Fundamentals of Fire Fighter Skills by Y57f2Z

VIEWS: 5 PAGES: 53

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Wildland and
Ground Fires
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          Objectives     (1 of 3)


• Define the terms wildland and ground
  fires.
• Define light fuels, heavy fuels,
  subsurface fuels, surface fuels, and
  aerial fuels.
• Describe how weather factors and
  topography influence the growth of
  wildland fires.

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          Objectives     (2 of 3)


• Define the parts of a wildland and
  ground fire.
• Describe how wildland and ground fires
  can be suppressed.
• List the hazards associated with
  wildland and ground firefighting.


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          Objectives     (3 of 3)


• Describe the personal protective
  equipment needed for wildland
  firefighting.
• Explain the problems created by the
  wildland urban interface.




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 What are Wildland Fires?                  (1 of 3)


• Defined by NFPA:
  – Unplanned and uncontrolled fires burning
    in vegetative fuel that sometimes includes
    structures.
     • Can consume grasslands, brush, and trees of
       all sizes
     • Incidence varies from season to season.
• Referred to by different terminology

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 What are Wildland Fires?                (2 of 3)


• Ground cover fires burn loose debris on the
  surface of the ground.
• Some fire departments respond to more
  wildland and ground fires than to structural
  fires.
• Many structural fire fighters are called on to
  extinguish wildland and ground fires at some
  point.
  – Must have proper training


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 What are Wildland Fires?               (3 of 3)


• Large wildland fires are handled by
  specialized agencies.
  – Each state has an agency designated to
    coordinate wildland firefighting.
  – There are federal agencies that are
    responsible for coordinating firefighting
    activities at large incidents.


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Wildland and Ground Fires and
       the Fire Triangle
• Wildland and ground fires require the same
  three elements as structural fires.
  – Fuel, oxygen, and heat
• In wildland and ground fires the conditions
  under which fuel, oxygen, and heat come
  together to produce a fire are different.
• Weather conditions have a great impact on
  wildland fire behavior.


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The Wildland Fire Triangle




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              Fuel (1 of 2)
• Primary fuel is area vegetation.
• Amount of fuel in an area ranges from
  sparse grass to heavy underbrush and
  large trees.
• Some fuels ignite readily and burn
  rapidly when dry.
• Others are harder to ignite and burn
  more slowly.

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                Fuel (2 of 2)

• Vegetative fuels can be located:
  – Under the ground (roots)
  – On the surface (grass and fallen leaves)
  – Above the ground (tree branches)




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              Fine Fuels
• Includes dried vegetation such as twigs,
  leaves, needles, grass, moss, and light
  brush
• Ground duff
  – Partly decomposed organic material on a
    forest floor
• Main type of fuel in ground cover fires
• Aid the ignition of heavier fuels

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                 Heavy Fuels
• Includes large brush, heavy timber, stumps,
  branches, and dead timber on the ground
• Slash
   – Consists of the leftovers of a logging operation
• Do not spread a fire as rapidly as fine fuels
• Can burn with a high intensity




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         Subsurface Fuels

• Located under the ground
• Roots, moss, duff, and decomposed
  stumps
• Fires involving subsurface fuels are
  hard to locate and extinguish.



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            Surface Fuels

• Located close to the surface of the
  ground
• Include grass, leaves, twigs, needles,
  small trees, and slash
• Brush less than 6' above the ground
• Sometimes called ground fuels
• Involved in ground cover fires

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               Aerial Fuels

•   Also called canopy fuels
•   Located more than 6’ above the ground
•   Usually trees
•   Includes tree limbs, leaves and needles
    on limbs, and moss attached to the tree
    limbs


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   Other Fuel Characteristics

• May determine how quickly the fuel
  ignites, how rapidly it burns, and how
  readily it spreads to other areas




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      Size and Shape of Fuel

• Size and shape of a fuel influences how
  it burns.
• Fine fuels burn more quickly than heavy
  fuels.
• Requires less heat to reach their ignition
  temperature


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        Fuel Compactness

• Influences the rate at which a fuel will
  burn
• Air cannot circulate in and around fuels
  that are tightly compacted.
• Subsurface fuels burn more slowly than
  aerial fuels.


