STRUCTURAL FF 1 Flashcards
What is the fire triangle made up of?
Fuel, Oxygen, Heat
What does disrupting the fire triangle mean for FFs?
By manipulating or disrupting the triangle, FFs can more effectively control and extinguish structural fires.
What is Pyrolysis?
Pyrolysis is the decomposition of a substance caused by heat.
What is latent heat vaporisation?
The amount of heat required to change a given mass of substance from a liquid to a vapour (eg water to steam)
What is the heat release rate?
The amount of heat energy released over time.
What is a flashpoint?
The lowest temp at which a substance produces a flammable vapour.
What is a Fire point?
The lowest temp at which a substance produces a vapour that can sustain a continuous flame. (usually a few degrees above the flashpoint)
What is an Auto Ignition temperature?
It is the temp at which a fuel will ignite on its own without any additional source of ignition.
What is the flammability range?
The ratio of fuel to air. (LEL-UEL)
The Ideal Mixture is when the ratio of fuel to air that burns with max intensity and efficiency.
Define the neutral plane:
The area between the under pressure (fresh air) and over pressure (hot fire gasses)
What is a gravity current?
Occurs when fresh air is denser than the hot gasses.
What is Thorton’s Rule?
As the fire accesses more O2 or as O2 increases, the heat release rate increases. Can lead to extreme fire behaviour.
What is a ventilation-controlled fire?
Simply put, in a ventilation-controlled fire, fire growth is limited by the available air supply. Can be categorised as vented or non-vented.
What is a fuel-controlled fire?
Fires with more than enough air for combustion. Eg: a free burning fire outside or a small fire in a kitchen pan
What are the four phases of basic fire progression?
- Developing Fire
- Flashover
- Fully Developed
- Decay
List the 7 signs of a Flashover:
- Ventilation-Controlled, vented fire
- Painful radiant heat.
- Low neutral plane
- Fingers of flames through smoke
- Hot Surfaces
- Increased Pyrolysis
- Increased turbulence of neutral plane
List the 6 Signs of backdraught:
- Ventilation-controlled, non-vented fire
- Lack of visible flame
- Dirty smoke
- Pulsating smoke through small gaps
- Whistling noise (air being drawn in)
- Extreme heat (blistering paint work, crazing in windows)
What is a fire gas explosion?
A smoke or gas explosion caused by formations of variable-sized flammable fire gases. Can exist in the fire compartment itself, or in adjacent compartments, entrance hallways, corridors and roof spaces. Gases are in ideal premixed state, awaiting an ignition source. Essentially a smoke or gas explosion.
List indicators of a Fuel Controlled Fire
Devleoping Fire
High Neutral Plane
Better visibility
Bright flame
Fire in decay stage
List indicators of a Venilation Controlled fire
Fully developed fire
Low neutral plane
Poor visibility
Air being drawn back into fire
Smouldering fire
Smoke pulsations from openings
Whistling sounds
What is a direct attack?
To extinguish a fire by direct surface cooling of the burning combustables
What is an exterior application?
To support interior ops by applying water on to the fire asap from the outside
What is an indirect attack?
To extinguish a fire by creating large amounts of steam. Gas cools and excludes oxygen. Usually used when fire is fully involved or to supress a suspected backdraught.
What is Gas Cooling?
Hose steam techniques to control the fire environment while FF advance during an attack. Prevent further spread of fire and reduces potential for flashover.
What ideal KPA is used for the branch?
700 (800 from the pump, 100 is lost in distance)
When should you use door entry techniques?
Any door entry
Only the fire attack team should gas cool, true or false?
False.
Ideal selection for branch for gas cooling:
700 KPA at branch
115-230 LPM,
45 degree cone (30-60 acceptable)
Ideal selection or Indirect attack?
700 KPA at branch
115-360 lpm
45 degrees
Ideal selection for Direct attack?
700KPA at branch
115-475 lpm
Straight stream
What are the different classes of fires?
A- Carbon based (furniture, strucutres)
B- Liquids (petroleum, kerosine)
C- Gasses
D- Metals (magnesium)
E- Electrical
F- Cooking oils and fats
What are the different fire extinguishers?
Water
Foam
Dry chemical powder
Carbon dioxide
Explain Charles’s law
-Gases expand when heated.
-Gases become less dense and will rise when heated.
Explain Gay-Lussac’s Law
-When gases are confined and heated, pressure increases.
-Increased pressure indicates higher temperatures
