Refresher_ _Ventilation_Basics by 2rwZZG

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									Refresher - Ventilation Basics
   Brantley County Fire Departments
            Monthly Training
  Conducted by the Atkinson Volunteer
            Fire Department
                July 2008
              Welcome
• Introductions
• Housekeeping




July, 2008    Atkinson Volunteer Fire Department   2
             Terminal Objective

 The student will demonstrate the principles
   of ventilation, a basic understanding of
building construction, the safety precautions
to be taken when ventilating a structure, and
 how to use the various types of ventilation
    through classroom participation and
                   discussion.


July, 2008       Atkinson Volunteer Fire Department   3
             Enabling Objectives

• Discuss principles of ventilation
• Identify the 5 classifications of building
  construction
• Identify several different roofing styles
• Identify safety precautions that should be
  taken when undertaking ventilation
  operations


July, 2008        Atkinson Volunteer Fire Department   4
             Enabling Objectives

• Discuss different methods of conducting
  ventilation
• Discuss techniques for ventilating different
  structure types and roof styles




July, 2008        Atkinson Volunteer Fire Department   5
Principles of Ventilation
             What is Ventilation?

  The planned, methodical, and systematic
   removal of pressure, heat, smoke, toxic
   gases, and flame from an area through
predetermined paths and the replacement of
     these products with cooler fresh air




July, 2008          Principles of Ventilation   7
             How does it work?

• Heat and smoke rise
• Path of least resistance
• Smoke moves horizontally and vertically –
  mushrooming




July, 2008        Principles of Ventilation   8
             Why do we ventilate?

•   Removal of smoke, heat, and fire gases
•   Improve visibility
•   Reduce potential harm to victims
•   Reduce stress on firefighters
•   Assist with fire control and extinguishment




July, 2008           Principles of Ventilation    9
                   Advantages
• Increased visibility
     – See the victim
     – Find the seat of the fire
• Increased effectiveness of fire attack
• Reduced possibility of flashover or
  backdraft
• Aids in property conservation
     – Small amount of ventilation damage results in
       larger reduction in overall fire damage
July, 2008               Principles of Ventilation   10
             Results Depend On

• Size and type of occupancy
• Extent and location of fire
• Whether fire is free-burning or smoldering




July, 2008         Principles of Ventilation   11
             Ventilation Concerns

• Fire travel by convection – greatest
  firefighting problem
     – May cause exposure fires and additional fires
       in fire structure
• Improper ventilation may increase fire
  spread




July, 2008             Principles of Ventilation   12
                 General Rule

         To open the fire building so that all
       accumulations of heat and combustion
        products leave by means of natural
                    convection




July, 2008             Principles of Ventilation   13
Building Construction
             5 Classifications

•   Type I – Fire Resistive
•   Type II – Noncombustible
•   Type III – Ordinary
•   Type IV – Heavy Timber
•   Type V – Wood Frame




July, 2008          Building Construction   15
             Type I – Fire Resistive

• Made of noncombustible materials
• Structural elements subject to damage by
  heat must be protected by noncombustible
  coverings
• 2 to 4 hour fire resistance rating
• Shopping malls, office buildings, etc…



July, 2008            Building Construction   16
             Type II - Noncombustible

• Made of noncombustible materials
• Structural elements subject to damage by
  heat generally not protected by
  noncombustible coverings
• 0 to 2 hour fire resistance rating
• Warehouses, repair shops, etc…



July, 2008            Building Construction   17
             Type III - Ordinary

• Exterior walls made of noncombustible
  materials
• Interior walls generally made of wood
• 0 to 1 hour fire resistance rating
• “Main Street USA”




July, 2008          Building Construction   18
             Type IV - Heavy Timber

• Exterior walls made of noncombustible
  materials
• Interior structural members made of heavy
  timbers
• Mills




July, 2008            Building Construction   19
             Type V – Wood Frame

