Fire resistance classes of the components

How long is a component stable in case of fire and what does F90 AB mean in this context? We provide an overview.

Fire resistance classes

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24 February 2023 Fire Safety

The fire resistance classes provide information about the fire behaviour of a component or building material. Based on the classification in a fire resistance class, it is clear how long a fire door, a fire protection wall or a cable bulkhead, for example, retains its functionality in the event of a fire.

Specifications for fire resistance classes

The individual specifications for the components and building materials to be used in a building are defined in the fire protection concept and must be adhered to for successful building acceptance. The classification in the fire resistance class is regulated for Germany in DIN 4102-2 (Reaction to fire of building materials and components) and at European level in DIN EN 13501-2 (Classification of construction products and construction methods for their reaction to fire). Both standards are valid. If you have any questions about the fire resistance classes, please contact us.

Classification of fire resistance classes according to DIN 4102-2

Example specification of fire resistance class: F30 / F60 / F90

The fire resistance class takes into account the three performance criteria load-bearing capacity, room closure and thermal insulation together. In the German standard DIN 4102-2, the fire resistance class is abbreviated with a letter such as "F". The number behind the F is the minimum number of minutes in which the functionality of the component can withstand at least. At F30 it would therefore be a fire resistance duration of 30 min. The fire resistance class is available in the following time stages: 30, 60, 90, 120 and 180 minutes.

Fire resistance class addition to the building material class

The fire resistance class can be extended by additions of the building material class and provides information about the fire stress (regulated in DIN 4102-1): 

  • A = non-combustible building material (e.g. sand, clay, gravel, cement, clay)  
  • B = combustible (e.g. hardwood, paper, straw, wood wool)

Fire resistance classes Table according to DIN 4102-2

Depending on the component, the fire resistance class is provided with its own code letter. The fire resistance class table according to DIN 4102-2 provides an overview.

Letter of fire resistance classComponent
FWalls, ceilings, columns, stairs
GFire-resistant glazing, windows
IInstallation shafts and ducts
KBarriers in ventilation pipes
LVentilation ducts and pipes
SCable Barriers
TFire protection closures such as fire doors, gates and roller shutters


Classification of fire resistance classes according to DIN EN 13501-2

Example specification of the fire resistance class: REI 30 / RE 60 / I 90 

The European standard DIN EN 13501-2 distinguishes the fire resistance class more differentiated and considers the three performance criteria individually: 

  • R = Load-bearing capacity 
  • E = Room closure 
  • I = Thermal insulation under fire  

In addition, only in the European standard, there are other fire resistance classes: 

  • W = radiation passage 
  • M = impact 

The number behind the letters represents the number of minutes in which the part retains its functionality. In DIN EN 13501-2, however, the time stages are more specific. 15, 20, 30, 45, 60, 90, 120, 180 as well as 240 minutes of fire resistance are possible.

Fire resistance classes Table according to DIN EN 13501-2

The fire resistance class can be indicated by additional performance criteria. The fire resistance classes table according to DIN EN 13501-2 gives an overview.

Letter of fire resistance classPerformance criterionDescription
CSelf-closing propertyStability under shock stress
ERoom closurePrevention of fire and gas penetration
IThermal insulation under fireLimiting the transfer of heat to the side facing away from the fire
MMechanical stabilityResistance to mechanical stress, e.g. due to an impact
PEnergy supply Maintaining the power supply of electrical cables
SSmoke permeabilityLimitation of smoke permeability, e.g. in ventilation flaps or noise protection doors
WThermal radiationLimitation of the passage of thermal radiation to the side facing away from the fire


Example of evaluation of performance criteria

The difference in classification in a fire resistance class between the two standards can be clearly illustrated with an example: If a fire protection ceiling remains stable for up to 80 minutes in the event of a fire, it can be designated according to European standard with the abbreviation R60 (load-bearing capacity for 60 minutes), even if the room closure gives up after 55 minutes and the thermal insulation after 40 minutes. If load-bearing capacity (R) and room closure (E) are assessed together, the (European) fire resistance class RE 45 applies. And if thermal insulation (I) is also taken into account, the fire resistance class REI 40 results. According to the German standard, only the classification F30 would be permissible here. 

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Fire resistance classes and technical classification

The topic of fire resistance classes also includes the technical classification of components and building materials such as fire-retardant. In the State Building Code (Landesbauordnung/LBO), the fire protection requirements for a component and building material are defined by the building class. The building classes differ in the type of building and height (see blog article Building classes and special buildings).

The fire resistance classes can be assigned to these German building authority requirements:

Technical classificationFire resistance class according to DIN 4102-02Duration of functionality in case of fire
Fire retardantF30 Fire resistance up to 30 minutes
Highly fire retardantF60 Fire resistance up to 60 minutes
Fire-resistantF90Fire resistance up to 90 minutes
Highly fire resistantF120Fire resistance up to 120 minutes
Top Highly fire-resistant F180Fire resistance up to 180 minutes

The issue of fire resistance class is more complex than it appears at first. We work according to both standards, depending on how the fire protection concept sets the specifications. If you want to build or renovate a building, we will be happy to support you in its execution.

Conclusion on the fire resistance classes

Both standards are valid. The European standard is much more detailed than the German standard.


German standard

DIN 4102-2 

European Standard

DIN EN 13501-2 

Time stages59
Performance criteria3 pieces, but combined5 pieces, are considered individually
Evaluation of performance criteriaAll 3 criteria must be metPerformance criteria can be assessed separately

If you have the choice, the European standard gives you more flexibility in fire resistance classes, even if the European standard is a bit more complex. In addition, it can be assumed that the European standard will replace the German standard in the future.


Do you still have questions about fire resistance classes or do you need support with fire protection?

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