VENTILATION

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VENTILATION

• SECTION 8

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Assignment

• Prior to viewing this power point presentation
  the student shall read, study, and become
  familiar with Chapter 10, Ventilation Pages
  specifically referenced in this Basic Firefighter
  presentation will be pages 345 - 375
• After reading and becoming familiar with these
  pages, you may proceed with the viewing of this
  power point presentation

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VENTILATION

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

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TYPES OF VENTILATION

• Vertical
• Trench (strip)
• Basement

• Horizontal
• Natural
• Forced
• Mechanical positive-pressure
• Mechanical negative-pressure
• Hydraulic

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WHY VENTILATE?

• Aids in saving lives
• Aids in suppressing fire
• Aids in reducing property damage

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TODAYS INCREASING NEED FOR VENTILATION

• Increased fuel load in all occupancies due to
  increased use of plastics and other synthetic
  materials
• More products of combustion
• More dangerous products of combustion
• Tighter homes making heat retention greater
• Increased insulation
• Energy-saving glass
• Vapor barriers

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ADVANTAGES OF VENTILATION TO RESCUE OPERATIONS

• Improves visibility
• Allows for faster location of unconscious victims
  
• Simplifies and expedites rescue
• Makes conditions safer for firefighter and victims

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ADVANTAGES OF VENTILATION TO FIRE ATTACK
EXTINGUISHMENT

• Removes smoke, gases, and heat from building
• Facilitates entry of firefighters
• Reduces obstacles that hinder firefighters
• Increases visibility for quicker location of seat
  of fire

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ADVANTAGES OF VENTILATION TO FIRE CONTROL

• Reduces mushrooming
• Reduces flashover potential
• Reduces backdraft potential
• Controls fire spread

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ADVANTAGES OF VENTILATION TO PROPERTY
CONSERVATION

• Permits rapid extinguishment
• Reduces water, heat, and smoke damage
• Confines fire to an area
• Allows salvage operations and fire control to
  take place concurrently

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BACKDRAFT INDICATIONS

• Puffing
• Smoke
• Black Smoke
• Becoming Dense
• Yellow-Gray
• Walls Too
• Hot to Touch
• Dull Orange Glow
• of Visible Fire

• Pressurized
• Smoke Coming
• From Small
• Cracks
• Darkened
• Windows
• Rattling
• Windows
• Hot Unbroken
• Glass

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BACKDRAFT PREVENTION

• Top (vertical) ventilation is the primary method
  of preventing backdraft

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MAKING VENTILATION DECISIONS

• Is there a need for ventilation at this time?
• Heat, smoke and gas conditions within structure
• Structural conditions
• Life hazard

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MAKING VENTILATION DECISIONS

• Where is ventilation needed?
• Construction features
• Building contents
• Exposures
• Extent of fire
• Location of fire
• Top (vertical) openings
• Cross (horizontal) openings

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MAKING VENTILATION DECISIONS

• What type of ventilation should be used?
• Natural or mechanical
• Horizontal or vertical
• Hydraulic
• Do fire and structural conditions allow for safe
  roof operations?
• Smoke density, behavior, and color can aid
  firefighters in making ventilation decisions

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LIFE SAFETY HAZARDS IN UNVENTILATED BUILDINGS

• Obscurity caused by dense smoke
• Presence of toxic gases
• Lack of oxygen
• Presence of flammable gases
• Danger of back draft
• Danger of flashover and rollover

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FACTORS DETERMINING HORIZONTAL OR VERTICAL
VENTILATION

• Building type and design
• Number and size of wall openings
• Number of stories
• Number of staircases, shafts, dumbwaiters, ducts,
  roof openings
• Availability of exterior fire escapes
• Exposure involvement

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VENTILATION PROBLEMSHIGH RISE

• Number of
• Occupants
• Number of
• Internal Vertical
• Openings
• Smoke and Gas
• Stratification
• Number of
• Personnel
• Needed
• Communication
• Among Personnel
• Roof Ventilation

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VENTILATION PROBLEMS BASEMENTS

• Need to Descend
• through Heat and
• Smoke
• Blocked or
• Secured Outside Entrances
• Difficulty of Using
• Natural Ventilation

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VENTILATION PROBLEMS WINDOWLESS BUILDINGS

• Late Detection Delaying
• Ventilation and Creating Backdraft Conditions
• Horizontal Ventilation
• Difficult or Impractical
• Usually Require Mechanical Ventilation

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VERTICAL FIRE EXTENSION

• Opening for ventilation purposes before the fire
  is located may spread the fire to areas that
  otherwise would not have been affected