• Made of combustible materials
• May have up to 1 hour fire resistance
  rating
• Residential structures
• Most Type V structures built today use
  lightweight construction methods



July, 2008          Building Construction   20
              Roof Styles


•   Hipped               •    Mansard
•   Gable                •    Flat
•   Gambrel              •    Shed
•   Saltbox              •    Arched



July, 2008       Building Construction   21
             Hipped Roof - Simple

• All four sloping
  sides meet at a
  ridge across the
  top. Front slope
  is usually
  broader than the
  side sections




July, 2008           Building Construction   22
             Hipped Roof - Pyramidal


  • All four sloping
    sides come to a
    point at the top
    of the roof




July, 2008             Building Construction   23
                      Gable

• Two flat slopes that
  are joined together to
  form a ridge, thus
  creating a peak or
  triangle on the wall of
  the front façade




July, 2008             Building Construction   24
                  Gambrel


• Each side has two
  slopes; a steeper
  lower slope and a
  flatter upper one;
  associated with barns




July, 2008           Building Construction   25
                    Flat



• Contains no slope.
  May or may not have
  eaves




July, 2008         Building Construction   26
                   Saltbox


• A gabled roof with
  asymmetrical sides. It
  is said to resemble an
  eighteenth century
  salt box




July, 2008            Building Construction   27
                  Mansard


• A roof forming a
  double slope, two
  slopes on each of the
  four sides. The lower
  slope being steeper
  than the other




July, 2008           Building Construction   28
                       Shed


• One high pitched
  plane covering the
  entire structure.
  Often used for
  additions and
  porches




July, 2008             Building Construction   29
                   Arched

• Roof that curves from
  wall to wall, may go
  completely from
  ground to ground.
  Used in aircraft
  hangers, bowling
  alleys, and older
  grocery stores


July, 2008           Building Construction   30
             Roof Construction

• Rafter and beam
• Lightweight wooden truss
• Steel truss




July, 2008         Building Construction   31
             Lightweight Wood Truss
• Engineered with lumber sized smaller than
  traditional dimensional lumber
• Accounts for over 60% of all new construction
• Very short life expectancy when exposed to fire




July, 2008            Building Construction         32
             Lightweight Wood Truss



• Held together with
  gusset plates
  instead of nails




July, 2008             Building Construction   33
Safety Precautions
             Safety Precautions
• Always wear full PPE, to include SCBA
• Always vent at highest point possible
• Have hoselines in place to make interior
  attack
• Work with wind at back or side
• Never flow water into vent hole with
  personnel inside building
• Check roof stability before starting
  operations
July, 2008          Safety Precautions       35
             Safety Precautions

• Restrict number of personnel to minimum
  needed to accomplish task
• Work from roof ladder when cutting hole
• Watch out for overhead power lines
• Have secondary escape routes in place
• Check equipment before going on roof
• Do not cut main structural supports

July, 2008          Safety Precautions      36
             Safety Precautions

• Watch out for unsafe or deteriorating
  conditions
• Note and avoid any existing dead loads or
  obstructions
• Maintain communications
• Remove crew from roof when vent
  operations concluded


July, 2008          Safety Precautions    37
             Lightweight Construction

• Notify IC when lightweight truss
  construction found
• Avoid working around areas with roof
  mounted equipment
• Always expect imminent collapse when
  lightweight truss construction is being
  impinged by fire
• Work off of aerial ladders where possible

July, 2008             Safety Precautions     38
                 Backdraft



      Sudden violent reignition of a closed
     compartment fire when a new source of
             oxygen is introduced




July, 2008           Safety Precautions       39
             Backdraft Signs

• Smoke visible, but no flames
• Yellowish colored smoke
• Windows darkened over
• Smoke puffing from openings (breathing
  building)
• Smoke under pressure



July, 2008        Safety Precautions       40
                 Rollover



    Smoke and fire gases advancing along a
        ceiling until stopped by walls




July, 2008          Safety Precautions       41
                Flashover



• The sudden rapid ignition of all contents of
  a room or area
• Seconds to escape




