Recent fires in tall buildings occurring in for example London, Dubai, Sao Paulo and Tehran evidence the risk of high consequences of fires in tall buildings and difficulties for fire service interference in case of large fire spread. In order to reduce the risk of deadly and large damage fires in especially tall buildings it is of importance to limit fire spread and avoid collapse .
It was previously indicated that prescriptive fire safety regulations are mostly based on experience rather than on scientific facts. Therefore, the application of regulations for less conventional buildings, such as tall timber buildings, is questionable. In contrast with prescriptive requirements, performance based requirements, such as a requirement for a building to withstand a full fire without effective fire service interference, require accounting for the design and the function of the building. Multiple performance based methods for the fire safety design are available for buildings with conventional structural materials, i.e. steel and concrete. For buildings with timber as a structural material performance based structural design is rarely applied due to lack of methods available.
The number of tall buildings with timber as their main structural material is increasing globally, which involves new fire safety challenges. In contrast with more conventional structural materials for tall buildings, timber can fuel the fire and influence its duration and severity. A number of previous experimental studies have shown that enough contribution of exposed timber to the fuel of a fire can result in continuous fully developed fires. Additionally, events that lead to increased combustion, such as sudden exposure of initially protected timber or bond line failure in glued timber members, can lead to fire regrowth after a period of decay. Without effective sprinkler or fire service interference, these fires would eventually lead to collapse, which can lead to potentially unacceptable consequences in very tall buildings.