The 2017 Grenfell Tower fire in London, England caught worldwide attention.
The inferno reached the top of the 24-storey building in less than 30 minutes and claimed 72 lives. Blame for the rapid spread of the flames and toxic fumes has been largely placed on the selection and installation of the ACM (aluminum composite panels) exterior cladding system.
ACM has been a popular curtainwall and cladding since the mid-1990s. Its use can shorten construction time and reduce costs. In the case of Grenfell Tower, two types of cladding were used: Arconic’s Reynobond PE, two coil-coated aluminum sheets, fusion bonded to both sides of a polyethylene core; and Reynolux aluminum sheets. Beneath these, and fixed to the outside of the walls of the flats, was Celotex RS5000 PIR thermal insulation.
While this cladding system would not be approved on the same type and size of building in Canada, what should be of interest to Canadian contractors are the decision pathways that led to the selection of this particular cladding system.
The 900-page Phase 1 report from the Grenfell Inquiry released in October 2019 left many observers claiming that the actions taken by the project partners were largely ignored or minimized. Phase 2 of the inquiry, including witness testimony, commenced this month.
Testimony has revealed numerous communication lapses and expressions of self-interest involving several project partners in the Grenfell Tower renovation.
Even before the awarding of the refurbishment contract to main contractor Rydon, a consultancy working for the Grenfell Tower management organization asked Rydon for a “quick and dirty” check price to help prepare the procurement process. The inquiry was told that this was to assist in establishing a project budget.
Rydon ultimately won the contract over several other competing firms due to its low bid.
However, Rydon later realized it had made an “adding-up error.”
Its price should have been £212,000 higher.
Stephen Blake, Rydon’s refurbishment director at the time, testified that inquiries were made regarding cheaper alternatives to the zinc cladding originally specified by the architect.
Rydon proposed a face-fixed aluminum composite material (ACM) — a saving of £576,000.
However, Rydon only reported a savings of £293,368 to Grenfell’s managing organization and pocketed the rest for themselves. They rationalized this as “a mechanism” for Rydon to recoup most of the £212,000 “adding-up error.”
The inquiry also learned of dismissed concerns regarding fire spread. One of the Grenfell Tower architects said they were “miffed” at demands from a building safety officer aimed at preventing fire spreading up the tower, complaining it was causing cost increases and delays.
Furthermore, the lead fire safety consultant of the Grenfell Tower refurbishment admitted to ignoring a 2012 email from the architecture firm that included attachments containing details and drawings of a planned cladding system.
He told the inquiry that people are often copied on emails for big projects in “a sort of scattergun approach,” and that he would not have read the email unless “specifically asked to do so,” calling them “very lengthy documents.”
In any case, despite advising that aluminum cladding panels would not increase fire risk spreading across the building, the fire consultancy said it was, in fact, never consulted about the cladding system ultimately chosen, claiming they were effectively sidelined after Rydon became the main contractor in 2014.
By failing to act on multiple promises to appoint fire safety advisers after taking control of the project, Rydon came to rely on the building control department at Royal Borough of Kensington and Chelsea council, owners of the block, to advise on any safety problems.
Rydon’s former contract manager Simon Lawrence confirmed that the absence of a fire engineer on the team meant the ACM cladding was chosen without input from a fire safety consultant. He told the inquiry that he was unaware of any increased fire risk associated with the ACM cladding, but was comfortable with a system the company had used on previous social housing block projects.
— With files from The Guardian, Building UK, Building Design
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