Burning buildings

stellarfun

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Seems as there will be changes in the building codes, and possibly costly retrofits.

Design specifications seen by the Press Association suggest the renovation work carried out at Grenfell Tower included plans for a 50mm "ventilated cavity" next to 150mm of Celotex FR5000 insulation, which also has a Class 0 rating.
......
These panels, made by US firm Arconic, consist of Reynolux coated aluminium sheets over a Reynobond polyethylene core.

The firm's website says that the sheets have the highest A1 European fire safety rating and are "incombustible".

The interior comes in two forms, one with an A2 rating that is "non-combustible" and a second with a lesser B rating that is described on the website as "fire retardant" and "non-flammable, which prevents fires from spreading".

It is not clear which was used at Grenfell Tower.
http://www.heraldscotland.com/news/...l_burn_if_exposed_to_fire_of_sufficient_heat/


https://www.theguardian.com/uk-news...ralian-buildings-is-like-the-asbestos-problem
 
A NY Times Investigation.

https://www.nytimes.com/2017/06/24/world/europe/grenfell-tower-london-fire.html

The video cited in the New York Times article of the reaction of London Fire Brigade firemen as they rush to the fire.

http://www.bbc.com/news/uk-40330789

Arconic (formerly Alcoa) will no longer sell the cladding. Investors sold off the stock today, apparently fearing liability claims. Dozens of high rise buildings in Britain are clad with this particular cladding. I expect these will have to be categorized as unsafe for occupancy until re-clad.

https://www.nytimes.com/aponline/2017/06/26/world/europe/ap-eu-britain-london-fire.html
 
Edit: I wrote this before reading the NYT article above, which says the exact same thing. Perhaps use this post as a companion to that article, lol. At least all of my research agrees with theirs!

--

Here's the actual facade details for Grenfell Tower:

Big image because detail is important:
mYRoo0i.png


So a few things, the ACM (Aluminum Composite Material) panel installed was Reynobond PE, which is the cheaper option from the Reynobond offerings. PE indicates polyethylene core, which is combustible & does not meet fire standards. Had they used the more expensive fire retardant model Reynobond FR with a mineral core, which is fire retardant/limited combustible, the tragedy may not have happened to the extent that it did. You should not be immediately afraid of buildings clad in aluminum composite panels, as many architects do spec the fire retardant option for towers in the US, as the non-fire retardant model is not supposed to be used on towers in the US. An example of this is ADD Inc's MassArt Tree House which utilizes Alucobond Plus ACM panels. Alucobond Plus is Alucobond's fire retardant mineral core composite offering.

There are other factors besides the ACM panels that contributed to the spread of the fire. If you notice on the plan & wall section details above, insulation was also added to the facade. This insulation was found to be Celotex FR5000 rigid polyisocyanurate ("PIR"), which proved to be quite combustible despite claims otherwise. The positioning of the insulation proved particularly deadly. Notice that along the columns, an air gap was left between the insulation & the original precast column structure. This air gap is a simple way to let water weep out, but it is highly dangerous in the event of a fire. As we all know, fires accelerate with air flow and travel up air shafts quickly. If you notice in the pictures & video of the building burning, the fire traveled straight up the columns as it flailed around and lit other parts of the facade on fire. Additionally, the detail does not indicate appropriate firestopping that should be shown at each floor for the insulation & panel arrangement.

As to if this could happen in the US, you can never say never; Reynobond PE & Alucobond are often submitted as VE items to save money instead of Reynobond FR & Alucobond Plus and architects must be very vigilant when reviewing the submittals from contractors; however, a tragedy of this scale is unlikely due to key US fire & building code regulations. NFPA requires automatic sprinkler systems in any new or substantially renovated building with more than 4 units (residential) or a certain number of square feet per a variety of building use groups. Sprinklers knock out about 90% of small apartment fires to begin with, but ultimately sprinklers are really life safety devices (providing a safe means of egress) and aren't directly intended to save the building, although they do in most cases. Additionally, per IBC Chapter 10, at least 2 means of egress are also required from any point in the building with a travel distance not to exceed a certain amount per the building use group. Grenfell Tower & so many other UK tower blocks shockingly only have a single staircase (see plan). Oddly, according to the planning documents, the renovation actually added rated fire walls between the units on the floor that the fire is thought to have broken out on (see plan).

