Ch. 9: Ventilation Flashcards
Ch. 9: Norman – Ventilation
(NC #1)
Fire attacks buildings, constantly in search of more:
Fuel & oxygen
Ch. 9: Norman – Ventilation
(NC #2)
Both contestants (fire & FFs) need the same raw material in which to fight – (that raw material is?).
Whoever controls the ___ supply, wins the battle.
Oxygen (for both answers)
Ch. 9: Norman – Ventilation
(NC #3)
Used properly, ___ it can be the deciding factor in whether a bldg is saved or becomes a smoldering pile of debris:
Ventilation
Ch. 9: Norman – Ventilation
(NC #4)
Fig. 9-1: Letting the fire go up and out slows ___ and stops fire from ___. Both are good things:
- Slows horizontal fire travel,
- Stops it from banking down inside of the bldg.
Ch. 9: Norman – Ventilation
Section: Reasons for Ventilation (NC #5)
Ventilation can be defined as the process of:
Removing toxic products of combustion & replacing them with fresh air.
Ch. 9: Norman – Ventilation
Section: Reasons for Ventilation (NC #6)
To Chief Norman, ventilation is an ongoing battle between fire & FFs for:
Control of the bldg
Ch. 9: Norman – Ventilation
Section: Reasons for Ventilation (NC #7)
Serious fires that threaten the very existence of a structure demand ___ in order for interior forces to do their job.
Total ventilation
Ch. 9: Norman – Ventilation
Section: Reasons for Ventilation (NC #8)
If you don’t let out the ___, they will drive you out of the structure:
Products of combustion
Ch. 9: Norman – Ventilation
Section: Reasons for Ventilation (NC #9)
There are 2 main reasons for performing ventilation:
- Venting to allow attack teams to enter & operate w/in structure (vent for fire)
- Venting specific area to provide fresh air for breathing & improving visibility while searching (vent for life)
Ch. 9: Norman – Ventilation
Section: Reasons for Ventilation (NC #10)
The universal use of ___ has some people thinking that ventilation is less important than it was in the past just bc FFs can breathe:
SCBAs
Ch. 9: Norman – Ventilation
Section: Reasons for Ventilation (NC #11)
(CFPC) – There are 2 problems with this thinking:
1st – ignores victims who might be still be in the bldg – they don’t have masks.
2nd – it assumes FF’s masks will always protect them – not always so.
Ch. 9: Norman – Ventilation
Section: Reasons for Ventilation (NC #12)
“Textbook ventilation” creates only ___ that breaking double hung windows does:
Half the window opening
Ch. 9: Norman – Ventilation
Section: Reasons for Ventilation (NC #13)
When you are operating in ___ atmospheres, there is no place for glass conservation:
IDLH
Ch. 9: Norman – Ventilation
Section: Reasons for Ventilation (NC #14)
The 3rd problem with ineffective ventilation & SCBA use is the buildup of:
Heat that results when venting isn’t prompt & effective.
Ch. 9: Norman – Ventilation
Section: Reasons for Ventilation (NC #15)
Heat buildup results in:
Flashover
Ch. 9: Norman – Ventilation
Section: Reasons for Ventilation (NC #16)
3rd problem with ineffective ventilation (cont): The mask protects you against smoke, but offers no protection against:
Fire
Ch. 9: Norman – Ventilation
Section: Reasons for Ventilation (NC #17)
4th problem with thinking that ventilation is not as critical as it was in the past is that buildings are:
Being made tighter and tighter
Ch. 9: Norman – Ventilation
Section: Reasons for Ventilation (NC #18)
The ‘green bldg’ movement & energy conservation efforts will only increase our difficulties. The potential for ___ is increasing with every bit of insulation & window caulking that is applied:
Devastating backdraft explosions
Ch. 9: Norman – Ventilation
Section: Reasons for Ventilation (NC #19)
When distinguishing between venting for life and venting for fire, the key factor is:
The timing of the ventilation
Ch. 9: Norman – Ventilation
Section: Reasons for Ventilation (NC #20)
When distinguishing between venting for life and venting for fire, the key factor is the timing of the ventilation. VFL should begin (when):
VFL – begin as soon as life hazard is recognized.
Ensure venting draws fire away from life hazard.
Ch. 9: Norman – Ventilation
Section: Reasons for Ventilation (NC #21)
Immediate vertical ventilation has saved hundreds of lives by:
Preventing mushrooming & drawing fire away from the victims.
Ch. 9: Norman – Ventilation
Section: Reasons for Ventilation (NC #22)
Vertical ventilation should be a primary tactic at most ___ dwellings:
Most low-rise, non-fireproof multiple dwellings
Ch. 9: Norman – Ventilation
Section: Reasons for Ventilation (NC #23)
Venting for fire is normally delayed until:
Resources are in place for attack
should take place just as line begins attack
Ch. 9: Norman – Ventilation
Section: Reasons for Ventilation (NC #24)
VFF – Once an attack has begun, you can order the windows in the fire apartment, ___ to be vented (which ones and why):
Windows opposite the hoselines’ advance – to allow the POCs to be blown ahead & thereby speeding advance of the hoselines.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #25)
The venting of windows is called _____ ventilation.
