VentilationObjectives The student will:• Understand the importance of

ventilation.• Be able to identify when and where to

ventilate. • Understand the dangers of ventilation.• Be able to identify the different types of

roof construction.

Ventilation

Objectives Con’t• Know the different tools used for

ventilation. • Know how to explain and perform

vertical ventilation.

Ventilation

Overview• Importance of ventilation• Different techniques • Advantages and disadvantages• Precautions and dangers • Roof Types, and their construction• Tools needed for ventilation

Ventilation

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

Ventilation

Ventilation

Advantages• Rescue• Increases survivability of trapped victims• Improves visibility, and reduces heat

levels• Reduction of flashover and backdraft

potential• Fire attack• Fire spread control• Property Conservation

VentilationDisadvantages or Improper Ventilation• Fire spread• Accelerated burning• Puts firefighters in danger• Triggers Backdraft• Structural Integrity

VentilationDangers of ventilations• Light weight construction.• Can cause fire to intensify and spread.• Places firefighters in danger.• Backdrafts.• Weather conditions.

Ventilation

Complications• Lack of Pre-planning• Barred/Screen windows.• Overhead obstructions.• Access• Weather• Improper equipment• Man power

VentilationComplications (Con’t)• Visibility• Roof pitch/type

VentilationPerform Initial Size-up

• Life Safety• Conventional or Lightweight

Construction• Determine type and style of roof• Location/Extension of fire• Weather conditions• Does the roof look safe (risk vs benefit)

VentilationConventional Construction

• Size of structural members = strength

VentilationLight weight Construction

• Trusses• Members are under compression and

tension• Size of individual members are small• If one member fails, other members may

fail

VentilationSafety Considerations

• Minimum of two ladders for egress• Approach from uninvolved• Ladder strong areas of the roof• Ladder extended 5 rungs above roof line• Shut down saws before climbing• Minimum of 2 firefighters

VentilationSafety considerations Cont.

• Full PPE/SCBA• Utilize Portable Radio• Sound the roof!!!!!!• Watch out for guy wires/electrical wires• Coordinate cut with command• Keep the wind at your back• Work from weak to strong area of roof

VentilationSafety considerations Cont.• Always know your egress routs• Perform ongoing size-up• Only cut as deep as necessary• Do not cut structural supports• Cut away from your body• Make the cut as close over the fire as

possible

VentilationSafetyConsiderations Cont.

• Advise command when ventilation is complete

• Exit roof ASAP

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How

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VentilationVentilation Size-up • Is there a need. (Why)

• Where is it needed. (Where)

• Type needed. (How)

• Structural conditions allow for safe operations.

Timing (When)

VentilationCoordinated Fire Attack

• Vent as close to the point of origin as possible coordinating with interior attack crew.• Hose line ready and charged while

firefighters are advancing.• Ventilation of the fire room with outside

vent person.

Primary Consideration

RESCUE OR SUPPRESSION

PRIORITY WITH INTERIOR ATTACK

To keep smoke, heat, and gases away from

victim.

To reduce heat and Increase visibility

For firefighters

VentilationVertical Ventilation Opening the roof or using existing roof

opening to allow heated gases and smoke to escape.

Ventilation

Roof openings• Cut large opening

– Minimum 4’x4’– Windward side

• Smaller openings– May be necessary do to conditions

• Trench cut– From Exterior wall to exterior wall– 4’ wide

VentilationVertical Ventilation• Uses:• Attics• Areas open to the roof

Ventilation

Ventilation

VentilationRoof Construction• Lightweight wood or metal joist• Heavy steel trusses• Wood “I” beams• Built-up roof• Concrete Roofs• Metal roofs

VentilationLightweight wood or metal trusses• Trusses in place of rafters• Wood or metal decking• Built-up roof• Allows horizontal fire spread • Fails after 5-10 minutes of fire exposure

VentilationHeavy steel trusses• Metal decking with built-up roof• Starts to fail at 1000 degrees

Ventilation

Wood “I” beams• Substitute for lightweight trusses• Contributes fuel to the fire• Fails within 5 to 10 minutes of fire

exposure

Ventilation

Concrete roofs• Precast concrete• Lightweight concrete• Reinforced concrete• To vent this type is difficult and time consuming• Use natural openings, skylights, scuttles,

ventilators, stairwells

Ventilation

Metal roofs• Light-gauge steel• Corrugated galvanized sheet metal• Aluminum• Vent with power saws using metal cutting

blades, axe, or sheet metal cutters.• Use natural openings

Ventilation

Flat Roof• Industrial, commercial, and apartment

buildings• Frequently pierced by chimneys, vent

pipes, shafts, scuttles, and skylights• May be surrounded and or divided by

parapets• May have HVAC unit on them

VentilationFlat roof construction• Wooden, metal, or concrete joist• Wooden or metal decking• Waterproof materials, insulation, gravel• Reinforced, lightweight concrete, or

precast concrete

VentilationBuilt-up roof construction

OR PLYWOOD

GRAVEL

Ventilation

Built-up Roof• Opening built-up roof

– Remove gravel if present– Make inspection cut– Cut insulation and composition down to

decking– Remove materials, sound roof for rafters or

bar joist, then cut decking and remove.– Be careful not to cut to deep to avoid causing

structural damage to the rafters

Ventilation

VentilationOpening a flat roof • Determining the location of the opening

– Location and extent of fire – Wind direction– Exposures– Obstructions

• Open using the built-up roof method.

Ventilation

Pitched Roofs• Rafters or trusses• 1X boards or plywood sheeting• Felt paper• Shingles- wood, asbestos, composition,

metal, slate or terracotta tile.• May be gypsum slabs, approximately 2”

thick, laid between metal trusses.

Ventilation

VentilationOpening a pitched roof• Determine the location of the opening

same as flat roof• Place roof ladder on the windward side

of opening• Locate the rafters• Cut opening working the farthest

distance from you towards yourself• Remove the decking• Push a tool into the hole to open a

possible ceiling below

Ventilation

Arched Roofs• Bowstring truss• Trussless arched roof• Lamella roof

Ventilation

VentilationOpening an arched roof

• Cutting is the same as a pitched roof• Use of a roof ladder would be unlikely• Because of the potential for sudden collapse

under fire conditions, roof operation should be done from an aerial ladder or tower.

Ventilation

Hand tools• Axe• Halligan bar• Pike poles• Sledge hammer• Ladders

Ventilation

Power tools• Vent saws• Chain saws• Circle saws• Reciprocating saws

Ventilation

Power tool safety• Proper maintenance• Know tool operations and capabilities• PPE• Start tool before taking to operational

area• Never carry, hoist, or climb while

running• Keep front arm stiff while operating tools• Work with a partner

Ventilation

Review• Discussed the importance of ventilation• Discussed the advantages and disadvantages

of ventilation• Discussed precautions and dangers of

ventilation• Discussed the different types of roofs, and their

construction• Discussed the tools needed for ventilation