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Ventilation

Ventilation. Objectives 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. Objectives Con’t.

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Ventilation

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  1. Ventilation

  2. Objectives 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.

  3. Objectives Con’t • Know the different tools used for ventilation. • Know how to explain and perform vertical ventilation.

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

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

  6. 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

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

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

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

  10. Complications (Con’t) • Visibility • Roof pitch/type

  11. Perform 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)

  12. Conventional Construction • Size of structural members = strength

  13. Light weight Construction • Trusses • Members are under compression and tension • Size of individual members are small • If one member fails, other members may fail

  14. Safety 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

  15. Safety 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

  16. Safety 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

  17. SafetyConsiderations Cont. • Advise command when ventilation is complete • Exit roof ASAP

  18. Ventilation ? Where When How

  19. Ventilation Size-up • Is there a need. (Why) • Where is it needed. (Where) • Type needed. (How) • Structural conditions allow for safe operations. Timing (When)

  20. Coordinated 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.

  21. 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

  22. Vertical Ventilation Opening the roof or using existing roof opening to allow heated gases and smoke to escape.

  23. 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

  24. Vertical Ventilation • Uses: • Attics • Areas open to the roof

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

  26. Lightweight 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

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

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

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

  30. 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

  31. 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

  32. Flat roof construction • Wooden, metal, or concrete joist • Wooden or metal decking • Waterproof materials, insulation, gravel • Reinforced, lightweight concrete, or precast concrete

  33. Built-up roof construction GRAVEL OR PLYWOOD

  34. 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

  35. Opening 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.

  36. 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.

  37. Opening 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

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

  39. Opening 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.

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

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

  42. 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

  43. 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

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