July, 2008          Safety Precautions       42
             Flashover Signs

• Rollover progressing close to floor
• Large amounts of flame and heat with little
  smoke
• Tunnel Effect




July, 2008          Safety Precautions      43
                What Can Go Wrong

• Fatality
     – September 14, 2002
             • A firefighter died after falling through roof while
               observing another firefighter conducting ventilation
               operations. The deceased firefighter was not
               wearing SCBA.
                – Source – NIOSH Fatality Assessment and Control
                  Evaluation Investigation Report 2002-40




July, 2008                       Safety Precautions                44
                What Can Go Wrong

• Near Miss
     – March 1, 2003
             • Firefighters were conducting search operations in
               low attic when one firefighter felt a jerk to his
               helmet. The firefighter immediately dropped to the
               floor and the interior crew exited the building.
               Observation of struck firefighter’s helmet revealed
               where chainsaw from vent operations struck him.
                – Source – National Firefighter Near Miss Reporting
                  System Report 05-0000339



July, 2008                         Safety Precautions                 45
                What Can Go Wrong

• Near Miss
     – January 13, 2007
             • Firefighters were conducting trench ventilation
               operations on a church made from lightweight
               truss construction. Personnel were operating from
               an aerial ladder when 40 feet of roof collapsed,
               sending a 30 foot fireball into the sky.
                – Source – National Firefighter Near Miss Reporting
                  System Report 07-0000726




July, 2008                         Safety Precautions                 46
                What Can Go Wrong

• Near Miss
     – December 19, 2005
             • Firefighters were conducting vent operations on an
               ice covered roof and were having trouble getting
               back to their ladders. Personnel from a
               neighboring department were able to move an
               aerial ladder to the crew to aid in exiting roof.
                – Source – National Firefighter Near Miss Reporting
                  System Report 07-0000854




July, 2008                         Safety Precautions                 47
                What Can Go Wrong

• Near Miss
     – December 7, 2007
             • Firefighters were conducting training on ventilation
               operations when the chain and chain guide came
               off chainsaw.
                – Source – National Firefighter Near Miss Reporting
                  System Report 07-0001157




July, 2008                         Safety Precautions                 48
Ventilation Methods
             Direction of Travel

• Horizontal
• Vertical




July, 2008          Ventilation Methods   50
             Horizontal Ventilation

• Uses natural
  openings in
  occupancy
• Doors and windows
• Effective in
  basements and high
  rise structures



July, 2008            Ventilation Methods   51
             Horizontal Ventilation

• Technique
     – Open leeward side openings first, highest
       point possible
     – Open windward side openings next, lowest
       point
     – Coordinate openings used with Command
     – Select openings used with future ventilation
       operations in mind


July, 2008              Ventilation Methods           52
             Horizontal Ventilation

• Advantages
     – Quick to deploy
     – Minimal effort to conduct
     – Relatively Safe




July, 2008               Ventilation Methods   53
             Horizontal Ventilation

• Disadvantages
     – Limited to natural openings
     – Access to openings may be hindered
     – Does not use natural flow of heat and smoke
     – May change dynamics of fire attack
     – May cause increase in fire spread
     – Can be affected by prevailing weather
       conditions


July, 2008              Ventilation Methods          54
             Vertical Ventilation

• Considered most
  effective avenue to
  exhaust smoke and
  fire gases
• Openings made
  above fire
• Highest point closest
  to fire


July, 2008            Ventilation Methods   55
             Vertical Ventilation

• Technique
     – Utilize existing openings first
     – Consider using stairwells and shafts
     – When creating opening, make one large
       opening rather than several small openings
     – Get off roof when completed




July, 2008              Ventilation Methods         56
             Vertical Ventilation

• Advantages
     – Allows heat and smoke to follow natural
       movement pattern
     – Best for reducing potential for backdraft
     – Can assist in localizing fire due to ventilation
       hole placement




