ao link

My Account

Grenfell Tower Inquiry diary week 27: ‘What will happen if one building made out [of] PE core is in fire and will kill 60 to 70 persons?’

Insight12.03.212.00 PM by Peter Apps

The most explosive revelations this week at the Grenfell Tower Inquiry came from those who did not attend, as the evidence which would have been presented to Arconic witnesses was displayed in their absence. Peter Apps reports

Sharelines

Grenfell Tower Inquiry diary week 27: ‘What will happen if one building made out [of] PE core is in fire and will kill 60 to 70 persons?’ #ukhousing

On Wednesday afternoon, counsel to the inquiry Richard Millett QC presented the evidence that would have been put to Claude Wehrle, Gwenaelle Derrendinger and Peter Froehlich, the three witnesses from cladding manufacturer Arconic who are refusing to attend the inquiry.

This included a chilling prescient warning of the Grenfell Tower fire issued in 2007.

The week also saw evidence from the providers of cavity barriers, window panels and the first of several witnesses from the British Board of Agrément (BBA), which certified the cladding panels.

‘We could have a major problem that could cost [Arconic] a lot of money’

The story began in 1997, with the classification of one of Arconic’s cladding panels – Reynobond 160 PE – to the ‘Class 0’ fire standard – the minimum required standard under English guidance for use on a high-rise building.

Almost 20 years later, Grenfell Tower would be clad with Reynobond 55 PE, a newer version of the same product produced in France rather than the US. But as Arconic never retested the panel following this rebrand, was the 1997 test enough to say its panel met the standard?

Mr Wehrle, a senior member of the technical team and one of those who refuse to give evidence, said in his witness statement he had “no reason to suppose” there was any difference between the two products.

But Mr Millett pointed to a document which suggested there may have been “a change in the recipe” in making the cladding panel following failed tests in Poland in 2005. Such a change would invalidate the prior test.

The inquiry was also shown an email from Colin Southgate, the UK sales manager, in July 2006 which warned that the 1997 classification would expire in March 2007. He said the expiry could mean “a major problem that could cost [Arconic] a lot of money in potential claims and legal costs”.

Mr Millett said the email raised questions about whether there was “a gap in the certification for the UK” and if so “why it wasn’t closed with new tests”.

“We have always more and more projects coming in the ‘public housing and private development’ segment”

While further testing to English standards may not have been done on the Reynobond PE 55 product, tests to new European standards were commissioned in late 2004.

As we heard when Claude Schmidt, the president of Arconic’s French arm, gave evidence last month, these tests covered the two ways the cladding panel could be fitted to a building: one that involved bolting it to the wall with rivets and another that involved bending it into ‘cassettes’.

The riveted panels obtained a ‘B’ grade – the required standard for high rises in many countries, including the UK as an alternative to Class 0. But the cassettes failed spectacularly, burning 10 times as fiercely and being given a basement grade of E.

Arconic, as we now well know, did not advertise this fact to the market and continued selling its panels as Class B. Mr Wehrle's witness statement said this was because he believed it was a “rogue result”, but Mr Millett (pictured above) said he would have liked to ask why the option of taking further tests to prove this theory was not taken.

Mr Wehrle would go on to write in an internal email in 2011 that the B grade on the riveted panel had been obtained “by ‘arranging’ the system to pass”. Mr Millett said he would have liked to ask Mr Wehrle whether that meant “manipulated”.

Following this testing, in March 2006 Mr Southgate held a meeting in Luton with some figures from the French headquarters. He emphasised the need to get a certificate from the BBA confirming the classification of the panels.

“We have always more and more projects coming in the ‘public housing and private development’ segment,” notes from the meeting said. “We have here projects of several 10,000 sqm in discussion. It could represent in 2006; 50% of the market... In the segment, we have always to show the official certification from the BBA.”

The BBA is a highly respected certification body in the construction sector, producing certificates confirming the performance of construction materials. Arconic resolved to obtain such a certificate for its Reynobond 55 cladding.

‘Hard tactics may have helped our situation’

The process of obtaining this certificate began in November 2006 with a meeting at the BBA’s office in Watford.

Arconic’s notes of the meeting showed it issued a “threat to stop all dealings with BBA unless a satisfactory solution was found” to the classification of the product.

The BBA agreed to look at a price reduction, and eventually cut its bill from £24,000 to £16,500.

The document also said: “I have suggested that it could be better to validate the material... rather than the whole system.”

Mr Millett said this “critically” raised the question as to why Arconic would have preferred a validation of the material rather than the system.

The implication, of course, is that Arconic did not want the certificate to pick up on the disastrous performance of its panel when bent into cassette form.

But when Hamo Gregorian (pictured above), a former project manager at the BBA, gave evidence a day later, he said it was the BBA’s practice to assess individual materials not systems.

In conclusion, the Arconic meeting noted: “Very positive meeting and hard tactics may have helped our situation.”

Mr Millett said he would have liked to ask Arconic witnesses what “hard tactics” referred to. When he put this question to Mr Gregorian, he could not shed any light and said he did not recall the meeting.

