In the Fire resistance configuration dialog box, you make the basic settings for the fire resistance design of members and surfaces ("fire resistance design"). Here you define how long the objects have to resist the fire exposure and which sides of the cross-section or surface are exposed to the fire.
The concept of design configurations is described in the chapter Timber Design. The fire resistance configurations are also matched to the standard that you have defined in the model base data for the timber design.
Members
In the Members tab, you make the settings for the fire design of members and member sets.
The design is currently limited to simple rectangular cross-sections
and circular cross-sections
. For all other cross-section types, you receive an error message.
Required Duration of Fire Resistance / Duration of Exposure
Define how long the members have to resist the fire, that is, how long the fire exposure is effective. Some standards offer options for typical requirements. However, you can also specify the fire duration user-defined.
Fire Exposure
Using the check boxes, you can control which sides of the cross-section are exposed to the fire.
For a circular cross-section
, the definition of the fire exposure is not relevant, since the cross-section is reduced over the entire perimeter.
The charring due to the fire duration and fire exposure of the cross-section results in a residual cross-section for which the design is performed according to the applicable standard.
Surfaces
In the Surfaces tab, you make the settings for the fire design of surfaces.
Settings for Fire Design
Define how long the surfaces have to resist the fire, that is, how long the fire exposure is effective. When designing according to EN 1995-1-2 [1], you can specify whether the fire takes place on a wall or a ceiling and whether a heat-resistant bonding of cross-laminated timber layers is present in each case. With heat-resistant bonding, the charring is linear. If the bonding is not heat-resistant, a step-shaped charring course is assumed.
The 'thickness to neglect the layer reduced by fire' defines the minimum thickness of a layer for the design: The layer is only taken into account if its remaining thickness after charring is greater than the specified value. Thinner residual layers are not taken into account.
Fire Exposure
Specify which side(s) of the surface are exposed to the fire. The surface side 'Top (-z)' is the negative surface side (that is, opposite the local z-axis), the surface side 'Bottom (+z)' the positive surface side.
Using the check boxes 'Initially protected from top/bottom', you can define whether the surface is protected against fire exposure by certain measures, for example fire protection cladding in the form of gypsum plasterboards. If this is the case, specify the parameters such as the failure time of the fire protection cladding. It describes from when the fire exposure becomes effective for the surface.
Standard Parameters
The Standard Parameters tab manages the standard-specific parameters.
Here you can check and, if necessary, adjust the charring rates, coefficients, or adjustment factors.
Design Situation for Fire
For the design in case of fire, a design situation type or limit state type with the name Fire must be selected on the design side. If this is not the case, no fire resistance design takes place! Therefore, assign the appropriate type in the Design Situations table.
If you have created a design situation for the fire in the RFEM dialog box Load Cases and Combinations, the type is preset accordingly.
