Fire ventilation

When a room or a fi re
cell is considered to be
lost it can often be better
to focus on protecting
adjacent rooms, for
example by creating
openings and venting
the adjacent room.
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Fire ventilation of adjacent rooms
When a fi re in one room is fully developed it can be more
appropriate to implement fi re ventilation in adjoining
rooms than to vent the room where the fi re is burning. The
purpose of this is to prevent the spread of the fi re and hot
gases to non exposed rooms (e.g. adjoining fi re cells).
Fire ventilation of adjacent rooms is normally implemented
as the pressurising of these rooms (see below) or by
creating openings in the roof. The openings can then be
made as a trench, i.e. the physical separation of the roof
between the part that is burning and the part of the building
that is not yet damaged. These openings can, however,
be made both horizontally and vertically, and can also be
combined with mechanical ventilation.
Mechanical fi re ventilation
Mechanical ventilation can be implemented by using fans.
Negative pressure ventilation means that fi re gases is sucked
out from the fi re room or from adjacent rooms. Positive
pressure ventilation (PPV) means that air is pressed into a
room exposed to fi re with the help of fans, in combination
with a swift fi re attack. It is also possible to pressurise adjacent
rooms. There is often very little to distinguish the pressurising
of adjacent rooms from positive pressure ventila-