Ventilation Flashcards
Tactical ventilation contributes too what factors?
- Life safety
- fire attack and extinguishment
- fire spread control
- reduction in flashpoint & backdraft potential
- property conservation
Ventilation
Is the systematic removal of heated air, smoke, and fire gases from a burning building and replacing it with cooler air.
What increases firefighter safety and reduces interior temperatures?
Timely and effective ventilation
What does effective ventilation improve?
Visibility, permits firefighters to move more rapidly to extinguish the fire
Ventilation opening made in the upper portion of a building is known as what?
Chimney effect
Where should you ventilate?
Directly over the fire, any openings else where can contribute to fire spread
What is key to ventilation teams?
Closely coordinating with fire attack teams and rescue
Convection causes what effect when gases rise from the fire?
Mushrooming
After ventilation why is it important to extinguish the fore as soon as possible?
Increased air supply can feed the fire and allow more growth to occur
What occurs between the growth and fully developed stage that causes auto ignition?
Flashover
Signs for potential backdraft?
- excessive heat
- smoke stained windows
- smoke puffing in intervals
- little visible flame
- black smoke becoming yellow
Decision for ventilation after the following questions are asked?
- Is there a need for ventilation at this time?
- Where is ventilation needed?
- What type of ventilation should be used?
- Do fire and structure conditions allow for safe roof operations?
- Are the vent personnel trained and equipped under these circumstances?
What is the first consideration when ventilating?
Safety of firefighters and occupants
What effects do smoke and gas have in a building?
- visual impairment
- toxic gases
- lack of oxygen
- flammable gases
- backdraft
- flashover
What is important to remember about smoke?
It is fuel that has not yet ignited
Before ventilation on a building what is key to know about the structure?
- number and size of walls
- number of stories, staircases, elevator shafts, ducts and roof openings
- exterior fire escapes
- any adjoining structures
- roof construction
- built in fire protection
What is the fastest and easiest way to determine building questions?
Pre-incident plan
What is the term when fire and smoke spread rapidly through pipe shafts, air handling systems, staircases and ex…?
Stack effect
What is the best method for ventilation on high rise buildings?
Horizontally and using Mechanical devises and HVAC systems
What is one of the most challenging situations a firefighter will face?
Basement fires
What factor complicates the ventilation process?
Windowless buildings
What are some ways fire extension occurs?
- stairways and elevator shafts
- balloon framing
- lapping or exterior flame spread
- beams, pipes or floor to floor
What is key about deciding where to ventilate?
- existing openings
- location of fire
- building construction
- wind direction
- condition of building and fore spread
- potential roof collapse
- effect it would have on fire
- effect without
- attack teams readiness
- ability to do so
What are the three major types of roofs?
Flat, pitched, and arched
Ventilation can occur after the Ic does what?
- determine it can be done safely
- type of construction
- location
- safety
- escape routes
- personal and tools
When ventilating what are some safety precautions to follow?
- work with wind
- note obstructions
- secondary means of escape
- ensure structure supports arnt cut
- guard opening to prevent fall hazard
- use lifelines and ladders
- watch for wires
- full PPE
- caution when using tools
- extend ladder 3 to 5 rungs above the roof
- aerial ladder should be even with roof
- structure integrity
- walk on structure points
- ensure ceilings are fully punched
What are some warning signs or an unsafe roof?
- melting asphalt
- spongy roof
- smoke coming from roof
- fire coming from roof
Roof covering?
Part of the roof exposed to weather
When making a ventilation you should cut what?
A square 4x4
Flat roofs
Are commonly found on commercial, industrial, and apartments and single family
Arched roofs have what two designs?
Bowstring trusses
Lamellar trusses
What are two types of concrete roofs?
Precast
Poured in place
What must be used for metal roofs?
Metal cutting saws with cutting blades
Trench ventilation
Used to stop the spread of fire in a long narrow structure
What are some factors that reduce the effectiveness of ventilation?
- improper use of fans
- excessive window breaking
- fire streams directed into vent openings
- breaking sky lines
- explosions
- burn through roof
- additional openings
Horizontal ventilation
Venting smoke and fire through horizontal means
What are factors that lead to horizontal vent?
- attic is not involved
- multi stories where the fire is below top floor
- vertical vent unsafe
- daylight beams
- cold smoke
The side of the building the wind is striking?
Windward
Wind is not striking
Leeward
What is important to remember about venting?
It should not occur until a charges hose line is in place
What are two ways to force ventilate?
Mechanically and hydraulically
Positive forced vent?
Blowing fresh air in
Negative forced vent?
Expel smoke
What two ways are used to power portable fans?
Electric and gasoline
Churning?
When the negative fan isn’t sealed the smoke will pull back into the room
Positive pressure vent
High volume fan to creat lightly higher pressure forcing the air out
What is the area where the ppv is places?
Entry point
The blower is placed how far outside the entry point?
4-10ft
Hydraulic vent?
Fog pattern covering 85-90% of the window or door and the nozzle should be at least 2ft back
