Fires involving external cladding systems can have a major impact on human life, business and property.
BRE, the UK’s leading building and fire research body, has issued updated guidance on the fire performance of external thermal insulation for walls of multistorey buildings.
These fires can result from the breakout of a fire within the building or due to an accidental or malicious external fire starting on balconies or in the local area around the building such as a wheelie bin or an area of stored materials.
There is potential for fire to spread quickly via the external cladding system and break back into the building through windows in upper storeys potentially breaching compartmentation within the building.
As well as people in the building, firefighters on the ground and evacuating occupants face potential risks from the collapse of a building’s cladding system or flaming debris from the system as a result of fire. The performance of cladding on external walls when exposed to fire is therefore a key concern when assessing risks to people and property.
Fire performance of external thermal insulation for walls of multistorey buildings (BR 135) was first published in 1988 in response to the increasing use of thermal insulation as part of refurbishment programmes on existing multistorey residential tower blocks.
The newly published third edition of BR 135 reflects the changing drivers in the construction market, such as the increase in use of external wall cladding systems in the new-build market and the increasing thermal performance requirements.
The guidance draws together experience gained from recent fires involving external cladding systems and updates the guidance on external fire performance for the materials and technologies now used in their construction. The performance-based approach, recognised by UK Regulating bodies, provides an experimental methodology that enables building professionals to use new and innovative materials while maintaining fire safety.
This guidance will be useful to manufacturers, designers, architects and Local Authority Building Control Officers.
