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Grenfell cladding does not meet marketed standard in new test

The same type of cladding as used on the walls of Grenfell Tower has failed to obtain the fire safety rating it was certified and marketed as having, in a new, privately commissioned test.

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Molten polyethylne flows out of the cladding panels during the test (picture: Ian Abley)
Molten polyethylne flows out of the cladding panels during the test (picture: Ian Abley)
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Grenfell cladding does not meet marketed standard in new test #ukhousing

The cladding used on the walls of Grenfell Tower has failed to obtain the fire safety rating it was certified and marketed to, in a new privately commissioned test #ukhousing

The British Board of Agrément (BBA) certified the Reynobond PE cladding panels – aluminium sheets with a polyethylene core – as Class 0 in 2008. Manufacturer Arconic subsequently marketed them as achieving this standard.

But senior technical designer Ian Abley has funded a new test of surplus stock of the same material by international certification and testing house Warrington Fire. The test was technically invalidated after 16 minutes when the polyethylene melted as the panels were heated.

Before a ban on combustible materials in December, official guidance said Class 0-rated materials can be used as the “external surface” of walls of buildings over 18m. Many experts cite this standard as the reason for the material’s use on high rises.

This is the first testing of the product’s rating since the fire. It raises difficult questions for the BBA about why it issued the certificate in January 2008, which said that the panels “may be regarded as having a Class 0 surface”.


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Dr Barbara Lane, an expert witness at the Grenfell Inquiry, has already described the BBA certificate as “factually inaccurate”. She said she was aware of nine previous tests of Reynobond PE products in which they did not meet Class 0 standards.

Arconic withdrew Reynobond PE from sale following the fire. However, Mr Abley obtained surplus stock from a cladding supplier for the test.

He then paid Warrington Fire the £2,149 fee for running a Class 0 test on the material, which he said was “Zerobond” – a fictitious product he said he wanted to take to market.

The material passed one of the two stages involved in the Class 0 test, as flames did not spread over the surface of the material, despite it physically bowing from the heat.


Related Files

Zerobond - J409708-CJ190318BS 476 Parts 6 and 7 Summary Iss1. WF 30.05.19.pdfPDF, 130 KB

It came close to passing the second stage, which involves placing a square of the material in an oven for 20 minutes, with the temperature not permitted to rise above certain levels.

However, molten polyetheylne flowed out of the centre of the panel after 16 minutes, invalidating the test.

Mr Abley said: “The result shows how close the product came to passing. If the polyethylene had stayed firm for another four minutes, I would have been able to take it to market.”

The BBA said it could not comment, as it did not want to prejudice the Grenfell Inquiry or the police investigation.

A spokesperson for Arconic said: “We did not commission the test and it was not commissioned on our behalf, and therefore it would be inappropriate for us to comment.”

What the new tests showed

What the new tests showed
The surplus Reynobond cladding panels before the test (Picture: Ian Abley)
  • To obtain a Class 0 rating, a material must pass tests detailed in parts six and seven of British Standard 476. The part seven test assesses the spread of flame across a material after a pilot gas flame is applied to its surface and it is rotated in front of a heating element. The part six test assesses ‘fire propagation’ by placing a sample of the material in an oven for 20 minutes, during which its temperature must stay within an acceptable range.
  • The so-called “Zerobond” passed the surface spread of flame test, as flames did not travel across the aluminium surface. It obtained this pass despite the panels physically bending from the heat as the polythene core softened. For this test, the material is held in a water-cooled frame which helped it to survive the 10 minute test despite bowing.
testing step 2
The bowed panel after the test of surface spread of flame, which it passed (Picture: Ian Abley)
  • In the fire propagation test, the material was on course to secure a pass. However, 16 minutes in, the polyethylene in the middle of the cladding panel began to melt. This then poured out of the test oven in a molten stream (pictured below). This meant the test was invalidated, and the material could not obtain a Class 0 certificate.
test step 3
Molten polythene flows out of the furnace, causing the material to fail the test (Picture: Ian Abley)
  • This raises tough questions for the BBA and Arconic about why the material was certified and marketed as Class 0.
  • A Class 0 fire rating means the material may be used on the ‘external surfaces of the walls’ of a high-rise building, according to the government’s official building guidance, Approved Document B.

