Chapter 13: Tactical Ventilation

Kerf Cut

-A single cut the width of the saw blade made in a roof to check for fire extension.

Incident Stabilization

-Because tactical ventilation reduces interior temperature, potential for extreme fire behavior, and fire spread, it can be effectively combined with fire attack to stabilize an incident. -Incident stabilization means controlling and extinguishing the fire and is accomplished in stages: >Locating the fire >Confining the fire to the room, area, or structure of origin >Extinguishing the fire

Disadvantages of Mechanical Ventilation

-Can cause a fire to intensify and spread -Depends upon a power source -Requires special equipment -Requires additional resources and personnel

Unsafe Roof Conditions

-In addition to sounding, you should always look for the warning signs of an unsafe roof before stepping on to it. -Roofs supported by lightweight or engineered trusses may fail early in a fire and are extremely dangerous to work on or under. -Preincident planning can help identify these roofs.

Risks to Firefighters

-In addition to the hazards that endanger occupants, hazards to firefighters include: >Visual impairment caused by dense smoke >Lack of oxygen >Presence of toxic gases >Presence of flammable gases >Possibility of rapid fire development

Positive Pressure Ventilation

-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 the exit opening.

Other Resources

-Resources needed for tactical ventilation include forcible entry tools, power saws, fans or blowers, smoke ejectors, flexible ducts, stacking and hanging devices, and other support systems, electrical power cords, and generators.

Natural Ventilation

-Techniques that use the wind, convection currents, and other natural phenomena to ventilate a structure without the use of fans, blowers, and smoke ejectors.

Horizontal Smoke Spread

-Tendency of heat, smoke, and other products of combustion to rise until they encounter a horizontal obstruction. -At this point they will spread laterally (ceiling jet) until they encounter vertical obstructions and begin to bank downward (hot gas layer development)

Air Flow

-The movement of air toward burning fuel and the movement of smoke out of the compartment or structure.

​4.​When performing tactical ventilation, the highest incident priority is: (733) ​A.​life safety. ​B.​risk mitigation. ​C.​extinguishment. ​D.​incident stabilization.

A

30.​Which type of ventilation requires no additional personnel or equipment to set up and maintain? (745) ​A.​Vertical ​B.​Hydraulic ​C.​Natural horizontal ​D.​Mechanical horizontal

C

Mechanical Ventilation

-Any means other than natural ventilation. -This type of ventilation may involve the use of blowers and smoke ejectors.

PPV Advantages

-Firefighters can set up PPV blowers without entering the smoke-filled environment. -PPV is equally effective with either horizontal ventilation or vertical ventilation because it supplements natural air currents. -Removal of smoke and heat from a structure is more efficient. -The velocity of air currents within a building is minimal and creates little, if any, effects that disturb the building contents or smoldering debris. -Yet, the total exchange of air within the building is faster than using NPV alone. -Fans powered by internal combustion engines operate more efficiently in clean air. -The cleaning and maintenance of fans used for PPV is significantly less than those needed for NPV fans. -PPV is effective in all types of structures, particularly in large, high-ceiling areas where NPV is ineffective. -Heat and smoke may be directed away from unburned areas or egress paths. -Exposed buildings or adjacent compartments can be pressurized to reduce fire spread into them.

Firefighter Duties

-Firefighters should be familiar with the location and operation of controls that will shut down the HVAC system when necessary. -While you may need to shut down the HVAC system during a fire, clearing the system of residual smoke and restoring it to operation are the responsibilities of the building engineer or maintenance superintendent. -Because an HVAC system may draw fire into the ducts along with the heat and smoke before it shuts down, the ductwork may create additional fire damage by conducting heat through the metal of the duct. -Check combustibles adjacent to the ductwork in case conduction has caused additional fires. -Only building engineers or the maintenance superintendent should operate building systems to assist in ventilation. Incorrectly operating the system may create a more hazardous situation and cause severe damage to the property.

Exhaust opening

-Intended and controlled exhaust locations that are created or improved at or near the fire to allow products of combustion to escape the building.

