Flashcards in B-122 Ventilation Deck (32)
Ventilation is ___
the systematic removal and replacement of heated air, smoke and gases from a structure with cooler air.
Ventilation facilitates ___
firefighter entry into an involved structure by improving visibility and life safety for those operating inside the building.
What will size up determine regarding ventilation?
* what type of ventilation is needed
* determine where ventilation will take place
Considerations that influence ventilation decisions which include but are not limited to:
* Roof type (flat, arched, pitched, or truss)
* Type of building involved
* Location of the fire
* Duration of the fire
* Extent of the fire
* Existing roof openings
* Safety of personnel
* Possibility of fire spread
What are the four types of ventilation that can be utilized?
Natural ventilation refers to technique of:
making openings in the structure and allowing the ambient wind, weather conditions and natural convection currents to ventilate the structure.
consists of opening up doors and windows an the leeward side of the fire area so the heat and smoke that is trapped within the building can escape.
Horizontal ventilation is effective for:
smaller, primarily residential buildings with light to moderate fire conditions
Horizontal ventilation can be accomplished with limited staffing but requires personnel to know:
1. the layout of the building
2. where interior companies are located before opening up
3. the presence of any fire extension
Prior to performing vertical ventilation, personnel must ensure that:
1. The escaping smoke and fire gases have a direct path out of the structure
2. That such travel does not spread the fire or interfere with occupants trying to exit out of the building.
Vertical ventilation is ideally done ____
directly over the seat of the fire
Roof lines are used to ____. Do not operate hose line ____ unless ordered by the IC.
* protect personnel and external exposures
* into the ventilation hole unless ordered to do so by the IC.
Signs of roof collapse
* distortion in the roof surface
* smoke coming from cracks
* spices in the roof covering and sagging
Personnel should make a small inspection hole in the roof near the ladder whenever:
fire conditions below the roof are not known
A vertical ventilation hole should be a minimum of ____
4' x 4'
One big hole is better than several small holes
Vertical ventilation openings should be created as close as possible to ____
the ridge line
When lighting the roof area from aerial ladders, be sure to light the area ____
high above the working area at side angle so crews are not blinded by the cross lighting.
Mechanical ventilation is the process of ____
using fans and water systems to force the heat smoke and other products of combustion out of a structure.
Mechanical ventilation can be accomplished with ____
HVAC systems, exhaust fans, blower fans, and water streams
When accomplishing negative pressure ventilation smoke ejectors should be set up to ____
take advantage of any ambient wind conditions.
Fog streams should not be used for ventilation if:
* it will damage items that have been removed for protection
* it will create exterior or adjourning building damage
* it will damage the inside of the room from which it was directed.
A PPV fan should be placed ____ from the doorway, so that its cone of air ____
* 6' to 10'
* extends beyond the opening's boundaries and into the structure.
During PPV, while using multiple fans, the larger blower should be placed ____ the smaller blower when different sized fans are used. Fans should be positioned so the first fan is located ____ from the doorway and the second fan another ____ behind the first fan.
* in front of
* 3' to 5'
* 3' to 5'
In order for PPV to be effective, personnel must ensure that they:
* place fans away from the point of entry on the unburned side of the fire, so crews can easily enter/ exit the building
* Control the amount of airflow into the building, too many opening or exit points will reduce effectiveness.
* Place multiple fans in tandem when additional air is required
* Never direct a fire stream into an operating PPV exit
* Close any/ all windows, doors and opening to properly direct air flow into specific fire or densely affected smoke areas.
PPV in large buildings and multistory buildings are ____
complex in nature and often require the coordination of a designated ventilation sector.
Personnel should realize that a blow torch effect or fire blowing out the far exit may occur and that this is ____
normal and predictable.
During PPV, adjacent structures should be ____, and concealed spaces must be ____
* checked for extension
Personnel should conduct a proper ____ of the building and identify the ____ present prior to initiating ventilation operations.
* risk analysis
* smoke conditions
Commonly referenced smoke color, and the fires associated with them:
* Yellowish/ greenish under pressure
* Heavy, rolling, black under pressure
* Incipient fire
* wood or natural products
* Hydrocarbons, plastics and other synthetics
* Indication of an oxygen deficient fire with backdraft potential
* Conditions common with impending flashover