H O P T F B Flashcards
(23 cards)
Choose all statements that are true. (Partial credit is given but wrong answers also lose credit)
Smoldering combustion can have a longer residence time than flaming combustion
Smoldering combustion is hotter than flaming combustion
Smoldering combustion causes more smoke than flaming combustion
Smoldering combustion always happens only after flaming combustion
Smoldering combustion can have a longer residence time than flaming combustion
Smoldering combustion causes more smoke than flaming combustion
List the phases of Combustion
- Preignition
1a. Dehydration
1b. Pyrolysis
- Ignition
- Combustion
3a. Flaming combustion
3b. Smoldering combustion
- Extinction
T or F
Convection is heat transfer by molecular activity
False
___________ is the only heat transfer method that moves heat to the center of a long
conduction
What are the 3 legs of the Fire Fundamental Triangle?
Which leg do firefighters most frequently try to remove?
The three legs of the fire fundamental triangle are oxygen, heat, and fuel.
The leg that firefighters most frequently try to remove is fuel, because without the fuel they would take away the fire, it is a lot harder to take away oxygen or heat from a fire due to the nature of our atmosphere. So the removal of fuel is what is frequently removed since it is a more manageable and reacts pretty well in decreases fire activity.
T or F
The more energy required to pre-heat fuels (i.e. dense, wet fuel) the faster the rate of spread.
False
B. What is an inversion? Describe the types of conditions responsible for producing an inversion. Why is this important for fire management?
An inversion is when in an area as you go up in elevation the temperature also goes up, making a cap on where smoke will stop. This is important for fire management because as you go up in an inversion the RH is lower because temperatures are higher. In this situation when RH is lower there is more chance for combustion which can be really dangerous. This is very important because typically as you go up in elevation the temperature goes down, so in these situations they cannot be addressed the same way.
Ground fire
surface fire
flame length
dew point
rate of spread
equilibrium moisture content
moisture of extinction
heat transfer
combustion
dehydration
relative humidity
fire intensity
heat per unit area
Rothermel’s surface fire spread equation outputs include: (Choose all that apply)
fire intensity
fine dead fuel moisture
heat per unit area
surface area/volume
fire intensity
heat per unit area
know the parts of a fire
Rhothermal Equation
In the equation below, the top of the equation represents the
_______________
and the bottom of the equation represents the
_______________
exothermic; endothermic
What are the three main components of the fire behavior/environment triangle? Pick one leg and briefly discuss how changes in this component cause increases and decrease fire behavior. For example, if sunshine was a leg (it is not), how do changes in sunshine increase and decrease fire behavior.
Fuels
Weather
Topography
2nd part-
Fuels- Increases in fuel load increase fire behavior (and inverse);
Weather- increases in windspeed increase fire behavior (and inverses);
Topography- increase in slope increase fire behavior.
Wind increases fire behavior by:
carrying away moist air which dries out fuels more quickly
supplying more oxygen to the fire
blowing out embers to stop the fire
preheating fuels ahead of the fire front
carrying away moist air which dries out fuels more quickly
supplying more oxygen to the fire
preheating fuels ahead of the fire front
Consider the following types of fuel in April in Arizona. List the fuels in order of increasing fuel moisture content (FMC). Live white fir needles (1 year old), dead gambel oak litter, live aspen leaves.
- dead gambel oak litter
- live white fir needles (1 year old)
- live aspen leaves
Briefly explain how fuels are classified into 1-hour, 10-hour, 100-hour and 1000-hour fuels. Why are their classes based on time? Are these live or dead fuels?
Fuels are classified into 1-hour, 10-hour, 100-hour and 1000-hour fuels depending on their surface to area ratio as well as their density. Their classes are based on time because it is very dependent on its environment, the amount of time that it takes these fuels depends on how long it takes for the fuel to reach equilibrium with its environment. For instance, there might be a small twig and a downed log on the forest ground and a rainstorm had just hit. It would take the small twig about an hour to reach equilibrium with its environment, however it would take a downed log far longer such because of its surface area to ratio that would not allow it to reach equilibrium at the same rate as the 1 hour fuel.
T or F
The smaller the difference between dry bulb temperature and wet bulb temperature, the higher the relative humidity.
True
Choose 1: (Cheatgrass or 3 inch wood)
______ has a lower rate of spread.
3 inch wood
T or F
An increase in slope decreases fire rate of spread.
False
What act first acknowledged the beneficial role of natural fire?
Wilderness Act
Transfer Act
National Environmental Policy Act
Healthy Forests Restoration Act
Wilderness Act
hat are the differences between the original 13 Anderson Fuel Models and the “new” 40 Scott and Burgan fuel models?
Scott and Burgan’s fuel models have more fuel models and cover more fuel types than Anderson’s.
Scott and Burgan’s fuel models were designed for the worst case scenarios only
Anderson’s fuel models easily take into account different live fuel moistures
Scott and Burgan’s fuel models are dynamic
Anderson’s fuel models handle areas with high humidity well.
Scott and Burgan’s fuel models have more fuel models and cover more fuel types than Anderson’s.
Scott and Burgan’s fuel models are dynamic
Qig is related to ___________
Pb is related to __________
W is related to ___________
Qig is related to
ignition
Pb is related to
bulk density
W is related to
wind
What (year) Federal Fire Policy do we currently adhere to?
What was the major fire event that led to this change? (Year and Fire)
2001 Federal Fire Policy is correct. Major Event- 2000 Cerro Grande Fire.
T or F
The smaller the difference between dry bulb temperature and wet bulb temperature, the lower the relative humidity
False