July, 2008                Ventilation Methods             57
             Vertical Ventilation

• Disadvantages
     – Time Consuming
     – Inherently dangerous
     – Equipment malfunctions
     – Building construction




July, 2008             Ventilation Methods   58
             Ventilation Methods

• Natural
• Mechanical
• Hydraulic




July, 2008          Ventilation Methods   59
             Natural Ventilation

• Uses existing air flow and convection
  currents
• Openings may be existing or created
• Horizontal or Vertical




July, 2008          Ventilation Methods   60
             Mechanical Ventilation

• Negative pressure
• Positive pressure




July, 2008            Ventilation Methods   61
             Mechanical Ventilation

• Negative Pressure
     – Pulling smoke and fire
       gases out of
       occupancy through
       use of a vacuum
       condition




July, 2008                 Ventilation Methods   62
             Mechanical Ventilation

• Negative Pressure – Technique
     – Horizontal ventilation style
     – Fan Placement
     – Supplements other ventilation methods




July, 2008             Ventilation Methods     63
             Mechanical Ventilation

• Negative Pressure – Advantages
     – Effective when other methods are not
     – Helps maintain positive control of operations
     – Supplements other ventilation directions and
       methods
     – Can be faster than natural ventilation
     – Applicable to all types of structures
     – Reduces churning of air in structure


July, 2008              Ventilation Methods            64
             Mechanical Ventilation

• Negative Pressure – Disadvantages
     – May cause fire to spread and intensify
     – Needs external power source
     – Can interfere with ingress and egress to
       structure
     – Requires firefighter to stand during placement
     – Requires opening to be sealed around fan



July, 2008              Ventilation Methods         65
             Mechanical Ventilation
• Positive Pressure
   – Pushing smoke and
     gases out by creating
     an overpressure
     condition inside
     occupancy
   – Considered the current
     method of choice for
     horizontal ventilation




July, 2008                Ventilation Methods   66
             Mechanical Ventilation

• Positive Pressure – Technique
     – Horizontal ventilation style
     – Fan Placement
     – Exhaust opening near seat of fire
     – Close off areas not to be vented
     – Most effective when doors and windows still
       intact



July, 2008              Ventilation Methods          67
             Mechanical Ventilation

• Positive Pressure - Advantages
     – Method of choice
     – Does not interfere with ingress or egress
     – Quick set-up
     – Does not require entry into occupancy
     – Does not require explosion proof fans
     – Does not require gases to pass through fan



July, 2008              Ventilation Methods         68
             Mechanical Ventilation

• Positive Pressure – Disadvantages
     – Requires special equipment
     – May cause fire spread
     – Noise
     – Must have preexisting air flow path




July, 2008              Ventilation Methods   69
             Hydraulic Ventilation


• Utilizes Venturi
  Principle to create
  vacuum which pulls
  smoke and fire gases
  out of occupancy




July, 2008           Ventilation Methods   70
             Hydraulic Ventilation

• Technique
     – 30 degree fog pattern on nozzle
     – Cover at least 85% of window
     – Leave window corners open
     – Nozzle should be at least 2 feet from window




July, 2008              Ventilation Methods           71
             Hydraulic Ventilation

• Advantages
     – Rapid to deploy
     – Minimal equipment requirements
     – Effective in any occupancy type




July, 2008             Ventilation Methods   72
             Hydraulic Ventilation

• Disadvantages
     – Water Usage
     – Water Damage




July, 2008            Ventilation Methods   73
Ventilation Techniques
             Horizontal Ventilation


• Step 1
     – Position yourself
       to the side of the
       opening selected
       to be removed




July, 2008                  Ventilation Techniques   75
             Horizontal Ventilation



• Step 2
     – Maintain control
       of tool and break
       window at highest
       point reachable




July, 2008                 Ventilation Techniques   76
             Horizontal Ventilation



• Step 3
     – Remove rest of
       glass in window




July, 2008               Ventilation Techniques   77
             Horizontal Ventilation




