Fire resistance capability | Fire resistance class
In the state building codes (LBO), general requirements are set for the fire resistance of structural components of buildings and are divided into fire-resistant, highly fire-retardant and fire-retardant. The fire resistance capability of load-bearing and bracing building components refers to their stability in the event of fire, in the case of space-enclosing building components, such as walls and ceilings, their resistance to the spread of fire (space closure).
Fire resistance classes (fire resistance duration) are based on fire tests. These indicate the period of time over which components (and their building materials) or parts of buildings (e.g. walls, ceilings, doors, etc.) are stable or maintain their function when exposed to fire.
According to DIN 4102, these are specified in 30-minute increments:
• F30 (fire retardant): fire resistance duration of min. 30 minutes,
• F60 (highly fire retardant): min. 60 minutes,
• F90 (fire resistant): min. 90 minutes,
• F120 (highly fire-resistant): min. 120 minutes,
• F180 (extremely fire-resistant): at least 180 minutes.
Components with F120 and F180 are generally only used in buildings that have very high fire protection requirements. These are not further described in the LBOs. The previous German system of standards will eventually be replaced by the European standard DIN EN 13501. In the future, there will be nine different time categories (15, 20, 30, 45, 60, 90, 120, 180 and 240 minutes).
In addition, the performance criteria for components are defined more precisely:
• Load capacity R (Résistance),
• Room closure E (Étanchéité),
• Thermal insulation I (Isolation),
• Radiation passage W (Radiation) - indicates how long the component prevents the passage of radiant heat when exposed to fire
• Impact stress M (Mechanical) - specifies the resistance to mechanical effects in case of fire
The first three criteria can also be found in DIN 4102, the other two are only available in the European standard. The difference is that the German fire resistance classes do not differentiate between the different performance criteria.
Example:
If, in the event of a fire, the temperature on the side facing away from the fire increases, the wall is assigned to fire resistance class F30, even if it would be much better in terms of load-bearing capacity and room closure.The new performance criteria according to DIN EN 13501, however, allow the properties to be considered separately. If the aforementioned wall construction remains stable for up to 100 minutes in the event of fire, it can be classified with the abbreviation R 90, even if the room closure fails after 70 minutes and the thermal insulation after 40 minutes. If the load-bearing capacity and the room closure are considered together, the wall is classified with RE 60 and REI 30 is the fire resistance class, if the thermal insulation is also taken into account.