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             Fuel Continuity
• Refers to the relative closeness of wildland
  fuels
• Are close together or touch each other
• Allows fire to spread from one area of fuel to
  the next
• Have a sufficient supply of air to support rapid
  combustion
• Burn much more rapidly than fuels that are
  compact

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             Fuel Volume

• Refers to the quantity of fuel available in
  a specific area
• Amount of fuel in a given area
  influences the growth and intensity of
  the fire.




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             Fuel Moisture
• Refers to the amount of moisture contained in
  a fuel
• Amount of moisture in a fuel influences the
  speed of ignition, the rate of spread, and the
  intensity of the fire.
• Fuels with high moisture content will not
  ignite and burn as readily.
• Fuel moisture varies with the amount of rain
  that has fallen.

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                Oxygen
• Oxygen is needed.
• Not usually an important variable in the
  ignition or spread of the fire.
• Air movement influences the speed with
  which a fire moves.
• Wind speeds the process of combustion
  and influences the direction the fire
  travels.

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                   Heat
• Sufficient heat must be applied to fuel in
  the presence of adequate oxygen to
  produce a fire.
• Three categories of factors may ignite
  wildland and ground fires:
  – Natural causes
  – Accidental causes
  – Intentional causes

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               Weather

• Weather conditions have a large impact
  on the course of a wildland fire.
• Moisture
• Wind




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            Moisture (1 of 2)

• Relative humidity
  – Ratio of the amount of water vapor present
    in the air compared to the maximum
    amount the air can hold at a given
    temperature
  – A major factor in the behavior of wildland
    and ground fires
  – Varies with the time of day and year

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             Moisture (2 of 2)

• Precipitation
  – Moisture falling from the sky helps to
    increase the relative humidity.
  – Absorbed by plants
     • Makes them less susceptible to combustion
  – When there is adequate precipitation, fire
    risk is lower.


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                   Wind

• Has the ability to move a fire at great
  speed
• Effect of wind on a wildland and ground
  fire is similar to fanning a fire to help it
  burn more rapidly




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            Topography            (1 of 2)

• Refers to the changes of elevation in the
  land, the position of natural, and manmade
  features
• Has a great impact on the fire behavior
• When fires burn on flat land, much of the fire
  heat will rise into the air.
• When the elevation rises in the direction the
  fire is traveling, the fire heat ignites a greater
  quantity of fuel and increases the speed of
  fire spread.

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         Topography        (2 of 2)


• Natural barriers, such as streams and
  lakes, may help contain fires.
• Manmade barriers such as highways
  also make it easier to contain a fire.




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Anatomy of a Wildland Fire                      (1 of 4)

  • Area of origin
     – Location where fires begin
  • Head of the fire
     – Main or running edge of a fire
     – Part of the fire that spreads with the
       greatest speed




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Anatomy of a Wildland Fire                 (2 of 4)


• Heel of the fire or the rear of the fire
  – Side opposite the head of the fire, often
    close to the area of origin
• Finger
  – Narrow point of fire caused by a shift in
    wind or a change in topography
  – Can grow and produce a secondary
    direction of travel for the fire

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Anatomy of a Wildland Fire                (3 of 4)


• Pocket
  – A dangerous place for fire fighters because
    it is an area of unburned fuel surrounded
    on three sides by fire
• Island
  – An unburned area surrounded by fire



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Anatomy of a Wildland Fire                 (4 of 4)


• Spot fire
  – New fire that starts outside areas of the
    main fire
• Green
  – Area of unburned fuels
• Black
  – Areas that have already been burned

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  Methods of Extinguishment

• Cooling the fuel
• Removing the fuel
• Smothering




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     Cooling a Wildland Fire

• Water is used to cool.
  – Backpack pump extinguishers
  – Booster tanks from apparatus
  – Aircraft




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        Removing Fuel         (1 of 2)


• Removal of fine fuels can be
  accomplished with:
  – Fire broom
  – Steel fire rakes
  – McLeod fire tool
• Removal of heavier brush:
  – Adze
  – Pulaski axe

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        Removing Fuel            (2 of 2)


