Tower block fire - london

[C.R.A.Z.Y]

Yeah because that's what people are suggesting
And actually claiming it would have had no effect on the speed at which the fire spread is equally ridiculous !

The insulation had poor fire protection, using cladding that has a better fire resistance would almost certainly have slowed things down!



If number 3 has a higher fire resistance than obviously it takes longer for number 1 to start burning

 

[Hagar]

minimum 15 year stretch for murder right ?

No, it could be manslaughter due to gross negligence (still carries a possible life term but not a mandatory one).

It is greatly down to whether a sufficient proper risk assessment was carried out originally on the scheme and whether that was modified following the material changes.

 

[ubersonic]

You're getting it mixed up. The original uses a .5mm zinc on a core. It still would have needed the 70 odd mm of insulation behind it which is what caught fire.

No that's wrong.

This is a diagram of the exterior of the building, the "insulation" is fine and fire resistant:

This is a diagram of the "cladding" in the above diagram, the core is flammable and caused this disaster:

I think your confusion is you think it was the insulation that burned and spread the fire when in fact it was the flammable core in the aluminium cladding. The original spec Zinc cladding with fire resistant core would have not had the same outcome (nor would the FR version of the aluminium cladding.

 

[Maccapacca]

You're confusing the 3mm of insulation within the cladding to the 70mm of insulation for well insulation

 

[wildman]

Yeah because that's what people are suggesting
And actually claiming it would have had no effect on the speed at which the fire spread is equally ridiculous !

The insulation had poor fire protection, using cladding that has a better fire resistance would almost certainly have slowed things down!

I think you are getting confused. The cladding is a single polymer / metal sheet that is placed over the insulation behind it which is fixed to the outerwall. As the dfire went from the inside out the outer layer of metal wouldmake no difference if the insulation behind was already on fire as the fire would have just gone directly up behind the metal torching all the insulation that was fixed to the outer building wall.

this cross section shows how cladding works in general

The aluminium PE pannels in this case would have been the weather protection layer and not the actual insulation layer. Those reynobond pannels are not 20cm thick slabs that are bolted on to the external walls you know ?

 

[ubersonic]

You're confusing the 3mm of insulation within the cladding to the 70mm of insulation for well insulation

It was the 2mm of flammable insulation in the 3mm Reynobond PE cladding that initially caught fire and spread it, not the fire resistant Celotex RS5000 insulation.

 

[C.R.A.Z.Y]

The insulation didn't catch fire via the original concrete external wall, instead it caught fire as the cladding was compromised due to its rubbish fire resistance.
Once the cheap cladding was compromised the fire could spread rapidly up via the airgap as the flames then probably had direct access to the insulation with no cladding protection

It was the 2mm of flammable insulation in the 3mm Reynobond PE cladding that caught fire and killed everyone, not the fire resistant Celotex RS5000 insulation.

Actually my understanding was both were eventually burning, however it was the fault of the cladding that allowed the insulation to burn so quickly

 

[leaskovski]

Yeah because that's what people are suggesting
And actually claiming it would have had no effect on the speed at which the fire spread is equally ridiculous !

The insulation had poor fire protection, using cladding that has a better fire resistance would almost certainly have slowed things down!



If number 3 has a higher fire resistance than obviously it takes longer for number 1 to start burning

Does anyone have design drawings and ratings for joins? What happens at window recesses, for example, where the fire started? Obviously the cladding doesn't all come in one piece, how does the cladding join with other pieces? etc...

 

[wildman]

The insulation didn't catch fire via the original concrete external wall, instead it caught fire as the cladding was compromised due to its rubbish fire resistance.
Once the cheap cladding was compromised the fire could spread rapidly up via the airgap as the flames then probably had direct access to the insulation with no cladding protection




Actually my understanding was both were eventually burning, however it was the fault of the cladding that allowed the insulation to burn so quickly

your last sentence is in conflict. If the cladding allowed that to happen then it is because it was actually capable of resisting fire and therefore insulated the fire behind allowing it to reach temperatures that compromised the celotex insulating layer and then funnelled the fire up the building untill the aluminium finally gave out and combusted also. If the Alu pannel was crap it would have torched itself and spread the fire up on the alu outerskin of the building before the celotex went up which should then have given enough time for the building to get cleared. Something weird has happened here that no one yet knows what it was and i don't believe it is anything just as simple as the pannel itself.

This is the problem with all this armchair speculation, none of us has a clue what we are talking about

 

[C.R.A.Z.Y]

This is the cladding that should have been used on GrenFell:

A2 Cladding

"Polyethylene is a thermoplastic material, which ... melts and drips as it burns, spreading the fire downwards as well as upwards," architectural consultants Probyn Miers said in a note on insulation materials posted on its website.