Plan, note the SINGLE staircase!:

7sTyURa.png


(The additional staircase you see being removed in the plan above was a dedicated one for that former office space only. It did not continue up the tower. The typical tower floors are all what you see in the new plan on the right.)
 
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1 Staircase! That's crazy in any building built since the 1911
Triangle Shirtwaist fire.

Am I correct in thinking that the whole reason we have fire escapes on old buildings is that starting in 1912-ish, everyone everywhere in a multi-family in the USA needed a second means of egress , and that if you didn't you had to put one on, no matter how costly or ugly, and that 2 staircases was standard in buildings from that time on (and for that reason) including 2-deckers and 3-deckers built around Boston in the twenties.
 
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data,

Thanks for the graphics. In Dubai, they are requiring external sprinklers. The article indicates internal sprinklers proved to be ineffective.

http://www.thenational.ae/news/uae-...art-of-new-fire-safety-rules-for-dubai-towers

I would suppose that if you had 10, 15, 20 floors of a high rise burning simultaneously you could not get enough water to all the sprinkler heads to douse the fire.

As I said, sprinklers are not designed or intended to save the building/"put out the fire," only to provide a safe path of egress for enough time before the building is completely engulfed. This fact is probably the most misunderstood fact of fire protection engineering, along with the fact that all sprinklers don't activate at once (like in the movies -- rather, they act as heat melts a piece of the sprinkler where the fire is, which lets water out).

Also sidenote: I didn't read the NYT article until now and realize that I accidentally rewrote their whole analysis with my own analysis haha. At least my research aligns perfectly with theirs!

1 Staircase! That's crazy in any building built since the 1911
Triangle Shirtwaist fire.

Am I correct in thinking that the whole reason we have fire escapes on old buildings is that starting in 1912-ish, everyone everywhere in a multi-family in the USA needed a second means of egress , and that if you didn't you had to put one on, no matter how costly or ugly, and that 2 staircases was standard in buildings from that time on (and for that reason) including 2-deckers and 3-deckers built around Boston in the twenties.
Seriously, it blows my fucking mind. I would never live in a tower that only had 1 stair.

Yes, you are precisely correct about why all those fire escapes got tacked onto buildings in the US.
 
From my layperson's perspective, I have a hard time seeing how Alcoa / Arconic is to blame here.

As datadyne and others have pointed out, the manufacturer was very forthright with the fact that the siding in question was not fire retardant. It's not like they hid that fact or sold a faulty product that didn't meet its stated specifications. Another, more expensive version is sold as fire retardant by the same company. US building code (and the building codes of other countries that follow US standards) doesn't allow the non-fire retardant version to be used in this application precisely because of how it can burn. The UK does allow it, going against the grain of its peer nations.

This was a known issue, but the powers-that-be in the UK approved the siding for this use none-the-less. The powers-that-be were also cool with a residential tower with no fire sprinklers and only one staircase. They are the ones at fault here, not the manufacturer of the siding.

(As an aside, this is a good time to bring up the amazing fact that, with some reasonable caveats, there has never been a multiple occupant fatality fire in a fully sprinklered building.)
 
From my layperson's perspective, I have a hard time seeing how Alcoa / Arconic is to blame here.

As datadyne and others have pointed out, the manufacturer was very forthright with the fact that the siding in question was not fire retardant. It's not like they hid that fact or sold a faulty product that didn't meet its stated specifications. Another, more expensive version is sold as fire retardant by the same company. US building code (and the building codes of other countries that follow US standards) doesn't allow the non-fire retardant version to be used in this application precisely because of how it can burn. The UK does allow it, going against the grain of its peer nations.

This was a known issue, but the powers-that-be in the UK approved the siding for this use none-the-less. The powers-that-be were also cool with a residential tower with no fire sprinklers and only one staircase. They are the ones at fault here, not the manufacturer of the siding.

(As an aside, this is a good time to bring up the amazing fact that, with some reasonable caveats, there has never been a multiple occupant fatality fire in a fully sprinklered building.)
Yes to all of this. I maintain that what actually accelerated the fire was the use of polystyrene insulation with a significant air gap on the column enclosures. The ACM panels just burned at a typical rate. The insulation behind the panels on the other hand went up like a damn match.

