Underfloor systems

Fire protection in underfloor systems

System floors' directive
The master system floors' directive (MSysBöR) is of key significance for fire protection measures in underfloor systems. This directive is a supplement to the Master Cable Systems Directive (MLAR). The MLAR describes the fire protection requirements for the penetration of cables through classified walls and ceilings, the fireproof installation in emergency and escape routes and requirements for electrical function maintenance. In these validity areas, the three protection aims must be implemented: Protect fire sections, secure escape routes and maintain functions.

Focus on emergency and escape routes
The system floors' directive deals primarily with the installation of underfloor systems in emergency and escape routes (see also MLAR, Section 3.2.1). However, other rooms of a building may be subject to fire protection requirements for the system floors.

System floors
System floors are primarily approved in the necessary staircases, in rooms between necessary staircases and exits to the open air, as well as in the necessary corridors and other rooms. System floors are forbidden in safety stairwells.

The system floors' directive distinguishes between cavity floors and raised floors. Whilst cavity floors have a poured support layer made of screed, with a maximum cavity of 200 mm, raised floors are made of prefabricated support plates on a stand structure.

Poured floors
In most emergency and escape routes, poured floors are used. If underfloor systems are used here to supply electrical energy, then these ducts must fulfil certain requirements. Only inspection openings are permitted in these areas.