PPV Disadvantages

-The structure must be intact. -Interior carbon monoxide levels may be increased if the exhaust from fans powered by internal combustion engines is allowed to enter. -Hidden fires may be accelerated and spread throughout the building.

Smoke Ejectors

-These are electrically powered fans that have intrinsically safe motors that are placed in the smoke-filled atmosphere to push the smoke out. -They can also be used to push fresh air into the structure. They require the use of electrical power cords and generators to operate.

Hydraulic Ventilation

-Ventilation accomplished by using a spray stream to draw the smoke from a compartment through an exterior opening.

Windward Side

-the side or direction from which the wind is blowing.

13.​In a structure fire, what part of the flow path is an open doorway? (737) ​A.​Inlet vent ​B.​Outlet vent ​C.​Lower vent ​D.​Upper vent

A

10.​Which of the following is a reason that modern construction may tend to contain fires for longer periods of time? (736) ​A.​Smaller lot sizes ​B.​Energy efficient designs ​C.​Increased fire load of decorative items ​D.​Use of real wood and granite finishings

B

11.​Which fire behavior indicator can provide an indication of interior fire conditions by observing its volume, location, color, density, and movement? (737) ​A.​Heat ​B.​Smoke ​C.​Flame ​D.​Air flow

B

16.​The effect or lack of effect of fire streams indicates the size and extent of the fire when observing: (738) ​A.​heat. ​B.​flame. ​C.​smoke. ​D.​air flow.

B

27.​The means of mechanical ventilation involve pulling the smoke and fire gases out through an opening and pushing ___ into the structure and displacing the smoke and fire gases. (743-744) ​A.​oxygen ​B.​fresh air ​C.​a roof hook ​D.​a rotary saw

B

1.​What are the three incident priorities when performing tactical ventilation? (733) ​A.​Extinguishment, personnel safety, risk mitigation ​B.​Resource management, life safety, extinguishment ​C.​Life safety, salvage operations, pumper management ​D.​Life safety, incident stabilization, property conservation

D

17.​Which of the following causes air flow? (737) ​A.​Combustion of interior finishings ​B.​Introduction of oxygen into the burning materials ​C.​Escape of gases and flames from burning materials ​D.​Pressure differentials inside and outside compartment

D

18.​Which of the following factors determines the initial severity and extent of a fire? (739) ​A.​Adjacent exposures ​B.​Number of responding units ​C.​Availability of a water supply for suppression ​D.​Activation of fire detection and suppression systems

D

21.​Which of the following factors have a bearing on deciding where to ventilate? (740) ​A.​Number of bystanders ​B.​Cost of ventilation operations ​C.​Availability of rehabilitation facilities ​D.​Indications of potential structural collapse

D

23.​Ventilation that causes heat, smoke, and fire to be discharged through wall openings below the highest point of the building creates danger because: (741) ​A.​multiple ventilation points will be created from the openings. ​B.​oxygen levels will be increased for the upper levels of the fire. ​C.​fire streams will be unable to reach the higher levels of the fire. ​D.​rising gases will ignite portions of the building above exhaust point.

D

Air Flow

-Air flow is the movement of air toward burning fuel and movement of smoke out of the compartment. -Air flow indicators include velocity, turbulence, direction, and movement of the neutral plane. -Air flow follows a flow path. -There is an inlet vent where the air enters, a flow path (typically through the fire area), and an outlet or exhaust vent. -The flow path is the connection between the inlet and the outlet. -Air flow is caused by the following: >Pressure differentials inside and outside the compartment >Differences in density between the hot smoke and cooler air. -Cool air is drawn in toward a fire when the smoke generated by the fire pushes heated air toward the ceiling of a compartment.

Weather Conditions

-Any opening in a building, whether part of the building design or caused by the fire, allows the surrounding atmosphere to affect what is happening inside the building. -The most important weather related influence on ventilation is wind, although temperature, atmospheric pressure, precipitation, and relative humidity can affect tactical ventilation. -Wind conditions must always be considered when determining the proper means and location of tactical ventilation in all types of structures. -Wind can blow the fire toward an external exposure, supply oxygen to the fire, or blow the fire into uninvolved areas of the structure. -The means of tactical ventilation selected should work with the prevailing wind and not against it.