Horizontal ventilation
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #26)
Generally, horizontal ventilation for a life hazard must be coupled with:
An immediate rescue effort
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #27)
Generally, horizontal ventilation for a life hazard must be coupled with an immediate rescue effort – by either:
- A ff must enter the area & remove the victim -or-
* A hoseline must be brought in place to protect victim where they are trapped.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #28)
Fig. 9-2: Venting windows can be done to speed ___ or reach ___:
- Speed the hoseline’s advance
* Reach a victim trapped in the room behind the glass.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #29)
Fig. 9-2 (cont): Venting windows - done to speed hoseline’s attack or reach victim trapped in the room behind the glass. Coordination of this effort with ___ is crucial to success:
Fire attack
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #30)
The most important concept to remember when discussing ventilation is that it must be:
Of sufficient volume to win the battle with the fire
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #31)
Damage that results from fd efforts should be commensurate with -
- The amount of damage the fire is causing
* As well as the extent of the life hazard
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #32)
Question raised – when should you break a window as opposed to opening it from the inside? A good rule of thumb is to:
Let fire be the guide, not smoke
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #33)
CFPC – If you can stand up and manipulate the locking devices, go ahead and:
Open the window
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #34)
CFPC - If it (window) seems stuck & you aren’t being subjected to a lot of heat – & if smoke isn’t impending any other operations, you should probably:
Look for another means of venting
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #35)
If you are driven back by down by heat when you try to stand up, or if the smoke is severely hindering visibility or manipulating SCBA use – action is:
Glass should be broken when the hoseline is charged.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #36)
If fire is low intensity (food on stove or smoky mattress, etc) – open, don’t break windows. ___ ventilation is often beneficial in moving this cool smoke.
Mechanical ventilation
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #37)
In low intensity fire (food on stove, smoky mattress, etc) – open, don’t break windows. Mechanical ventilation is beneficial in moving this cool smoke & it poses few of the dangers present when using ___ during working structure fires.
Fans
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #38)
Window venting is the most suitable type of ventilation for most fires in houses & similar size structures that have ___ ratios:
High window-to-room-size ratios
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #39)
As a guide/rule of thumb – ‘if you can stand up long enough to manipulate locks, then raise windows. If can’t stand up that high or that long due to heat – take the glass.’ Considerations to make when breaking glass, 1st → have an idea of:
Progress of fire control & search efforts.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #40)
As a guide/rule of thumb – ‘if you can stand up long enough to manipulate locks, then raise windows. If can’t stand up that high or that long due to heat – take the glass.’ 2nd factor to consider when breaking glass is conditions will:
Conditions likely to worsen before they get better
review/state 2 factors to consider before breaking glass
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #41)
Venting not only provides fresh air to trapped victims, but also improves conditions for firefighting, leading to:
Earlier control
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #42)
Venting not only provides fresh air to trapped victims, but also improves conditions for firefighting, leading to earlier control. FFs will also be less subject to ___ & ___ if hoselines are operating on the fire.
Disorientation or becoming trapped
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #43)
Breaking glass provides ___ as much window-opening area as raising double hung windows:
Twice as much
THIS WAS A TEST QUESTION!
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #44)
Breaking glass provides twice as much window-opening area as raising double hung windows. Since these (double hung) are predominant windows in the majority of ___ bldgs, ffs must be prepared to break glass if conditions require:
Residential
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #45)
FFs must time their ventilation efforts properly.
- Venting too early will allow:
- While delaying ventilation will subject:
- Too early: allows fire to extend.
- Delaying: subjects FFs to unnecessary punishment from heat.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #46)
Generally, venting for life should take place just as:
The hoseline begins its attack
best coordination is via radio
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #47)
(CFPC) – M of attack team should give the word to take the windows just as the nozzle team opens the nozzle. If radios aren’t available, person creating the vent should wait until:
The sights & sounds of hose-stream operation (stream & fire knockdown) confirm that the line has indeed begun operating.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #48)
A problem the fire service is just beginning to recognize involves the construction of newer types of windows on the market. What makes them different from most older models are:
The materials used, especially Thermoplane glass & the style of construction.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #49)
Newer windows on the market – In tightly sealed areas, windows are typically glazed with ___ energy efficient glass:
Double or triple pane energy efficient glass.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #50)
Windows glazed w/ double or triple pane energy efficient glass - must make exception to sequence of ventilating as the attack begins. In this case, a sudden admission of ___ as the attack crew enters can have catastrophic results:
Oxygen
extreme fire growth or even backdraft is possible
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #51)
When you encounter energy efficient windows, undertake venting (when and while):
Undertake window venting asap - while attack team is in safe area (preferably behind closed door)
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #52)
(CFPC) – If not possible to, it may be desirable to:
Delay venting until the hose stream has thoroughly cooled fire area
(otherwise we risk FFs being caught in flashovers)
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #53)
Usual classic warning signs of flashover include:
- Open flame growing progressively to the ceiling, then rolling along ceiling.
