Essentials of Firefighting (4th Edition)
Chapter 10-Ventilation
FF1 Test Review

What are some problems with modern energy conservation practices?

  • heat retention
  • flashover

What is the importance of ventilation?

  • increases visibility
  • decreased danger of trapped occupants
  • reduces chance of flashover or backdraft
  • property conservation
  • facilitates entry
  • improves life-safety for rescue and other fire fighting operations

What happens when insulation is installed over a fire-rated roof covering?

  • heat retention
  • fire rating drastically reduces
  • premature roof failure

What kind of information gathering process will alert firefighters to the problems they might encounter in ventilation?

  • pre-incident planning
  • What are the different types of roof coverings?
  • wood shingles
  • composition shingles
  • composition roof paper
  • tile
  • slate
  • synthetic membrane
  • built-up tar
  • gravel surface

What is ventilation?

  • the systematic removal and replacement of heated air, smoke, and gases from a structure with cooler air.

What are the 3 locations that ventilations are made?

  • vertical (roof or topside ventilation)
  • horizontal (using wall openings such as doors or windows)
  • forced (using fans or fire streams)

What does proper ventilation do?

  • it simplifies and expedites rescue by removing smoke and gases that endanger trapped or unconscious occupants
  • makes conditions safer for firefighters and improves visibility so that unconscious victims may be located more easily
  • reduces obstacles, such as limited visibility and excessive heat, that hinder firefighters while they perform fire extinguishment, salvage, rescue, and overhaul procedures
  • assists in making damage reduction possible

What is the chimney effect?

  • drawing air currents from throughout the building in the direction of the opening
    made directly over the fire, it tends to localize the fire

What does the channeling effect cause?

  • aids in the removal of smoke, gases, and heat from a building and permits firefighters to locate the fire and proceed with extinguishment

What does rapid extinguishment provide?

  • reduces water, heat, and smoke damage
  • reduces the amount of water needed to extinguish the fire

How is smoke removed from buildings?

  • by controlling heat currents
  • by dissipating smoke through the expansion of water as it turns into steam
  • by mechanical processes

What is a hazard of water streams through ventilation holes?

  • steam may upset the thermal balance and heat may come down on fire crews inside the structure

What does convection cause?

  • heat, smoke, and fire gases travel upward to the highest point

What is mushrooming?

  • heat, smoke, and fire gases that are trapped and begin to accumulate, bank down and spread laterally to involve other areas of the structure

What does ventilation do to fire conditions?

  • it increases the supply of fresh air and will feed the fire and eventually allow it to grow

What should be in place an ready when ventilating?

  • hoselines should be in place and ready to move in and attack the fire due to fire spread with introduction of fresh air feeding the fire

How does ventilation reduce flashover potential?

  • it removes the heat necessary for materials to reach their ignition temperatures

What type of ventilation is required to reduce backdraft potential?

  • topside or vertical ventilation

What are the warning signs of a backdraft?

  • smoke-stained windows
  • smoke puffing at intervals from structure (appearance of breathing)
  • pressurized smoke coming from small cracks
  • little visible flame
  • black smoke turning dense gray-yellow
  • confinement and excessive heat

When may ventilations need to be performed?

  • before rescue operations begin, depending on fire conditions

What are some hazards that can be expected from the accumulation of smoke and gases in a building?

  • obscurity caused by dense smoke
  • presence of poisonous gases
  • lack of oxygen
  • presence of flammable gases
  • flashover and backdraft

What is the density of smoke in direct ratio to?

  • suspended particles (the more dense the smoke, the more suspended particles)
  • As burning increases, what happens to the density and color of the smoke?
  • it may increases and may become darker because of the large quantities of carbon particles

What are the initial factors in determining horizontal or vertical ventilation?

  • number and size of wall openings
  • number of stories, staircases, shafts, dumbwaiters, ducts, and roof openings
  • availability and involvement of exterior fire escapes and exposures

What is the personnel demand on high-rise compared to residential dwellings?