 

[Chris Wilson]

Presidential advisers, government advisers, consultant psychologists, terrorism experts, civil engineering consultants, the forums GDP must be awesome

 

[C.R.A.Z.Y]

Diagrams in a 2016 Arconic brochure for its Reynobond panels describe how PE core panels are suitable up to 10 metres in height.

Panels with a fire resistant core - the FR model - can be used up to 30 metres, while above that height, panels with the non-combustible core - the A2 model - should be used, the brochure says.

Grenfell Tower is more than 60 metres tall.

Source

 

[wildman]

Source

Diagrams in a 2016 Arconic brochure for its Reynobond panels describe how PE core panels are suitable up to 10 metres in height.

that's all well and good, but unless the manufacturers specification clearly states it shouldn't be used in buildings over that height, then technically speaking the contractors used materials that met the specs required.

Reynobond PE specs

http://www.arconic.com/aap/north_america/catalog/pdf/brochures/reynobond_pe.pdf

installation guidance

3.02 Installation A. Erect panels level and plumb, in proper alignment and relation to substructure framing and established lines. B. Panels shall be erected in accordance with an approved set of shop drawings. C. Panel anchorage shall be structurally sound and per engineering recommendations, if required. D. Where aluminum materials come in contact with dissimilar materials, a bituminous paint or caulking tape shall be installed to insulate between the dissimilar materials. Factory applied protective paint or G-90 galvanized steel is considered adequate insulation.

No mention anywhere of limitations on building height usage. It is the technical specifications that will be held up in a court of law as to whether the materials were fit and proper for use.

Don't get me wrong I am not trying to defend either the council or the contractors here, and I really think the reason these people died was purely because they were poor council tenants and the authorities did the bare minimum they were legally required to do. But the bottom line is you are trying to put 2 and 2 together and coming up with 5.

 

[ubersonic]

that's all well and good, but unless the manufacturers specification clearly states it shouldn't be used in buildings over that height-

You mean like:

The brochure also issued a blunt warning that cladding can be a fire risk.

"When conceiving a building, it is crucial to choose the adapted products in order to avoid the fire to spread to the whole building. Especially when it comes to facades and roofs, the fire can spread extremely rapidly," the brochure said.

"As soon as the building is higher than the fire fighters’ ladders, it has to be conceived with an incombustible material."

-----------

The question does beg asking, if they thought it important to add the information that the cladding shouldn't be used on tall buildings too the 2016 brochure, why did they not think it important to notify the customers who ordered it for use on Grenfell tower in 2014...

 

[wildman]

You mean like:

​

yes and my holiday brochure had pictures of topless women, but I saw none when i got there. The technical specifications will be what are held to scrutiny as these are borne directly from the testing that was done. If the technical specifications were fabricated to make it appear like the panels met specs then someone is going to jail. if the specifications were true and the panels according to the tests they were subjected to passed and were considered appropriate to the useage they were put to then that will be what counts in court. Now if the testing regime to certify the panels was weak then that needs to be addressed, but that cannot be the fault of the builders / contractors as they do not conduct the safety tests on the materials, they use the information provided on the technical specification documents. Moreover warning are usually included purely for insurance and legal reasons, that way of something goes wrong the manufacturer can say,"look we had a warning to say this **** could happen".

At the end of the day technical specs are king, it's what are used to make design decisions.

 

[ubersonic]

At the end of the day technical specs are king, it's what are used to make design decisions.

Oh I agree, I have previously said in this thread that I was running that project there's a good chance I would have ordered the PE cladding because the data sheet gives the impression it meets the regs when it doesn't (however I would like to think I would at least have browsed through the brochure and seen the warning).

As far as I am concerned the manufacturer salesperson is guilty of gross negligence manslaughter, the only question left in my mind is if the buyer on the contractors end is culpable too.

 

[Tefal]

Read it again, "same official fire rating".
.

As opposed to an unofficial rating?

 

[ubersonic]

As opposed to an unofficial rating?

There are multiple ratings, the one it's referring too is the one for surface flame spread, in which pretty much all metal sandwich panels will score equally, it doesn't matter if the insulation in between them is made of asbestos or napalm.

 

[wildman]

As far as I am concerned the manufacturer salesperson is guilty of gross negligence manslaughter, the only question left in my mind is if the buyer on the contractors end is culpable too.

I fear that the buyer (council / contractor) have a get out of jail free card on this one, because they will just wave the specs around saying it met the overall class 0 rating. I also fear that because of this the inquiry will be a whitewash.

 

[thenewoc]

At the end of the day if the cladding burns it shouldn't be used on a tower block, at least not one as high as Grenfell. All the tests of whether it burns or not doesn't take account of the real life scenario of it being used on a residential building like this with many people having windows open in the height of summer, possibly not at home to raise early alarm, window dressings such as blinds, curtains or nets that are all highly flammable to further spread fire.