unsafe, it's the use of it in large areas without firestops?

I would expect my larch cladding would be highly dangerous if installed over a large elevation with a cavity behind, and no firestops. Nobody's calling for larch cladding to be banned outright, though.

[Jeremy Harris]

On 04/07/2017 at 19:14, Crofter said:

Surely it's not the Reynobond itself that's unsafe, it's the use of it in large areas without firestops?

I would expect my larch cladding would be highly dangerous if installed over a large elevation with a cavity behind, and no firestops. Nobody's calling for larch cladding to be banned outright, though.

 

Personally, I doubt that the 2mm of PE inside the aluminium skins of the Reynobond was a significant factor at all.  The 150mm of RS5000 that was bonded and fixed directly to the existing concrete was almost certainly the major fuel component.

 

The major issues seem to have been a failure to consider the whole design from a fire risk perspective, and a reliance on the individual materials approvals in isolation.  A major contributory, perhaps fundamentally causal, issue was the apparent absence of proper fire stops around openings, that should have stopped fire escaping from the kitchen window of the burning flat from getting into the ventilation cavity behind the Reynobond, and in front of the RS5000.  Once the RS5000 was hot enough to give off flammable gasses, then the fire could quickly propagate up behind the cladding. 

 

Even if the cladding had been something like stainless steel sheet I think the outcome may well have been much the same, as I can't see how a 2mm thick layer of PE could add much in the way of additional fuel to this fire.

[gravelld]

On 01/07/2017 at 17:07, JSHarris said:

The more information that seems to being revealed about the way product approvals have been undertaken, the more shocked I'm becoming.  I started from a position where I already suspected that a lot of approvals weren't worth the paper they were written on, so I shouldn't be surprised, but the extent to which this seems to have been going on is simply incredible.

 

Emissions tests, press self regulation, private building control... it all stinks and it's all in the name of "light touch regulation".

 

I'm actually against over regulation, but going the other way is similarly toxic.

 

Self regulation does not work when incentives are not aligned.

[MikeSharp01]

Looks like at last they have decided to test the system instead of the core of just one part of it: http://www.bbc.co.uk/news/uk-40520596 not sure why it took them so long, there must have been a motive I am just at a loss to see what it might have been unless they wanted everything to fail.

 

[richi]

Because Something Must Be Done (and that was something)

 

Edited July 6, 2017 by richi
unobfuscate

[SteamyTea]

About the same as we al worked out in a few hours of it happening.

https://www.theguardian.com/uk-news/2017/jul/13/grenfell-tower-building-control-warned-about-refit-insulation-plan

 

I hope the Guardian keeps up the pressure.

[Jeremy Harris]

Except they are, like other media outlets, getting their chemistry very confused.  For some reason, the media seem to consistently assume isocyanate is isocyanide, when it's not even really a related compound.  This Wiki entry is reasonably accurate: https://en.wikipedia.org/wiki/Isocyanate , note this sentence:

Quote

Isocyanates should not be confused with cyanate esters and isocyanides,

 

The reported "cyanide poisoning" cannot be related to the insulation, for a couple of reasons.  Firstly, isocyanates do not produce hydrogen cyanide when they degrade under heat - there are no cyanide compounds in the stuff.  Secondly, hydrogen cyanide has a flash point of around -18 deg C, so will ignite and burn if there is any naked flame nearby, and by burning it will become relatively non-toxic.

 

The reported "cyanide poisoning" is most probably either irritation from isocyanate (a strong irritant, but not very toxic) or it may be a cyanide compound given off by the degradation of furnishings in one or more of the flats.  The latter seems quite likely, as a lot of older soft furnishings contained pretty nasty compounds.

[SteamyTea]

Not being a chemist I can forgive them that confusion, though it should be put right.  Write them a letter.

 

I think it was the mid 80's that they made furniture 'fireproof' so that should not be the cause of poisoning as not many people will have 30 year furniture.

 

Listening to the Radio report this morning, there is talk about reviewing and tightening the building regs.  They also mentioned general apathy in the building trade with regard to regulations.

Will be interesting to see what comes out of it all.

[dpmiller]

Oddly enough I was watching a program a few nights back on Quest about plane crashes and it alluded to earlier "fireproofing" techniques actually producing more smoke and (if conditions were right) burning hotter than non- proofed items.

[PeterW]

Burning upvc can produce cyanide compounds 

[SteamyTea]

Just seen this, it is about fires in timber framed places (flats mainly).

https://www.theguardian.com/uk-news/2017/jul/17/fears-use-timber-frames-blocks-flats-grenfell-tower-fire

[Crofter]

Sorry for the macabre twist, but is Grenfell the biggest loss of life in a single UK incident since Lockerbie?