Wood as a building material is experiencing a renaissance in modern architecture worldwide. The demand for this building material for construction, housing and living is growing and the availability of wood has an immense socio-economic impact.
Not least because of the advantages of this building material:
- impresses with its durability, environmental friendliness and sustaina
- is an inexpensive, renewable raw material that is well suited as a building material
- in the event of fire, its mechanical properties withstand the same static dimensioning far longer than unprotected steel
In short: wood has a low density combined with a high load-bearing capacity and is also easy to process.
The quality of construction timber is regulated by relevant standards. In terms of load-bearing capacity, chemical resistance and weight, timber offers advantages over steel and prestressed concrete structures at a similar price.
In contrast to steel strength, the strength of wood is not dependent on temperature. In the event of a fire, a protective carbon layer forms, which slows down the burning process and guarantees the load-bearing capacity for longer than unprotected steel beams with an identical static design. This must be taken into account when installing fire protection measures required by building regulations.
Wood is also subject to special requirements with regard to functional integrity in the event of fire.
Statics: The structural component is sufficiently dimensioned for the building.
Hot design: This defines the extent to which the component must be dimensioned beyond the basic service condition in order to ensure the stability of a building for a required fire duration in the event of a fire.
Material: The component must be made of solid wood.
Fire resistance in practice
Structural fire design refers to the mathematical verification of building components or load-bearing structures that are exposed to fire. In general, a certain fire resistance period must be given so that the users of the building have time to leave it.
The emergency services must also be able to enter the building and initiate rescue measures without being endangered.
DIN 4102 describes the "Fire behavior of building materials and components". Part 12 specifies the requirements for electrical cable systems in terms of circuit integrity maintenance.
In addition to the mathematical verification for the service condition, load-bearing timber constructions must also be designed for a fire resistance period of 30 or 60 minutes with a fire load on one or more sides, depending on the construction, in accordance with the standard temperature-time curve in accordance with DIN 4102 Part 2 or DIN EN 1363-1 on the basis of e.g. DIN 4102 Part 4 or DIN EN 1995-1-2 ("fire design").
For fastening the cable support and installation systems, an additional backing of the immediate fastening area in the shear joint between the cable support system and the load-bearing timber component with the fire protection boards of building material class A1 listed on the right is prescribed. These prevent or reduce the burning of the timber construction in the area of the fastening of the support system to the timber construction and ensure that the connection to the timber construction remains intact due to the increased bending stress of the support system.
If fire resistance class F30 or F60 is required, fire protection boards with a minimum thickness of 20 mm must be used. Further requirements with regard to setting depths, edge distances, reduced support distances and cable loads can be found in the expert opinion no. GA-2017/115a-Mey and the general building authority test certificates mentioned therein.
Special screws are required for secure installation on timber components. The wood screws from Niedax offer reliable fastening to wood to ensure functional integrity in accordance with DIN 4102-12.
