Yet more on Grenfell and panel testing

[Chris Hogg]

On the BBC News this morning: The original specifications for the cladding on Grenfell tower was for zinc panels, but the specifications were later changed for aluminium panels, saving £293K.

and

Lord Porter, Chair of the Local Government Association, says that it is just not credible that the cladding on all 137 tower blocks tested so far should fail fire safety tests, i.e. 100% failure rate. He says the tests are not being conducted on the actual panels in their entirety, but only on the core of the panels, and thus are not representative of what happened in reality. He calls for a re-think in the way the panels are being tested.

BBC IPlayer Radio 4 , approximately 1 hr 52 minutes in.

[Andy Burns]

It's taken the journos long enough to figure that out, we knew it here (and that the original zinc ones were specified as FR rated, the aluminium ones didn't specify PE/FR/A2 rated) ages ago ...

[Jim GM4DHJ ...]

what a surprise .....

[Dave Plowman (News)]

Think it was pointed out very soon after the fire that the company who made the panels made three versions - with differing fire resistance and prices. (lowest price poorest fire resistance) And that the cheapest one was chosen - even although it was banned for high rise in other countries.

But surely a change from zinc to ally would require a planning permission change too? Since it looks very different?

[Andy Burns]

We know the supplier has stated they provided the PE version.

Yes, the original planing docs stated zinc/FR and a subsequent materials approval stated aluminium without stating PE/FR/A2, neither of those are BR docs, but it seems there *are* no BR docs for Grenfell as the work was done under a Building Notice.

See msg-id for references to K&C planning website.

[Dave Plowman (News)]

Wonder if a small scale private development would get away with changing the look of it after obtaining planning permission?

[JoeJoe]

The issue is whether the cheaper option complied with building and fire safety regulation. If it did then the council was well within its right to choose either.

[Martin Brown]

Swapping from a FR (possibly an A2 grade given the price difference) to the cheapest nastiest PE product they could find. It is an interesting legal question as to whether the suppliers who knowingly supplied these materials for the refurbishment of a building that they knew to be 70m tall against their own guidelines of no more than 18m broke any laws.

Not convinced zinc vs aluminium metal surfaces made that much difference to the flammability but the choice of internal core certainly did.

He has it exactly backwards. It is entirely credible that the tests now being done are representative of the way that the block of flats failed. What was wrong was the original dodgy testing regime that passed them!

I do agree that there isn't much point in testing more samples of PE cored cladding in the vain hope that some will not burn. The problem now is to find all the high rise buildings with this crap on the outside.

It was the original play a blowtorch/radiant heater onto the middle of a huge panel test that was unrealistic because it ignored the obvious edge weaknesses that a fire will inevitably attack first.

credible technical engineering ability to investigate this disaster. I hope that he can unpeel this onion and find all the factors that contributed to the very rapid spread of flames over the exterior.

[Tim Watts]

And yet, what seemed to happen in reality is the whole damn lot went up!

It does not take Einstein to realise if you make the system out of all "non combustible"[1] products, the result will be safe.

Any other approach and you are at the mercy of various untestable edge cases (eg "it's not combustible, unless you have a lot of it with plenty of airways").

[Andy Burns]

Yes material change applications, or non-material change applications happen after initial planning approval all the time, sometimes they're approved, other times rejected ...

[Roland Perry]

In message , at 09:14:34 on Fri, 30 Jun 2017, Chris Hogg remarked:

Are they really stripping off the aluminium and testing just the core?

Or as I've been saying all along, applying the flame to the end of the panel rather than in the centre of the outside. The former is much more like the situation at Grenfell, even if there may not be an official approval test using this methodology.

Remember, the testing is to see if Grenfell could potentially be repeated at other towers, *not* whether the Grenfell cladding was itself compliant with whatever regulatory scheme was in place at the time.

[Dave Plowman (News)]

Know I shouldn't, but when I hear that surname linked to anything to do with councils, I shudder. ;-)

[Andy Burns]

I'm sure when I first heard of the appointment, it was said he was setting his own terms of reference for the inquiry, but then I heard him say the scope might not be as wide as some of the survivors were wished.

[Tim Streater]

By zinc, d'ye mean pure zinc or galvanised iron/steel? I assume the latter, as zinc by itself is fairly reactive and also burns (prolly more easily than ally, I'd have thought).

[Andy Burns]

Shirley not?

[Andy Burns]

This was the original spec

[sm_jamieson]

If would you observed is the case:

Retired lawyer ?

1. Setting the terms within his own technical expertise ?
2. Limiting the terms to minimise work for the promised remuneration ?
3. Limiting the terms to match the required timescale ?
4. Setting reasonable terms and warning about other's unreasonable expectations ?

Settings his own terms and then complaining about them, or suggesting others might complain about them, is the sort of thing that I wish interviewers would pull people up on, but they never seem to. Where's Paxman when you need him ? Or Hard Talk on the BBC news channel.

Of course the investigation of such a tragic event would never be manipulated, would it ?

Simon.

[Chris Hogg]

Ah yes, Shirley

Shuddering would seem a fairly mild reaction. No relation to Gary though

[sm_jamieson]

That says VMZ Composite is a multilayered panel made up of two sheets of zinc that are 0.5 mm thick and thermo-glued on either side of a mineral-rich polyethylene core for optimum reaction to fire.

Still PE, but "mineral rich" ?

Simon.

[Tim Streater]

Blimey. 0.5mm of zinc either side of the panel. Can some chemist explain why that is not a fire risk? AISB, zinc burns.