Commonly used UK aluminium cladding system fails safety tests

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A government panel reviewing building regulations and fire safety in England says a cladding system using aluminum composite material (ACM) with a fire-retardant polyethylene filler and phenolic foam insulation doesn't meet criteria for use in tall buildings.

The results of the latest round of tests to determine how different combinations of ACM panels and insulation behave in a fire were released Aug. 21 by the Department for Communities and Local Government (DCLG).

The finding puts another 22 buildings over 18 meters (59 feet) tall on England's list of structures likely to need safety improvements. In all, 228 buildings have cladding that may have to be replaced or modified.

The latest test results apparently surprised officials at Kingspan Group plc, which makes phenolic foam. They expected that kind of insulation to pass the test when installed under non-combustible panels, the BBC reported on Aug. 21. The Kingsport, Ireland-based company intends to commission further tests with a different combinations of flame retardant and non-combustible ACMs to improve the base of available evidence, the BBC also reported.

The Kingspan logo was visible on charred remnants of the 24-story Grenfell Tower in London, which quickly was engulfed by flames on June 14, killing at least 80 people and displacing hundreds. About 5 percent of the tower insulation reportedly was a brand called Kooltherm manufactured by Kingspan.

The bulk of the building had been wrapped with polysiocyanurate (PIR) foam insulation for energy efficiency and covered with ACM panels that had a combustible PE core for affordable aesthetics added during a 2016 renovation. The PIR foam, which was made by Celotex, a Saint-Gobain company, was beneath Reynobond composite cladding, which consisted of two sheets of aluminum with a PE core produced by New York-based Arconic Inc.

The three building product manufacturers issued statements after the fire. Kingspan said its product was installed as "part of a combination for which it was not designed and which Kingspan would never recommend." Celotex said it would stop supplying its RS5000 brand insulation for use in high-rise, rainscreen cladding systems "pending further clarity." And Arconic curtailed sales of its Reynobond PE for tall buildings,

Following the tragedy, London officials began reviewing the mix of materials used for residential towers and other structures. A building safety program also was implemented to test seven different combinations of ACM cladding, fillers and insulation and to take corrective steps.

Testing is complete on six of seven cladding and insulation combinations. Results released Aug. 14 show ACM panels with a limited combustible filler and PIR foam insulation can meet criteria for tall buildings. And, ACM panels made with a fire-retardant PE core and stone wool foam insulation can meet regulations, according to Aug. 11 test results.

One other test of ACM panels with mineral cores and non-combustible mineral wool insulation is yet to be completed but is expected to pass.

The first test was done on ACM panels with an unmodified PE filler and PIR foam — a combination of materials used on the Grenfell Tower and 82 other buildings in England. The results released July 28 show even with cavity barriers, this cladding combination fails to meet building guidance.

The second test was done on ACM panels with an unmodified PE core and stone wool insulation. This cladding system also failed, according to results released Aug. 3. England has 111 buildings with this kind of exterior facade.

The third test looked at ACM panels with fire-retardant PE filler and PIR foam insulation. This system failed, too, according to results issued Aug. 8. There are 13 high-rise buildings with this cladding combination.

Building owners and landlords are being advised about what safety measures and remedial steps they can take to mitigate fire risks.

In addition, Prime Minister Theresa May met privately with some of the former residents of Grenfell Tower on Aug. 23. She told BBC they were pleased to learn the Kensington and Chelsea Tenant Management Organization, the group in charge of housing in west London, will be stripped of its powers. The organization lost the public trust, council members of the Royal Burough of Kensington and Chelsea (RBKC) said. They are looking at all options to manage the burough's 9,760 public housing properties.

Both the council and tenant managers are facing questions in a public inquiry and a criminal probe in which a Scotland Yard official sees "reasonable grounds" that "corporate manslaughter" was committed, according to the Evening Standard newspaper.

The inquiry will focus on the cause of the fire; the means by which it spread; decisions related to the tower's refurbishment and management; the adequacy of building regulations, fire regulations, other legislation, and industry guidance related to high-rise residential building design, construction and equipment; fire prevention and fire safety measures in place at Grenfell Tower; and the response of the London Fire Brigade.

In the meantime, some 180 households of Grenfall survivors are in need of permanent housing and hoping to stay in the area near their schools and jobs. They received letters dated Aug. 22 from DCLG that say, "RBKC is currently exploring options with a number of developers to secure further local properties, to help you get what you need."

The department also put 750,000 pounds ($960,000) into a new Community Anchor Fund to fund agency programs and volunteers providing survivors a range of services, including mental health and emotional support. One former Grenfell resident, Zahra Shamji, 21, told London's MixMag Media that her friend died in the fire and she has been living for the last two months in hotels and any accommodations she can find.

"Things have changed quite dramatically in our area. Almost overnight my neighborhood doesn't feel the same," Shamji said "It feels dead, I can't hear kids playing outside, I don't see a lot of my neighbors in the block. It's a ghost town and seeing the tower all burnt like that has made me feel sad. I have nightmares at night fearing for those at the top that didn't make it."

Despite the losses many still cope with, the neighborhood's annual Notting Hill Carnival, which celebrates West Indian culture and draws about 2 million people, going ahead as scheduled. One DJ said: "People will be partying in the streets under the sky coffin, there's no escaping it."

A moment of silence is planned for 3 p.m. Aug. 28. In their letter to residents, two DCLG officials said, "We will both observe our own minute's silence to show our respect for, and unity with, you."


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