• Sometimes saws are used to remove
  heavy brush and trees from the fire.
  – Hand saws to gasoline powered chainsaws
  – Tractors, plows, and bulldozers
• Backfiring
  – When properly set can burn an area of
    vegetation in front of the fire, thereby
    creating an area devoid of vegetation

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  Removing the Oxygen                (1 of 2)


• Smothering
  – Most commonly used when overhauling
    the last remnants of a wildland and ground
    fire
  – Earth is often thrown on smoldering
    vegetation to prevent flare-ups.
  – Not as useful during the more active
    phases of a fire

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  Removing the Oxygen                (2 of 2)


• Compressed air foam systems (CAFS)
  – Combines foam concentrate, water, and
    compressed air to produce a foam
  – Sticks to vegetation and structures in the
    fire’s path
  – When the heat of the fire reaches the
    foam, it absorbs the heat and breaks down
    the foam.
  – This cools the fuel.

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          Types of Attacks

• Direct attack
• Indirect attack




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            Direct Attacks
• Mounted by containing and
  extinguishing the fire at its burning edge
• Fire fighters might smother the fire with
  dirt, use hoses to apply water to cool
  the fire, or remove fuel.
• Dangerous to fire fighters because they
  must work in smoke and heat close to
  the fire

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           Indirect Attacks
• Most often used for large fires that are too
  dangerous to approach through a direct
  attack
• Mounted by building a fire line
• Can be mounted using hand tools or by using
  mechanized machinery
• Most appropriate when the topography is so
  rough that a direct attack is dangerous or
  impossible

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        Priorities of Attack

• IC must assess and evaluate the
  priorities for preserving lives and
  property before determining how to
  attack a wildland fire.




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Safety in Wildland Firefighting

• Fighting wildland and ground fires is
  hazardous duty.
• Shares many of the hazards of
  structural firefighting plus additional
  hazards:
  – Driving, falls, smoke and fire, and falling
    trees


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Hazards of Wildland Firefighting
                       (1 of 2)

• Driving in rough terrain
  – Risk of rollover
• Working in rough terrain
  – Risk of falls
• Burns and smoke inhalation
  – Wear PPE
  – Use SCBA in conditions where needed

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Hazards of Wildland Firefighting
                      (2 of 2)

• Falling trees
  – Trees of all sizes can fall with little warning.
• Electrical hazards
  – Wires that drop on vegetation may ignite.
  – Difficult to see at night and in smoky
    conditions



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Personal Protective Equipment
• One-piece jumpsuit, or a coat, shirt, and
  trousers
  – Meet the requirements of NFPA 1977
  – Garments should be constructed of a fire-resistant
    material like Nomex®
  – Wear an approved helmet with a protective
    shroud, eye protection, gloves, and protective
    footwear.
  – Respiratory protection
     • Filter mask


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             Fire Shelters

• Lifesaving piece of equipment
• Thin reflective foil layer attached to a
  layer of fiberglass
• Designed to reflect about 95% of a fire’s
  radiant heat for a short period of time
• Fire fighters use their fire shelters when
  unable to reach safety in time.

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 Wildland Urban Interface            (1 of 2)


• The mixing of wildland with developed
  areas
• Creates a massive problem for fire
  departments in many parts of the
  country
• Wildland fires regularly ignite buildings
  and become structure fires.

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 Wildland Urban Interface                    (2 of 2)


• Wildland urban interface
  – Explain the mixing of wildland with developed
    areas
  – Area where undeveloped land with vegetative
    fuels is mixed with manmade structures
• Fires in this zone present a significant life
  safety hazard.
• Many areas do not have adequate municipal
  water systems.

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            Summary        (1 of 2)


• Wildland fires are unplanned and
  uncontrolled fires burning in vegetative
  fuel that sometimes includes structures.
• Fire fighters need to understand the
  factors that cause fire ignition and affect
  the growth and spread of wildland fires.



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           Summary       (2 of 2)


• Growth of the fire is influenced by
  weather factors and by the topography
  of the land.
• Assess and evaluate the priorities for
  preserving lives and property.
• The wildland urban interface creates a
  massive problem for fire departments.

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