Chapter 16: Ventilation Flashcards Preview

EFRS Class 144 final > Chapter 16: Ventilation > Flashcards

Flashcards in Chapter 16: Ventilation Deck (19)
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1
Q

Ventilation

A

As applied to firefighting is the planned and systematic, release and removal of heated air, smoke and toxic gases from a confined area and controlled replacement of these products of combustion with a supply of cooler, fresh air

2
Q

Presure and Heat transfer

A

both move from an area of high to an area of low

and will follow the path of least resistance

3
Q

Advantages of Ventilation

A
  • Rescue op.: makes atmosphere in the structure more tenable
  • Fire attack: easier to rapidly extinguish.
  • Property damaged minimized
  • Thermal layering: disturbance is minimized
  • Reduce backdraft/flashover
  • Fire spread: tends to localize fire
4
Q

Mechanics of ventilation

A

regardless of how its achieved,its simply the movement of air from high-pressure location to a lower pressure location

5
Q

Vertical & Horizontal Ventilation

A

-Can be achieved through Natural, Forced: Mechanical, Hvac, and Hydraulic means

when ventilating you want the wind at your back

6
Q

Vertical Ventilation

A

Defined as the vertical Channeling of heat, smoke, and gases which is achieved by creating an opining above the fire either by means of existing openings or by cutting the roof. Vertical ventilation provides an opening for the rising and expanding smoke and fire gasses to leave the structure

7
Q

when doing Vertical Ventilation…

A

Always wear PPE & SCBA

  • Work on windward side of hole
  • Have a charged hose line for safety
  • Do not throw Debris on crews below
  • Always sound the roof before you move
8
Q

4 types of roof cuts

A

Kerf Cut: slot cut width of chain to determine direction of fire spred

Inspection cuts: Small Tri angle

Louvered Cut: large rectangular openings

  - length-ways: 3 rafters
   - width wise between 4 rafters

Trench cuts

9
Q

5 things to consider before opening a roof

A
Location of seat of fire
Wind Direction
Extent of Fire
Obstructions
Exposures
10
Q

Horizontal Ventilation

A

Defined as the horizontal channeling of heat, smoke and gases through wall openings such as windows and doors allowing cooler air to enter

11
Q

when doing Horizontal Ventilation…

A

it uses natural openings
open leeward side first
Windward side second

12
Q

NPV

A

Use mechanical means to develop artificial circulation to pull or draw products of combustion of a structure

generate low pressurer gradient inside

13
Q

PPV

A

Use mechanical means to create a positive pressure gradient that pushes the products of combustion from a structure

dont fight the wind

air should be introduced from un burnt side

exit to same size or smaller than opening

14
Q

Do not PPV if

A

Fire is ventilation controlled / under ventilated state.

if we add air+ back draft, flashover, smoke explosion

15
Q

pluses of PPV

A

can be done from outside the structure
it can be controlled
flow path can be direct away from points of egress
equipment does not block door ways

16
Q

dis advanteges

A

needs power
Specilized equipment
Must coordinate with other sectors
pushes lots of air into the building

17
Q

Hydraulic vent

A

Negative pressure ventilation

draws gases/heat from compartment

must cover 85-90% of opening and 2’ away from it

limited by size of room & opening
Exterior exposures 
Hose line
fire control 
wind direction
18
Q

Highrise vent

A

use one stair well for vent and another for fire operations/evac

natural vent of high rise depends on stack effect

19
Q

natural vent of high rise depends on stack effect

A
  • natural stack: hotter inside than out= gases leaving
  • revers stack: hotter outside than in=gasses going back into building
  • Mushroom: similar to stratification but caused by a barrier not temp

stratification: fire gases no longer rise and spread laterally this is due to a temperature equalization