A manager at an organisation carrying out cladding fire tests has accepted a “fundamental error” was made in a trial of flammable insulation which was eventually used on Grenfell Tower, the inquiry into the disaster has heard.
Tony Baker, a fire resistance test laboratory manager at the Building Research Establishment (BRE), suggested there had been a “concerted effort” by insulation maker Celotex to conceal a fire-resisting material from inspectors.
But after seeing images of the cladding “rig” set up for the test, he added: “It’s obviously not hidden that well.”
His evidence related to a cladding system fire test paid for by Celotex and carried out at the BRE “burn hall” in May 2014.
Celotex used the successful test to market its combustible rigid foam insulation called Rs5000 as safe for high-rise buildings.
But its employees had added fire-resisting white magnesium oxide boards behind two ruby-coloured cement fibre panels, while the rest of the rig was covered by white panels, the inquiry has heard.
Celotex’s ex-assistant product manager Jonathan Roper has told the inquiry his superiors said to remove any mention of the magnesium oxide in promotional brochures and admitted the omission was a “fraud on the market”.
On Wednesday, Mr Baker was shown images of the cladding test rig being taken down after the fire assessment which showed white boards in areas which had previously been orange.
He said the difference “should have” occurred to him but “clearly it didn’t”, and agreed with inquiry lawyer Kate Grange QC there was nothing in the officially listed components “which could explain what that was”.
Ms Grange said: “Can we agree that was a very basic error in the checking of the report?”
Mr Baker said: “Yes, in hindsight, yes it is.
“I don’t know how I made a fundamental omission, error such as that.”
Asked why magnesium oxide boards were not included in the test report, he said: “Obviously the test report has been to the client as well and they haven’t highlighted the issue.
“I would expect us to pick it up but I would also expect the client to pick it up as well.
“It would seem there was a concerted effort to seem to hide it from us, although from photo 18 there, it’s obviously not hidden that well.
“I wasn’t actually aware of this situation until after the Grenfell issue.”
The BRE was established in 1921 as a Government-funded national centre for research into building materials and construction methods.
It was privatised in 1997 and has since had to rely on work from commercial clients and paid-for research. It is now under the ownership of a charitable trust.
The BRE’s cladding test supervisor Phil Clark previously told the inquiry he did not pick up on the presence of the magnesium oxide and it had been “playing in my mind for a long time”.
“To this day I still can’t think why I missed it. I can’t account for it at all,” he told proceedings last month.
He rejected suggestions he was aware of it, as alleged to the inquiry by Mr Roper.
The BRE was not involved in testing or classifying the specific cladding system used on Grenfell Tower, which combined Rs500 insulation with plastic-filled aluminium composite material (ACM) cladding panels.
The inquiry has already found the ACM panels were the “principal reason” the flames covered the tower so quickly by acting as “a source of fuel”, while combustible insulation was deemed to have “contributed to the rate and extent of vertical flame spread”.
Celotex, part of the French multinational Saint-Gobain group, withdrew the test in 2018.
It has said in a statement to the inquiry: “In the course of investigations carried out by Celotex after the Grenfell Tower fire, certain issues emerged concerning the testing, certification and marketing of Celotex’s products. These matters involved unacceptable conduct on the part of a number of employees.
“They should not have happened and Celotex has taken concerted steps to ensure that no such issues reoccur.”
The inquiry is examining how Grenfell Tower came to be coated in flammable materials which contributed to the spread of flames which shot up the tower in June 2017, killing 72 people.