  • four to six (4X to 6X) as great
  • Where should vertical ventilation be placed?
  • directly over the fire

Does ventilation have to be performed before fire suppression?

  • NO, ventilation does not have to be performed before fire suppression, however, there is a greater risk of the fire spreading into uninvolved portions of the structure.

When must top-ventilation in high-rise buildings be considered?

  • during pre-incident planning

When ventilation a roof with a stairwell door, what should you do?

  • block the door open or remove the door from it's hinges

What is the stack effect?

  • natural upward movement of smoke and heat throughout a building

Why is access to basements difficult?

  • firefighters must descend through the worst heat and smoke to get to the seat of the fire

What happens when ventilation of a windowless building is delayed?

  • the fire is allowed to gain headway and/or backdraft conditions might be created

What type of ventilation do windowless buildings usually require?

  • mechanical ventilation

What is lapping?

  • when flame extends to other exterior openings and enters upper floors

List some reasons for vertical fire extension.

  • convected air currents
  • conduction of heat through pipes and other heat conducting mediums
  • between walls due to convection
  • floor and roof collapse
  • through floor and ceiling openings where fire products fall through

Name factors that have bearing on where to ventilate.

  • availability of natural openings
  • location of fire and direction in which to draw the fire
  • building construction
  • wind direction
  • extent of fire
  • structural integrity
  • effect that ventilation will have on the fire and exposures
  • attack crew's readiness
  • ability to protect exposures

What must be in place before ventilating and why?

  • adequate personnel and equipment must be in place and ready
  • fire increases in intensity when the building is opened

Where should attack crew enter a building?

  • as close to the fire as possible

Where should charged hoselines be placed upon ventilation?

  • at the point of entry of attack crews
  • at critical points of exposure

What is vertical ventilation?

  • opening the roof or existing roof openings for the purpose of allowing heated gases and smoke to escape to the atmosphere

What are the three prevalent types of roof shapes?

  • flat
  • arched
  • pitched

What are six common styles of roofs?

  • mansard
  • gambrel
  • hip
  • shed
  • butterfly
  • lantern

What is the primary consideration in ventilating procedures?

  • the phase in which the fire has progressed (extent of the fire)

After what considerations can a fire officer start vertical ventilation?

  • consider the location, duration, and extent of the fire
  • consider type of building involved
  • observe safety precautions
  • identify escape routes
  • select place to ventilate
  • move personnel and tools to roof

Name the responsibilities of the roof officer.

  • ensure only required openings are made
  • minimize secondary damage
  • coordinate with attack crew efforts
  • ensure safety of all personnel assisting in ventilation efforts

Name some safety precautions when vertically ventilating.

  • secondary means of escape
  • angle of cut not towards body
  • wind direction (wind at back or to side)
  • obstructions or excess weight on roof
  • do not cut main structural supports
  • guard the opening
  • evacuate the roof promptly
  • use safety measures to prevent slipping (lifelines, roof ladders, etc)
  • exercise caution around electrical wires
  • wear full PPE and SCBA
  • out of range of axes
  • start power tools on ground and turn off to hoist
  • extend ladders at least 5 rungs above roof
  • check roof's structural integrity
  • be aware of melting asphalt, "spongy" roofs, smoke and/or fire coming from roof
  • work in groups of at least 2 with no more than necessary

Where should ventilation crew be positioned during opening procedures?

  • closer to egress (no holes between egress)
  • with wind at back

What should the first consideration of the fire officer be when deciding to ventilate?

  • Life Hazards

Name some existing roof openings.

  • scuttle hatches (square and large enough to climb onto roof)
  • skylights
  • monitors (sides may contain glass or louvers made of wood)
  • ventilating shafts
  • stairwell doors

Which roof opening does not provide adequate ventilation?

