Flashcards in Chapter 13 Tactical Ventilation Deck (58):
Term that refers to the removal of heated air,smoke,and fire gases from a structure and replacing them with cooler air.
The planned systematic and coordinated removal of heated air, smoke, gases or other airborne contaminants from a structure, replacing them with cooler, fresher air to meet the three incident priorities.
Controlling and extinguishing fire in stages is what?
A houses foot print size for residential homes have increased ................between 1973 and 2008. In addition the lot sizes have decreased ............,reducing firefighter access and increasing potential exposure risk.
150 percent, 25 percent.
Name four fire behavior indicators that should be considered in a tactical ventilation.
Smoke, Air Flow, Heat, Flame
Name four smoke indicators that can paint a picture of interior fire conditions.
Volume of smoke. Location of smoke discharge. Smoke color,density, and pressure. Movement of smoke
The movement of air toward burning fuel and the movement of smoke out of the compartment or structure.
Name four air flow indicators.
Velocity. Turbulence. Direction. Movement of the neutral plane.
Name two causes of air flow.
Pressure differentials between the outside and inside. Differences in density between the hot smoke and cooler air.
The connection between the inlet and the outlet.
Name three heat indicators.
Blistering paint. Bubbling roof tar. Crazed glass.
Name two primary considerations in determining if tactical ventilation should be used.
Stage of fire. Whether the fire is fuel or ventilation controlled.
Weather conditions such as wind, temp, atmospheric pressure, precipitation, and relative humidity all can effect tactical ventilation. Which of these has the largest effect?
List tools that are used to complete tactical ventilation.
Forcible entry tools. Power Saws. Fans or Blowers. Smoke Ejectors. Flexible Duct, Stacking and Hanging Devices. Support Systems. Electrical power cords. Generators/
T or F For vertical ventilation to be effective, a horizontal inlet opening at or below the level of the fire is needed to provide a flow patch for fresh air to enter the structure.
Name two types of tactical ventilation.
Horizontal and Verical
Name the means of horizontal and/or vertical ventilation.
Natural, Mechanical, Hydraulic
What means of ventilation should be chosen when a fire is burning below ground in a structure?
Mechanical or Hydraulic
Can horizontal ventilation be effective in buildings with daylight basements?
When performing natural ventilation should the outlet or inlet be opened first?
outlet on the leeward side.
Oldest type of mechanical ventilation. Smoke is pulled from the structure. Fresh air is drawn in. Fans should be on the leeward side to work with the wind and not against it.
Negative pressure ventilation
The flow path should be keep as ..........as possible. Every corner causes turbulence and decreases ventilation efficiency.
The direction opposite from which the wind is blowing. The protected side.
The side or direction from which the wind is blowing.
The use of a fan to create a slightly higher pressure inside of a structure. Requires good fire ground discipline, coordination, and tactics.
Positive pressure ventialtion
To maintain the positive pressure inside a structure it is important to control location, number, and size of what?
When using PPV to evacuate smoke from a multistory building, what floor should be first?
The one with the most smoke.
PPV is equally effective with horizontal and vertical ventilation because it supplements what?
Natural air flow currents
The main problem with using PPV in above ground operations is what?
Coordinating the opening and closing of doors in the stairwell being used to ventilate the building.
Used to clear a room of smoke, heat, steam, and gases after a fire has been controlled.
What percentage of the opening should be covered by the stream pattern and what minimum distance away from the opening should you be when performing hydraulic ventilation?
85-90%, 2 feet back (nozzle tip)
Intended to aid in reaching and extinguishing the fire.
Offensive Vertical Ventilation
Meant to stop the spread of fire and contain it in one area of the structure.
Defensive Vertical Ventilation
When cutting a roof you should work with the wind at your?
back or side
While performing vertical ventilation remain aware of overhead obstructions within the reach of what?
Where should you walk whenever possible before and after performing vertical ventilation?
Load bearing walls and strongest points of a structure.
Firefighters should always sound a roof, especially if the roof is what?
Obstructed by smoke or damage.
Name four warning signs of possible unsafe roof conditions.
Melting asphalt. Spongy roof. Smoke coming from the roof. Fire coming from the roof.
Used to help to determine the location and direction of travel of a fire in an attic or cockloft.
Name two inspection hole techniques.
Kerf cut. Triangle "A" cut.
A disadvantage of a kerf cut is what?
Heat from the fire can cause the tar or membrane to melt and seal up the cut.
A single cut the width of the saw blade in a roof to check for extension.
A inspection cut technique that provides the most reliable info of conditions beneath the roof.
Offensive ventilation involves making an opening over the seat of the fire at or near the highest point of the roof.
What are two critical points to remember when creating a exhaust opening?
A square or rectangular cut is easier to repair. One large opening at least 4' x 8' is much better then several small openings.
Rectangular exhaust opening cut in a roof, allowing a section of roof deck to be tilted, while still connected to the center rafter.
Louver Cut or Vent
Strips of wood attached to rafters.
May be attached to solid sheathing or to battens.
Slate or tile roofs
The curvature of this type of roof prevents a roof ladder from being secured to the roof. Make a inspection cut as soon as you step on the rood to determine construction and fire location.
Two other names for a trench cut.
Trench or strip ventilation
Must be created at least 30' from the fire and only after a offensive vertical vent cut has been made. Typically 3'-4' wide. Have a charged hose line ready. Cut small inspection holes on both sides of this cut to determine fire location and spread. Assign a roof safety officer to observe.
T of F When the IC determines that the main body of fire is too great to extinguish, they will decided to take a defensive stance and abandon efforts to save the currently burning part of the building.
Windowless buildings will require what type of ventilation?
Personnel required for search and rescue and firefighting operations in high-rise buildings is often how many times greater then is required for a fire in a typical low-rise building?
Phenomenon of a strong air draft moving from the ground level to the roof level of a building. Affected by building height, configuration, and temp differences between the inside and outside air.
Tendency of heat, smoke, and other products of combustion to rise until the encounter a horizontal obstruction. At this point they will spread laterally (ceiling jet) until they encounter a vertical obstruction and begin to bank downward (hot gas layer development).
Horizontal smoke spread
Heat and gas travel up until they reach the top of the building or they are cooled to the surrounding air temp. When the temp is equally the stop rising and spread horizontally.
Stratify (form layers).
What should be placed at the bottom floor of a stairwell used to evacuate occupants?
A fan creating PPV