Balcony fire risks

20 Dec Balcony fire risks

Balconies are a growing feature of urban development as designers strive to harness precious outdoor space, especially in high rise buildings. But careful consideration must be given to materials and structural design to mitigate the risk of a balcony fire spreading to other parts of the building. This is the finding of a new BRE Global report for the UK’s Department of Communities and Local Government (DCLG) carried out under the “Investigation of Real Fires” contract.

The report, “Fire safety issues with balconies”, cautions that design choices to prevent thermal bridging or improve insulation in balcony structures to meet Part L of the UK’s Building Regulations may be compromising fire safety under Part B. At the same time, Part B provides no specific fire design guidance for balconies, except when they act as a means of escape. This effectively means that there are no statutory requirements accounting for external fire spread from the incorporation of balconies in a structure, leaving their resolution open to interpretation of the Building Regulations.

Citing several case studies of fires in high rise residential developments, the report reveals that fires which start on a balcony can be quite severe and may spread to the balcony above, or to the flat above via windows. The presence of inappropriate cladding material can also promote fire spread up the entire façade of the building. These conditions could endanger the lives of residents on higher floors and may cause burning material to fall to the ground, with potential spread downwards or to adjacent buildings.

Some of the highlighted investigations showed that in meeting the requirements of Part L there had been an adverse effect on compliance with Part B.

One such case involved a fire on a concrete balcony installed with timber decking and timber battens, underlain by polyethylene spacer rings and foam insulation covered by a woven plastic sheet. The fire spread to involve insulation behind cladding systems on external walls, and to the balcony ceiling which had expanded polystyrene insulation behind a render. It also spread under the decking to the balcony of the neighbouring flat on the same level.

To date, there have been no known fatalities caused by fire spread from a balcony fire to warrant an amendment to current regulations. However, changes in building design and materials to meet energy performance criteria are clearly affecting the potential outcome of a balcony fire. This issue must now be carefully considered by designers, specifiers, property developers, managers, risk assessors, and fire-fighters, the report stresses.

Current high demand for housing and the premium put on private outdoor space is likely to see a proliferation in balconies in new developments, with inevitable impacts on the risks of balcony fires. BRE Global reported on six fire incidents in 2015 compared with just one in 2005.

The potential remains for a fire on a balcony construction which does not adequately consider all parts of the Building Regulations to pose a significant life safety issue.

The full report is available at: http://www.bre.co.uk/filelibrary/Fire%20and%20Security/FI—Fire-safety-and-balconies-July-16.pdf

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