- High heat & smoke.
- Rapid ignition of surrounding combustibles.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #54)
Today’s energy conservation practices can turn occupancies into kilns, where a slow-burning fire can:
Dry out all of the combustibles in the area.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #55)
If the rate of burning reaches ___ stage, then the entire area is ready to flashover:
Free burning stage
wasn’t as common in older bldgs
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #56)
Other factors that energy efficient windows introduce are (4):
- The difficulty in venting them with a __:
- Difficulty of clearing the entire sash area for:
- Hose stream.
- Entry or escape.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #58)
The inability to clear the horizontal sash in the middle of a double hung window is possibly a more dangerous effect. Many of the new windows are ___ construction that bends & bounces back into shape when struck by a tool:
Rolled vinyl construction
more effort is involved in removing vinyl sashes than is required for wooden ones
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #59)
Other styles of (new windows) – are ___ framed and may defy even repeated blows with an axe.
Aluminum frame windows
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #60)
After the placement of the initial attack hoseline and the designation of an interior search team, quite possibly the next most crucial position to be covered is:
The outside ventilation (OV) team.
note: this context is in the ‘newer windows’ section of the chapter
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #61)
The OV (outside ventilation) team is responsible for (4):
- Immediate exterior survey of structure
- Locating victims
- Locating seat of fire
- Creating FF escape routes
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #62)
Another potentially life-threatening development regarding window ventilation has developed as a result of ___ in recent years:
Hurricane damage
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #63)
Research has shown that much of the damage from a hurricane results when windows are broken by:
Flying debris – thus allowing the wind to enter the inside of the structure and push the roof off from underneath.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #64)
(CFPC) – As a result, several bldg codes, predominantly in ___ areas, are starting to specify window glazing that is resistant to impact:
Hurricane-prone coastal areas such as Florida.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #65)
(CFPC) – the result is windows that are absolutely impossible to vent using conventional methods. They are tested to resist a ___ w/out penetration:
9 lb 2x4 shot out of a canon at 34 mph
our common tools will result in cracking, but no effective ventilation
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #66)
There are several manufacturers & different formulations of glazing, depending on:
Size of the opening to be enclosed & desired strength.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #67)
(New e/e windows) – Some materials consist if up to 3 layers of plastic sandwiched between outer layers of glass. A very common formulation involves glass sandwiched around a:
Polycorbonate plastic such as Lexan
Image illustration is Fig. 9-3, on next card
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #68)
Fig. 9-3: High-security, impact-resistant glazings such as glass-Lexan-glass sandwiches are increasingly popular & require special tools & techniques to ventilate for rescue or escape. FFs operating in areas where these are common must realize:
That escape may not be possible through such a window.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #69)
Sandwich windows – extremely strong & are also finding use for the security they offer. The sandwiched effect of the 2 materials is far superior to either individually. The sandwich is superior to glass in resistance to breaking, and the outer glass also serves to protect the plastic, which in previous single use could be destroyed by:
Being coated with lighter fluid and then ignited.
in NYC, used in public housing developments in areas of high vandalism
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #70)
(Sandwiched glass) – Striking this glass with our common tools will result in ___, but no ___:
Result in cracking, but no effective ventilation.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #71)
(Sandwiched windows) – The best way to breach the glazing is to use a __, if available:
Circular saw with a standard carbide-tipped (wood cutting) blade if available.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #72)
Sandwiched windows – breaching glazing w/ carbide-tipped blade on circular saw; extra precautions are necessary in this operation due to effect blade has on material. That effect is:
Very fine chips & dust from both dust and plastic will be thrown off.
(Everyone in vicinity of operation should be on air from SCBA to avoid inhaling this mixture as well as to keep it out of their eyes)
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #73)
Sandwiched windows – if saw if not available, its possible to cut through this type of window using the blade of an axe. More difficult and cutting procedure is __ (2):
But avoid ___:
- Use short chopping strokes,
- Cutting nearly perpendicular to the pane
• Avoid striking the glazing at 90 degree angle.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #74)
Sandwiched windows – when cutting through using the blade of an axe → the last thing you want to do is:
Drive the head of the axe completely through the glass – bc it gets stuck easily and is difficult to pull back through.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #75)
If (saw or axe) methods unsuccessful, may be possible to create openings through walls w/ less difficult - be prepared for more than you expect. In many places where impact-resistant glazing has been installed, ___ may have been used for much the same reasons:
Impact-resistant wall materials
(there’s even impact resistant wallboard available that is Lexan backed – making breaching such a partition wall nearly impossible with standard hand tools)
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #76)
Areas that routinely encounter such security or hurricane precautions should assign an OV team early in the incident to:
Locate & clear all life-threatening obstructions.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #77)
(CPFC) – OV Team will require which tools ___:
And for wood-frame bldgs, a ___ would also be beneficial:
- Circular saw w/ carbide tip blade, in addition to tools they already carry.
