A catastrophic fire June 14, 2017, at Grenfell Tower, a London high-rise public housing building–killing at least 80 occupants–has developed into a tragedy of the commoners. It is not being visited on British elites. In its aftermath, officials of the current, Tory government spared no effort–to offload blame. Suspicions pointed at building materials that quickly spread flames up the outside of the building.
Philip Hammond, the famously arrogant Chancellor of the Exchequer, tried to claim that materials used in a recent renovation of Grenfell Tower had been banned under the British building code. He was promptly refuted by reporter David D. Kirkpatrick, writing in the New York Times.
The officials patched together a national emergency action, ordering managers of public housing that had used similar building materials to submit samples for so-called “fire safety” testing–but not managers of private housing. Without waiting for results or advice, the Camden council, in north London, ordered evacuations of five high-rise public housing buildings that had been renovated using such materials.
A testing mystery: Building contractors and materials manufacturers had stated that their practices met standards of the British building code, which include standards for fire resistance. A few days after the catastrophe, however, Tory officials said some samples of materials they received had failed “fire safety” testing–tending to offload blame. At ten days after the catastrophe, the officials disclosed that all 60 samples from public housing tested to date had failed. How could that be?
Nothing from mainstream British news sites explored the obvious conflict. One story in the Guardian said recent tests “lack transparency,” but it stopped there. Absent gross fraud, the “fire safety” tests hastily arranged by officials of the Tory government somehow had to differ from tests claimed to have been performed by manufacturers and builders under the British building code.
The current building code allows two approaches. Individual materials can be tested for “fire spread,” using British Standard BS 476 procedures and regulations. Otherwise, a large sample of an assembled “cladding system” can be tested using British Standard BS 8414 procedures and classified under British Research Establishment BRE 135 regulations.
Manufacturers usually test for “fire spread” using BS 476, or a European equivalent, and builders usually seek materials so tested. The alternative via BS 8414 and BRE 135, or European equivalents, is much more costly to test. Moreover, that approach would limit application to a specific “cladding system” design and to its choices for multiple materials and fastenings.
Potentially flammable materials used on the exterior of Grenfell Tower were Celotex RS5000 insulation, 6 inches thick, and Reynobond PE rainshield, 1/8 inch thick–both manufactured in Europe. Both those materials burned in the catastrophe, but most news reports ignored the rigid polyisocyanurate foam insulation and focused only on the rainshield. It consists of a solid polyethylene core and two thin aluminum outer layers.
If Reynobond PE rainshield gets hot–only around 300 F–highly flammable polyethylene in the core will melt. Liquid might leak from an edge and ignite, or an entire metal layer might release, exposing polyethylene to fire. However, BS 476 test procedures do not create such conditions. They subject a patch in the middle of a rainshield panel to a small flame for a minute. The outer metal layer does not burn, and the brief heating does not melt the whole core and release the metal, so such a panel of rainshield material passes that test.
Mystery resolved: At some time on Monday, July 3, according to automatic logging by other sites, British Research Establishment (BRE) staff, who had been performing emergency “fire safety” testing for Tory government officials, added notes to one of their Web pages describing what they were doing. BRE staff admitted they had used rogue “screening tests” to measure “gross heat of combustion” of materials, not a standard test–such as International Standards Organization ISO 1716–and not a test for “fire spread” or for “combustibility.”
According to the BRE statement, “procedures set out in the [ISO] standard [for heat of combustion] have not been followed.” BRE staff did not test for “combustibility” either, as Tory officials have repeatedly claimed–that is, whether a material will catch fire, under some specified condition. Instead, BRE staff have been scraping out core fragments from samples of rainshield material and then measuring how much heat will be produced when the fragments are forced to burn in an artificial environment of pure oxygen.
Now it is clear why tests according to the British building code might pass but tests recently reported by Tory officials might fail. They are different tests. Rogue tests being carried out by the BRE staff do not measure whether materials will catch fire under controlled conditions. Instead they measure how much heat is produced when core fragments scraped from the materials are forced to burn.
The rogue tests, of course, have not been systematically validated against actual risks of building fires. Such a process would involve extended experiments, analysis, documentation and review. If compared, for example, against longstanding, carefully developed BS 8414 procedures and BRE 135 regulations, rogue tests might either overestimate or underestimate fire hazards from practical situations.
Other options: Little noticed by the public, some building materials apparently similar to those used at Grenfell Tower have passed the rogue test ordered by Tory government officials and conducted by BRE staff. The headline for an article on the BBC News site did not help, saying, “Three hospitals fail fire safety.” The text, however, claimed that “cladding at 11 sites passed the checks, while the other 19 sites which flagged up potential fire safety issues have been told they do not need to take further action.”
The Tory government still has not ordered testing of private housing or commercial buildings, but Health Secretary Jeremy Hunt started a national emergency action to test hospital buildings. When reported by BBC News, 30 had passed the rogue test or been exempted, and only three had failed. Apparently British hospital renovations were more cautious in some ways than those performed by public housing authorities.
Three main grades of metal-clad rainshield materials have been marketed in Europe for about 25 years. They are often designated “PE” (polyethylene core), “FR” (fire-retardant core) and “A2″ (limited combustibility core)–the last one a classification from the European Normative EN 13501 fire-resistance standard.
The Alucobond company of Switzerland introduced an “A2″ product in the early 1990s. Like most other such products, its core is nonflammable mineral wool plus a few percent by weight of polymer binder. At very high temperatures the polymer will char, but flames will not spread far. This type of product is more expensive and more difficult to install than other composite rainshield products. The distribution of results obtained by BRE staff suggest that “A2″ products may pass their rogue test, while “PE” and “FR” products may fail.
Lessons learned and unlearned: Some building renovation managers apparently took more cautious approaches than others. However, the Tory government’s attempt to shift blame for the Grenfell Tower catastrophe onto project designers and managers and onto materials manufacturers amounts to a scam.
The core of the problem has been grossly inadequate building code regulations–allowing an irresponsible alternative to carefully developed fire resistance standards. That is compounded by lack of fire suppression measures, particularly requiring fire sprinklers in high-rise buildings.
The British government had ample, local warning about the potential for a catastrophe. In 2009, the Lakanal House fire in Camberwell, similar in many respects, killed three women and three children. Nothing of much significance was ever done to prevent another such disaster.
The current, Tory government nominated Sir Ken Knight, who compiled a report on the Lakanal fire, to head a panel that is to examine “safety actions” in the aftermath of the Grenfell Tower catastrophe. Sir Ken Knight had advised against regulations requiring fire sprinklers in high-rise buildings.
Former Tory housing minister Gavin Barwell told the House of Commons in October, 2016, that the British Building Regulations for fire safety would be reviewed in response to the Lakanal House disaster, but he did nothing. His punishment, after being defeated for re-election, has been to serve as chief of staff to the prime minister, Theresa May.
– Craig Bolon, Brookline, MA, July 6, 2017
Three hospitals fail fire safety checks, BBC News (UK), July 4, 2017
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Richard Hartley-Parkinson, Man overseeing Grenfell disaster previously advised against fitting sprinklers, London Metro, June 28, 2017
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Resistance to fire: EN 13501, the European standard, Odenwald Faserplattenwerk (Amorbach, Germany), 2017
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Prashant Thakkar, 1992 market introduction of Alucobond A2, Glazing Shopee (Vadodara, India), 2017
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Fire safety: Approved Document B, The Building Regulations 2010, [British] National Archives (effective April, 2007, as amended through 2013)
Craig Bolon, High-rise fire in London: needless catastrophe, Brookline Beacon, June 21, 2017