This said, MA is actually one of 3 states + DC that have *EXEMPTED* NFPA-required material fire testing standards which means Reynobond PE *COULD* be used on a tower in MA, even though you are not supposed to. Luckily, a number of architects are playing it safe and using Reynobond FR & Alucobond Plus.

http://www.npr.org/2017/06/24/53410...-on-cladding-suspected-in-grenfell-tower-fire
 
This is a link to a Chicago Tribune (AP) article from January 2016, narrating the problems worldwide with this type of cladding. That was about the same time that they were installing the cladding on Grenfell Tower. The article references a cladding fire in Shanghai that killed 58 people.
http://www.chicagotribune.com/business/ct-dubai-tower-fire-20160119-story.html

From the Tribune article.
Local experts have suggested as many as 70 percent of the towers in the Dubai may contain the material, though they acknowledge the figure is only an estimate as there are apparently no official records.

"There's an exposure because there's a lot of them and unfortunately they don't come with an 'X' on the building to know which ones they are," said Sami Sayegh, global property executive in the Middle East and North Africa for insurance giant American International Group, Inc.

The Grenfell Tower cladding was not functional, it was installed solely for aesthetics, to mask the brutalism concrete of the original. (Given the intensity of this fire, it appears the concrete held up well.) And the aesthetics were apparently done to make the tower's appearance more pleasing to the wealthier residents of Kensington and Chelsea.

The casualty insurance coverage for Grenfell Tower was about 20 million pounds. The insurer estimates the ultimate cost is likely to be over one billion pounds, making it the largest single building loss in European history.

As for Alcoa / Arconic's financial exposure, IMO, the company would be in a better position if its sales/marketing material for the UK had provided greater notice of potential risk, other than simply stating 'consult your local authority' and passing the buck. For its UK customers, Arconic omitted language in its marketing material for Europe, --which declared that the cladding was prohibited from being used on a building higher than 10 meters.
 
Yeah I forgot to mention the building had CIP conc shear walls on the interior & precast spandrels and columns on the exterior. Knowing this while the fire was burning, it was annoying to listen to the media keep saying the tower was in "danger of collapse." I fully expected it to stand on its own. Concrete is remarkably fire resistant and the brutalist structure is actually what kept the building from outright collapsing. You can see in the post-fire photos that the original concrete spandrels & columns behind the panels and PIR rigid insulation (that were totally burnt off) are still remarkably in tact and simply just burnt, but largely not damaged structurally. Definitely puts a stamp on the benefits of concrete construction and makes people in the towers recently being built in Boston feel a little bit safer about the structure they are living in.
 
The cause of the fire was an exploding refrigerator. The refrigerator was against an exterior wall, near a window. The London Fire Brigade responded, and extinguished the refrigerator fire. As they were leaving, they noticed the cladding had caught fire. The London Fire Brigade has few ladder / aerial tower trucks; half as many as Boston, even though London is a much larger city. As the fire was on the fourth floor, in Boston, the fire department would likely have raised a ladder to the apartment where the fire was, and caught any spread to the cladding.

But back to the first sentence in the preceding paragraph. The refrigerator was made by Hotpoint, now Whirlpool, last decade. the model is discontinued. That model could and would not be sold in the United States. The reason? The back was made of plastic, not metal. Why such a design? Because they could get away with it; there was no regulation or standard in the UK prohibiting such.

Now Whirlpool has a big liability mess on its hands, and the real possibility that claims against it will far exceed all the profit Hotpoint made selling these refrigerators.
 
The Grenfell Tower cladding was not functional, it was installed solely for aesthetics, to mask the brutalism concrete of the original. (Given the intensity of this fire, it appears the concrete held up well.) And the aesthetics were apparently done to make the tower's appearance more pleasing to the wealthier residents of Kensington and Chelsea.

This is a false narrative being pushed by various media. The rainscreen and insulation system was installed to improve the energy performance of the building.
 
This is a false narrative being pushed by various media. The rainscreen and insulation system was installed to improve the energy performance of the building.

Yes, in addition to this, the renovations also included double-glazed windows, as all the old UK tower blocks had single.
 
archibald and data, thanks for the clarification.
____________________________
Cladding from 120 high-rise buildings in 37 local authority areas in England has now failed fire safety tests, the prime minister has said.

Theresa May told the Commons it was a 100% failure rate, as all of the samples submitted so far since the Grenfell Tower fire had failed.