- Carbide-tipped chain saw.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #78)
Factors that influence choice of vertical or horizontal ventilation or both include:
- Size & location of fire,
- Construction of bldg,
- Available staffing, and -
- The effects of the weather, particularly the wind.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #79)
___ ventilation is often preferred at minor to moderate fires:
Horizontal
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #80)
A mattress fire will produce large quantities of smoke, but there’s rarely a need for mechanical ventilation. In fact, vertical ventilation may not be very effective, since:
The low heat levels of an early stage mattress fire don’t make the smoke rise very rapidly.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #81)
Horizontal ventilation is often easier & faster to perform than vertical ventilation because it takes advantage of __. In addition, h/v can be performed from:
- Man-made openings (doors, windows)
* Ground level or from 1 man portable ladder
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #82)
Vertical ventilation usually requires ___, to get to the roof:
A longer ladder, and thus more personnel
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #83)
In most cases, horizontal ventilation is less costly to repair than vertical ventilation unless there is a:
Preexisting opening such as a skylight at the roof level.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #84)
Certain roofs can indicate the type of ventilation required. Peaked roofs on many private homes, are usually much more easily vented by ___, than by cutting the roof itself:
Smashing windows in gable ends or dormers.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #85)
Flat roofs of ___ construction would defy all but the strongest venting efforts:
Poured concrete
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #87)
Vertical ventilation is often a deciding factor in whether the fire is stopped or continues to expand. Burning materials produce ___, which take up huge volumes of space, 100s of times the volume of the original burning material.
Hot gas
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #88)
Burning materials produce hot gas, which take up huge volumes of space, 100s of times the volume of the original burning material. This gas, naturally tries to rise. When it cannot, it:
Spreads out horizontally
Creates measurable pressure that will push through smallest opening
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #89)
(CFPC)¬ - If you can create a way for mushrooming to go up & out of bldg, gas will:
Take large a part of heat energy with it, rather than allowing it to remain inside.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #90)
Horizontal venting of large quantities of hot gas is hindered by fact that – as it flows along, under the ceiling toward open window – it (does what)?
Radiates heat in all directions.
This means combustibles are being preheated & ff’s heated as well
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #91)
Benefits of vertical ventilation include horizontal fire extension is slowed dramatically. In addition, visibility & heat conditions improve rapidly as:
Fresh air is drawn at lower levels to replace the hot gas that is exiting out of the top.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #92)
Not every fire demands, or even allows for vertical ventilation. 2 examples of fires that probably won’t benefit from opening the roof:
- Relatively minor fires with little heat buildup.
* Fires in lower portions of structures, remote from vertical openings.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #93)
(Examples of fires) where will be greatly aided by vertical ventilation:
- Attics
- Cocklofts
- Floor directly below fire floor
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #94)
Fig. 9-6: Fire venting through the opening in a roof is a good sign. It means:
The spread of fire under the roof is being slowed.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #95)
Natural ventilation – by heating up products of combustion, fire has made its by-products mobile. All we have to do is open doors, windows or skylights and the smoke readily pours out. This is called natural ventilation since it is based on ___:
It is based on the natural action of heated gas.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #96)
Occasionally, the natural process is insufficient to remove ___ rapidly enough to allow FFs to finish their tasks without difficulty:
Products of combustion
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #97)
At times, smoke may be so cool that natural ventilation won’t work. Smoke will hang down low, keeping CO & HCN w/ it. Or fully developed fire knocked by sprinklers but not fully extinguished. Both cases are candidates for what type of vent:
Mechanical vent - to move gas that wouldn’t otherwise be displaced easily.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #98)
Depending on resources available & fire situation, mechanical ventilation can involve:
- Hoselines
- Portable fans
- Bldg vent systems
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #99)
Venting can be done either by:
Both methods accomplish the objective of:
- Sucking contaminated air out or
- Blowing fresh air in.
