Ventilation

1. Ventilation

2. Goal Given information on ventilation the firefighter will be able to identify when and where to safely apply ventilation so that heat, smoke, and gases can be removed from a structure to improve conditions for fireground operations. This will be done to a written test accuracy of 75% and complete the practical evolutions in the allotted time to the instructor’s satisfaction.

3. 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.

4. Objectives Con’t • Know the the different tools used for ventilation. • Understand the compilations of ventilation • Have an understanding of positive and negative pressure ventilation. • Know how to explain and perform vertical ventilation.

5. Objectives Con’t • Know how to explain and perform natural ventilation. • Know how to explain and perform horizontal ventilation.

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

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

8. 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

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

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

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

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

13. Ventilation ? Where When How

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

15. 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.

16. 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

17. Types of Ventilation • Natural • Horizontal • Vertical • Mechanical

18. Natural Ventilation – The means of ventilating a structure without the assistance of powered equipment.

19. Natural Ventilation • Wind. • Currents created by the fire. Use Caution!!!

20. Horizontal Ventilation – Is the venting of heat, smoke and gases through wall openings such as windows and doors.

22. Horizontal Ventilation Uses: • Residential • Multistoried structures • Large unsupported open spaces.

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

24. Natural Opening • Sky lights • Scuttle Hatches • Windows • Doors • Shafts • Ventilators • Stairways

25. 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

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

28. Mechanical Ventilation (Forced) – The means of ventilating a structure with the assistance of powered equipment. Positive-pressure ventilation (PPV), and Negative-pressure ventilation (NPV)

30. Positive-pressure ventilation (PPV) • Induces fresh air into a confined area or structure resulting in an increase of pressure in that area which forces contaminated air through pre-selected and/or controlled openings • Must coordinate with operation, and attack crews

31. PPV Advantages • Two times more effective than NPV • Does not block doorways • Does not expose personnel to contaminants while positioning blower • Provides fresh air, reduces heat, and CARBONMONOXIDE during overhaul operations

32. Disadvantages • Noisy • Not effective if there are to many openings • Can cause fire spread, or ignite smoldering embers • Raise CO levels with gas fans.

33. PPV Fan Placement • A single fan should be placed so the cone of pressurized air JUST covers the opening • Tilting the fan back about 20-30-degrees will enhance the operation • Square box type fans can be stacked to achieve the same effect.( one fan on top of the other)

34. Single unit operation Exhaust opening should b ¾’s to twice the size of entrance EXHAUST PATH Back far enough to seal the opening

35. YES! If you don’t have standard PPV blowers on your apparatus, simply use NPV devices and stack them on top of each other, then reverse their positioning placing exhaust side in. - SMOKE EJECTORS -

36. PPV Fan Placement • Two fans one in front of the other (series, tandem, or in line) • Front fan (Largest) about 2 feet from opening, and the back fan will be set back far enough to cover the opening with pressurized air • Two or more fans side by side(parallel or dual) • Fans should sit side by side and back far enough to cover the opening with pressurized air

37. Series, tandem, or in-line EXHAUST Positive Pressure DISTANCE 2-3 feet Larger Fan Back far enough to seal the opening

38. Parallel or dual

39. Exhaust opening • Most effective when the exhaust opening is three quarters to two times the size of the entrance opening. • Varies do to size of the fan or the amount of fans operating. • Optimum efficiency is easily obtained by a combination of training and practical experience.

40. Determine PPV fan Size for a Given Structure • Apply the PPV Rule of Thumb - Single family dwelling with up to 2,000 square feet: 18- to 21-inch fans - Ranchers and multistory dwellings up to 4,000 square feet: 24-inch fan - Larger structures (greater than 4,000 square feet) require multiple fan application with 2 to 3 24-inch fans - Always use multiple fans on high-rise structures 10 floors or greater

41. Negative-pressure ventilation • Draws contaminates from interior to the exterior causing a negative-pressure in the contaminated area allowing fresh air to enter from an outside source through another opening.

42. Advantages • Usually operates off of a 110 volt • Usually explosion-proof motor

43. Disadvantages • Exposes personnel to the contaminated area • Placement in doorways and windows require hangers, straps or other accessories to position them effectively • Block entrances and hallways • Contaminates are drawn through the fan causing additional cleanup and maintenance

44. Mechanical Devices • Gas Fan • Electric Fan • Mobile units • HVAC systems • Exhaust Systems • Hose steams (Hydraulic)

45. Gas Fans • 2-cycle and 4-cycle engines • 18 to 24 inch in diameter • 3200 to 15,000 CFM • Many different manufactures and styles • Maintenance ( Gas, oil, and air filters ) • Can cause CO levels to rise in structure

46. Electric Fans • Both PPV and NPV • Require electric cords • NPV fans sizes 16 to 24 inch, from 2 to 3 hp • Square or circular encased, including motor • PPV fans are 18 to 24 inch, from 3200 to 30,000 CFM

47. Mobile ventilation units • Diesel • PTO • Hydraulic • 30,000 to 211,000 CFM

48. HVAC Systems • Some are designed to reverse to draw out contaminated air from buildings • Maintenance personnel from building will provide that information • If unsure Turn units off. • Preplanning

49. Exhaust Systems • Some buildings have systems in place for other uses. • Maintenance personnel from building will provide that information • Preplanning

50. Hose Stream (Hydraulic)