July, 2008           Ventilation Techniques   78
             Mechanical Ventilation
• Negative Pressure
     – Secure fan at top of
       opening
     – Seal rest of opening
     – Remove all drapes,
       shades, etc… from
       around opening
     – Check direction of
       exhaust before
       starting


July, 2008                Ventilation Techniques   79
             Mechanical Ventilation

• Positive Pressure – Single Fan
     – Ensure fan is ready for operation prior to
       placement at opening
     – Have fan at ventilation point running at idle
     – When called for, increase speed of fan
     – Position fan 6 to 10 feet from opening
     – Ensure discharge opening is smaller than fan
       opening


July, 2008             Ventilation Techniques      80
             Mechanical Ventilation

• Positive Pressure – Single fan




July, 2008           Ventilation Techniques   81
               Mechanical Ventilation

• Positive Pressure – Multiple Fans
     – Fans Side by Side
             • Double Doors
             • Large Windows
             • 6 to 10 feet from opening
     – Fans Stacked
             • First fan 3 to 5 feet from opening
             • Second fan 6 to 10 feet from opening



July, 2008                     Ventilation Techniques   82
             Mechanical Ventilation

• Positive Pressure – Multiple Fans stacked




July, 2008           Ventilation Techniques   83
             Vertical Ventilation

• Pre-existing openings
• Created openings




July, 2008          Ventilation Techniques   84
             Vertical Ventilation

• Pre-existing openings
     – Skylights
     – Stairwell or Elevator shafts
     – Scuttle hatches
     – Attic vents




July, 2008              Ventilation Techniques   85
                  Vertical Ventilation

• Tools Needed
     – Pike pole, 6 foot minimum
     – Pick head axe
     – Power saw
             • Chainsaw with depth gauge
             • Rotary saw
     – Ladders
     – Charged hoseline


July, 2008                    Ventilation Techniques   86
                   Vertical Ventilation

• General Procedure
     – Determine where to ventilate
             • As close to fire as possible
             • Highest point possible
     – Extend ladder 3 to 5 rungs above roof edge
     – Sound roof
     – Deploy roof ladder
     – Sound to determine roof supports


July, 2008                      Ventilation Techniques   87
                     Vertical Ventilation

• General Procedure – con’t
     – Mark out location for opening
     – Remove roofing material (shingles, etc…)
     – Cut opening, 4x4 feet in size
             •   Furthest cut
             •   Top cut
             •   Bottom cut
             •   Closest cut
     – Pry up cut material

July, 2008                      Ventilation Techniques   88
             Vertical Ventilation

• General Procedure – con’t
     – Inform Command when ready to open ceiling
       below opening
     – Open ceiling when ordered to
     – EXIT ROOF when done




July, 2008            Ventilation Techniques       89
             Vertical Ventilation

• Safety concerns
     – WEAR ALL PPE
     – Ensure roof stability BEFORE getting on roof
     – 2 means of egress from roof
     – Minimum personnel needed
     – DO NOT flow water into opening
     – Notify Command if lightweight truss
       construction discovered


July, 2008             Ventilation Techniques         90
             Vertical Ventilation

• Safety concerns – con’t
     – Work with wind at back or side
     – Use ladders or other means to keep from
       sliding off roof
     – Be aware of electrical lines and antennas
     – Do not carry running power tools up ladder




July, 2008             Ventilation Techniques       91
             Trench Ventilation
• Defensive
  tactic used to
  stop fire
  spread
• Very labor
  intensive
• Cut is 4 feet
  wide going
  from roof edge
  to roof edge
July, 2008         Ventilation Techniques   92
Ventilation Specifics
             1 or 2 Family Dwelling

• Numerous roof styles and designs
• Most new houses are lightweight
  construction
• May have basements
• Can be multiple stories
• May or may not have sprinklers



July, 2008            Ventilation Specifics   94
             1 or 2 Family Dwelling