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WAYS IN WHICH VERTICAL FIRE EXTENSION CAN OCCUR

• Through stairwells, elevators, and shafts by
  direct flame contact or by convected air currents
  
• Through partitions and walls and upward between
  the walls by flame contact and convected air
  currents
• Through windows or other outside openings where
  flame extends to other exterior openings and
  enters upper floors

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WAYS IN WHICH VERTICAL FIRE EXTENSION CAN OCCUR

• Through ceilings and floors by conduction of heat
  through beams, pipes, or other objects that
  extend from floor to floor
• Through floor and ceiling openings where sparks
  and burning material fall through to lower floors
  
• By the collapse of floors and roofs

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VENTILATION OPENING LOCATION SIZE FACTORS

• Availability of natural openings
• Fire location
• Building construction
• Wind direction
• Fire phase
• Building condition
• Building contents

• Roof type and condition
• Effects on fire
• Effects on exposures
• Attack crews readiness
• Ability to protect exposures
• Size

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VERTICAL VENTILATION
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VERTICAL VENTILATION

• Opening the roof or existing roof openings to
  allow heated gases and smoke to escape to the
  atmosphere

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PRE-VENTILATION SAFETY PRECAUTIONS

• Consider type of building involved
• Consider location, duration, and extent of fire
• Observe safety precautions
• Identify escape routes
• Select place to ventilate
• Move personnel and tools safely to roof

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SAFETY RESPONSIBILITIES OF THE LEADER ON THE ROOF

• Ensuring that only required openings are made
• Directing efforts to minimize secondary damage
• Coordinating crews efforts with those of
  firefighters inside building
• Ensuring the safety of all personnel assisting in
  opening of building

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SAFETY GUIDELINES FOR VERTICAL VENTILATION

• Observe wind direction in relation to exposures
• Work with wind at your back or side
• Note existence of obstructions or excess weight
  on roof
• Provide a secondary means of escape for roof
  crews
• Take care not to cut main structural supports

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SAFETY GUIDELINES FOR VERTICAL VENTILATION

• Guard the opening to prevent falls
• Evacuate roof promptly when work is complete
• Use lifelines, roof ladders, or other means to
  protect personnel from falling off roof
• Make sure roof ladder (if used) is firmly secured
  over roof peak before operating from it
• Exercise caution in working around electric wires
  and guy wires

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SAFETY GUIDELINES FOR VERTICAL VENTILATION

• Ensure that all personnel on roof are wearing
  full PPE, including SCBA
• Keep out of the range of those handling axes and
  operating power saws
• When using axe, beware of overhead obstructions
  within axe range
• Start power tools on the ground to ensure
  operation always shut off before hoisting or
  carrying to roof
• Angle all cuts away from body

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SAFETY GUIDELINES FOR VERTICAL VENTILATION

• Extend ladders at least five rungs above roof
  line and secure ladder
• Always check roof for structural integrity before
  stepping or jumping onto it
• Use pre-incident plans and surveys to identify
  dangerous roofs supported by lightweight or
  wooden trusses
• Work in groups of at least two, but no more
  people than absolutely necessary to get the job
  done

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SAFETY GUIDELINES FOR VERTICAL VENTILATION

• Know the warning signs of an unsafe roof
• Melting asphalt
• Spongy roof
• Smoke coming from the roof
• Fire coming from the roof

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ROOF TYPES
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ROOF TYPES
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FLAT ROOFS

• Most commonly found on commercial, industrial,
  and apartment buildings
• Structurally similar to the construction of a
  floor that consists of wooden, concrete, or metal
  joists covered with sheathing
• Opened according to construction materials

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OBSTACLES ON FLAT ROOFS

• Satellite dishes
• Electrical and guy wires
• Television antennas
• Heating and air conditioning equipment
• Water towers

• Swimming pools
• Roof gardens
• Clotheslines
• Pet cages
• Existing roof openings

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PITCHED ROOFS

• Are elevated in center and form a pitch to edges
• Require same opening procedures as for a flat
  roof, except for slipping precautions

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ARCHED ROOFS

• Are constructed with or without trusses for
  support
• Are cut similar to flat or pitched roofs, but are
  more difficult because of roof curvature
• Should be ventilated only from an aerial ladder
  or platform extended over roof

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CONCRETE ROOFS

• Are extremely difficult to break if made of
  precast or reinforced concrete avoid opening
  this type
• Can be opened with penetrating tools if
  constructed of lightweight concrete materials

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METAL ROOFS

• Are made from several different kinds of metal
  and constructed in many styles
• Are cut with a power saw, axe, or a large
  sheet-metal cutter

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THE END