11 Ventilation Size Up Flashcards
pg 286
Tactical ventilation
Methodical thought out approach to changing the vent profile of a structure.
any action on the part of firefighters to ventilate a structure- from opening doors and breaking windows to setting up ventilation fans - tactical ventilation efforts because they are done with intent and purpose.
pg 286
Natural ventilation profiles
composed of factors that occur without outside intervention.
Any efforts or actions taken by firefighters are tactical vent, because they are done with intent and purpose
pg 286
Decisions on how to implement tactical ventilation efforts should be determined by
The IC
pg 287
Ventilation contributes to incident stabilization by (3)
Improving visibility
and releasing heat,
allowing attack crews to locate and control fire
pg 287
Vent contributes to property conservation by
Drawing heat and fire out and away from other parts of the building, reducing property loss
pg 302
Whenever possible, vent should take advantage of
Natural ventilation, implemented in concert with existing atmospheric conditions.
note: if conditions allow natural ventilation is the best option because it requires no additional personnel or equipment to set up and maintain.
pg 303
In some situations, natural vent may be inadequate and therefore what must be used
Mechanical ventilation, aka forced ventilation, using fans, blowers, smoke ejectors and hydro vent/ hose streams
pg 300
Ventilation crew must get into position and be ready to make the ventilation opening as soon as:
forcible entry is completed and rescue and attack crews are ready to enter.
pg 289
In their zeal to do the best possible job, fire fighters assigned to ventilate a burning building sometimes develop tunnel vision. Therefore FF must be trained to quickly but thoroughly size up the situation. Some agencies use the simple approach: (3)
What do we have, (situation)
What are we going to do (actions/ tactics)
What do we need (resources)
pg 289
Four stages of fire development
Incipient
growth
Fully developed
Decay
pg 289
Fire is fuel controlled during what stages of fire development
Incipient and early growth stages
pg 289
Introducing air into a fuel controlled compartment will
Initially slow the progression to flashover by removing hot gasses and cooling interior, but will grow soon if not controlled
pg 289
Fire is likely to become vent controlled during what stages of development,
Through growth stage and toward fully developed
pg 290
From a size up perspective, one of the most important indicators of fire conditions inside is
The behavior of visible smoke outside
smoke behavior that FFs should look for when sizing up a working structure fire are:
- smoke volume
- smoke color and density
- Air flow (pressure)
pg 290
In regard to breathing smoke, firefighters should
Never breathe smoke
pg 291
Whitish great smoke generally indicates what type of fire
Celluloid or class A materials burning is oxygen abundant atmosphere
pg 291
Black smoke is an indicator of
hydrocarbons such as Petroleum based products, plastics, anything burning in oxygen limited environment.
291
Two categories of smoke density
Optical density and opacity
Physical density
pg 291
Optical density and opacity
How difficult it is to see through smoke
pg 291
Physical density of smoke
How buoyant the smoke is. If it’s quick rising- buoyant. Related to temperature of smoke.
pg 292
Light haze of smoke lazily moving on the top floor could indicate
Intense attic fire
pg 293
For vent purposes, size up the following four critical building construction factors should be considered:
- Age and type of building
- Positive construction features
- Negative construction features
- Occupancy specific construction features
pg 293
When burned by fire, full dimension lumber behaves how in comparison to nominal dimension lumber
Full dimension holds its strength better than Normal. But because it’s older and therefore dryer, is more susceptible to ignition than newer nominal.
pg 295
Although lightweight and cost effective construction methods are used to save money, they often increase
Increase collapse potential because of longer spans and enclosed void spaces with structural members having more surface area or mass ratios
pg 295
Positive construction features
tend to resist effects of fire, reduce spread, and reduce collapse potential. Steel members Self closing fire doors Sprinklers Built in fire suppression Smoke vents, Elevator shafts
pg 296
Built in fire suppression systems (3)
non sprinkled
Halogenated system,
Co2
Dry chem
note: Protect single compartment like hood over stove or computer bank
pg 298
Elevator shafts can be a ventilation hinderance and benefit because
Hinderance when providing avenue for fire and smoke spread to other levels
Benefit when providing a means to vent thought passing through other floors
pg 298
Ideally, roofs with panelized systems or other systems prone to early collapse should have
Automatic smoke vents, thereby preventing firefighters from walking on dangerous roof surfaces to vertical vent
pg 298
Firefighters should frequently visit and pre plan buildings undergoing modification because
They will be familiar with changes and possible hinderance to operations and Id ways to mitigate the problem.
pg 298
Negative building features are (definition)
Ones that do not resist effects of fire, promote fire spread, increase collapse potential, and make entry more difficult.
pg 298
Negative building features
Elevator shafts Synthetic materials Planters and other landscape features Security measures Occupancy related features
pg 299
Planters and other landscape features can be a hinderance to firefighting because
They may keep apparatus further from building and make placement of ladders difficult.