Horizontal Ventilation

-Any technique by which heat, smoke, and other products of combustion are channeled horizontally out of a structure by way of existing or created horizontal openings such as windows, doors, or other openings in walls. -Typically portions of one or more of the horizontal openings will also serve as an air inlet.

Type of Ventilation

-Based on the many factors, the Incident Commander determines the type of ventilation used - and if and where it is needed. -The type of ventilation (vertical vs. horizontal) and the means of ventilation (natural vs. mechanical) used must be the most appropriate for the situation.

Inspection Holes

-Before cutting any type of ventilation hole, you should cut an inspection holein the roof. -Inspection holes help to determine the location of a fire and the direction of travel of a fire that is located in an attic or cockloft. -Inspection holes are used in both offensive and defensive ventilation operations. -There are two primary types of inspections holes: the kerf cut and the triangle ("A") cut.

Location for Ventilation

-Before selecting a place to ventilate, firefighters should gather as much information as possible about the fire, the building, and the occupancy.

Sounding the Roof

-Before stepping off a ladder, parapet wall, or other place of safety onto the roof of a burning building firefighters should sound the roof by striking the roof surface with the blunt end of a pike pole, rubbish hook, or axe. -You should practice this procedure on various roofs in your area so that you can learn to recognize the difference in the feel and the sound of supported and unsupported areas of a roof.

Vertical Ventilation

-Before vertical ventilation operations begin, the IC must: >Determine the need for ventilation >Determine the operation can be done safely and effectively >Consider the age and type of construction involved >Consider the location, duration, and extent of the fire >Observe safety precautions >Identify escape routes >Select the place to ventilate >Move personnel and tools to the roof

HVAC Systems

-Built-in HVAC systems can contribute to the spread of smoke, fire, and toxic gases throughout a structure. -These systems are usually controlled from a panel in a maintenance and operations center in the basement or at ground level. -At the control panel, you will usually find a diagram of the building duct system along with information on smoke detection and fire suppression systems built into the HVAC ductwork. -These systems are designed to shut down the HVAC system automatically when smoke or fire is detected in the ducts.

Trench Ventilation

-Defensive tactic that involves cutting an exhaust opening in the roof of a burning building, extending from one outside wall to the other, to create an opening at which a spreading fire may be cut off.

Blowers

-Fans that are used to push fresh air into a structure. -They may be powered by electricity, gasoline engines, or hydraulically. -Blowers that are not intrinsically safe may only be used to push fresh air into the structure.

Location and Extent of Fire

-First-arriving units must quickly determine the size and extent of the fire as well as its location. -Creating tactical ventilation openings in an uncoordinated manner can spread the fire to uninvolved areas of the building and cut off escape routes for building occupants. -The severity and extent of the fire depend upon a number of factors, including: >Fuel type >How long it has been burning >Activation of fire detection and suppression systems >Degree of confinement -The stage of the fire and whether it is fuel or ventilation controlled are a primary consideration in determining tactical ventilation procedures.

Using a Power Saw

-General safety procedures: >The saw operator must have good footing and maintain control of the saw at all times. >When working on a pitched roof from a roof ladder, a rubbish hook, or Halligan can be used to provide a secure foothold for the saw operator. >Turn off the saw when it is being transported to or from the point of operation - especially when moving up or down a ladder.

Smoke Control Systems

-In addition to HVAC systems, many buildings with large open spaces, such as high-rises, shopping malls, and buildings with open atria, are equipped with built-in smoke control systems. -These systems are designed to confine a fire to a small area by compartmentalizing the building when smoke or fire is detected by automatically closing doors, partitions, and windows, as well as HVAC systems. -Smoke control systems usually have a system diagram at the control panel. -The panel should indicate where the alarm originated and which automatic closers were activated.

