Load-bearing capacity and usability of timber buildings
Thanks to findings from research and development as well as many years of experience in timber construction, the fire protection authorities have been able to remove many restrictions for timber constructions. Nowadays, fire protection regulations deal with timber as a building material without any special regulations. If the high quality requirements of the fire protection regulations are met, timber components can be used in all uses and for all building categories.
Wooden buildings have already proven their load-bearing capacity in the past: The palace of Knossos on Crete, built around 1700 BC, was constructed with wooden pillars and cedar timbers built horizontally into the walls. It survived a severe earthquake around 1400 BC virtually undamaged. The columns and beams of Greek temples and the framework of the mud-brick walls were made of wood until 600 BC.
Compliance with the SIA structural standards
Modern timber constructions guarantee structural safety and serviceability by complying with the SIA structural standards. Specialist planners and timber construction companies vouch for this. Unusual events such as fire and earthquakes are also investigated through analyses in various design situations. The variety of construction timber, wood-based materials and fasteners in combination with modern planning and production tools enables the designer to design an optimised load-bearing structure for every new construction project.
Research and predictability
The flammability of wood is widespread, but its behaviour in the event of fire is well researched and predictable. The similar strength properties at high temperatures as well as the low thermal conductivity due to the insulating carbon layer and the escaping water vapour make this building material stand out. The efficient fire safety of timber constructions is confirmed by extensive fire tests. With appropriate dimensioning or in combination with other materials, fire resistances of up to 240 minutes can be easily achieved. In contrast to steel and reinforced concrete constructions, timber constructions remain stable even at extremely high temperatures.
Fire protection standards for timber components in Switzerland
Fire-resistant timber components that are protected with non-combustible panels are considered non-combustible according to Swiss fire protection regulations. This shows the recognition of the fire protection authorities for the results of extensive studies, which prove that the combustibility of a building material is not the decisive criterion, but rather that the correct fire protection design of a construction has a greater influence on the fire behaviour. Current regulations permit the use of wood in various construction applications without restrictions and even in high-rise buildings under certain conditions. Timber therefore has a wide range of applications in all building categories and uses.
Safe timber surfaces in interior spaces
The requirements for structures in safety-sensitive areas such as vertical escape routes are met by suitable timber components with non-combustible fire protection cladding. Visible wooden surfaces are permitted in interior rooms, with the exception of escape routes.
Compliance with quality requirements
Thanks to the “Fire safety and wood” research and development project, which has been running since 2001, comprehensive technical and methodological principles and safe designs for timber components have been developed. An industry-specific quality assurance system defines the fire safety-related quality standards for wood in construction. In Switzerland, high-quality timber buildings are erected in strict compliance with quality requirements. The Lignum documentation on fire protection serves as a guideline and shows the many different ways in which wood can be used to ensure the correct realisation of timber components in small, large or tall buildings. It corresponds to the current state of the art in fire protection in accordance with Swiss regulations.