VENTILATION

1. VENTILATION

2. Ventilation Practices

3. Basic ObjectivesVentilation Practices • 8-1.1 Define the principles of ventilation, and identify the advantages and effects of ventilation. • 8-1.2 Identify the dangers present, and the precautions to be taken in performing ventilation. • 8-1.3 Demonstrate opening various types of windows from inside and outside, with and without fire department tools. • 8-1.4 Demonstrate breaking window or door glass, and removing obstructions. • 8-1.5 Using an axe, demonstrate the ventilation of a roof and a floor. • 8-1.6 Demonstrate ventilation using a water fog. • 8-1.7 Define the theory of a back draft explosion. • 8-1.8 Identify the signs of a potential flashover.

4. Intermediate ObjectivesVentilation Practices • 8-2.1 Demonstrate the use of different types of power saws and jack hammers. • 8-2.2 Identify the different types of roofs, demonstrate the techniques used to ventilate each type, and identify the necessary precautions. • 8-2.3 Identify the size and location of an opening for ventilation, and the precautions to be taken during ventilation. • 8-2.4 Demonstrate the removal of skylights, scuttle covers, and other covers on roof tops. • 8-2.5 Demonstrate the types of equipment used for forced mechanical ventilation.

5. Advanced ObjectivesVentilation Practices • 8-3.1 Identify and demonstrate natural and mechanical methods for horizontal ventilation of a structure. • 8-3.2 Identify and demonstrate natural and mechanical methods for vertical ventilation of a structure. • 8-3.3 Identify the location of the opening, the methods to be used, and the precautions to be taken when ventilating a basement.

6. Introduction • Ventilationis the systematic removal and replacement of heated air, smoke, and gases from a structure, with cooler air • Ventilation facilitates entry by firefighters and improves life safety for rescue and other firefighting operations • Ventilation increases visibility, decreases danger to trapped occupants by channeling away hot, toxic gases, and it reduces the chance of flashover or backdraft

7. Introduction • Because the increased use of plastics and other synthetics have greatly increased the fuel load in all occupancies, modern technology requires a greater emphasis on ventilation • The products of combustion are becoming more dangerous and are in larger quantities than ever before • Prompt ventilation for the saving of lives, suppression of fire, and reduction of damage is just as important, if not more so, than it ever has been

8. Introduction • Today’s energy conserving houses create additional ventilation issues • Energy saving glass, steel entry doors, and building vapor barriers make heat retention much greater • This means when there is a fire, the heat is retained better, and flashover can occur faster than in a less insulated structure

9. Introduction • A roof covering is the exposed part of the roof {the part we see every day} and its purpose is to protect against the weather • It can be wood shingles, composition shingles, composition roofing paper, tile, slate, synthetic membrane, or built up tar and gravel • This is important to us because it may be subjected to sparks or blazing embers from another source • Insulation over the covering retains heat and may reduce fire rating drastically, causing premature roof failure

10. Introduction • All the preceding mean that the need for ventilation is increased and it must be accomplished much sooner than in the past • We must know how the roofs in our area are constructed • Pre Incident plans need to note roof construction and any areas of a roof over or added insulation • Not any light weight building materials as they can be a serious collapse hazard

11. Introduction • When the officer decides ventilation is needed, they must consider the precaution necessary to control the fire and assure the safety of teams performing the task • The team must wear full PPE, including SCBA and have a charge hose line available • Before, during , and following the operation it is important to consider the possibility of fire spreading through out a building and the danger of exposure fires

12. IntroductionVentilation Tools • All PPE • Charged Hose Line • Forcible Entry Tools • Chain Saw • Rotary Saw • Ladders

13. Ventilation and Rescue

14. Advantages of Ventilation Rescue Operations • Proper Ventilation simplifies and expedites rescue by removing smoke and gases that endanger trapped or unconscious occupants • Replacement of heat, smoke, and gases with cooler, fresh air helps victims breathe better • This will also make condition safer for firefighters and improve visibility so that we may more easily locate the victims

15. Ventilation and Fire Attack or Extinguishment

16. Advantages of Ventilation Fire Attack & Extinguishment • Vent team and fire attack must coordinate closely • When the hole is cut, a chimney effect is created in the structure • If this hole is cut directly over a fire, it tends to localize the fire – If it is made on the other side of the structure, it may well contribute to the spread of the fire into unburned areas • Good ventilation will lessen the chances of steam burns to firefighters and increase visibility