Building Construction

-Knowledge of the building involved is a great asset when decisions concerning tactical ventilation are made. -Building characteristics to be considered include: >Occupancy classification >Construction type >Floor area and compartmentation >Ceiling height >Number of stories above and below ground level >Number and size of exterior windows, doors, and other wall openings >Number and location of staircases, elevator shafts, dumbwaiters, ducts, and roof openings >External exposures >Extent to which a building is connected to adjoining structures >Type and design of roof construction >Type and location of fire protection systems >Contents >Heating, ventilation, and air conditioning (HVAC) system -This information can be obtained from the preincident plan, inspection reports, or observation of similar types of structures. -Be aware that during the past 50 years, building construction in North America has changed drastically. -The image illustrates the differences between older and newer homes.

Risks to Occupants

-Life hazards in a structure fire are generally lower if the occupants are awake. -If the occupants were asleep when the fire developed and are still in the building: >Occupants may have been overcome by smoke, fire, and gases - some may still be alive; others may have perished. >Occupants might have become lost in the structure. >Occupants may be alive and taking refuge in their rooms because the doors were closed.

Mechanical Horizontal Ventilation

-Mechanical ventilation is necessary when the natural flow of air currents and the currents created by the fire are insufficient to remove smoke, heat, and fire gases. -Mechanical ventilation is accomplished through negative pressure or positive pressure.

Positive-Pressure Ventilation (PPV)

-Method of ventilating a confined space by mechanically blowing fresh air into the space in sufficient volume to create a slight positive pressure within and thereby forcing the contaminated atmosphere out the exit opening.

Recirculation

-Movement of smoke being blown out of a ventilation opening only to be drawn back inside by the negative pressure created by the ejector because the open area around the ejector has not been sealed

Offensive Ventilation Methods

-Offensive ventilation involves making an opening over the seat of the fire at or near the highest point of the roof. -The type of exhaust opening and the method for making it will depend on the type of roof in which the opening is being made. -When cutting an exhaust opening in any type of roof, there are two critical points to bear in mind: >A square or rectangular opening is easier to cut and easier to repair after the fire. >One large opening, at least 4 x 8 feet (1.2 m by 2.4 m), is much better than several small ones.

Stack Effect

-Phenomenon of a strong air draft moving from ground level to the roof level of a building. -Affected by building height, configuration, and temperature differences between inside and outside air.

Leeward Side

-Protected side; the direction opposite from which the wind is blowing.

Louver Cut or Vent

-Rectangular exhaust opening cut in a roof, allowing a section of roof deck (still nailed to center rafter) to be tilted, thus creating an opening similar to a louver. -Also called center rafter cut.

General Reasons for Tactical Ventilation

-Reducing interior heat levels -Decreasing rate of fire spread -Reducing potential extreme fire behavior -Improving interior visibility -Improving firefighter efficiency -Improving victim survival potential -Reducing smoke damage and property damage

Roof-Cutting Operations

-Rotary saws, carbide-tipped chain saws, or a chain saw with adapted features are excellent for roof-cutting operations because they are faster and less damaging than axes or other manual cutting tools.

Staffing

-Staffing requirements range from two firefighters to multiple companies. -In a small structure, ventilation may only require two firefighters to open doors and windows to allow the fresh air to enter and the smoke to exit. -Additional personnel and companies are required when it is necessary to make a roof opening or activate fans and smoke ejectors.

External Exposures

-Structures located adjacent to the fire building can be affected by radiation and/or direct flame contact. -Window-mounted air conditioning units or HVAC intake vents may draw smoke into adjacent buildings as well. -Nearby structures and vegetation can be ignited if hot fire brands or embers are carried aloft by convection. -Fire may be drawn into exterior windows or openings of the adjacent exposures.