• General method of choice
     – Horizontal (Natural/Mechanical)
• Basement fires
     – Consider cutting first floor over fire and near
       window
     – Vent basement with PPV from exterior
       basement entrance



July, 2008               Ventilation Specifics           95
               1 or 2 Family Dwelling

• Attic Fires
     – Verify type of construction if possible
     – Attack from below if safe to do so
     – Horizontally vent using gable vents or attic
       vents
             • Pull vents from aerial if possible




July, 2008                       Ventilation Specifics   96
             1 or 2 Family Dwelling

• Vent while making entry
• Coordinate with Command concerning
  openings to ventilate
• Open only where necessary when
  necessary




July, 2008            Ventilation Specifics   97
             Multiple Family Dwelling

•   Multiple construction methods
•   Multiple roof styles
•   Multiple stories
•   Larger fire load
•   May be sprinklered
•   Lightweight construction becoming more
    prevalent

July, 2008             Ventilation Specifics   98
             Multiple Family Dwelling

• General method of choice
     – Dependent on construction type
     – Dependent on fire floor
             • Horizontal for lower floors
             • Vertical for upper floors




July, 2008                       Ventilation Specifics   99
             Multiple Family Dwelling

• Open cockloft fire
     – Open existing openings first
     – Consider trench cut to stop fire movement




July, 2008              Ventilation Specifics      100
             Commercial Building

•   Come in all shapes and sizes
•   Can fall into any construction classification
•   Generally large square footage
•   Most have flat roofs
•   May or may not be sprinklered
•   Generally have multiple stories



July, 2008            Ventilation Specifics    101
             Commercial Building

• Be aware of
     – Dead loads on roof
     – Unprotected structural members
     – Lightweight construction methods
     – Concrete roofs




July, 2008             Ventilation Specifics   102
                 Commercial Building

• Ventilation method will depend on fire
  location and construction classification
• When venting roof
     – Use existing openings first
             • Skylights
             • Elevator shafts
             • Stairwells
• Preplan

July, 2008                       Ventilation Specifics   103
             Shopping Centers

• Assume no fire stop in place
• Avoid spongy or sagging sections of roof
• Use existing openings first
• Be aware of roof attachments and
  overhangs
• As last resort cut roof openings



July, 2008         Ventilation Specifics     104
             Fire Resistive Structures

• Windows are opening of choice
• Building may have fire pressurization or
  smoke removal system in place
• Preplan




July, 2008             Ventilation Specifics   105
                  Size Up

•   Which ventilation method will work best
•   Are resources available
•   What are fire conditions
•   Where is the fire
•   Is roof stable enough
•   How long will it last



July, 2008           Ventilation Specifics    106
               Pitched Roofs

• Can go from very shallow to very steep
• Generally covered with asphalt shingles
     – May also have wooden shakes, metal sheets,
       or clay or ceramic tile
• Most common pitch roof style is gable
• Most newer structures are constructed of
  lightweight construction


July, 2008             Ventilation Specifics   107
                 Pitched Roofs

• Use roof ladder regardless of pitch
     – Use aerial if pitch too steep
• Tool of choice
     – Chainsaw
• Full PPE




July, 2008               Ventilation Specifics   108
               Mansard Roof

• Variable pitch
     – Traditional Mansard has 2 angles
     – Modern Mansard has steep side and flat
       center
• Generally covered with shingles on angles
  and tar and gravel on flat portions
• Large open voids under roof
• Work off aerial if roof ventilation is needed

July, 2008             Ventilation Specifics    109
               Flat Roof

• Generally seen in multi occupancy type
  structures
• Often have large dead loads
• Tar and Gravel over Concrete
• Use existing openings rather than cut new
  ones
• Preplan


July, 2008         Ventilation Specifics   110
                   Problems

• Steel Plating
     – Placed over existing roof openings
     – May cover entire roof
• Covered Windows
     – Steel grating
     – Masonry block
• Roll up security gates


July, 2008              Ventilation Specifics   111
Questions???

								
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