Ventilation Basics
The planned, systematic, and coordinated removal of heated air, smoke, gases, or other airborne contaminants from a structure
Tactical Ventilation
The wind direction firefighters should work to keep wind at their backs when working in wind speeds of 10mph or faster.
The primary tool used for pulling or opening ceilings
Pike pole
This method takes advantage of natural air flow and requires no additional personnel or equipment to maintain
Natural horizontal ventilation
The easiest and fastest inspection hole, made by a single cut. The width of the blade
Kerf Cut
The state a fire enters when it has consumed most of its available oxygen and is waiting for a new supply to continue growing.
Ventilation-limited decay
Two
Useful for monitoring the impact of ventilation and identifying possible ventilation locations
TIC (thermal imaging camera)
For NPV to be effective, the area around the smoke ejector must be this to prevent "recirculation"
Sealed
A defensive opening consisting of two parallel cuts extending from one exterior wall to the other to create a defensive line
Trench Cut
The action that has the most impact on the success of tactical ventilation.
Controlling oxygen availability
Melting asphalt, sagging HVAC units, and a "spongy" feel when sounding
Indicators of possible roof collapse
A heavy curtain used to cover exterior window and door openings to prevent wind from adversely affecting ventilation
When PPV is used to control the flow path within a structure in conjunction with fire suppression
Positive Pressure Attack
THe phenomenon in high-rises where heated smoke travels upward and then stratifies horizontally
Stack Affect
Controlling fire growth/spread
Evacuating smoke during overhaul
Controlling where hot gases/smoke exhaust
The two assumptions firefighters should make about any structure fire to guide their ventilation decisions.
Lightweight construction
Fire is Ventilation limited
The type of ventilation that uses a spray stream from a fog nozzle to entrain smoke and gases
Hydraulic ventilation
The primary disadvantage of hydraulic ventilation
Firefighter must remain in a heated, hazardous atmosphere
The minimum number of rungs ground ladders should extend above the edge of the roof or parapet wall
Three
A rapid fire development event that will occur if ventilation is performed without coordination with fire attack.
Flashover
The action that must be taken immediately if any piece of ventilation equipment fails a routine inspection.
Marking OOS (out of service)
Equipment used to artificially lower the pressure inside a structure so fresh air moves in more quickly
Negative-pressure ventilation
When performing a PPV, the surface area of this must be greater than the surface area of the intake
Exhaust opening
Where PPV fans should be located when using a secondary stairwell for evacuation in a high-rise fire
Bottom Floor