Horizontal Ventilation

-Structures that lend themselves to the application of horizontal ventilation include: >Buildings in which the fire has not involved the attic or cockloft area >Involved floors of multistoried structures below the top floor, or the top floor if the attic is uninvolved >Buildings so weakened by the fire that vertical ventilation is unsafe >Buildings with daylight basements >Buildings in which vertical ventilation is ineffective

General Procedures for PPV

-Successful positive-pressure ventilation requires good fireground discipline, coordination, and tactics. -General procedures for PPV include: >The location where the fan or blower is set up is called the entry (inlet) opening or point. >Once that location is selected, an exhaust opening or point must be created. >The size of the exhaust opening varies with the size of the entry opening and the capacity of the blower used. >The exhaust opening may be a window or doorway. >A blower is placed outside the entry opening. >For a normal, single, 3-foot wide (0.9 m) door, the distance between the door and the fan should be 4 to 6 feet (1.2 to 1.8 m). >This distance may need to be altered for larger door openings. -It is important that the cone of air from the blower completely covers the doorway opening. -To maintain the positive pressure inside, it is important to control the location, number, and size of exterior openings.

Advantages of Mechanical Ventilation

-Supplements and enhances natural ventilation -Ensures more control of air flow -Speeds the removal of contaminants -Reduces smoke damage -Promotes good public relations -Even in the absence of fire, contaminated atmospheres must be quickly and thoroughly cleared from a building or other confined space. -Confined spaces containing low oxygen levels can benefit from the introduction of fresh air as the contaminated atmosphere is removed. -Flexible ducting can be used to reach contaminated atmospheres

Cont.

-Tactical ventilation should only be performed when fire attack hoselines and teams are in place and ready to advance toward the fire. -Successful tactical ventilation depends on: -Careful planning -Knowledge of building construction -Knowledge of fire behavior -Systematic application of procedures for removing the contaminants -Coordination with other fireground activities

Negative-Pressure Ventilation (NPV)

-Technique using smoke ejectors to develop artificial air flow and to pull smoke out of a structure. -Smoke placed in ejectors are windows, doors, or roof vent holes to pull the smoke, heat, and gases from inside the building and eject them to the exterior.

Considerations Affecting the Decision to Ventilate

-The Incident Commander (IC) will make the decision to ventilate a structure. -The decision is based on a number of factors including: >Risks to occupants and firefighters >Building construction >Fire behavior indicators >Location and extent of the fire >Type of ventilation >Location for ventilation >Weather conditions >Exposures >Staffing and available resources

Means of Ventilation

-The means used for horizontal and vertical ventilation are natural, mechanical, and hydraulic. -In general, mechanical or hydraulic ventilation is indicated when: >The location and size of the fire have been determined. >The layout of the building is not conducive to natural ventilation. >Natural ventilation slows, becomes ineffective, and needs support. >The fire is burning below ground in the structure. >The involved area within a compartment is so large that natural ventilation is inefficient. >The type of building or the fire situation dictates its use.

Negative Pressure Ventilation

-The oldest type of mechanical ventilation. -Smoke ejectors are used to expel (pull) smoke from a structure by developing artificial air flow or enhancing natural ventilation. -Smoke and fire gases are drawn out of the structure and fresh air is drawn into the structure by the negative pressure the fans have created.

Communications with Incident Command

-The roof ventilation team should be in constant communication with their supervisor or the IC. -Responsibilities of the roof ventilation team leader include: >Ensuring that the roof is safe and only the required openings are made. >Directing efforts to minimize secondary damage. >Coordinating the team's efforts with those of firefighters inside the building. -Ensuring: >The safety of the personnel involved >Two means of egress from the roof >An adequate exhaust opening size >The team leaves the roof as soon as the assignment is completed

Internal Exposures

-The the building occupants, contents, and any uninvolved rooms or portions of the building. -The routes the smoke and heated fire gases would naturally travel to exit the building may be the same corridors and passageways that occupants need for evacuation and firefighters need for working. -Ventilation that causes heat, smoke, and sometimes fire to be discharged through wall openings below the highest point of the building creates the danger that the rising gases will ignite portions of the building above the exhaust point. -Heat and fire gases may be drawn into open windows or attic vents, and they may also ignite the eaves of the building or adjacent structures.

Defensive Ventilation Method

-The trench cut (also referred to as trench or strip ventilation) is a defensive operation and should NOT be confused with or used as offensive vertical ventilation. -A trench cut is used to create a fire break to stop the spread of fire in common attic structures or large structures. -Though this tactic can be time consuming or physically taxing on personnel, it does work well in large buildings, especially if they have a common cockloft or attic. -A trench cut is made only after the IC has determined that the main body of the fire is too great to extinguish, and defensive ventilation is needed. -The opening must be created at least 30 feet (9.1 m) ahead of the advancing fire and only after the offensive vertical ventilation opening has been made.