• Removing all of the contaminated air & replacing it with fresh air.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #100)
Ventilation using a ___ or ___ is one of the earliest and simplest means of mechanical ventilation:
Fog or spray stream
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #101)
Ventilation using a fog or spray stream is 1 of the earliest & simplest means of mechanical ventilation. It is by far the least demanding in terms of:
Personnel
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #102)
Ventilation using a fog or spray stream is 1 of the earliest & simplest means of mechanical ventilation. It is by far the least demanding in terms of personnel. This method relies on the fact that:
A spray of water entrains air with it, carrying the air out in a stream
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #103)
Mechanical Ventilation – Fog or Spray Stream: Several factors that affect how much air, thus smoke a stream can move:
- Volume of water flowing
- Velocity of stream
- Geometry of the opening and stream
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #104)
Mech. Vent; Fog/Spray Stream: Factors that affect how much air, thus smoke a stream can move → 1st – volume of water flowing, since each tiny water droplet brings along a limited amount of:
Air
The more water flowing → the more air is moved.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #105)
Mech. Vent; Fog/Spray Stream: Factors that affect how much air, thus smoke a stream can move → 2nd is velocity of the stream, which is a function of:
The pattern of the stream & the nozzle flowing pressure.
the higher the NP, the more air that is moved
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #106)
M-Vent; Fog/Spray Stream: Factors that affect how much air - thus smoke a stream can move; 2nd (cont): The pattern that moves the most air from an area is 1 that is ___. And degree is:
- 1 that is tight enough to move the stream & gas out of the area, yet wide enough to entrain large amounts of air.
- Generally this is in the range of about 30 degree fog pattern.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #107)
Fig. 9-7: The use of a fog pattern to assist ventilation is a very useful technique. It can also be performed with a solid-tip nozzle by only:
Opening the shutoff partway
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #108)
Fig. 9-7 (cont): Fog pattern to assist in ventilation:
- ___ optimum angle of pattern:
- Nozzle distance to window ___ optimum:
- 30 – 35 degrees
- 6-8 ft
(Higher = better NP)
(Gallonage higher = greater air flow)
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #109)
M-Vent; Fog/Spray Stream: Factors that affect how much air, thus smoke a stream can move → 3rd factor is geometry of the opening & stream. By standing ___ back from the window/door & adjusting the pattern to cover just the opening, you create a:
6 – 8’
Venturi effect – which will add to the efficiency of the stream itself.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #110)
(CFPC) – At times, 6-8’ positioning won’t be possible/practical. In case of a well-involved comm. area of md size, to get 6-8’ away from the window may mean you have to pass a lot of smoldering material. When you begin your ventilation efforts, fresh air drawn towards nozzle can cause:
The smoldering material to burst back into flame, drawing all the heat smoke past the nozzle team.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #111)
(CFPC) – In this case, its better to give up some efficiency & remain farther back, using a ___ to reach the door:
Narrower stream
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #112)
Mechanical Ventilation with a fog or spray stream → If practical, keep the fire between ___ & ___ until you are sure there is little danger from a fanned rekindle.
Nozzle & the vent point
This NC ties into previous cards
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #113)
Mech. Vent w/ Fog: Danger of fanning into life a smoldering fire is possible w/ all types of mechanical vent. FF’s on line can darken such fire down. Since/bc:
The volume of air moved is generally much larger & occurs faster than if you rely on natural ventilation.
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #115)
Mech. Vent w/ Fog: Of course there are drawbacks to using a hose stream. Areas where this procedure can’t be used include (3):
- Minor fires where h2o damage is concern,
- In areas of poor water supply (drain of using part of avail. water supply to move smoke may mean running short on water for fire control)
- In areas of below freezing temps (if spray will land result in ice/fall hazards)
Ch. 9: Norman – Ventilation
Section: Types of Ventilation (NC #116)
Smoke ejectors, blowers, exhaust fans & other portable devices suffer none of the drawbacks of the hoseline except the same problem of a:
Forced draft over smoldering embers
(Problems on such devices can develop regarding availability of power supply, personnel requirements, storage space, whether explosive gas is present, etc – but usually can be overcome)
Ch. 9: Norman – Ventilation
Section: Negative Vs. Positive Pressure (NC #117)
___ ventilation offers FFs a great opportunity to channel POCs where we want them to go:
Mechanical
Ch. 9: Norman – Ventilation
Section: Negative Vs. Positive Pressure (NC #118)
Various types of smoke removal devices offer choice of modes of operation, either sucking smoke out of bldg or blowing fresh air in. For the 1st 20 years of mechanical ventilation, the most common use was ___ devices:
Exhaust devices, sucking smoke through the mechanism.
Ch. 9: Norman – Ventilation
Section: Negative Vs. Positive Pressure (NC #119)
Exhaust devices – suck smoke through the mechanism → proved ineffective. Bc fans never fit an opening correctly – makeshift methods used to block off openings around sides of the unit. Penalty for not doing so resulted in:
Churning
Ch. 9: Norman – Ventilation
Section: Negative Vs. Positive Pressure (NC #120)
Churning results when/is:
Results in some air from outside being drawn into the bldg & blown out again through the fan.
Ch. 9: Norman – Ventilation
Section: Negative Vs. Positive Pressure (NC #121)
Churning results in some air from outside being drawn into the bldg & blown out again through the fan. This means fan isn’t using all of its capacity to move smoke, bc:
Some percentage is wasted moving clean air outside.
