7-Ops-5.3 Fire dynamics Flashcards
According to the BFES Operations Manual, What does fire dynamics encompass?
a. Only chemistry and material science
b. Only fluid mechanics and heat transfer
c. Interaction of chemistry, material science, fluid mechanics, and heat transfer
d. Only fluid mechanics and engineering
C
Fire dynamics is the field of study that encompasses how fires start, spread, develop, and extinguish. To characterize fire behavior meaningfully, fire dynamics must incorporate the interaction of chemistry and material science and the engineering disciplines of fluid mechanics and heat transfer. In addition, one must also consider the interactions of fire with structures, materials, and people in order to fully understand the fire dynamics of a given fire incident
According to the BFES Operations Manual, Fire dynamics involves understanding the interaction of fire with:
a. Chemistry only
b. Materials only
c. Structures, materials, and people
d. Engineering disciplines only
C
Fire dynamics is the field of study that encompasses how fires start, spread, develop, and extinguish. To characterize fire behavior meaningfully, fire dynamics must incorporate the interaction of chemistry and material science and the engineering disciplines of fluid mechanics and heat transfer. In addition, one must also consider the interactions of fire with structures, materials, and people in order to fully understand the fire dynamics of a given fire incident.
According to the BFES Operations Manual, Fire dynamics is essential for:
a. Firefighters only
b. Operations firefighters only
c. All members on the fireground
d. Researchers only
C
For over 200 hundred years firefighting has been a process of trial and error with varying results. Firefighting equipment upgrades and building construction changes have made it necessary to step back and take a hard look at the science of fire. This science is called Fire Dynamics, which in simple terms is the study of how fires start, spread and develop. Understanding Fire Dynamics or Fire Behavior will assist operations firefighters in developing strategies and tactics, when being dispatched and on arrival to a fire incident.
According to the BFES Operations Manual, What is fire dynamics, in simple terms?
a. The study of firefighting tactics
b. The study of how fires start, spread, and develop
c. The study of fire equipment
d. The study of building construction
B
which in simple terms is the study of how fires start, spread and develop.
According to the BFES Operations Manual, Knowledge of fire behavior assists firefighters in:
a. Developing fire equipment
b. Developing strategies and tactics
c. Constructing buildings
d. Conducting trials
B
New innovations in firefighting equipment have allowed operations to take place deeper into the hostile environment. Knowledge of fire behavior will greatly assist a firefighters understanding of potential hazards and catastrophic fire events. Recognizing these events early will aid in mitigating the contributing factors and allow a process for deciding to continue with a tactic or retreat. Modern construction materials and methods are contributing to fires of higher energy and greater potential for structural compromise. Knowing the building profile and fire progression will be of great value to arriving crews when developing a strategy or tactic.
According to the BFES Operations Manual, What is the Heat Release Rate (HRR) measured in?
a. Watts
b. Kilograms
c. Newtons
d. Joules
A
Heat Release Rate (HRR) - The rate at which fire releases energy-also known as power. HRR is measured in unit of Watts (W), which is an international system unit equal to one joule per second. Depending on the size of fire, HRR is also measured in Kilowatts (equal to 1,000 Watts) or Megawatts (equal to 1,000,000 Watts). (NFPA 921)
According to the BFES Operations Manual, Heat Flux is measured in:
a. Celsius
b. Kelvin
c. Watts
d. Kilowatts per square meter
D
Heat Flux - The rate of heat energy transferred per surface unit area- kW/m2 (NFPA 921)
According to the BFES Operations Manual, Heat transfer within solids is known as:
a. Radiation
b. Conduction
c. Convection
d. Temperature
B
Conduction - Heat transfer within solids or between contacting solids
According to the BFES Operations Manual, What is the glass transition temperature of polycarbonate?
a. 140°C
b. 230°C
c. 250°C
d. 300°C
A
140 284 Glass transition temperature of polycarbonate
According to the BFES Operations Manual, At what temperature does water boil and produce steam?
a. 100°C
b. 140°C
c. 200°C
d. 250°C
A
100 212 Water boils and produces steam
According to the BFES Operations Manual, What is the traditional fire development curve based on?
a. Lack of fuel
b. Lack of oxygen
c. Lack of heat
d. Lack of wind
A
The Traditional Fire Development curve shows the time history of a fuel-limited fire.
According to the BFES Operations Manual, In the Fire Behavior in a Structure curve, what leads to a rapid increase in fire growth?
a. Closing doors and windows
b. Adequate oxygen
c. Depleted oxygen
d. Reduced ventilation
B
Early in the fire growth stage there is adequate oxygen to mix with the heated gases, which results in flaming combustion. As the oxygen level within the structure is depleted, the fire decays, the heat release from the fire decreases and as a result the temperature decreases. When a vent is opened, such as when the fire department enters a door, oxygen is introduced. The oxygen mixes with the heated gases in the structure and the energy level begins to increase. This change in ventilation can result in a rapid increase in fire growth potentially leading to a flashover (fully developed compartment fire) condition.
According to the BFES Operations Manual, Extreme Fire Events may include:
a. Flashover
b. Backdraft
c. Smoke explosion
d. Flame over
e. All of the above
E
Extreme Fire Event can be classified as a Flashover, Backdraft, Smoke Explosion or Flame Over (Roll Over).
According to the BFES Operations Manual, What is flashover?
a. The phase where burned human tissue becomes numb
b. A condition in which unburned fuel ignites in the ceiling layer
c. The most dangerous stage of fire
d. Heat transfer by electromagnetic waves
C
Flashover is the transition phase in the development of a contained fire in which surfaces exposed to the thermal radiation, from fire gases in excess of 600℃, reach ignition temperature more or less simultaneously and fire spreads rapidly through the space. This is the most dangerous stage of fire.
According to the BFES Operations Manual, What is the blowtorch effect related to?
a. Wind-driven fires
b. Backdraft
c. Flameover
d. Traditional fires
A
Wind Driven Fires
Definition:
Blowtorch Effect: Unidirectional flow from floor to ceiling
Overview:
A wind-driven fire may be described as one where external wind or ventilation-forced pressure causes strong air movements, affecting the severity of fire spread. It is often used to describe fires that may also be referred to as forced-draft, wind-assisted, force-vented, or blowtorched.