Vertical Ventilation

-Ventilating at a point above the fire through existing or created openings and channeling the contaminated atmosphere vertically within the structure and out the top. -Done with openings in the roof, skylights, roof vents, or roof doors.

Vertical Ventilation Risks

-Vertical ventilation presents the following increased risks: >Placing personnel above ground level >Working on both peaked and flat surfaces >Working above the fire >Working on roofs that may have been weakened because of age or fire damage -The IC must assess these risks, implement safety precautions. -The IC also determines if the operation is offensive or defensive, defined as follows: -Offensive: >Intended to aid in reaching and extinguishing the fire. -Defensive: >Intended to stop the spread of fire and contain it in one area of the structure.

Flames

-Visible flames may provide an indication of the size and location of the fire, for example, fire showing from one window vs. fire showing from all windows on the fire floor. -The size and extent of the fire may also be indicated by the effect (or lack of effect) of fire streams on flaming combustion. -Flames visible from outside the structure can allow firefighters to assess flame indicators along with ventilation and air flow. -Do not rely solely on the presence or location of flames to assess an incident.

Fire Behavior Indicators: Heat

-Visual indicators of heat include blistering paint, bubbling roofing tar, and crazed glass. -Scanning buildings with a thermal imager or infrared sensor can provide data on internal temperature differences. -You may also determine the presence of increased temperatures through touch or feel on your skin even at a distance.

Natural Horizontal Ventilation

-When conditions are appropriate, natural horizontal ventilation works with existing atmospheric conditions, taking advantage of natural air flow. -When directed by the IC, windows and doors on the leeward side of the structure are opened first to create an exit point. -Openings on the windward side of the structure are then opened to permit fresh air to enter, forcing the smoke toward the exhaust openings. -If only a single opening is made, such as opening a door, this vent will serve as both the inlet for air and the exit for smoke.

Property Conservation

-When smoke, gases, and heat are removed from a burning structure, the fire can be confined to a specific area. -If sufficient personnel are on scene, salvage operations can begin outside the immediate area of the fire even while fire control operations are being conducted. -Because tactical ventilation increases the speed with which you can extinguish interior fires, it reduces the fire damage in a structure. -Less water will be needed and, consequently, there will be less water damage to the structure and its contents.

PPV in Multistory Buildings

-When using PPV to ventilate a multistory building, it is best to apply positive pressure at the lowest point. -One or more blowers are placed at ground level. -Positive pressure is then directed throughout the building by opening and closing doors until the building is totally evacuated of smoke.

Reasons for Tactical Ventilation

-While the term ventilation is the traditional word used in the fire service, the activity described in this chapter is more accurately referred to as tactical ventilation. -Tactical ventilation is the planned, systematic, and coordinated removal of heated air, smoke, gases or other airborne contaminants from a structure, replacing them with cooler and/or fresher air to meet the incident priorities of life safety, incident stabilization, and property conservation.

14.​Which fire behavior indicator provides visual indicators such as blistering paint or crazed glass? (738) ​A.​Heat ​B.​Flame ​C.​Smoke ​D.​Air flow

A

19.​Which of the following factors is a primary reason that firefighters should not create tactical ventilation openings in an uncoordinated manner? (739) ​A.​Can spread fire to uninvolved areas ​B.​May damage roof of structure by creating openings ​C.​Can cause fire streams to have negative affect on fire ​D.​Creating openings does unnecessary damage to the structure

A

22.​Which of the following weather conditions has the most influence on ventilation operations? (740) ​A.​Wind ​B.​Precipitation ​C.​Temperature ​D.​Atmospheric pressure

A

24.​A small structure fire that requires ventilation consisting of opening doors and windows requires at minimum: (742) ​A.​two firefighters. ​B.​three firefighters. ​C.​four firefighters. ​D.​five firefighters.

