What makes a building a high-rise?
While a high-rise is a risky building from the point of view of fire protection, other criteria are also hugely relevant, such as social compatibility. This can be characterised by families and child-friendliness, isolation, criminality and vandalism. From the point of view of town planning or city design, tall buildings are often referred to as a building that exceeds the current profile, even if they do not formally fulfil the criteria of the authorities.
The profile of a structure is determined differently depending on the situation, for example, four or five storey buildings can be far more prolific when built next to a two or three storey building.
The Definition of 'High-Rise' in Germany
The Federal Republic of Germany has a clear definition for high-rise buildings from a construction perspective, due to increased safety requirements for any structure above five storeys. This is laid down in the model building code of ARGE building, and accordingly in individual country building regulations (for example, Hessian building regulation paragraph two):
High-rise buildings are buildings in which the floor of at least one living space is more than 22m above the natural or fixed terrain surface.
The reason for setting the 22-meter (72 feet) limit – which was decided as a result of fire safety research, conducted using customary devices of the fire brigade – is essentially due to the necessity of an effective use of turnstiles.
For higher buildings, i.e. high-rise buildings, additional fire protection measures must be taken in Germany, such as separate escape staircases. The requirements arise from the high-rise directive and are predominantly implemented in the building regulations and additional individual regulations. In Frankfurt, the laws of Hesse are applied, while high-rise building regulations (HochhVO) govern the special requirements of the legislature for the construction and operation of all tall buildings.
Further regulations are applied when a high-rise building in Germany has a height of 60 meters (197 feet) or more. In such cases, stricter fire resistance is prescribed for escape routes, and the stairwells must be equipped with ventilation so that they remain smoke-free in the case of fire.
High-rise vs Skyscraper
There is no exact definition of what a skyscraper is. In recent years, however, a definition has been established on an international level, which states that a building with a height of at least 100 meters corresponds to a skyscraper.
However, skyscrapers also have a number of further differentiations: the term ‘Supertall’ refers to skyscrapers that have a height of at least 300 meters.
Here at the Skyline Atlas, all buildings are referred to as high-rise buildings when they have at least 10 storeys. Hereby, we follow the international recommendation of Phorio. For more information on definitions of real estate data, please visit Phorio Standards.
Type of Architectural Design
Depending on the architectural design of the building, a distinction is made between point blocks (“Punkthochhaus” in German) with a more square footprint and slab blocks (“Scheibenhochhaus” in German) with a longitudinally rectangular footprint. If more than 2 (usually 3) wings can span the a central axis of the entrance, staircase and lift(s), the architectural designs are called winged blocks (“Sternhochhaus” in German). There also commonly exist high-rise buildings with a “T”-shaped floor plan.
The city centre of Frankfurt is today dominated by skyscrapers.