LONDON Planning documents detailing the refurbishment of a residential tower block in West London where at least 12 people died in a fire on Wednesday did not refer to a type of fire barrier that building safety experts said should be used when high rise blocks are being re-clad.
The local authority which owns Grenfell Tower in Kensington declined to confirm whether fire barriers were installed on most floors between the insulation panels attached to the exterior of the building as part of the renovation.
Rydon Group, the construction company which undertook the work, also declined to say whether they had been used, but said the revamp "met all required building control, fire regulation and health and safety standards."
"We are shocked to hear of the devastating fire at Grenfell Tower and our immediate thoughts are with those that have been affected by the incident," a Rydon spokesperson said in an emailed statement.
The government department in charge of regulating building work - the Department for Communities and Local Government - did not respond to Reuters' questions, including whether such fire barriers were required by law.
It later issued a statement saying "it would not be appropriate to comment on the cause of the fire."
Legal experts declined to express an opinion on whether fire barriers are required by law.
A 2012 planning document published by The Royal Borough of Kensington and Chelsea, which included detailed diagrams of the planned new panelling and the materials used in the new skin, did not include reference to the barriers, according to a Reuters review.
The only new cladding elements depicted or listed in the "Sustainability and Energy Statement" were wall fixings, exterior zinc panels and polyisocyanurate insulation panels.
It is not clear if the document represented the final design used in the refurbishment of Grenfell Tower, a 24-storey 1970s apartment block home to hundreds of residents, or whether fire barriers recommended by industry bodies were installed.
Save for a few of the lower floors, Grenfell Tower was engulfed in flames, trapping families in the upper storeys.
Witnesses said the flames spread quickly up the building as most residents slept, and photographs later on Wednesday showed an almost entirely blackened, smouldering shell.
The 8.7 million pound ($11.08 million) refurbishment was completed last year. It involved the application of new external cladding and replacement windows, with the aim of improving heat and noise insulation, according to council documents.
The application of insulating layers to the outside of buildings is common, but it is also recognized by some architects and construction safety specialists as a potential fire risk.
That is because the area between the new exterior panel and the existing wall – which is usually filled with insulating material – becomes a potential channel for flames to rise up along the sides of the building, safety experts said.
The London Fire Brigade said it did not yet know the cause of the fire.
"We have heard a number of theories about the cause of the fire at Grenfell Tower," said the Royal Borough of Kensington and Chelsea, the local authority which owns the block.
"All of these will be thoroughly investigated as part of the formal investigation which has already begun," it said in a statement.
Documents published by the Building Research Establishment (BRE) and industry body the Insulated Render and Cladding Association recommend that fire-proof barriers be installed at each floor to make it harder for flame to travel up the gap in between the new and old skins.
"There is potential for the fire to propagate throughout the system if adequate fire barriers are not installed ... the installation of fire barriers at each floor level above the first floor level (i.e. starting with the second storey) should be considered," the BRE said in a publication entitled "Fire performance of external thermal insulation for walls of multi-storey buildings".
Reuters was not able to determine how widely or how closely these guidelines were followed in similar renovations, and it was not clear what impact the guidelines would have had in the case of Grenfell Tower.
The BRE is an organisation that provides safety guidelines for the construction industry, and, although it does not have regulatory powers, it is widely considered as the setter of best industry standards.
(Editing by Mike Collett-White)