FLAMMABLE MATERIALS, UK – You’d have thought it wouldn’t happen again. The fire at The Cube building on Bradshawgate in Bolton, northern England, on 15 November spread rapidly due to its plastic external cladding, just as with the Grenfell disaster.
Fortunately, this time no one died: all occupants got out safely, although two were injured and one had to be rescued by firemen.
Forty fire engines and specialist appliances and 200 firefighters battled all night to control the blaze.
The block was clad in HPL, a high-pressure laminate, made of wood-based layers impregnated with resin that are consolidated under heat and high pressure according to one manufacturer’s website. They are different to the aluminium composite material cladding used at Grenfell Tower, which has a core of materials such as polyethylene, polyurethane, sandwiched between two skins of aluminium.
However, the fire has once again prompted questions as to whether the UK government’s review of cladding, fire risk and building regulations has been comprehensive enough.
The Cube had been converted from offices to student accommodation for 220 students in 2015. It’s managed for Bolton University by Valeo Urban Student Life.
The shocking truth is that it’s five years since an HPL system combined with combustible insulation failed a fire test, and 10 years since HPL panels helped spread another fire at Lakanal House which killed six people and injured 20 and nothing has been done about reducing the danger in similarly clad buildings.
Architects like both ACM and HPL because sheets can be cut to suit a project’s aesthetic requirements and colours interchanged to create attractive façades.
After Grenfell, ACM was banned on buildings over 18 metres. The Cube is under 18 metres.
Grenfell Tower used Reynobond PE ACM cladding, reported by the press as being “cheaper, more flammable” than Reynobond FR, which has a fire-retardant core.
ACM and HPL are also linked to the Wooshin Golden Suites fire in Busan (2010) and the Lacrosse Tower fire in Melbourne (2014).
“This is not how any building should react to a fire in the 21st century, let alone a building in which people live,” according to Matt Wrack, the UK Fire Brigades Union general secretary, about the Bolton fire.
Gordon Cooke, a fire safety engineer, said: “I would not expect HPL [alone] to produce a fire of that severity. It’s likely to be due to plastic foam insulation on the inside. I would be concerned about using such a material in a building where people sleep.”
The government knew HPL was dangerous – but not this dangerous
The type of HPL mentioned in planning documents for The Cube is rated as “combustible” with a “medium contribution to fire”, according to EU standards.
The government admitted in July that cladding using any type of HPL panels with combustible insulation was very unlikely to prevent fire spreading.
Former housing minister Kit Malthouse answered a question from Labour’s Steve Reed, admitting her department had been aware that HPL had failed a large-scale fire test.
This test, using BS8414, must be passed by any cladding for it to be used on buildings over 18m tall (as Grenfell was).
Malthouse said: “We are aware of one BS 8414 test carried out in the UK in 2014 on High Pressure Laminate panels in combination with a combustible insulation material.
“This test was commissioned by a private company, and the department only became aware of the test in November 2018.”
He continued: “We understand that the arrangement tested failed to meet the criteria for passing the test.”
Only in July this year were the results of the test published.
The advice that followed said, “the view of the expert panel is that the level of risk from unsafe HPL systems is not as high a risk as unsafe systems using ACM Category 3 panels.”
It advised the priority for building owners should be to remove ACM cladding first, followed by “remediation” of HPL.
These experts seem to have been proved wrong. Although we await the full investigation results from the Bolton fire, it would seem that HPL is just as dangerous as ACM.
The BS8414 test on HPL (FR) (Class B-s1,d0) panels with mineral wool insulation (conducted because this type of HPL panel is commonly used on residential buildings of 18m) successfully achieved the performance criteria.
But an external wall system using Class C or D HPL panels failed the test.
But because the government has only been concerned with buildings over 18 metres post-Grenfell, the experts’ advice was only that towers over that height using Class C or D HPL panels should be made safe.
What materials are unsafe?
External wall systems that incorporate combustible material (including insulation and facing panels) and are known to have been used on existing buildings and should be tested include, but are not limited to:
- Metal Composite Materials (MCM) faced with other metals besides aluminium such as zinc, copper, and stainless steel;
- High Pressure Laminates (HPL);
- and rendered insulation systems.
All will perform differently when exposed to a fire.
As with ACM, some HPL panels incorporate fire retardant chemicals.
The official line is that “only materials that are of limited combustibility (class A2 or higher) should [be] used, unless the system has achieved BR135 classification via a BS 8414 test.”
Spandrel panels (including window and infill panels) are also part of the external wall of the building and should be checked in the same way.
Replacing the cladding
Unsafe buildings must be made safe. Greater Manchester’s Labour Mayor Andy Burnham has told Prime Minister Boris Johnson that people living in tower blocks must be given “peace of mind.”
The huge number of high-rise buildings makes collecting data on cladding systems a difficult job for cash-strapped councils, universities and housing associations, especially when private owners of leased buildings are hard to trace or refuse to cooperate.
A year ago, ministers gave councils the power to strip the materials and reclaim the multimillion-pound cost from landlords.
Replacement of ACM cladding on the 436 high rise blocks where it’s been found to be used in the UK has been glacial.
Work to replace it was completed on just four high-rise buildings in England last month, according to the government’s October report on progress to tackle the issue in the wake of the Grenfell tragedy.
169 ACM-clad private-sector residential high-rises remain unchanged. Hundreds more have HCL cladding. Then there are many more below 18 metres in height.
In August this year, owners of flats in high-rise blocks wrapped in combustible cladding in other parts of Greater Manchester asked the housing secretary, Robert Jenrick, for help to find the money to strip their buildings of all kinds of combustible cladding.
After three months, they were told that money would be made available to remove only ACM and not HPL.
Labour candidate Clive Betts, chair of the Commons housing committee until recently, said: “Any material which is not of limited combustibility should not merely be banned from new buildings but taken off existing ones.” He estimates the cost at £3 billion (AU$5.71 billion).
It’s obvious that the £200m (AU$381 million) currently set aside by government for the remediation of private sector residential buildings with ACM cladding will not be nearly enough.
The G15 (a group of London’s largest housing associations) recently put the bill at £6.9bn (AU$13.13bn) and the ongoing costs of implementing the new regulatory system as much as £90,000 (AU$171,000) per building per year.
The independent Chartered Institute of Housing has called on the Government to create a “building safety fund” to support the remediation works on existing buildings.
Thousands of residents around the country now are sleeping less easily in their beds since last Friday, with no end to their nightmare in sight.
David Thorpe is the author of Passive Solar Architecture Pocket Reference, Solar Technology and Sustainable Home Refurbishment.