In many instances, the load-bearing substrates for floor constructions need to be regarded as ceilings from a building perspective. This type of ceiling must meet the requirements for fire protection defined by the building and usage. In new buildings, this is factored in by the executive planner and virtually doesn’t affect the executive screed or flooring installer.
The situation looks a bit different for renovations. The planner also holds sole responsibility here, of course. But if a new floor construction is built on ceilings, especially on wooden beam ceilings, assessing the fire safety requirement can become much more complex.
Because fire protection is a highly sensitive topic, it may happen that the planner will require a higher level of protection in case of doubt than prescribed by regional building regulations. This can lead to some floor constructions becoming sidelined as alternative offerings, unless they were definitely suitable for the intended application. In these instances, it can also be quite useful for the tendering installer to provide basic knowledge about structural fire protection. They can at least raise valid questions in the planning specifics, and contribute reasonable flooring structure possibilities as alternatives in the planning process.
The building regulation requirements regarding fire protection are listed in the Model Building Regulation (MBR) for all of Germany. Because building law in Germany is subject to state autonomy, the respective regional building regulation is legally binding in a given state. The regional building regulations (RBR) are based on the Model Building Regulation (MBR), but do not have to be identical in content. To make the current overview not too complicated, the designs refer solely to the MBR. Of course, the planner(!) must ensure that they fulfil the requirements of the applicable RBR. As previously mentioned, the requirements for fire protection depend on the building and usage. The dedicated building classes are listed in section 2 of the MBR. The distance to other buildings is a defining factor for fire protection requirements, along with building height and number and size of units. In addition, there are a number of further regulations for special types of building, such as high-rises, meeting places, or hospitals. The requirements for cellar ceilings are also higher in comparison to storey ceilings.
The building classes listed in section 2 of the MBR are summarised in the following chart with their associated features. In the “fire resistance class” column, the associated fire resistance classes from section 32 of the MBR are listed. The chart provides a quick initial overview of the fire resistance classes that are demanded.
|Building class||Type of building||Building height||Units||Unit area||Resistance class|
|1||free-standing||max. 7 m||max. 2||max. 400 m²||no requirements|
|2||-||max. 7 m||max. 2||max. 400 m²||fire-retardant (F30)|
|3||-||max. 7 m||-||-||fire-retardant (F30)|
|4||-||max. 13 m||-||max. 400 m² per unit||highly fire-retardant (F60)|
|5||All others||fire-resistant (F90)|
At this point it is emphasized once again that the list is merely a rough overview. The list should help the installer gain a basic understanding and point out where the underlying information can be found. Under no circumstances should the installer be involved in design planning! The information presented could be quite helpful for productive technical discussions between planners and contractors under this premise.