Basic Ventilation Flashcards
What is the definition of “ventilation”?
The planned, methodical, and systematic removal of pressure, heat, smoke, toxic gasses, and flame from an area and the replacement of these products with cooler, fresh air
Ventilation improves visibility which can help us locate _____ quicker.
Victims
Can ventilation alone put out a fire?
NO, but it is a critical component
Heat and smoke will take the path of _____ resistance
Least
An opening will release pressure and pull ____, ____, and ____ to the opening
Heat, smoke, and fire
Why is ventilation a “double edged sword”?
It will eventually make the fire worse
Poorly placed ventilation openings will pull the fire toward you
What is a “ventilation limited” fire?
A fire that is limited by the amount of air (O2) that is available to the fire
What is a “fuel limited” fire?
A fire that is limited by the amount of fuel that is available to the fire
What are the limiting factors for an outside fire and a compartment fire?
Outside- Fuel
Compartment- O2`
What are the 3 types of ventilation?
Vertical
Horizontal
Built-in
What are the 2 types of vertical ventilation?
Self
Fire department initiated
What are the 2 types of horizontal ventilation?
Natural
Forced
What are the 3 types of forced horizontal ventilation?
Positive pressure
Negative pressure
Hydraulic
What is “self-ventilation”?
When the fire has burned through the roof decking
If the fire has self-ventilated, can we still be on the roof or under it?
NO
Self-ventilation is cause to think about transitioning to a _____ attack
Defensive
What is the general rule about a roof that is unsafe to be on top of?
That it is also unsafe to operate underneath it
What is the most effective way to exhaust smoke and fire gasses from a building?
FD initiated vertical ventilation
Where should vertical ventilation openings be located?
The highest point above the fire, or directly over it(or as close to directly over it as possible)
What dangerous fire “explosion” can vertical ventilation help prevent?
Backdraft
How does vertical ventilation help prevent a backdraft?
It allows the smoke and hot gases to exit the vent hole prior to introduction of oxygen
What are the 6 factors to consider for ventilation?
Life safety hazards Visible smoke conditions The building involved If there is a need Where to ventilate The type of ventilation
What are the 4 things included in ventilation equipment?
PPE with SCBA
Tools
Ladders
Hose line
What are the 5 things you need to consider before taking that first step?
Is there fire showing from the roof? Is there any roof sag? What is the type of roof? Is there smoke or fire? Is there slate or tile on the roof that will make traversing difficult?
How many escape routes must you have when ventilating?
2 at the strong points of the roof
Ladder and approach from the unburned side and have a 2nd ladder opposite of the first one
Do you need to always have your air on while ventilating?
YES
Where should you initially start your saw?
On the ground
If the roof has a steep pitch you should…
Utilize a roof ladder or cut off aerial ladder
When sounding off on a roof with tile or slate….
Break the tile/slate and sound off on the roof underlayment
When walking on a roof you should be walking on at least a ____ or ____
Joist or rafter
What are the 3 kinds of existing roof openings that you can utilize?
Skylights
Stairwells
Scuttle doors
Which is better, 1 large hole or multiple small holes?
1 large hole
What is the minimum opening for a residential structure?
4x4
What is the minimum opening for a commercial structure?
8x8
What is the rule of thumb for a commercial opening?
10 percent of the roof surface
You should cut with the wind to your ____
Back
You should work ____ your ladder when cutting a vent hole
Toward
Can you direct a hose stream through the vent hole?
NEVER!!!
When vertical ventilation is used in conjunction with forced ventilation, what 2 things must you know?
Know the fire location an status
Make sure that it’s not an attic fire
What are the 4 types of vent holes that we will cut?
Vertical ventilation hole
Inspection hole
Trench cut
One rafter louver cut
What are the 2 types of inspection holes?
Kerf cut
Triangle cut
Is a trench cut an offensive or defensive operation?
Defensive
What needs to be in place to defend the trench?
Hose lines
Is anybody inside on the fire side of the trench?
NO
What is horizontal ventilation?
Venting of heat, smoke, and gases through wall openings such as windows and doors
What are the 3 instances that horizontal ventilation is used?
Smaller fires that don’t require vertical ventilation
Buildings that cannot be vertically ventilated easily
Buildings with a compromised roof structure
What are 3 examples of buildings that cannot be vertically ventilated easily?
High-rise
2 story building with fire on 1st floor only
Basements
What is natural horizontal ventilation?
Using the wind to ventilate a structure
What is forced horizontal ventilation?
Using fans, smoke ejectors, or other means to push or pull smoke out of a structure
With natural horizontal ventilation, which side should you open first? Which side should you open next?
Open leeward side first at the highest point
Open the windward side next at the lowest point
Why should you remove window screens?
They reduce airflow by 50 percent
What are the 5 advantages of forced horizontal ventilation?
More positive control over the fire
Supplements natural ventilation
Speeds removal of contaminants
No additional damage to roof of the structure
Reduces smoke damage which increases good PR
What are the 3 disadvantages of forced horizontal ventilation?
Introduces air in large volumes
Dependent on power source
Requires special equipment
What is hydraulic ventilation?
Using air movement of a fog stream to draw out products of combustion
What are the 4 disadvantages of hydraulic ventilation?
Increased water damage
Drain on available water supply
firefighters must be exposed to environment
Operation interrupted when air supply for firefighters runs out
With hydraulic ventilation, how far does the nozzle tip need to be from the window opening?
2 feet
With hydraulic ventilation, how much of the fog stream should cover the window opening?
85-90 percent
How much air will a nozzle flowing 95 gpm move?
5000 cfm
What is used for negative pressure ventilation?
Smoke ejectors
When placing smoke ejectors, should they exhaust with or against the wind?
With the wind
What are the 3 disadvantages of negative pressure ventilation?
Personnel are subjected to the atmosphere while setting up
Contaminates are drawn through the ejector
Doorways/windows are obstructed
What are the 4 advantages of positive pressure ventilation over negative pressure ventilation?
Firefighters are not exposed to environments
Fans not directly blocking ingress or egress
Twice as effective as NPV
Contaminants are not drawn through ejector
PPV efficiency can be improved by pressurizing ____ areas one at a time
Small
With PPV, how much of the air cone should cover the opening?
The entire opening
With PPV, maintain ___ exit point at a time
1
With PPV, the exit size should be ______________________ than the entry point to maintain positive pressure effect
Same size or smaller
Built in ventilation systems may automatically shut down if…
Smoke or heat is detected in the air ducts
OR… firefighters may have shut down the system
HVAC systems may draw in smoke and heat and ________________
Spread the fire
During fire conditions can firefighters attempt to operate smoke control systems?
NO
Building engineers should be called to operate them at the direction of fire personnel
A high rise building may need __-__ times as much staffing as residential fires
4-6
In a high rise building, the stack effect may spread smoke to….
Multiple floors
How do we typically ventilate a high rise building?
Utilizing a stairwell with roof access hatch
What are the 3 problems with ventilating a basement?
Must descend through the heat and gases
Limited openings with which to ventilate
Hard to access and possibly deep seated fires due to use as storage
With basement ventilation, should we utilize exterior basement windows opposite of the attack?
YES, when possible
If there are no exterior windows in a basement fire, where should you consider a vent hole?
In 1st floor near window
What are the 3 reasons that ventilation is more important now than ever before?
Construction
Equipment
Flow path
What is significant about modern construction and ventilation?
Increased synthetics
Increased air tightness
Increased fire load
When done properly, what ultimately should ventilation accomplish?
Decreases fire spread and increases visibility for fire attack
Inadequate or improper ventilation can cause…
Death or injury and cause destruction of the building
