ISFTA CO Ch. 9 Flashcards
Rapid fire growth usually occurs during which stage of fire development?
growth
Understanding fire dynamics is ….
understanding everything that can happen during the growth stage
T/F: If the fire enters a vent-limited decay phase it is in its final stage of development.
False
the area where sufficient air is available to feed the fire
combustion zone
A fire is in it’s growth stage until …
it has reached its peak heat release rate due to lack of fuel or oxygen
When a fire cannot grow without the introduction of new oxygen or fuel , it has left the (blank) phase and become (blank).
growth; fully developed
What are the two common routes to full development?
fire consumes all available oxygen and transitions to a state of ventilation-limited decay
The fire has enough oxygen to move through there growth phase and possibly through rapid fire development
The tendency of gases to form into layers according to temp, density and pressure
thermal layering
What can significantly alter thermal layering?
flow path / ventilation
The space between the air intake and the exhaust outlet
flow path
What causes the hot gas layer to spread downward within a compartment and laterally?
high pressure
(blank) can move through the hot gas layer.
Isolated (intermittent) flames
what is the net pressure of the neutral plane?
zero
what is a ceiling jet?
Hot fire gases and fuel rich smoke spread across the ceiling horizontally
Most residential fires that develop beyond the incipient stage become (blank)
vent limited
As efficiency of combustion decreases, (blank) decreases and the amount of unburned fuel within the hot gas layer increases.
heat release rate
refers to the rapid transition from the growth stage or early decay stage to a (blank)
Rapid fire development; ventilation limited, fully developed
(blank) are also incidents off rapid fire development, but they involve more than just one compartment of a structure
Smoke explosions
Four common element of a flashover:
Transition in F/D
Rapidity
Compartment
Pyrolysis
What two factors determine the likelihood of flashover occurring?
Sufficient fuel
Sufficient oxygen
High neutral place
early stages or F/d
high ceilings can hide well developed fires
fire above your level
Mid-level neutral plane
compartment not yet ventilated or
flashover approaching
very low-level neutral place
backdraft conditions
fire below you
an increase in low level ventilation prior to upper level ventilation
backdraft conditions
(blank) occurs in the decay stage, in a space containing high concentrations of heated flammable gases that lacks sufficient oxygen for flaming combustion
backdraft
backdrafts can occur with the creation of a (blank) or (blank) opening
horizontal or vertical
