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Click Icon Above for Movie
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This evolution utilizes the same garage as with the direct
attack evolution;
same fire loading, just a different method of attack. This
time the firefighters attack with a fog nozzle set on a fairly
wide pattern as if attempting to conduct a combination attack.
Obviously, the evolution was staged to demonstrate the adverse
effects of such an operation. The garage is unvented.
There is a window on the Baker side and a standard
doorway on the Charlie side, but these are nowhere near the
sizes of openings necessary to vent the expanding steam and fire
gases created. Remember, when used in this type of attack,
the volume of steam created is between 1500 and 4000 times the
volume of the water applied. This expansion is
instantaneous, therefore the expansion will overwhelm the
ability of relatively small openings to vent and the resultant
excess will inevitably blow back over the firefighters.
This can be seen here as the firefighters literally disappear
under the clouds of steam and fire gases. Additionally,
because the smaller and dispersed water droplets cannot
penetrate to the actual seat of the fire, the combustion
process continues until enough heat is absorbed from the room.
Notice also, that the fire eventually gains control of the attic
area. In this case, it's because the water from the fog
stream hit the ceiling drywall, causing it to fail. Once
the drywall was gone, there was no impediment to the fire
gaining access to the space above. Again, this was purposely done incorrectly for sake of
illustration. Lesson?: If any space is not
vented enough to relieve the products of a combination or
indirect attack and the attacking firefighters cannot
avoid any pressurized byproducts of such an attack, then a
direct attack should always be used. |
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