17. Ventilation and Salvage

18. Advantages of Ventilation Property Conservation • Property conservation will occur through good ventilation because the attack team will be able to find and extinguish the fire quicker • It will allow the water fog, smoke, heat, and gases to escape into the environment rather than remain in the structure • All of this will allow better salvage operations while the extinguishment is in process

19. MushroomingWhat Type of Ventilation is Needed?

20. Advantages of Ventilation Fire Spread Control • Convection will cause the heat, smoke, and gases to travel up to the highest point until they are trapped by a roof or ceiling • As they accumulate, they bank down and spread laterally to involve other areas • This process is called Mushrooming • Ventilation will reduce this effect • Fire must be put out quickly though or the extra air coming in will allow the fire to expand

21. Advantages of Ventilation Reduction of Rollover Potential~Firefighters should always stay as low as possible~

22. Advantages of VentilationReduction of Rollover Potential • Rollover is sudden ignition superheated unburned gases across the ceiling space • Unburned gases gather across the ceiling and when fresh air is supplied the ignite • Proper ventilation on the side of the fire opposite the firefighters will reduce chances of a rollover

23. Advantages of VentilationReduction of Flashover Potential

24. Advantages of Ventilation Reduction of Flashover Potential • Flashover is the transition between growth and fully developed fires • As original seat of the fire burns, everything else in a room is heated to its ignition temperature • Once reached, the entire room can burst into flames simultaneously with severe consequences to anyone in the room at this time • Ventilation can relieve this as it lets the heat escape before ignition temperatures are reached

25. Advantages of Ventilation Reduction of Backdraft Potential • High heat is available in a structure, but oxygen levels are too low to support combustion • A very dangerous condition exists because the sudden admission of oxygen can cause a sudden ignition called a backdraft • To prevent this, we need to provide vertical ventilation to release trapped heat and flammable products of combustion

26. Advantages of Ventilation Reduction of Backdraft Potential • We need to be aware of this potential and proceed cautiously if conditions are ripe for backdraft • Signs of potential backdraft include: • Smoke stained windows • Smoke puffing from the building {breathing} • Pressurized smoke from cracks in the building • Very little flame visible from the exterior • Black smoke becoming dense gray yellow • Confinement and excessive heat • IF ANY are seen, wait on vertical ventilation to be completed before you try to enter the building

27. Considerations for Ventilation • We must understand our overall plan of attack before we direct or order ventilation to be started • We must make a series of decisions that pertain to ventilation needs • These decisions should fall into the following order

28. Is There a Need for Ventilation at This Time? • This must be based on the amount of heat, smoke, and gas conditions within the structure, structural conditions, and the life hazards

29. What Type of Structure? Any Exposures?Where is Fire Located?

30. Where is Ventilation Needed? • This involves knowing construction features of the building, contents, exposures, wind direction, extent of the fire, location of the fire, location of top or vertical openings, and location of cross or horizontal openings

31. What Type of VentilationShould Be Used? • Horizontal? • Natural or Mechanical? • Vertical? • Natural or Mechanical?

32. Natural or Mechanical?

33. Do Fire and Structural Conditions Allow for Safe Roof Operations? • Must use all information available to you to answer this question • Will need input from the people in the structure and those going to the roof • To answer the questions, we have to evaluate several pieces of information and take into account many factors which are covered in the next several slides

34. Life Safety Hazard • The danger to human life is our utmost concern • Our first consideration is the safety of firefighters and occupants • Proper ventilation will be needed in conjunction with rescue operations • Dependant on the fire, ventilation may need to happen before rescue operations, or if conditions warrant, fire attack may need to come first – in some cases, both will have to be done at the same time

35. Life Safety Hazard • There are also hazards to us as firefighters • The type of building, whether natural openings are adequate, the need to cut through roofs, walls, or floors of varying types, all make the decision process more difficult

36. Life Safety Hazard • Some of the expected hazards due to an accumulation of smoke and gases can be: • Obscurity caused by dense smoke • Presence of poisonous gases • Lack of oxygen • Presence of flammable gases • Backdraft • Flashover