‘The panels may be regarded as having a Class 0 surface’

The BBA then produced its certificate of the Reynobond panels, signing and issuing it in March 2007.

Mr Gregorian project managed this process, but had no meaningful knowledge of fire safety regulations and relied heavily on another member of staff, Brian Haynes, to oversee the questions relating to fire.

Mr Haynes has provided a witness statement to the inquiry, but died earlier this year without giving verbal evidence.

Mr Gregorian revealed in his evidence that Mr Haynes consulted over the fire safety issues with Sarah Colwell, a senior figure at the Building Research Establishment (BRE), in preparing the certificate.

The eventual BBA certificate said Arconic’s Reynobond 55 panels “may be regarded as having a Class 0 surface”. This was sufficient assurance – seven years later – to persuade those refurbishing Grenfell Tower that the panel was suitable for a high-rise building.

But how the BBA reached this conclusion was not straightforward. The certificate covered the pure polyethylene-cored version of the panels as well as a fire-retardant version that was far less flammable.

The only Class 0 testing the BBA had been given by Arconic was a test from 2003 on this fire-retardant material.

It had also seen the test on the riveted system in 2004 which obtained a B grade. But Arconic never sent the the report of the catastrophic failure on the cassette system.

Asked repeatedly by Mr Millett why he did not seek testing on the cassette system as well, Mr Gregorian said he believed the way the panels were fitted to the wall was “irrelevant” to what the BBA was doing.

This was because its certificate was only for the material, not a system and he did not believe the way it was fixed to the wall had any bearing on its fire performance.

‘In such a case a person can die from the smoke emission within the first two or three minutes of the fire’

In September 2007, Gerard Sonntag, marketing manager at Arconic, and some colleagues made a trip to Norway to celebrate the 150th anniversary of Astrup, a major distributor of metals in the country.

During the visit, representatives from various companies gave presentations. One of these was given by writer and consultant Fred-Roderich Pohl who appeared for German metal company Otefal.

The subject of his presentation was the fire risk of ACM cladding – something he wrote about occasionally in industry journals. Mr Sonntag noted that this presentation was “a very high [shock]” to him.

He said he had compared the use of 5,000 sq m of polyethylene-cored ACM on a building as having the same “fuel power” as a 19,000 litre oil truck.

“All arguments were supported by the pictures who showed a tremendous big volume of smoke who [sic] is even much more dangerous than the fire himself [sic] because in such a case a person can die from the smoke emission within the first two or three minutes of the fire,” Mr Sonntag’s note added.

He then warned about the risk of this presentation being made to European regulators, warning that it could be “catastrophic” for ACM products if he did.

“Let’s imagine that Otefal organise a lobbying activity on the European [Parliament] and show such a presentation… the result could become catastrophic for the ACM products,” he wrote. “One of the arguments from Mr. Pohl was, ‘what will happen if only one building made out PE [polyethylene] core is in fire and will kill 60 to 70 persons, what is the responsibility of the ACM supplier?’”

He suggested Arconic should move to only selling the more fire-resistant cladding panel and launch a programme to reduce the cost of producing it at the same price as the polyethylene. We know that such a project was launched by Arconic in 2008, but the polyethylene remained on the market.

“Questions which arise would include: was there any discussion within Arconic, either before or after this meeting, about selling only ACM with an FR [fire-retardant] core? If there was, what happened to those discussions?” said Mr Millett.

‘The cassette one goes straight to E [which], if you let me be sarcastic, is close to the spontaneous combustion’

In 2011, Arconic carried out further European testing on its product. The test on the PE panel once more failed catastrophically.

Mr Wehrle said in his witness statement he now came to believe that the bend in the cassette system allowed the highly combustible polyethylene to pool, heat and ignite, producing a ‘flashover’ fire, whereas in the flat riveted panel, the plastic simply melted and drained out.

“What was his reaction when discovering that PE in cassette form was capable of producing a flashover event?” said Mr Millett. “Did he take steps to alert relevant customers or the BBA, or did he take any steps to remove the BBA [certificate] from circulation? If he didn’t, why was that?”

Just two days after receiving this test result, the BBA carried out a review of its certificate, but Mr Wehrle did not provide the failed cassette tests. He said in his witness statement he did not think they would be relevant to the Class 0 rating.

In November 2011 he emailed a Spanish customer to tell them that the cassette system had a Class E rating and advised them to use the fire-retardant product instead.

“We would like a brief explanation about how… the cassette one goes straight to E [which], if you let me be sarcastic, is close to the spontaneous combustion,” replied the customer. There is no evidence of a reply from Mr Wehrle.

‘It was a UK project and, unless the customer told me that they wanted FR, I would have quoted for PE’

In November 2013 Arconic carried out further tests, with the cassette system once more obtaining an E and the riveted panel this time obtaining a C. On 31 January, Arconic responded by rescinding its 2005 test and classifying both riveted and cassette panels as E.

This was communicated to all its sales people in Europe by email on 3 February. But Debbie French, the UK sales person, did not forward this information on to her customers.

In fact, a month later on 23 April 2014, she provided the BBA certificate to the team refurbishing Grenfell Tower, with its reference to out-of-date tests saying the product was Class B. She has previously said she did not believe the European classifications were relevant in the UK.

