Enclosure fires

Closed, bolted
sauna door
a loud bang. He saw a board come fl ying out, heard glass shatter
and smoke was streaming out through the main entrance. Unperturbed,
he made contact with the BA fi refi ghters. They responded
immediately, saying that that were in no danger.
In the areas adjacent to the stairwell on the ground fl oor, parts
of the under-roof had collapsed. This occurred even though the
stairwell formed its own fi re cell and so, was separated from the
adjacent rooms.
The worst damage was right at the top of the stairwell where
a section of glass had shattered, as well as a locked door had
been blown out and parts of the doorframe had broken loose.
Apart from the fact that large areas of the building were fi lled
with smoke, the damage was limited to the actual sauna itself,
which was totally gutted.
The likely course of events was as follows. The fi re had been
burning in the sauna for a long time and a large amount of the
heat and smoke gases had remained there. But the smoke gases
managed to escape, including to the stairwell, but the temperature
was not high enough to trigger the heat detectors. The
smoke gases in the stairwell also mixed with the air and reached
the fl ammability range. When the BA fi refi ghters opened the
door to the sauna there was a fuel-rich atmosphere in the sauna
room. The bluish fl ame which shot out from the sauna ignited
the smoke gases outside. The actual development of the fi re was
not as intense in the basement area as higher up in the stairwell.
This is where the worst damage was sustained.
BA1
BA2
Sauna
Path of action
Figure 120. A detailed
drawing of the sauna.
The path of action is
directly down from the
stairwell right to the
sauna. You should note
that a search was
carried out in the
ancillary rooms fi rst.
167