VENTILATION

State of GeorgiaBASIC FIRE FIGHTER TRAINING COURSE

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VENTILATION

The planned and systematic release and removal of heated air, smoke, and toxic gases from a confined area and the replacement of these products of combustion with a supply of cooler, fresh air.

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PROPER VENTILATIONAdvantages

Simplifies rescue Reduces flashover

hazards Reduces backdraft

hazards Reduces

mushrooming

Speeds extinguishment

Salvage operations Reduces damage Decreases danger Easier firefighting Confines the fire

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VENTILATION EFFECTS

PROPER Improved visibility Lower temperatures Safer working

conditions

IMPROPER Fire may Spread Potential Backdraft May delay rescue Potentially harmful to

occupants

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TYPES OF VENTILATIONNatural

Vertical Horizontal

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TYPES OF VENTILATIONForced

HydraulicMechanical

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TYPES OF FORCED VENTILATON

Mechanical• Depressurization

• Pressurization

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MECHANICAL VENTILATIONDepressurization

Advantages• effective when others are

not

• ensures positive control

• supplements other methods of ventilation

• may be faster than natural ventilation

• good public relations

Disadvantages• May cause fire to intensify

and spread

• Needs a power source

• Special equipment is required

• Interferes with egress and ingress

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MECHANICAL VENTILATIONPressurization

Disadvantages• Needs a power source

• Special equipment is required

• May cause fire to intensify and spread

Advantages• done without

entering structure

• doesn’t interfere with ingress or egress

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HYDRAULIC VENTILATION

Advantages• requires no special

equipment

• can be performed by the same firefighter

• removes smoke faster than mechanical ventilation

Disadvantages• increase in water

damage

• increases demand on water supply

• freezing of water

• time in is limited

• firefighters may remain in structure

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VENTILATIONConsiderations

Life safety conditions

Building conditions

Fire conditions

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BACKDRAFTEffects

Structural damage

Serious injury

Flying debris

Additional heat or fire damage

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BACKDRAFTPrevention

Control openings

Open slowly

Natural vertical ventilation

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ROOF TYPES

Flat

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ROOF TYPES

Pitched or Gable

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ROOF TYPES

Arched

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VERTICAL VENTILATION Safety Precautions

Wear full protective equipment Determine the safety of the building and roof

• IF UNSAFE … STAY OFF !!! Have a charged hose line ready and in position Coordinate ventilation with other crews Observe wind direction in relation to exposures

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Note the existence of and avoid obstructions or excessive weight on the roof

Extend ladder 3 to 5 rungs above the roof line

Sound the roof for structural integrity before stepping on to it

Provide two means of escape Use life lines, roof ladders or other means to

prevent slipping or falling

VERTICAL VENTILATION Safety Precautions

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Work in groups of two but no more than necessary

Use caution around electrical wires Use tools with caution and beware of others Start power tools on the ground; and shut

off before hoisting Avoid cutting main structural supports

VERTICAL VENTILATION Safety Precautions

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The angle of cut should be away from the body

Guard the opening in the roof

Evacuate the roof when ventilation is complete

Use support members of the structure for travel

VERTICAL VENTILATION Safety Precautions

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Wear full protective equipment Determine the safety of the building Work in groups Provide two means of escape Have a charged hose line ready and in

position to protect exposures Coordinate ventilation with other crews Use caution around electrical wires Use tools with caution.

HORIZONTAL VENTILATION Safety Precautions

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VENTILATION TOOLS

Pike pole

Pick-head axe

Power Saw

Ladders

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NATURAL VERTICAL VENTILATIONProcedure

Determine where to ventilate Ladder 5 rungs above the roofline Deploy roof ladder Locate roof supports Make the opening at least 4’ X 4’ Remove roof materials Cut decking alongside joist Pry up boards Open ceiling below

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NATURAL HORIZONTAL VENTILATION

Procedure

Determine where air is to be channeled Determine where to ventilate Open structure on windward side as low

as possible Open structure on leeward side as high

as possible.

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NATURAL TRENCH VENTILATION

Follow same safety precautions as for vertical ventilation

Determine where the opening is to be made• Ahead of the fire

Cut trench from one exterior wall to the other• 4 feet wide

Use same procedures as for vertical ventilation

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DEPRESSURIZATION VENTILATION

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PRESSURIZED VENTILATION

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HYDRAULIC VENTILATION