She urged local authorities and housing associations to "get on with the fire safety checks".

I believe count on Tuesday was 75 buildings. I am not sure what the test protocol is, but where n = 120 and 100 percent failure rate, that does surprise me.
 
Your information is very helpful; thank you.

I am confused by what I've read in the media.

Is this accurate?

* Cladding materials have changed over the years, with plastic-based materials becoming more popular, one reason being they are considered to be "greener" than other materials
* NFPA 285 testing became part of the International Building Code in 2000.
* In 2015, Massachusetts relaxed its fire code so that buildings of a certain height, if they have internal sprinklers, are not required to pass NFPA 285 testing.

But, is it > 40 feet above grade or > 75 feet above grade? The regulations I've read say 75 feet but the Globe article today said > 40 feet. That's a big difference.

I also read that there is concern that a building with an internal sprinkler system may not be sufficient in a fire because the cladding itself could catch on fire and burn without ever setting off an internal sprinkler system, in theory.

Sources of information:

https://www.bostonglobe.com/metro/2...-rises-fire/cYAN4JGSlKisbBDeh2O0jM/story.html

https://www.architects.org/sites/de...Gamache-HiRiseCode-9thEd -2Slide-Compress.pdf

http://www.npr.org/2017/06/24/53410...-on-cladding-suspected-in-grenfell-tower-fire

http://www.mass.gov/eopss/docs/dps/buildingcode/inf4/intro-9th-ed-ma-amendments-7-28-16-final.pdf

Edit: I wrote this before reading the NYT article above,
which says the exact same thing. Perhaps use this post as a companion to that article, lol. At least all of my research agrees with theirs!
 
John,

Even though Arconic has said it would no longer sell this type of cladding for use in buildings above a certain height, I expect the cladding will no longer be manufactured. Shrinking demand coupled with high exposure risk if it is newly applied in the future and caught fire should make it highly unprofitable to do so.

Read this Reuters article on emails regarding contemplated use of this cladding on Grenfell towers and one can appreciate the liability exposure now faced by Arconic. Arconic sold the cladding while seemingly knowing it was for a building that Arconic's own specs said this type of cladding should not be applied.

https://www.reuters.com/article/britain-fire-arconic-idUSL8N1JK2TZ
 
199 inspected-to-date buildings in Britain have problematic cladding. About 300 more buildings to be inspected. Of the 199, three are hospitals.

https://www.nytimes.com/interactive...c=edit_tnt_20170707&nlid=35684520&tntemail0=y


London Fire Brigade not only has relatively few ladder trucks, nearly all the trucks reach only a few stories.

https://www.nytimes.com/2017/07/08/world/europe/grenfell-fire-london-ladder.html

A couple things, as someone that has a background in the fire service (and is employed by a fire department, but in a civilian role):

1. The LFB (and the european fire service as whole) tend to operate very differently than the fire service in the US & Canada. This is due to their building construction and city layout. Their "bread and butter" over there is mostly fireproof dwellings that are compartmentalized - whereas the US is mostly wood (for example here in New England - 3 deckers are the usual "bread and butter"). They tend to go towards low volume, high pressure tactics vs the American method of high volume, low pressure water delivery.

2. Ladder trucks with aerials longer than 100 ft (or ~30 meters) are EXTREMELY rare. Typically most aerials here in the US max out at 100-110 feet. Others are shorter for various reasons (station size constraining truck dimensions, community layout, etc.) The LFB probably has short aerials for the reasons listed above - a 130' aerial does no good if the truck that it is mounted to can't make the turn onto the street. This is why Boston Fire is going back to a certain manufacturer for their fire apparatus, among other reasons.

3. Do not get me started on the ridiculousness that is the comment made by one of the occupants that is quoted at the end of the article.
 
How what's the deal on multistory wood-framed apartment buildings, such as the Cooper St ones in Waltham that seem quite the tinder boxes while under construction:

waltham7$small.jpeg


Once occupied, what enables these towers to (claim to) be significantly safer? Wallboard? Hair-trigger sprinklers? The simple act of installing doors and windows to cut down on draft?

The 1920s were big on switching to "fireproof construction" (steel, terracotta vaulting, concrete floors) for stuff that we've switched back to wood.

Is the wood in these under-construction blazes fireproofed at all? Or just standard building materials that we hope is protected (somehow) after being built?
 

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