CVFD Training – Ventilation Practices

1. CVFD Training – Ventilation Practices SFFMA Training Objectives: 8-01.05 – 8-01.08

2. Vertical Ventilation • Opening roof/existing roof openings for allowing heated gases, smoke to escape • Firefighters must understand basic types, designs of roofs (Continued) Firefighter I

3. Vertical Ventilation • Firefighters must know how roofs in the response areas are constructed (Continued) Firefighter I

4. Vertical Ventilation — Preincident Inspections • Identify • New construction projects • Existing construction • Use of lightweight building materials • Information that can alert firefighters Firefighter I

5. Likelihood of Roof Collapse During Vertical Ventilation • Based on • Volume of fire • How long fire has been burning • Type of construction • Level of protection • Load on roof Firefighter I

6. Responsibilities During Vertical Ventilation — Officer in Charge • Determine it can be done safely, effectively • Consider age, type of construction • Consider location, duration, extent of fire • Observe safety precautions (Continued) Firefighter I

7. Responsibilities During Vertical Ventilation — Officer in Charge • Identify escape routes • Select place to ventilate • Move personnel, tools to roof Firefighter I

8. Responsibilities During Vertical Ventilation — Leader on Roof • Ensure roof safe to operate on • Ensure only required openings made • Direct efforts to minimize secondary damage • Coordinate crew’s efforts with firefighters inside building (Continued) Firefighter I

9. Responsibilities During Vertical Ventilation — Leader on Roof • Ensure safety of all personnel • Ensure team leaves roof as soon as assignment completed Firefighter I

10. Safety Precautions During Vertical Ventilation • Check wind direction with relation to exposures • Work with wind at back/side to provide protection while cutting • Note existence of roof obstructions/excessive weight on roof (Continued) Firefighter I

11. Safety Precautions During Vertical Ventilation • Provide secondary means of escape for crews (Continued) Firefighter I

12. Safety Precautions During Vertical Ventilation • Ensure main structural components not cut while creating opening • Guard opening to prevent personnel falling into it • Evacuate roof promptly when ventilation complete (Continued) Firefighter I

13. Safety Precautions During Vertical Ventilation • Use lifelines, roof ladders, other means to prevent sliding/falling • Make sure roof ladder (if used) firmly secured over roof’s peak • Exercise caution when working around electric, guy wires (Continued) Firefighter I

14. Safety Precautions During Vertical Ventilation • Ensure all personnel on roof wear full PPE including SCBA • Keep other firefighters out of range of those swinging axes, operating saws • Caution axe users to be aware of overhead obstructions (Continued) Firefighter I

15. Safety Precautions During Vertical Ventilation • Start power tools on ground to ensure operation; shut off before hoisting/carrying to roof • Extend ladders 3-5 rungs above roof line, secure ladder • When operating from aerial ladder platforms, floor of platform even with/slightly above roof level (Continued) Firefighter I

16. Safety Precautions During Vertical Ventilation • Check roof for structural integrity before stepping on, continue sounding throughout operation (Continued) Firefighter I

17. Safety Precautions During Vertical Ventilation • Always walk on bearing walls, strongest points of roof structure • Ensure ceilings punched through to enhance ventilation Firefighter I

18. Unsafe Roof — Warning Signs • Melting asphalt • Spongy Roof • Smoke coming from roof • Fire coming from roof Firefighter I

19. DISCUSSION QUESTION What should you do if you are assigned to ventilate a roof and find warning signs present? Firefighter I

20. Roof Coverings • Part of roof exposed to weather • Types • Some susceptible to ignition from sparks, burning embers; others not • Some have coating of insulating material Firefighter I

21. Existing Roof Openings • Sometimes used for vertical ventilation • Rarely in best location/large enough • Usually supplement cut holes (Continued) Firefighter I

22. Existing Roof Openings • Scuttle hatches • Skylights • Monitors • Ventilating shafts • Penthouse/bulkhead doors Firefighter I

23. General Ventilation Considerations for Roofs • Square/rectangular opening easier to cut, easier to repair • One large opening better than several small Firefighter I

24. Flat Roofs • Commonly found on commercial, industrial, apartment buildings • Common on many single-family residences (Continued) Firefighter I

25. Flat Roofs • May/may not have slight slope for drainage • Frequently penetrated by chimneys, vent pipes, etc. • May be surrounded and/or divided by parapets (Continued) Firefighter I