Ch. 9: Norman – Ventilation
Section: Negative Vs. Positive Pressure (NC #122)
Other problems resulting from exhaust systems – debris, curtains, etc being drawn against the:
Intake screen – thus blocking the flow
Ch. 9: Norman – Ventilation
Section: Negative Vs. Positive Pressure (NC #123)
Another disadvantage is the location of a negative pressure fan, hanging up or near doorways used by personnel. Bc they blow outward, combustible gases are:
Drawn across the motor.
Are of explosion proof design when leave factory, but don’t count on it
Ch. 9: Norman – Ventilation
Section: Negative Vs. Positive Pressure (NC #124)
Blowing fresh air into the structure – the idea was originally tested as a way of reducing:
Stack effect
Ch. 9: Norman – Ventilation
Section: Negative Vs. Positive Pressure (NC #125)
Stack effect, that is the drawing of:
Heat & smoke toward staircases, and thus the point of attack in high-rise fires
Ch. 9: Norman – Ventilation
Section: Negative Vs. Positive Pressure (NC #126)
Experimentation has proved that by putting a positive pressure in a stairwell, the ___ can be reversed:
Flow of heated gases – enabling attack crews to gain a foothold on the fire floor.
LAFD has expanded on these experiments.
Ch. 9: Norman – Ventilation
Section: Advantages of Positive Pressure Ventilation (NC #127)
PPV has decided advantages of NPV in certain respects, the first is:
Efficiency
Ch. 9: Norman – Ventilation
Section: Advantages of Positive Pressure Ventilation (NC #128)
With PPV, the fan is set up (where) in regards to the desired opening:
Outside of the structure, 8 – 12’ away from desired opening.
Airstream from fan aimed to fully cover the opening. Larger doors at comm. structures may require several fans.
Ch. 9: Norman – Ventilation
Section: Advantages of Positive Pressure Ventilation (NC #129)
PPV – The moving airstream entrains more air along its sides as it flows, acting as a ___ to bring in more air as it passes through the opening.
Venturi effect
Ch. 9: Norman – Ventilation
Section: Advantages of Positive Pressure Ventilation (NC #130)
(CFPC) PPV – Venturi effect → The resulting movement of air into the structure pushes ___ ahead of it:
Smoke contaminated air
Ch. 9: Norman – Ventilation
Section: Advantages of Positive Pressure Ventilation (NC #131)
PPV → Just as when advancing a fog stream, you must provide a ___ for the gas opposite the entrance to speed the process:
Outlet
Ch. 9: Norman – Ventilation
Section: Advantages of Positive Pressure Ventilation (NC #132)
PPV – A fan can move (how much more) the volume of smoke compared to the negative mode, especially if churning occurs:
Almost twice as much
another way of looking at it – the same job can be done in half the time
Ch. 9: Norman – Ventilation
Section: Advantages of Positive Pressure Ventilation (NC #133)
PPV → experiments conducted by LAFD show that the best results can be obtained by (3):
- Clearing 1 section of the structure at a time by opening windows in room to be cleared.
- Then move to next room &
- Closing windows/doors to isolate 1st room.
Ch. 9: Norman – Ventilation
Section: Advantages of Positive Pressure Ventilation (NC #134)
Fig. 9-9: Venting a large structure using PPV should proceed in stages. Do not open all simultaneously, or the fan may not be able to:
Fan may not be able to move a sufficient volume of air to pressurize all the openings.
Ch. 9: Norman – Ventilation
Section: Advantages of Positive Pressure Ventilation (NC #135)
PPV → In setting up fans, take ___ into account. Work with it rather than against it.
Natural wind
Ch. 9: Norman – Ventilation
Section: Advantages of Positive Pressure Ventilation (NC #136)
PPV → In setting up fans, take natural wind into account. Work with it rather than against it. This method works best with which fires:
- Minor to moderate fires, where
* Smoke (rather than fire) is the greatest difficulty
Ch. 9: Norman – Ventilation
Section: Advantages of Positive Pressure Ventilation (NC #137)
With advanced fires that have self vented – the effect of fan’s airstream may be reduced or overpowered by ___ or ___, due to the large # of openings spread around the bldg:
- Fire’s convective currents &
* Outside air movements.
Ch. 9: Norman – Ventilation
Section: Advantages of Positive Pressure Ventilation (NC #138)
Since PPV fans are set back from doorway, they don’t clutter access routes. Types of fires which are prime candidates for PPV:
- Mattresses, stuffed chairs & other extra smoky fires, such as those -
- Partially extinguished by sprinkler systems
Ch. 9: Norman – Ventilation
Section: Advantages of Positive Pressure Ventilation (NC #139)
PPV fans also have a ready ability to remove flammable vapors safely. ___ & ___, for example may have collected in areas away from openings:
NG or propane
Ch. 9: Norman – Ventilation
Section: Disadvantages of PPV (NC #140)
PPV has some drawbacks, the most serious being the danger of:
Way to prevent this is to:
Fanning a smoldering fire into a serious conflagration.
