By Danielle Aumord

The public inquiry trawled through evidence in the absence of Arconic witnesses Claude Wehrle, Gwenaelle Derrendinger and Peter Froehlich and heard that they knew that their polyethylene cladding panels were highly combustible after numerous failed tests but that they continued to sell them as safe to use on high-rises.

We heard the backstory to the Grenfell, which was cladded with Arconic’s Reynobond 55 PE panels in 2016, a newer version of the firm’s Reynobond 160 PR. The former had been manufactured in France and the latter was produced on British soil just over a decade
earlier.

Reynobond 160 PR was classified as ‘Class 0’ fire standard, which was the minimum required standard under English guidance for use on high rise buildings. According to the Government’s official guidance, ‘Class 0’ materials adequately resist the spread of fire over the external walls of tower blocks. But Reynobond 55 PE hadn’t actually been retested, this was the problem.

Emails shown to the inquiry, as they ‘empty chaired’ Arconic’s witnesses, revealed the firm used ‘hard tactics’ as it sought certification that the product could be used on tower blocks.

Arconic, in 2006, threatened to “stop all dealings with BBA (British Board of Agrément) unless a satisfactory solution was found” to the classification of their product. The BBA then produced its certificate of the Reynobond panels in March 2007.

That year, Gerard Sonntag, Arconic’s marketing manager, attended a presentation by writer and consultant Fred-Roderich Pohl.

Pohl compared the use of 5,000 sq m of polyethylene-cored ACM (aluminium composite material) on a building as having the same “fuel power” as a 19,000 litre oil truck. ‘What will happen if only one building made out of PE core is on fire and will kill 60 to 70 persons, what is the responsibility of the ACM supplier?’, he wrote.

Pohl recommended that Arconic sell only the more fire resistant cladding panels in their portfolio but the polyethylene cladding stayed on the market.

Emails relating to international fires caused by polyethylene cladding in high-rise buildings, to and from Mr. Wehrle, in 2015 and 2016, were also heard by the inquiry. “I hope that PE will gradually be excluded from facade cladding because each time it is the image of all the
ACMs that takes a hit!”, he said.

Mr. Millet QC, lead counsel to the Inquiry, asked, “Why did Mr Wehrle hope that PE would gradually be excluded from facade cladding while Arconic was continuing to manufacture it and to sell it?”

In 2008, the BAA then produced another “inaccurate and misleading” certificate covering the Kooltherm K15 insulation which was found on parts of Grenfell. They produced the certificate by “extrapolating” information from other products rather than obtaining original test data, heard the inquiry.

Despite it being a combustible product, their certificate stated that the K15 installation boards “will not contribute to the development stages of a fire or present a smoke or toxic hazard.”

The inquiry was shown an email sent to the BBA in 2014 by government official Brian Martin, warning them of an error contained in its certificate for the Kooltherm K15 insulation. Mr. Martin described the issue as “a serious safety matter”.

The inquiry heard that the BBA also sent out information to all local authorities and housing associations in July 2017 informing them that testing carried out the Reynobond ACM found the product “was deemed to achieve a Class 0 fire rating” despite never having been provided with test data to validate this claim. The firm did not withdraw the certificate until November 2018, which was almost a year after they were notified about product tests showing poor fire performance.

Another hazard on the night of the Grenfell fire, were the cavity barriers.

Cavity barriers are meant to prevent fires from spreading but the inquiry heard that the barriers fitted at Grenfell by cavity barrier supplier, Siderise, ignited on the night of the fire.

It transpired that they had never tested barriers with gaps as wide as those they were required to on Grenfell, although they produced a report saying they could just nine days after the tragedy.

The inquiry continues.