26. Flat Roofs • May support water tanks, HVAC equipment, etc. • Structural part • Decking • Construction materials determine equipment necessary to ventilate Firefighter I

27. Pitched Roofs • Among most common are those elevated in center along ridge with roof deck sloping down to eaves along roof edges (Continued) Firefighter I

28. Pitched Roofs • Shed roofs — Pitched along one edge with deck sloping down to eaves at opposite edge • Most involve rafters/trusses • Have more pronounced downward slope than flat; may be steep (Continued) Firefighter I

29. Pitched Roofs • Procedures for opening similar to flat roofs; precautions must be taken to prevent slipping • Some types may require different opening techniques Firefighter I

30. Arched Roofs • Can span large open areas unsupported by pillars/posts • One type uses bowstring trusses (Continued) Firefighter I

31. Arched Roofs • Lamella or trussless arched roofs (Continued) Firefighter I

32. Arched Roofs • Procedures for cutting ventilation openings same as flat/pitched except no ridge to hook roof ladders; curvature of roof prevents roof ladders from lying flat Firefighter I

33. Precast Concrete Roofs • Can be fabricated off-site • Available in many shapes, sizes, designs • Some use lightweight material (Continued) Firefighter I

34. Precast Concrete Roofs • Lightweight usually finished with roofing felt and mopping of hot tar • Extremely difficult to break through • Existing openings should be used for ventilation on heavy roofs Firefighter I

35. Poured-In Place Concrete Roofs • Some lightweight concrete roof decks poured in place over permanent form boards, steel roof decking, paper-backed mesh, or metal rib lath (Continued) Firefighter I

36. Poured-In Place Concrete Roofs • Relatively easy to penetrate • Some can be penetrated with hammer-head pick or power saw with concrete blade • Heavier roofs require jackhammer/diamond-tipped chain saw Firefighter I

37. Metal Roofs • Made from several different kinds of metal; constructed in many styles (Continued) Firefighter I

38. Metal Roofs • Light-gauge steel roof decks can be supported on steel frameworks/laid over existing roof • Light-gauge cold-formed steel sheets used primarily for industrial buildings (Continued) Firefighter I

39. Metal Roofs • Except when covered with lightweight concrete, seldom covered with roofing material • Metal cutting tools/power saws with metal cutting blades must be used to open (Continued) Firefighter I

40. Metal Roofs • Often penetrated by roof openings • Older buildings may have roofs made of large pieces of sheet metal laid over skip sheathing Firefighter I

41. DISCUSSION QUESTION What are some examples of occupancies in your area? How would these occupancies need to be addressed when ventilating the building? Firefighter I

42. Trench Ventilation (Strip Ventilation) • Used to stop spread of fire in long, narrow structure (Continued) Firefighter I

43. Trench Ventilation (Strip Ventilation) • Performed by cutting large opening at least 4 feet (1.2 m) wide extending from one exterior wall to opposite exterior wall • Often, large ventilation opening is cut between trench cut and fire Firefighter I

44. Conventional Basement Ventilation • In absence of built-in vents from basement, heat and smoke from basement fires quickly spread upward (Continued) Firefighter I

45. Conventional Basement Ventilation • Can be accomplished several ways • Ground-level windows — horizontal ventilation • Windows unavailable — interior vertical ventilation Firefighter I

46. Factors Reducing Effectiveness of Vertical Ventilation • Improper use of forced ventilation • Indiscriminant window breaking • Fire streams directed into ventilation openings • Breaking skylights (Continued) Firefighter I

47. Factors Reducing Effectiveness of Vertical Ventilation • Explosions • Burn-through of roof, floor, wall • Additional openings between attack team, upper ceiling Firefighter I

48. Negative-Pressure Ventilation (NPV) • Oldest type of mechanical forced ventilation techniques — Using fans to develop artificial circulation/enhance natural ventilation (Continued) Firefighter I

49. Negative-Pressure Ventilation (NPV) • Fans placed in windows, doors, roof vent openings to exhaust smoke, heat, gases (Continued) Firefighter I

50. Negative-Pressure Ventilation (NPV) • NPV operations • Fan should be positioned to exhaust in same direction as prevailing wind • Technique uses wind to supply fresh air • If prevailing wind too light, fans can be positioned on windward side of structure to blow air into building (Continued) Firefighter I