37. Visible Smoke Conditions • We can make some ventilation and tactical decisions as we arrive at the scene based on what visible smoke conditions we have • The density of the smoke is in direct ratio to the amount of suspended particles • The conditions vary according to how burning has progressed • A developing fire and a decaying fire are two totally different fires and must be treated as such

38. Visible Smoke Conditions • An early stage fire will usually give off smoke that is of not much density • If large quantities of carbon particles are present, the smoke may become denser • As the building becomes more involved with fire, the smoke will become denser

39. The Building Involved • Building type and design are the initial factors to consider in determining whether to use horizontal or vertical ventilation • Some other factors to consider: • Number and size of wall openings • Number of stories, staircases, shafts, ducts, and roof openings • Availability and involvement of exterior fire escapes and exposures

40. The Building Involved • Get in good with the building department so they can let you know when buildings are altered or subdivided • Building permits can reveal information about the heating, ventilating, and HVAC systems and avenues of escape for smoke, heat, and fire gases • Adjoining buildings and how they are attached has a bearing on ventilation • Pre plans can provide valuable information and familiarity with the buildings in your area

41. Basements and Windowless Buildings • Basement fires are among the most challenging a firefighter will face • We basically have to descend through the chimney to get to the fire • Access can be by interior or exterior stairs, exterior windows, or hoist ways • Outside entrances may be blocked or secured by iron gratings, steel shutters, wooden doors, or combinations of these for protection from weather and burglars

42. Basements and Windowless Buildings • Many buildings have windowless wall areas • While they may not be a desirable means of escape, they are important considerations for ventilation • Windowless buildings create and adverse effect on firefighting and ventilation operations • Ventilation in windowless buildings may be delayed for a long time, allowing the fire to gain headway or to create backdraft conditions

43. Basements and Windowless Buildings • Problems in ventilating these building vary depending on the size, occupancy, configurations, and type of material from which the building is constructed • They usually require mechanical ventilation for the removal of smoke • The HVAC system can sometimes clear the smoke by itself • The drawback to this is that it can also spread the fire and it requires electricity to work

44. Location and Extent of the Fire • Depending on time from ignition until firefighters arrive, the fire may have traveled some distance • We must consider the location and extent of the fire when deciding on ventilation • Ventilation before fire location is know may spread the fire into unburned areas • Severity and extent of the fire usually depend on the type of fuel and amount of time it has been burning, installed early warning and fire protection devices, and degree of confinement of the fire • Phase of the fire is a primary consideration

45. Location and Extent of the Fire • Some means of vertical fire extension: • Through stairwells, elevators, and shafts by direct flame contact or by convected air currents • Through partitions and walls and upward between the walls by flame contact and convected air currents • Through windows or other outside openings where flame extends to other exterior openings and enters upper floors {lapping}

46. Location and Extent of the Fire • Some means of vertical fire extension: • Through ceilings and floors by conduction or heat through beams, pipes, or other objects that extend from floor to floor • Through floor and ceiling openings where sparks and burning material fall through to lower floors • By the collapse of floors and roofs

47. Selecting the Place to Ventilate • The ideal situation is one in which we have prior knowledge of the building and its contents • There is no exact rule except to open the roof “as directly over the fire as possible” • Some of the may factors that will have a bearing on where to ventilate include: • Availability of natural openings such as skylights, ventilator shafts, monitors, and hatches • Location of fire and direction in which the IC wants it to be drawn

48. Selecting the Place to Ventilate • Some of the many factors that will have a bearing on where to ventilate include: • Type of building construction • Wind direction • Extent of progress of the fire and the condition of the building and its contents • Bubbles or melting of roof tar • Indications of lessening structural integrity of the roof

49. Selecting the Place to Ventilate • Some of the many factors that will have a bearing on where to ventilate include: • Effect that ventilation will have on the fire • Effect that ventilation will have on exposures • Attack crew’s state of readiness • Ability to protect exposures prior to actually opening the building

50. Selecting the Place to Ventilate • Before ventilating, adequate personnel and fire control equipment must be ready because the fire may increase in intensity once the building is opened • Resources for the involved building and exposures need to be in place • Try to attack the seat of the fire {if safe} immediately after ventilation • Entrance should be made as close to the fire as possible, with charged hoses in place in case of flare up and at critical points of exposure