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© Luchtfoto Leuven: © Nationaal Geografisch Instituut, tel. 02/629 82 82. Toelating A1993.
Fire Safety
J . P. V E R I T E R [ S E C O ]
__ THE LEGAL FRAMEWORK __ THE BUILDING __ OVERRIDING HORIZONTAL DIMENSION
New buildings constructed in Belgium are required The requirements of Belgian law regarding fire In more conventional buildings, compartmentation
to comply with Belgian fire safety legislation. This safety are easy to apply to traditional buildings. is achieved by creating superimposed horizontal
legislation sets out a series of constructional and Yet it is obvious that the Tiensevest building is sections separated by concrete floors. This verti-
functional requirements which buildings must meet unconventional, requiring fairly special measures cality limits the horizontal distances to be covered
in order to “prevent the outbreak, growth and to be envisaged. in order to reach the emergency staircases, as well
spread of fire, to ensure the safety of people, to as allowing their more rational use (each staircase
preventively assist intervention by the fire __ PRESENCE OF ATRIA serves as many compartments as there are floors).
service” 1. In real terms, the analysis of a building
from a fire safety point of view systematically con- In the upper section of the building (levels 2 to 5), In the case of the Tiensevest building, adopting a
siders the 2 essential concepts of compartmenta- the general structure of the building is a succession “traditional” approach to evacuation would not
tion and evacuation. of offices and atria. As the project evolved, it have led to a very rational solution. The presence
quickly became apparent that the atria required to of external passageways not only permits the
The compartmentation of a building allows any be provided with mobile roofs. In case of fire, this more rational use of the emergency staircases
potential fire to be confined to a defined area, the enables the building to be transformed in a matter (each staircase potentially serves all compartments
surface of which is normally limited to 2,500 m2. of seconds, from a continuous unit to a series of at each floor level), but above all improves the
The effectiveness of the compartmentation serves independent entities. quality of the evacuation concept.
to limit the extent of the fire, the resulting damage The opening formed represents 50% of the roof
and the means required to extinguish it. area (in other words, a net opening of almost The quality of this concept is due to the extreme
The evacuation of the building must allow the 140 m2 per atrium!), so as to allow similar condi- redundancy of escape routes (providing the possi-
affected compartment to be evacuated within an tions to those outside the building to be created bility of using any staircase from each compart-
acceptable length of time, by following a safe within these spaces. The atria then become gen- ment) and the fact that communication between
escape route. This translates into a series of quan- uine "fire breaks" between office areas, thus cre- the staircases is safe (in the open) and transparent
titative (width and number of exits, distances to be ating an effective horizontal compartmentation. (simplicity and visibility). The same qualities are
covered, etc.) and qualitative criteria (redundancy The main challenge, from a technical point of view, also applicable to the intervention of the fire
and Rf-protection of escape routes, spaces to be is to design glass roofs that are able to open service.
avoided, etc.). without the need for an external supply energy
The current regulations are relatively severe with (i.e. under the effect of its own weight) for relia- __ COVERED STREET
regards to atria, requiring a system of extinction bility of operation.
and of smoke extraction to be provided. This The covered street forms a semi-protected com-
severity is explained by the fact that atria connect ____________________ munication route. The long Tiensevest side façade
a number of floors and do not provide the same is formed of glazing strips providing an opening
conditions as the outside environment from the 1 Royal Decree of 19 December 1997 (article 0.1 of annexes 2, 3 and 4). ratio of 30%, thus allowing this volume to be con-
point of view of fire and smoke transmission sidered as an external, naturally ventilated space.
between floors.