pg 300
Establishing and maintaining the required level of coordination, demands that everyone on the fire ground know and understand what
The incident action plan. IAP and how it affects each part of the operation
pg 300
Coordinating vent with rescue and fire attack generally involves three components
Timing,
Location
Method
pg 300
Deciding where to created the ventilation opening is often dictated by where the fire is located in the building and the stage of fire development. In general the ventilation opening should be made as close to the seat of the fire as safely possible. Some factors that have a bearing on where to ventilate include the following: (10)
Location of fire Location of occupants interior and exterior exposures Type of construction Purpose or use of occupancy Extend of fire progression Condition of building and contents Existing openings, skylights, vents, monitors Direction and velocity of wind Resource availability and capability
pg 301
Firefighters can sometimes use what to locate the fire from the outside if smoke and fire aren’t visible
Tic, or feeling, looking for discoloration or blistering
pg 301
If an area of the roof is unsafe due to fire conditions below, the vent hole should be made between
Between the fire, and uninvolved portion of the building.
If the fire is below the top floor, vertical vent may not be possible unless
An elevator shaft or other vertical channel is available
pg 302
Structures in which horizontal vent may be appropriate
Fires not large enough to necessitate roof opening
Windows or doors close to seat of fire
Seat of fire below top floor
Fire has not entered structural voids or concealed spaces
pg 302
Structures in which vertical vent may be appropriate
Fire in attic cockloft or top floor
With no windows and few exterior doors
With large vertical channels like, light wells, elevators, hoist ways etc
Fire has entered structural voids and concealed spaces.
pg 302
If conditions allow, natural vent is the best option because
It does not require additional personnel or equipment to set up and maintain
In general mechanical or forced ventilation is indicated when
Location and size of fire is determined
Layout of building doesn’t lend to natural vent
Natural vent slows, becomes ineffective, needs support
Fire burning below grade
Compartment with fire is so large natural vent is inefficient
Dictated by type of building and fire
pg. 303 exposures:
Because horizontal ventilation does not normally release heat and smoke directly above the fire, Fire fighters must consider the threat to internal exposures that channeling heat and smoke through a building can create. the Danger is?
there is sometimes a danger that they will ignite the structure above the point where they escape or may be drawn into windows about the ventilation opening by lapping, also known as autoexposure.
Emitting products of combustion from vent holes can cause what to nearby exposures
Ignition to exposures or extension to grass and other exposures from burning debris flying.
Two Important weather considerations for ventilation
Wind
Temperature
pg 304
Wind conditions must always be considered when determining the proper ventilation method. Wind blowing fire towards an external exposure, supplying oxygen to the fire, or blowing the fire into uninvolved areas of the building can reduce the benefits of horizontal ventilation. Fire fighters must remember that ventilation methods:
should be in concert with the prevailing wind, not against it.
pg 305
The temperature on a roof can be significantly higher than the temperture at street level. The crews are at risk of ____________ or even __________. and their productivity may be reduced because of _________ and _______.
heat exhaustion heat stroke fatigue dehydration note: these condition can cause vent crew to take longer than normal to complete their assignments.
pg 305
Cold temp can effect vent efforts by: (3)
Snow and increasing live loads on roof- collapse potential
Conceal potential hazards
Slippery surfaces
pg 286
Factors that contribute to the ventilation of a fire are known as
A ventilation profile
p.286
+If properly done, this action can contribute significantly to the achievement of all 3 of the universal goals on every incident:(L.I.P)
Tactical Ventilation
p.287
+Reduces the amount of physical stress FF’s have to endure inside a building during search and rescue and fire suppression operations.
Ventilation
p.287 Property Conservation
+These provide the shortest possible path by which fire and its products can leave the building which contribute to a reduction in property loss.
Properly sized and placed ventilation opening
p.287
+Any means other than natural ventilation
+To create or redirect the flow of air within building/compartment
Mechanical Ventilation (forced ventilation)
p.293 Ventilation Size Up
+4 critical building construction factors
- Age and type of building
- Positive construction features
- Negative Construction features
- Occupancy specific construction features
p.295 warning box!
+Because they can fail suddenly and unexpectedly during a fire, the IC should be notified whenever these materials are found during ventilation operations.
Lightweight Construction
p.295
+Building construction features that tend to resist the effects of fire, reduce fire spread, and reduce likelihood of structural collapse are known as?
Positive Construction Features
p.298
+Construction features that do not resist the effects of fire, promote fire spread, increase likelihood of collapse and make entry by FF more difficult are known as?
Negative construction features
pg 303
Ventilation operations can be seriously affected by:
both wind and temperature.
pg. 304 the most important weather-related influences on tactical ventilation are wind and temperature.
ch. 11 pg. 300
When the IC has decided that ventilation is needed, coordinating the ventilation operation with rescue and fire attack generally involves three components:
timing
location
method