A

26.​Opening doors or windows is an example of: (743) ​A.​natural ventilation. ​B.​vertical ventilation. ​C.​hydraulic ventilation. ​D.​mechanical ventilation.

A

28.​Hydraulic ventilation involves using a spray nozzle set on a ___ pattern to draw the smoke out an opening such as a window or door. (744) ​A.​fog ​B.​fan ​C.​vertical ​D.​horizontal

A

32.​Which side of an opening should a fan be placed for negative-pressure ventilation? (745) ​A.​Leeward ​B.​Interior ​C.​Exterior ​D.​Windward

A

7.​Which characteristic of modern single-family residential construction reduces firefighter access and increases potential exposure risks? (735) ​A.​Smaller lot sizes ​B.​Open floor plans ​C.​Larger structure sizes ​D.​Composite construction material

A

12.​Velocity, turbulence, and direction are indicators of: (737) ​A.​flame. ​B.​smoke. ​C.​air flow. ​D.​air pressure.

C

15.​Which fire behavior indicator provides visual indicators such as the size and location of the fire? (738) ​A.​Heat ​B.​Smoke ​C.​Flame ​D.​Air flow

C

2.​Which of the following is a reason for performing tactical ventilation? (733) ​A.​Decreasing reliance on fire streams ​B.​Decrease costs of fireground operations ​C.​Reducing potential extreme fire behavior ​D.​Reducing need for interior fire operations

C

20.​Which of the following personnel determines if ventilation is necessary? (739) ​A.​Battalion chief ​B.​Senior firefighter ​C.​Incident Commander ​D.​Any firefighter can make the determination

C

25.​Cutting a hole in the roof above the fire or opening existing roof access doors, scuttles, or skylights are all examples of: (742) ​A.​inlet ventilation. ​B.​outlet ventilation. ​C.​vertical ventilation. ​D.​horizontal ventilation.

C

3.​Incident stabilization means: (733) ​A.​reducing interior temperatures. ​B.​increasing oxygen concentration. ​C.​controlling and extinguishing the fire in stages. ​D.​increasing the number of smoke-free paths of egress.

C

5.​Which statement about tactical ventilation is MOST accurate? (733) ​A.​Tactical ventilation must be performed before fire attack. ​B.​Tactical ventilation is implemented after the fire is confined. ​C.​Tactical ventilation can be combined with fire attack to stabilize an incident. ​D.​Tactical ventilation should not begin until the incident is stabilized.

C

6.​Tactical ventilation reduces fire damage in structures and limits water damage because it: (734) ​A.​focuses on the use of foam to fight interior fires. ​B.​allows for the use of fire streams with lower pressures. ​C.​increases speed with which interior fires can be extinguished. ​D.​allows salvage operations to begin simultaneously with fire attack.

C

29.​Allowing natural air currents and pressure differences to move smoke and heat out of the building is natural: (745) ​A.​exhaust ventilation. ​B.​vertical ventilation. ​C.​hydraulic ventilation. ​D.​horizontal ventilation.

D

31.​Use of smoke ejectors to expel smoke and draw fresh air into a structure is a use of: (745) ​A.​positive-pressure ventilation (PPV) ​B.​positive-exhaust ventilation (PEV) ​C.​negative-exhaust ventilation (NEV) ​D.​negative-pressure ventilation (NPV)

D

33.​When the natural flow of air currents and the currents created by the fire is insufficient to remove smoke, heat, and fire gases, what type of ventilation is necessary? (745) ​A.​Vertical ​B.​Hydraulic ​C.​Protected ​D.​Mechanical

D

8.​Which of the following is a characteristic of older structure construction? (735) ​A.​Smaller lot sizes ​B.​Larger structure sizes ​C.​Wall cavities filled with synthetic insulation ​D.​Windows that could be opened for ventilation

D

9.​Which characteristic of modern construction produces large quantities of toxic, combustible gases during a fire? (736) ​A.​Energy efficient designs ​B.​Treated wood components ​C.​Lightweight structural components ​D.​Use of plastics and other synthetic materials

D