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Fire Fighter I > Tactical Ventilation > Flashcards

Tactical Ventilation Flashcards

1
Q

What is tactical ventilation?

A

The planned and systematic removal of heated air, smoke, gases or other airborne contaminants from a structure, replacing them with cooler and/or fresher air to improve life safety, incident stabilization, and property conservation. It is a tool to control a fire. It is also used during overhaul and loss control to evacuate smoke from structures after the fire has been extinguished.

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2
Q

What does it mean to be in control of the fire?

A

Using ventilation and water application to influence fire behavior.

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3
Q

At what temperature does the facepiece begin to soften?

A

300° F

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4
Q

What is the maximum temperature that firefighter PPE can handle?

A

500° F

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5
Q

Can you intentionally ventilate a structure in order to make it fuel limited and intentionally burn off all the fuels to smother the fire?

A

No amount of ventilation will cause the fire to become fuel-limited or prevent flashover.

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6
Q

Can you just use ventilation to extinguish a fire?

A

No, ventilation and water application are both required to extinguish any fire.

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7
Q

Why do gases inside the structure move outwards when ventilation occurs?

A

Because the hot gas is less dense, it rises and moves towards areas of lower pressure.

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8
Q

When is ventilation most effective during supression operations?

A

When used in conjuction with immediate water application.

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9
Q

What are the four effects of tactical ventilation to the conditions in the structure?

A
  • Increased oxygen
  • Reduced toxic gases and vapors
  • Reduced temperatures
  • Increased visibility
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10
Q

How can tactical ventilation assist in the rescue of victims?

A

Tactical ventilation can be used to alter the fire’s flow path away from trapped victims.

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11
Q

What are six safety considerations for tactical ventilation?

A
  • Careful planning
  • Observations communicated to IC
  • Following procedures for removing contaminants
  • Coordination with other fireground activities
  • Recongnition that all openings in the structure contribute the the ventilation
  • Recognition of environmantal factors and their effects on ventilation
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12
Q

In terms of situational awareness specific to tactical ventilation, what conditions require your awareness at all times?

A
  • Location of fire
  • Fire behaviour and changes to it
  • Effects that ventilation will have of the fire
  • Effectiveness of the ventilation
  • Locations where smoke is escaping the structure
  • Building construction
  • Structural integrity of building
  • Building contents and their condition
  • Indicators of structural collapse
  • Location of powerlines and solar panels
  • Two escape locations for roof crews
  • Changes to roof’s integrity
  • Coordination of ventilation efforts with fire attack efforts
  • Wind direction and speed
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13
Q

What is an unplanned ventilation?

A

When windows break or holes appear in the wall on roof as a result of the fire.

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14
Q

What two assumptions should firefighters always make about any structure fire when information is limited?

A
  1. The structure is made of lightweight construction
  2. The fire in the structure is ventilation limited
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15
Q

At what speed can a fire become wind-driven?

A

Winds as slow as 10 mph can affect structure fires, potentially making them wind-driven. If winds are at these speeds or faster, firefighters are safest working with the wind at their back.

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16
Q

What is an exposure and how can they be affected by tactical ventilation?

A

These are things to which the fire could spread; they can be internal or external. Internal exposures include building occupants, contents, and uninvolved rooms to which the fire could spread. External exposures include adjacent structures, nearby structures, and vegetation.

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17
Q

What are five signs of potential roof collapse?

A
  • Melting asphalt
  • Smoke escaping through a hole in the roof
  • Roof is on fire
  • Heavy objects on the roof have fallen through or are sagging
  • Roof feels spongy
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18
Q

What are the four most common tools used for creating openings for tactical ventilation?

A
  • Axes
  • Power saws
  • Chain saws
  • Pike poles
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19
Q

What are the sevent types of air movement equipment?

A
  • Air movement devices - blowers, fans, and smoke ejectors
  • Hoselines and nozzles - used for hydraulic ventilation
  • Flexible ducts - used to control the flow of fire gases and smoke
  • Stacking and hanging devices - used to position are movement devices such as fans in doors and windows
  • Generators and power cords - used to power electric devices
  • Wind control devices - heavy curtains to cover doors and window openings to block wind
  • Smoke control devices - heavy curtains to cover doors and window openings to limit ventilation
20
Q

What are the 3 methods of horizontal ventilation?

A
  1. Natural horizontal - involves opening doors and windows to allow air currents and pressure differences to remove smoke and heat from the building
  2. Mechanical - the use of fans and ejectors to create pressure differences
  3. Hydraulic - uses water streams to ventilate compartments and create pressure differences
21
Q

How does wind assist natural horizontal ventilation?

A

When the IC gives the order, windows and doors on the downwind side of the structure (low pressure side) should be opened first to create an exhaust point. Openings on the upwind side (high pressure side) are then opened to permit fresh air to enter, forcing the smoke toward the exhaust openings.

22
Q

What is positive pressure ventilation (PPV) versus negative pressure ventilation (NPV)?

A

Creating negative pressure means artifically lowering the pressure inside the structure so that fresh air from outside moves in more quickly. NPV is a technique using smoke ejectors to develop artifical air flow and to pull smoke out of a structure. Smoke ejectors are placed in windows, doors, or roof vent holes to pull the smoke, heat, and gases from inside the building and eject them to the exterior.

In contrast, creating positive pressure means artifically increasing the pressure inside the structure so that smoke and fuel gases move toward the lower pressure openings more quickly. PPV is a method of ventilating a room or structure by mechanically blowing fresh air through an inlet opening into the space in sufficient volume to create a slight positive pressure within and thereby forcing the contaminated atmosphere out of the exit opening.

23
Q

True or false: horizontal ventilation involves opening a ventilation hole in the ceiling to allow the natural boyancy of the hot gases to clear the structure.