  • Scuttle Hatches

Which roof opening can be hard to shatter and how should they be opened?

  • skylights containing Lexan or Plexiglas cannot be shattered
  • they should be opened by removing the frame
  • opened easiest by knocking glass out (shatter-type glass)

How should a roof monitor be opened to provide ventilation?

  • force hinges of at least 2 sides to create the required ventilation

What is an inspection hole?

  • made with three cuts forming a small triangle

What size should a roof opening be?

  • at least 4ft. X 4ft.

What is a parapet?

  • low wall or divider on a flat roof (30in. tall-divides or surrounds flat roofs)

What are the different shingle types?

  • wood
  • metal
  • composition
  • asbestos
  • slate
  • tile

What is the primary use of trench/strip ventilation?

  • set up well ahead of the advancing fire for the purpose of setting up a defensive line at which the fire will be stopped
  • strip should be at least 4ft. wide and extend from one exterior wall to the other

How should openings be made in metal roof construction?

  • cut through with power saw or pry up in sheets

On what type of roof must firefighters work from an aerial ladder and why?

  • arched roofs
  • because of the danger of collapse
  • on bowstrings trusses, if one fails, they all fail

Where will the first fire extension of a basement fire usually go?

  • basement fires usually extend to the attic

What makes fire spread through balloon-frame construction?

  • wall studs are continuous from foundation to roof
  • there may be no fire stops between foundation and roof

How should fire streams be operated over ventilation openings?

  • projected slightly above the horizontal plane (cools thermal column and extinguishes sparks)

What types of structures lend themselves to horizontal ventilation?

  • residential not involving attic
  • involved floors of a multi-story building below the top floor or top floor if attic is not involved

What are some ways in which horizontal extension occurs?

  • corridors, halls, passageways
  • convected air currents
  • radiation
  • flame contact
  • flash burning
  • through walls and interior partitions
  • through conduction of pipes, beams, etc
  • through wall openings

What are the internal exposure considerations of horizontal ventilation?

  • routes of gases and smoke may be the same one's used by occupants to escape
  • rescue procedures may be hampered

What can happen if a windward door is opened before a leeward door?

  • it may pressurize the building and upset thermal layering
  • windward=wind going into structure
  • leeward=wind in same direction as exit

What does negative-pressure ventilation do?

  • pulls smoke out of structure (fans placed in openings eject smoke)

What does churning action do?

  • lets smoke re-enter the structure after leaving structure (through alternate openings)

Why should the discharge stream of air on smoke ejectors be avoided?

  • it may pick up particles and eject them out of the fan (flying particles)

At what point is best to provide positive-pressure ventilation?

  • at the lowest point possible

Why must positive pressure ventilation be carefully coordinated?

  • to insure that all doors are opened/closed systematically

What are some disadvantages of positive-pressure ventilation?

  • carbon monoxide levels may be increased (due to combustion engine)
  • intact structure is required
  • hidden fires may be extended

What are some advantages of positive pressure ventilation?

  • done without entering structure
  • equally effective for horizontal or vertical ventilation
  • more efficient removal of smoke and heat
  • velocity of air current is minimal
  • does not interfere with ingress or egress
  • cleaning of equipment takes less time
  • applicable to all types of structures

What percentage of a door or window must a fog-stream cover for hydraulic ventilation?

  • 85 to 90%

How far from the opening must hydraulic ventilation be?

  • at least two feet from nozzle tip

What are some disadvantage of hydraulic ventilation?

  • water damage to the structure is increased
  • firefighter must remain in contaminated atmosphere to ventilate
  • ventilation has to be interrupted if firefighter must perform other operations
  • ice is a problem in freezing temperatures

Does hydraulic ventilation increase the amount of water needed to put out a fire?

  • NO, it only increases the total amount used at the fire scene

What are some dangers of HVAC systems?

  • they can contribute to fire spread
  • must be operated by building engineers if used for ventilation