Have a charged hoseline in place & ready to operate.
Ch. 9: Norman – Ventilation
Section: Disadvantages of PPV (NC #141)
(CFPC) - If fire is a ___, it may not be possible to expose it & darken it down fast enough to prevent considerable extension.
Concealed space
Ch. 9: Norman – Ventilation
Section: Disadvantages of PPV (NC #142)
Another possible situation involves separate fires in remote areas, as is common in ___ incidents:
Arson
Ch. 9: Norman – Ventilation
Section: Disadvantages of PPV (NC #143)
The effect of blowing fresh air from a fan onto a fire is the same as when it is directed out of a bellows onto a blacksmith’s ___ - the fire intensifies:
Hearth
Ch. 9: Norman – Ventilation
Section: Disadvantages of PPV (NC #144)
PPV → Fan mustn’t be allowed to ___ on the opposite side:
(Continued on next card)
Blow the fire towards any victims or FFs on the opposite side.
Ch. 9: Norman – Ventilation
Section: Disadvantages of PPV (NC #145)
PPV → Fan mustn’t be allowed to blow fire towards any victims or FFs on opposite side. For this reason, PPV must not be used if FFs are entering the bldg from:
Any points other than where the fan is operating.
Requires coordination if VES is to be employed
Ch. 9: Norman – Ventilation
Section: Disadvantages of PPV (NC #146)
Fig. 9-10: PPV should not be used at the same time entry into a bldg is made from the outside via:
VES.
(Fan can drive POC, including flames to the just vented area – as its designed to, but a victim you are trying to rescue & FF entering will be directly in its path)
Ch. 9: Norman – Ventilation
Section: Disadvantages of PPV (NC #147)
PPV requires coordination between M’s. Personnel should follow proper sequence of opening/closing windows as each room is cleared. If there are many openings in close proximity to ___, smoke filled area may receive little ventilation as fresh air simply re-circulates to the outdoors:
Door being used for PPV
Ch. 9: Norman – Ventilation
Section: Disadvantages of PPV (NC #148)
Coordinate PPV. Follow proper sequence of opening/ closing windows as ea. room is cleared – won’t be effective if don’t. If lots of windows open in close proximity to PPV door – smoke filled area will receive little ventilation bc:
Fresh air supply will re-circulate to outdoors.
Ch. 9: Norman – Ventilation
Section: Disadvantages of PPV (NC #149)
Naturally, in bldgs where there is a suspected life hazard, the principle of venting for life demands that:
Windows be taken out.
Ch. 9: Norman – Ventilation
Section: Disadvantages of PPV (NC #150)
If a FD becomes too infatuated with PPV, they may find that their desire to keep windows in tact will have an adverse effect on:
Any victims inside who need fresh air to survive.
Ch. 9: Norman – Ventilation
Section: Disadvantages of PPV (NC #151)
The fan can also provide fresh air to trapped occupants, but if there is a ___ in their vicinity, there is a risk of any fire between the victims and the fan right at the victims:
Exhaust opening
Ch. 9: Norman – Ventilation
Section: Disadvantages of PPV (NC #152)
A basic tenet for an interior FFs search for a life hazard is to vent as you move, provided:
The fire won’t be extended by venting
Ch. 9: Norman – Ventilation
Section: Disadvantages of PPV (NC #153)
A basic tenet for an interior FFs search for a life hazard is to vent as you move, provided the fire won’t be extended by venting. That is exactly the (same/opposite) ___ pattern desired to make PPV work most effectively:
Opposite
Ch. 9: Norman – Ventilation
Section: Disadvantages of PPV (NC #154)
The decision to use PPV should be made only after considering all of the factors that affect the situation. Before starting the fan, the IC should know the answers to the following: (1st of 7) – Where is ___:
Life hazard, including FFs
Ch. 9: Norman – Ventilation
Section: Disadvantages of PPV (NC #155)
Decision to use PPV - made after considering all factors that affect the situation. Before starting the fan, the IC should know the answers to the following: (2nd of 7) – What is ___ of fire:
What is location & extent of fire? Is it in void spaces?
Ch. 9: Norman – Ventilation
Section: Disadvantages of PPV (NC #156)
Decision to use PPV - made after considering all factors that affect the situation. Before starting the fan, the IC should know the answers to the following: (3rd of 7) – What is status of:
What is status of all hoselines? Are they operating or ready to operate?
Ch. 9: Norman – Ventilation
Section: Disadvantages of PPV (NC #157)
Decision to use PPV - made after considering all factors that affect the situation. Before starting the fan, the IC should know the answers to the following: (4th of 7) – What degree of ___ is present?
What degree of confinement is present? If fire already self-vented, PPV may not be useful.