A

False. That is verticle ventilation.

24
Q

True or false: during wind assisted ventilation, the high pressure, or intake point is opened first and then the low pressure, or exit point is opened.

A

False. The low pressure point is opend first so that the gases are not all swirled up in the structure.

25
Q

True or false: if you plan on opening a door to enter the structure, it is a good idea to open another door on the opposite side of the structure to let out the exhaust.

A

True, but only if you have a charged hose ready to apply water as soon as the doors are opened.

26
Q

When do mechanical ventilation methods become necessary?

A

When the natural ventilation is insufficient to clear the structure of the smoke, heat, and toxic fire gases.

27
Q

Why is mechanical horizontal ventilation used after fire suppression?

A

Contaminated atmospheres must be cleared quickly to reduce smoke damage and remove contaminants.

28
Q

True or false: when creating positive pressure, fans blow air into the structure.

A

True.

29
Q

What are some of the disadvantages of mechanical ventilation?

A
  • Requires power source
  • Requires special equipment
  • Requires the use of personnel
30
Q

What are some of the advantages of mechanical ventilation?

A
  • Enhances natural ventilation
  • Ensures more control of air flow
  • Speeds removal of contaminants
  • Reduces smoke damage
31
Q

What is a positive pressure attack (PPA)?

A

Controlling the flow within the structure using positive pressure during the initial stages of the fire, before suppression. When PPA is performed correctly it reduces the thermal effect on firefighters as they perform an interior operation. If PPA is not applied correctly, the potential for rapid fire development and spread surges. Note that PPA works best on fires confined to a compartment.

32
Q

What are the two main considerations for a positive pressure attack?

A

Fire location and exhaust-to-intake size ratio. This ratio compares the surface area of all exhaust openings with the surface area of all compartment intake openings. For PPA to be effective, this ratio must be greater than 1 to 1.

33
Q

True or false: during positive pressure attack, the exhaust opening must be located in the same room as the fire.

A

True. This keeps the heat inside the room where the fire is located, and prevents spread.

34
Q

How can firefighters reduce the pressure created by the fire so that positive pressure attack can be effective?

A

They can cool down the room with water.

35
Q

True or false: in positive pressure ventilation, it is ok to have multiple exhaust points because it ventilates the structure faster.

A

True. Once the fire is extinguished, there is no need for the intake-to-exhaust ratio as the fire is no longer creating pressure that the fan needs to overcome.

36
Q

What is hydraulic ventilation?

A

When a firefighter uses a fog nozzle to create a wall of water, which they place at the intake to clear all the smoke. They stand inside the structure and shoot the water outside to create low pressure inside the structure.

37
Q

What is vertical ventilation?

A

Vertical ventilation involves creating openings in a roof or using existing roof openings such as skylights to channel smoke, hot gases, and products of combustion out of the structure. Note that this should be done as close to the fire as safely possible. In addition, for vertical ventilation to be effective a horizontal inlet opening at or below the level of the fire is needed to provide a flow path for fresh air to enter the structure.

38
Q

What are some safety precautions for vertical ventilation?

A
  • Work with the wind at your back
  • Ensure that structural supports are not cut
  • Guard the ventilation opening to prevent personnel from falling into it
  • Make sure the roof ladder (if being used) is firmly secured before working from it
  • Wear full PPE including SCBA
39
Q

True or false: vertical ventilation is used far less often than horizontal ventilation.

A

True. Vertical ventilation is more dangerous and impractical than horizontal ventilation.

40
Q

What is sounding a roof?

A

Striking the surface of a roof to determine its stability before putting weight on it. Note that this will only determine if the sheathing is intact. It will not provide any information about structural members / structural integrity. Therefore the sheathing may be intact, but the roof trusses underneath could have failed and will fail under your weight.

41
Q

When firefighters get to the roof to ventilate, what are the steps?

A
  1. Sound the roof
  2. Cut an inspection hole before cutting any type of ventilation hole
42
Q

What are the 2 types of inspection holes used for vertical ventilation?

A

Inspection holes help to determine the location of a fire, the presence of fire below the roof, and construction features of the roof. Comparing observations from multiple inspection holes can also provide information about fire spread. There are 2 primary types:

  1. Kerf cut - a single cut in the roof that’s made with a rotary saw, chain saw, or axe. The hole should be the same width as the saw or axe. If flames come through the cut, leave the area and do not provide with ventilation cuts.
  2. Triangle cut - three overlapping cuts that form a triangle. If fire is visible, inform the IC and suspend ventilation.
43
Q

What are the advantages of a Kerf cut over a triangle cut and vise versa?

A

Kerf cuts are faster and can quickly determine if the fire is burning directly below the firefighters due to the presence of smoke or flame.

The Triangle cut is slower, but it allows the firefighter to see into the roof and gather more information.

44
Q

What is a trench cut?

A

A trench is cut in the roof of large buildings in an effort to save a portion of the building by halting the advancing fire. Two parallel cuts at least 4 feet wide are made along the length of the structure and the material in between is pushed down into the building. Firefighters can then attack this defensible area with hose streams when the fire ventilates at the trench cut. A trench cut is usually ordered by the IC when he’s determined that the main body of the fire is too large to extinguish.

45
Q

Which ventilation method is most commonly used for basement fires?

A

Horizontal ventilation in conjuction with water application.

46
Q

What is the stack effect?

A

When fires burn in a high rise, the smoke rises and accumulates in the upper levels.

47
Q

What is horizontal smoke spread?

A

Smoke rises when it is hot but once it cools to the temperature of the surrounding air, it spreads horizontally. This can happen during ventilation if the exhaust hole is smaller than the intake hole.

Fire Fighter I (15 decks)

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