Chapter 10 Flashcards
The primary mission on the fireground is life safety, therefore, fire control, search, and ventilation/nonventilation become primary tactical objective.
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Conditions, staffing, and resources should drive fire ground tactics and tasks.
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We now know that, apart from fire department operations, three things impact the survivability of a given space in the structure, the proximity to the fire, the elevation in the space, and whether or not the room/volume is isolated from the fire.
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At residential fires, fire control and ventilation are there to support the primary search.
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When multiple high-priority tasks must be accomplished sequentially, fire control should be the first priority. Rescue of trapped occupants is the first strategic priority but not necessarily the first tactical priority.
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More people are saved by a well-placed and advanced hose line than by any other tactic.
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When high-priority tasks can be accomplished simultaneously, it is important to support and protect the rescue or search operations using hose lines and flow path management.
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Regardless of the assigned priorities of on-scene crews, a fire control crew should not overlook the needs of a trapped occupant, and a rescue or search crew should not disregard the risks presented by active fire.
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Water reduces the impact of radiant heat or direct flame contact on exposed surfaces.
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A water curtain is not effective on radiant heat transfer as direct application.
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Direct water application to exposed surfaces using straight or solid stream or large droplet fog is the preferred technique.
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Exterior control - transitional attack:
Tactical objective - The objective is to improve occupant tenability and interior conditions for fire control.
Preferred Technique is a stationary straight or solid stream hand line through the bottom third of an opening, at a steep angle, deflected off the ceiling in the fire room, with care taken to not disrupt the flow path.
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Reducing surface temperature of unignited fuels stops pyrolysis.
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Interior advancement:
Steam conversion reduces temperature causing contraction and dilution of smoke, resulting in reduced flammability and radiation.
A flow and move technique is most effective in dwellings with a known fire location, or if a shut down and move technique is utilized, reapplication of water as needed to control heat rebound of fire is necessary.
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Firefighters should avoid advancing under a superheated thermal layer without cooling as they advance.
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Hose stream air entrainment should be limited when no vent is available opposite the fire.
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PPE can be quickly compromised during interior advancement within a convective flow.
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Interior fire control:
Direct fire control should be conducted as soon as the fire seat is located and can be reached with a water stream.
Preferred technique - Straight or solid stream, applied in an unbroken pattern directly to burning fuels, where compartment/room is unvented opposite the attack line.
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The ideal position is the air intake side of the flow path with flow path control.
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Smoke or surface cooling prior to direct attack may be appropriate.
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Interior indirect attack:
Application is made from outside the fire compartment/room that remains under-ventilated.
Smoke or surface cooling may be appropriate to gain access to the fire prior to indirect attack. Indirect water application can be utilized for shielded fires.
Preferred technique: Water is applied form the exterior of the compartment/room utilizing a fog stream.
Fog application from a position exposed to resultant outflow of heated smoke and steam can be dangerous.
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Decisions about when and where ventilation is needed and the methods employed is to be guided by an understanding that, in the absence of effective water being applied on the fire, air increases the HRR and potential for rapid fire development.
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Anticipate rapid fire development if ventilation is increased absent the application of water for both planned and unplanned ventilation.
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Horizontal Ventilation:
Preferred technique: Door control and limited ventilation may be used until effective water is on the fire.
Failure to coordinate ventilation with effective water application will increase heat release rate.
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Vertical Ventilation:
Preferred Technique: Door control and limited inlet ventilation until vertical outlet is established. A 4x4 ft hole is rarely sufficient for effective ventilation.
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Positive Pressure Attack:
Fans are used to create a pressure differential influencing the flow of smoke, air, heat, and flame from the inlet to the exhaust. PPA in domestic floor plans with many rooms and closed doors is more effective.
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PPA will not be effective on a fire located in an open floor concept plan or any floor plan with high ceilings.
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An exhaust larger than the inlet must be provided in the fire room to allow for effective PPA.
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PPA is not replacement for using the reach of your hose stream.
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During PPA, extension into void spaces when using PPA is directly related to the exhaust capabilities of the void space.
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PPA does not negatively affect the survivability of occupants behind a closed door.
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PPA preferred technique: Exhaust ventilation should be established prior to mechanical ventilation at the inlet.
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When PPV is used post fire control, in single-story residential structures, the more openings made in the structure during PPV, the more efficient it is at ventilating the structure.
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PPI is contra-indicated in compartments impacted by fire extension from the compartment of origin.
Preferred technique: All inlet and exhaust openings should be controlled to maintain desired pressure differential and isolate the fire.
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