Material and testing failures
“One very significant reason why Grenfell Tower came to be clad in combustible materials was systematic dishonesty on the part of those who made and sold the rainscreen cladding panels and insulation products,” the report said “They engaged in deliberate and sustained strategies to manipulate the testing processes, misrepresent test data and mislead the market.”
That systematic dishonesty, Moore-Bick said, included the deliberate manipulation of testing process, and calculated attempts to mislead purchasers that the combustible materials complied with the provisions of the statutory guidance that advised against their use. This was compounded by the failure of two bodies providing certificates of compliance with building regulations, the British Board of Agrément (BBA) and Local Authority Building Control, to properly scrutinise the information they were given.
The Building Research Establishment (BRE) was slammed for poor practices and lack of scientific rigour. It highlighted weaknesses in the way it carried out tests and its record-keeping, exposing it to manipulation by “unscrupulous” product manufacturers. “Senior BRE staff gave advice to customers such as Kingspan and Celotex on the best way to satisfy the criteria for a system to be considered safe, thereby compromising its integrity and independence,” the report said.
Indeed, it said that a significant reason combustible cladding was used at Grenfell was “systematic dishonesty” on the part of those who made and sold the cladding and insulation. “They engaged in deliberate and sustained strategies to manipulate the testing processes, misrepresent test data and mislead the market,” it said. “In the case of the principal insulation product used on Grenfell Tower, Celotex RS5000, the BRE was complicit in that strategy.”
Arconic’s Reynobond 55 PE rainscreen panels comprise two thin sheets of aluminium, filled with highly combustible polyethylene. The flat sheets of material are cut to size and attached to a metal subframe; at Grenfell this was done via a cassette system rather than rivets, rendering it extremely dangerous, something the inquiry found Arconic already knew, and had concealed.
It had failed to withdraw it from the market in favour of a fire-resistant alternative that was already available, and without informing UK customers when it was unsuitable. “That was not an oversight,” it said. “It reflected a deliberate strategy to continue selling Reynobond 55 PE in the UK based on a statement about its fire performance that it knew to be false.”
Celotex had been looking to break into the market for high-rise insulation with its RS5000 polyisocyanurate insulation, a market created and dominated by Kingspan and its K15 insulation. The report found it embarked on a “dishonest scheme” to mislead customers and the market, with fire-resistant magnesium oxide boards inserted into the test rig when assessing the system according to BS 8414. The resulting report from BRE failed to mention these boards. Celotex then used the misleading report to market RS5000 as the first PIR board to pass BS 8414 (despite this being a method for testing wall systems rather than individual materials), and as acceptable in buildings more than 18m high.
Kingspan was also heavily criticised. The report stated that from 2005 Kingspan had “knowingly created a false market” in insulation for 18m-plus buildings, regardless of its design or any other components. Again, claims of successful tests under BS 8414 were falsely used to promote the individual insulation material. “As Kingspan knew, K15 could not honestly be sold as suitable for use in the external walls of buildings over 18m in height generally, but that is what it had succeeded in doing for many years,” the report said.
It relied on a single test carried out in 2005 on a system whose components did not reflect a typical external wall, and continued to rely on this test despite the composition of the product being changed a year later. Subsequent tests on systems incorporating the new version of K15 were “disastrous”, yet the product remained on the market.
The company also concealed the change in composition from BBA, and later gained a certificate from LABC containing false statements about K15. When the BBA certificate was reissued in 2013, Kingspan persuaded BBA to include a statement implying it had limited combustibility. Later tests on systems incorporating K15 did not use the current marketed product, but modified or trial versions. These tests were still used to support K15 on 18m-plus buildings until late 2020.
Statements from Celotex and Kingspan
Celotex, which was sold by Saint Gobain to Soprema at the end of 2023, said in a statement that it is considering its contents with care, and that has sought to understand and learn from the issues raised by the fire. “Independent testing commissioned following the review demonstrated that the cladding system described in Celotex RS5000 marketing literature met the relevant safety criteria.,” it said. “We also understand that Government testing in August 2017 showed that a cladding system incorporating RS5000 and a non-combustible aluminium cladding panel met the relevant standards. These systems were substantially different from that used at Grenfell Tower, which incorporated combustible cladding panels.” It added that it does not design and install cladding systems, including at Grenfell; these decisions were made by construction industry professionals, it said
“Since the fire, we reviewed and improved process controls, quality management and the approach to marketing within the Celotex business to address the issues discovered and ensure that the culture, systems and processes relating to product compliance and product safety meet industry best practice.”
Kingspan has also commented. “We welcome the publication of today’s report which is crucial to a public understanding of what went wrong and why,” it said. “It explains clearly and unambiguously that the type of insulation (whether combustible or non-combustible) was immaterial, and that the principal reason for the fire spread was the PE ACM cladding, which was not made by Kingspan.”
It added that the company has long acknowledge the “wholly unacceptable historical failings” in part of its UK insulation business. “These were in no way reflective of how we conduct ourselves as a Group, then or now,” it said. “While deeply regrettable, they were not found to be causative of the tragedy. Kingspan has already emphatically addressed these issues, including the implementation of extensive and externally-verified measures to ensure our conduct and compliance standards are world leading.”
