Chapter 4 Fire dynamics Flashcards
True or false?
Oxidizers are not combustible
True
Energy is the capacity to perform _____?
Work
Potential energy available for release in combustion process is ________
Heat of combustion
What are the 4 variables that affect fuel release rates
-Chemical composition
-Arrangment
-Density of fuel
-Available oxygen for combustion
What are the two measurements of heat and energy?
Joules and BTU
Converting water to steam would be what kind of reaction?
Endothermic reaction
True of false?
Auto-ignited temperature is always lower than a piloted ignition temperature
FALSE
As the heat transfers to gaseous combustion products, they expand and do what?
Move up and rise away due to buoyancy
What chemical combines with hemoglobin and excludes oxygen from being transported from the brain?
Carbon Monoxide
What causes release of of Hydrogen cyanide?
Incomplete combustion of substances that contain nitrogen and carbon
True or false?
Gases always move from areas of lower pressure to areas of higher pressure
FALSE
True or false?
A higher heat release rate is directly correlated to higher temperature
False
Multiple question on radiation, convection, conduction
Convection
What is known as the reducing agent in a combustion reaction?
Fuel
In vapor density, if a gas is denser than 1.0, will it rise or sink ?
Sink
Explain the difference between flash point and fire point?
Answer
What are the 3 key factors that control how the fire develops?
-Fuel properties
-Ventilation available
-Heat conservation
Rearange the four stages of fire development:
- Growth stage
-Decay stage
-Incipient stage
-Fully developed stage
- Incipient
-Growth
-Fully developed
-Decay
When a fire starts to spread horizontally because of the ceiling, it is called
Ceiling jet
True of false?
A decaying fire means it is safe
FALSEEEE
What are the two reasons for a fire to start decaying
Not enough oxygen to maintain combustion and heat release has decreased to the point that fuel gases will not ignite
Explain what a flash-over is
A rapid transition between growth and fully-developed has new oxygen introduced and starts up again
If a room has a lower neutral plane and a flashover is imminent, is it because the room is fuel limited or ventilation limited?
Ventilation limited
What is the difference between flash-over and backdraft?
Ignition because of heat rising in a ventilation limited room causing everything to combust vs explosion because a sudden intake of oxygen in a non-ventilated room
A smoke explosion can occur when a bunch of unburned fuel gases and oxygen come in contact with….
An ignition source
