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Grenfell cladding '14 times combustibility limit' | Grenfell cladding '14 times combustibility limit' |
(35 minutes later) | |
Burning cladding on Grenfell Tower would have released 14 times more heat than a key government test allows, the Victoria Derbyshire show has learned. | |
Energy emitted from the cladding and insulation would have been equivalent to burning 51 tonnes of pinewood, University of Leeds research suggests. | Energy emitted from the cladding and insulation would have been equivalent to burning 51 tonnes of pinewood, University of Leeds research suggests. |
The cladding's plastic core would have burned "as quickly as petrol", it said. | The cladding's plastic core would have burned "as quickly as petrol", it said. |
The contractors who fitted the cladding and insulation said they both passed all regulations. | The contractors who fitted the cladding and insulation said they both passed all regulations. |
'Boards of wood' | 'Boards of wood' |
According to data released by French authorities, and seen by the BBC's Victoria Derbyshire programme, the cladding would have released 43.2 MJ/kg of heat. | According to data released by French authorities, and seen by the BBC's Victoria Derbyshire programme, the cladding would have released 43.2 MJ/kg of heat. |
The European A2 standard for "limited combustibility" is three MJ/kg. | The European A2 standard for "limited combustibility" is three MJ/kg. |
The foam insulation underneath the cladding was, separately, thought to emit around 26 MJ/kg of heat. | The foam insulation underneath the cladding was, separately, thought to emit around 26 MJ/kg of heat. |
Figures from UK government tests have not yet been made publicly available. | Figures from UK government tests have not yet been made publicly available. |
An estimated 18 tonnes of insulation foam and eight tonnes of cladding panels were attached to the tower, analysis of planning documents by the University of Leeds suggests. | An estimated 18 tonnes of insulation foam and eight tonnes of cladding panels were attached to the tower, analysis of planning documents by the University of Leeds suggests. |
The energy released when all these combustible materials burned would have been equivalent to around 51 tonnes of pinewood wrapped around the building in two thin 12mm sheets, separated by a 50mm gap with holes cut out for windows, it says. | The energy released when all these combustible materials burned would have been equivalent to around 51 tonnes of pinewood wrapped around the building in two thin 12mm sheets, separated by a 50mm gap with holes cut out for windows, it says. |
"If you set that on fire near the bottom you can imagine what would happen and how fast the fire will grow," Dr Roth Phylaktou, a senior lecturer specialising in fire and explosion engineering at the university, told the BBC. | "If you set that on fire near the bottom you can imagine what would happen and how fast the fire will grow," Dr Roth Phylaktou, a senior lecturer specialising in fire and explosion engineering at the university, told the BBC. |
"This is not dissimilar to the wood cribs that we use in fire science to create fast-growing fires that reach a large size very quickly." | "This is not dissimilar to the wood cribs that we use in fire science to create fast-growing fires that reach a large size very quickly." |
Dr Phylaktou believes the configuration of the cladding and the foam - known as polyisocyanurate (PIR) - was "optimum for vertical fire spread". | Dr Phylaktou believes the configuration of the cladding and the foam - known as polyisocyanurate (PIR) - was "optimum for vertical fire spread". |
"This explains the speed of the fire propagation. The polyethylene in the cladding would have burnt as quickly as petrol," he added. | "This explains the speed of the fire propagation. The polyethylene in the cladding would have burnt as quickly as petrol," he added. |
He believes the air gap between the insulation and the external cladding panels on Grenfell Tower may have created a so-called "chimney effect", increasing the speed of the fire spreading. | He believes the air gap between the insulation and the external cladding panels on Grenfell Tower may have created a so-called "chimney effect", increasing the speed of the fire spreading. |
"The insulation formed another combustible layer underneath which would also give off toxic fumes," he added. | "The insulation formed another combustible layer underneath which would also give off toxic fumes," he added. |
Withdrawn from sale | Withdrawn from sale |
The type of PIR foam used, Celotex RS5000, and the brand of cladding, Reynobond PE, have now been withdrawn from sale for use in buildings over 18m high. | The type of PIR foam used, Celotex RS5000, and the brand of cladding, Reynobond PE, have now been withdrawn from sale for use in buildings over 18m high. |
Even if cladding or insulation do not meet the European A2 standard for limited combustibility, they can theoretically still be allowed on the outside of a tall building if combined with other components in a whole system which passes a different type of test, known as BR135. | Even if cladding or insulation do not meet the European A2 standard for limited combustibility, they can theoretically still be allowed on the outside of a tall building if combined with other components in a whole system which passes a different type of test, known as BR135. |
An independent company, BRE, is now conducting tests for the government to see how different combinations of insulation and cladding perform in the event of a serious fire. | An independent company, BRE, is now conducting tests for the government to see how different combinations of insulation and cladding perform in the event of a serious fire. |
BRE also conducts fire tests for the private sector and a local government leader has called for the release of test data which is considered commercially confidential. | BRE also conducts fire tests for the private sector and a local government leader has called for the release of test data which is considered commercially confidential. |
In its marketing Arconic, which manufactures Reynobond PE panels, has never claimed the product met the "limited combustibility" standard. It said it was only "one component" in the overall cladding system. | In its marketing Arconic, which manufactures Reynobond PE panels, has never claimed the product met the "limited combustibility" standard. It said it was only "one component" in the overall cladding system. |
Saint-Gobain, which manufacturers the Celotex RS5000 PIR, said it could not comment while there was an investigation into the circumstances around the Grenfell Tower fire. | Saint-Gobain, which manufacturers the Celotex RS5000 PIR, said it could not comment while there was an investigation into the circumstances around the Grenfell Tower fire. |
Watch the Victoria Derbyshire programme on weekdays between 09:00 and 11:00 on BBC Two and the BBC News channel. | Watch the Victoria Derbyshire programme on weekdays between 09:00 and 11:00 on BBC Two and the BBC News channel. |