Ch. 9: Norman – Ventilation
Section: Disadvantages of PPV (NC #158)
Decision to use PPV - made after considering all factors that affect the situation. Before starting the fan, the IC should know the answers to the following: (5th & 6th of 7) – What ___ are available?
What exhaust openings are available or can be created?
What PPE equipment is available? Will power supply create any issues (noise, exhaust fumes) at CP?
Ch. 9: Norman – Ventilation
Section: Disadvantages of PPV (NC #159)
Decision to use PPV - made after considering all factors that affect the situation. Before starting the fan, the IC should know the answers to the following: (7th of 7) – What ___ exists in vicinity of fan?
What environmental factors exist in vicinity of the fan?
i.e. dust, weeds, powders, etc – materials that may be drawn into fan, impending ops
Ch. 9: Norman – Ventilation
Section: Disadvantages of PPV (NC #160)
Decision to use PPV - made after considering all factors that affect the situation. Before starting the fan, the IC should know the answers to the following 7 questions – Review, all start ‘what is’ except #1:
- Where is life hazard (including FFs)
- What is location/extent of fire? Voids?
- Status of hoselines? Operating/ready to?
- What degree of confinement is present?
- What exhaust openings avail/can be made?
- What PPE equipment avail?
- Environmental factors around fan?
Ch. 9: Norman – Ventilation
Section: Vertical Ventilation – Taking the Lid Off (NC #161)
Once fire achieves headway, it builds up ___ of its own within the structure:
Pressure
Ch. 9: Norman – Ventilation
Section: Vertical Ventilation – Taking the Lid Off (NC #162)
At times, such pressure is substantial & is responsible for creating the advancing flame front through the fire area as additional gas distills from the burning fuel and expands. The natural tendency of if for the heated gas to:
Rise
Ch. 9: Norman – Ventilation
Section: Vertical Ventilation – Taking the Lid Off (NC #163)
The mushroom effect is:
- Natural tendency for heated gas is to rise;
- When restrained from rising →
- It spreads out horizontally & then starts to bank down.
Ch. 9: Norman – Ventilation
Section: Vertical Ventilation – Taking the Lid Off (NC #164)
Ways to prevent horizontal fire spread:
The most effective & efficient way to prevent horizontal fire spread is:
- Build a fire resistive partition,
- Position countering hose stream,
- Let gas continue on its upward journey, where it wants to go – most effective/efficient way
Ch. 9: Norman – Ventilation
Section: Vertical Ventilation – Taking the Lid Off (NC #165)
Preventing horizontal fire spread, most effective/efficient way is to let the gas continue on its upward journey, where it wants to go. This is best accomplished in multistory structures by:
Making an opening directly over any vertical arteries that the fire is exploring.
Ch. 9: Norman – Ventilation
Section: Vertical Ventilation – Taking the Lid Off (NC #166)
(CFPC)¬ – The most common vertical artery is:
Staircase
THIS WAS A TEST QUESTION
Ch. 9: Norman – Ventilation
Section: Vertical Ventilation – Taking the Lid Off (NC #167)
By providing an opening of sufficient size at the top, the fire can continue skyward without:
Extending horizontally
Ch. 9: Norman – Ventilation
Section: Vertical Ventilation – Taking the Lid Off (NC #168)
Sometimes staircases continue past the floor, ending in a bulkhead w/ a door leading to the roof. ___ (complete what) as your 1st action upon reaching the roof:
Open this door (leading to roof) and check inside for trapped occupants.
Ch. 9: Norman – Ventilation
Section: Vertical Ventilation – Taking the Lid Off (NC #169)
FFs should recognize the bldgs where ___ is possible and, in the event of a serious fire, make efforts to open this as soon as possible:
Vertical ventilation
Ch. 9: Norman – Ventilation
Section: Vertical Ventilation – Taking the Lid Off (NC #170)
Many multistory bldgs have a ___ over the staircase:
Skylight
Ch. 9: Norman – Ventilation
Section: Vertical Ventilation – Taking the Lid Off (NC #171)
Fig. 9-12: The skylight over a stairway is a ready-made opening at the highest point of the ___ that is the interior staircase:
The chimney
Ch. 9: Norman – Ventilation
Section: Vertical Ventilation – Taking the Lid Off (NC #172)
Many multistory bldgs have skylight over staircase – by either removing skylight or breaking panes, you can quickly provide ventilation over stair this critical artery. In breaking the skylight, remember:
Other personnel will most likely be ascending stairs.
Ch. 9: Norman – Ventilation
Section: Vertical Ventilation – Taking the Lid Off (NC #173)
(CFPC)¬ – Give members below some warning of falling glass & don’t drop entire housing through the opening. Besides calling out, “I’m taking the skylight” on the radio, 1st:
Break a single pane of glass 1st, and then pause for a few seconds.
(falling glass will signal to members on the stairs, and they can take steps to protect themselves)