It came close to passing the second stage of the test as well – which involves a 225mm square of the material being placed into an oven for 20 minutes, with the temperature not permitted to rise above certain levels.

The material was on course to pass the test up until 16 minutes, when molten polyethylene flowed out of the centre of the panel invalidating the test and meaning it could not gain a Class 0 certificate.

The BBA declined to comment when asked by Inside Housing what testing it had based the original 2008 certificate on.

The result of the new test comes a BBC investigation last year claimed Arconic was aware following testing in 2014 and 2015 that some of the panels had a lower fire safety rating.

In response to that investigation, the BBA said it had not been notified about the results of the new tests.

Mr Abley, who has written about building safety in the aftermath of Grenfell and paid for the test after receiving a payment protection insurance compensation payout, said: “This new test raises questions for the BBA about why they judged Reynobond as Class 0 in 2008. There is no doubt in my mind that their certificate opened up the market for Reynobond for it to be used as cladding on high rise housing like Grenfell Tower.

The significance of the BBA certificate

The significance of the BBA certificate
The front sheet of the 2008 certificate issued by the BBA
  • The BBA describes itself as “the UK’s leading construction certification body”. It was set up by the government in 1966, but became an independent not-for-profit company in 1983. It primarily issues certificates for construction products used in the UK.
  • The chief executive of the company is Claire Curtis Thomas, who stood down as a Labour MP in 2010 after it was revealed in the expenses scandal of 2009 that she was among the highest claimants.
  • In January 2008, the BBA provided a certificate for Reynobond panels, asserting that they “are judged to meet the Class 0 requirements”. It is not clear what, if any, fresh testing was carried out on the panels before the BBA issued the certificate.
  • Before Grenfell, official building guidance stipulated Class 0 as the standard for the “external surfaces of walls” of tall residential buildings. Many people, including government officials, said before the fire that this applied to cladding.
  • Marketing for Reynobond described its PE cored product as Class 0, based on the BBA certification and a test from 1997.
  • Since Grenfell, the government has claimed that the standard for cladding should never have been Class 0, but instead should be the higher standard of ‘limited combustibility’. This has been disputed by many industry figures
  • On Grenfell, the Reynobond cladding was combined in a system with combustible insulation. The BBA certificate applied only to the panels and could not be used to justify the compliance of the system as a whole.
  • The certificate did also clarify that “for resistance to fire, the performance of a wall incorporating this product can only be determined by tests from a suitably qualified laboratory and is not covered by this certificate”.
  • There is evidence the certificate was considered during the refurbishment. The Grenfell Inquiry heard the certificate was emailed from Arconic to Harley Facades, which installed the cladding system on Grenfell. It was also emailed to main contractor Rydon and architect Studio E. However, experts said there was no evidence the certificate had been provided to building control officials as evidence of the system's compliance.

He added: “The result also shows how close the product came to passing. If the polyethylene had stayed firm for another four minutes, and Warringtonfire had been able to issue a Class 0 Summary Report, I would have been able to take it to market. Those responsible for including Class 0 in Approved Document B must explain why they believed it was suitable for cladding.”

It is understood the evidence from the test has been passed to the Metropolitan Police and the Grenfell Inquiry.

In defence of its guidance, the government has consistently argued since the fire that the cladding panels should have been ‘limited combustibility’, as the plastic in the core of the panel should be deemed a ‘filler material’.

But this argument has been rejected by many experts. Documents uncovered by Inside Housing last year also reveal officials were urged to alter guidance before the fire to make this clear.

A spokesperson for the BBA said it could not comment, as it did not want to prejudice the inquiry or the police investigation.

A spokesperson for Arconic said: “We did not commission the test and it was not commissioned on our behalf, and therefore it would be inappropriate for us to comment. We will continue to cooperate with the public inquiry and all authorities investigating the tragic fire.”

In its closing statement to the first phase of the inquiry, Arconic said that it would have been “entitled to assume” that the cladding was being used in line with UK guidance.

It added that while the BBA certificate was emailed to Harley Facades, the inquiry had also heard there was “no evidence” it was used to support a building control application or as evidence of compliance with the regulations.

A summary report can be downloaded below. For full reports contact Ian Abley via email at abley@audacity.org

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