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In May 2004, the Safety Academy held a
flashover training course in Sweden for its
German-speaking customers. On the first
day, we travelled to the Academy's training
grounds where, after receiving an introduction
into the phenomena of rollovers and
flashovers, and of course an essential safety
briefing, we took part in exercises designed
to put what we had learnt into practice and
firmly anchor our new knowledge – largely
arranging the lessons ourselves.
In the afternoon, it was time for us to familiarize
ourselves with hollow jet nozzles.
The facility pictured in Figures 1 and 2 is
used to teach fire-fighters how to handle
the jets. Using the appropriate type of jet
(adapted to the container), the flame is
forced to the rear part of the container.
Changing the type of jet causes the flames
to react in different ways.
What happens during a fire in a room?
Once all the “students” had completed this
exercise, the next container awaited. This
container, which served as a laboratory, gave
the students the chance to observe the progression
of a fire in a confined space. The
room's furnishings were simulated using
basighardboard with a surface area of 10 m2,
equivalent to just a fraction of the amount
of wood chipboard which would be found in
a proper room.
The chipboard was supposed to subsequently
release gas, creating the conditions for a
flashover. During the training, the different phases of a fire were explained. First, the
initial fire was lit, and zones of positive and
negative pressure were created. Then, the
first tongues of flame started to lick the
neutral zone, until a flashover occurred with
a slight rise in pressure. The flames were
then extinguished by the students, giving
them once again the chance to practise
using the hollow jet nozzle and familiarize
themselves with the necessary actions and
equipment.
Pretty hot: above 752 °Fahrenheit
The next day focused again on the flashover
container, with the students taking over part
of the training themselves. They controlled
the container and documented the progress
of the fire – under the supervision of the
trainers, of course. Temperatures measured
at the ceiling of the fire room were well above 752 °Fahrenheit (such high temperatures
are needed for wood to release its
gases).
To give everyone a break from the physical
activity, a tour of the Academy’s training
facility was on the agenda after lunch: the
Safety Academy provides training in aircraft fires, basement fires, petrol station accidents,
high-altitude rescue and incidents in chemical
plants.
Ignitiable mixtures
After the tour, two of the students organized
a theoretical lesson. Using a “bang box” and
the “aquarium”, various gas mixtures were created in a container and allowed to explode.
Both experiments were intended to
reinforce the students' knowledge of explosive
mixtures.
On the final day of the training course, the
flashover container was entered once again,
and here too it was the students themselves
who organized the exercise, with the trainers
merely observing and supervising. Obviously,
the trainers would have been able to intervene
if necessary at any time to ensure
the safety of the students.
Next we were able to put into practice what
we had learnt in an operations container.
An operations container comprises two containers
joined together at an angle. This is
where fire-fighters practice how to advance
through a smoke-filled room to reach another
room behind. Teamwork is essential
during such manoeuvres, and the fire-fighters
have to keep close to the floor while moving
forward, carrying their heavy equipment
with them. As the trainers put it “You have
to get down as low as possible!” Other exercises
which can be conducted here are
temperature control with the aid of the jet
nozzle, cooling of fire gases and opening of
doors.
The lunch break gave us a chance to rest.
Afterwards, the backdraft container was
prepared and ignited, the students watching
the exercise from outside. It was quite an
experience for us all to see for ourselves
the extent of the smoke gas explosion and
the noise it made.
Dräger Safety AG & Co. KGaA
Safety Academy
DrägerSafetySolution
Carsten Joester
Revalstr. 1
D-23560 Lübeck |
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Dräger Safety AG & Co. KGaA |
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Revalstrasse 1 |
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23560 Luebeck, Germany |
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Tel +49 451 882 0
Fax +49 451 882 2080
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