The panels were approved for use on the tower by planners in July 2014, but not actually sold until March 2015. This was after Ms French had left the company and the sale was handled by Ms Derredinger and Mr Froehlich.

Internal documents show the fact that the panels would be used on Grenfell Tower in the extremely combustible ‘cassette’ form was logged on Arconic’s system in April 2015.

The panels were then sold to CEP Architectural Facades, the company which cut them to shape for the tower and sold them on.

Ms Derrendinger said in her witness statement that she does not remember if PE was specifically requested. But she added: “It was a UK project and, unless the customer told me that they wanted FR, I would have quoted for PE.”

“One question on this document is whether PE was requested by CEP specifically or whether it was Arconic’s assumption that PE was required,” said Mr Millett.

We also saw an email run from March 2014 relating to Woodberry Down, an estate regeneration in Hackney, east London. Here, the refurbishment team requested data on the polyethylene-cored cladding but were sent a cut-down four-page report on the fire-retardant version instead. The tower block has since been remediated.

“We are in ‘the know’ and it is up to us to be proactive… AT LAST”

We then saw a series of emails from and to Mr Wehrle relating to ACM fires in high-rise buildings around the world.

In June 2015 he was sent a report of a fire in the Lacrosse Tower in Melbourne, Australia, which ripped through ACM balconies.

The report included references to seven other instances of large fires in buildings with ACM on their walls.

On 16 October 2015, Mr Wehrle sent images of the aftermath of a fire at a medical centre in Riyadh, Saudi Arabia, which utilised fire-retardant panels. The images showed the fire spreading extensively but only at the lower levels.

“In PE the fire would have spread over the entire height of the tower,” Mr Wehrle wrote in October 2015. “Long live FR!”

On New Year’s Eve in 2015, a further fire spread extensively at the Address Hotel in the Middle East. “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!” wrote Mr Wehrle.

“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?” said Mr Millett. Finally, a fortnight later on 19 January 2016, Mr Wehrle forwarded images of a fire in Strasbourg at a building neighbouring a tower clad with the Reynobond product.

“We were very lucky,” he wrote, addressing the email to five senior staff members. “Fortunately the wind didn’t change direction but we really need to stop proposing PE in architecture. We are in ‘the know’ and it is up to us to be proactive… AT LAST.”

“The question is: what happened to Mr Wehrle’s warning to senior management?” said Mr Millett “Did they do anything about this and, if so, what?”

Cavity barriers and window panels

The inquiry also heard witnesses from cavity barrier supplier Siderise, including Christopher Mort, technical officer for fire (pictured above), which raised significant questions about the testing of cavity barriers used in rainscreen systems.

These barriers are supposed to prevent the spread of fire in the gap behind the cladding panels and the insulation which is fixed flush to the wall.

But because water needs to drain and evaporate, they do not fully close the gap. Instead, they leave a 25mm gap and are supposed to fully close in the event of a fire.

But they are tested in between solid concrete blocks and then used in real-world scenarios where the cladding panel may bend, crack or even (as was the case at Grenfell Tower) ignite. So is this testing truly realistic?

You can read our reports of the evidence from Siderise witnesses here and here.

The inquiry also heard from Chris Ibbotson, the managing director of Panel Systems, the company that sold window panels for Grenfell Tower which were made of highly combustible polystyrene panels, sandwiched between aluminium sheets.

He explained that his company sold polystyrene panels as default unless a better fire performance was requested because it “has lots of attributes as a thermally insulating core”.

He said he did not know that Grenfell Tower was a high rise – despite the name of the building appearing on invoices – and he did not know about particular regulations covering high rises.

For more on combustible window panels, you can read our 2019 investigation here.

Grenfell Tower Inquiry: week 27 headlines

Grenfell cladding firm used ‘hard tactics’ in obtaining certificate for product, inquiry hears

The manufacturer of the cladding panels used on Grenfell Tower used “hard tactics” in negotiations with a UK certifying body as it sought a certificate implying the panels were suitable for use on high-rise buildings, documents disclosed by the inquiry reveal.

Grenfell cladding firm considered possibility of fire killing ‘60 or 70’ people in 2007

A senior manager at Arconic wrote an internal document in 2007 pondering what its responsibility would be if a fire involving its product killed “60 or 70” people in a high-rise building, the inquiry heard.

Fire barrier installation on Grenfell ‘some of the worst I've seen’ says supplier

The fire barriers installation work on Grenfell Tower was “some of the worst I have ever seen” and would have required replacement if inspected, a senior figure at the manufacturer has said.

Grenfell fire barrier supplier wrote report covering use on tower nine days after fire

The fire barriers used on Grenfell Tower had only ever been tested in a narrower gap than the one they were required to fit on the tower, with an ‘extended field of application’ report produced nine days after the blaze.

Grenfell Tower Inquiry phase two: weekly diaries

Module one: the refurbishment

Week one: A vivid picture of a broken industry

After a week of damning revelations at the opening of phase two of the Grenfell Tower Inquiry, Peter Apps recaps the key points