14 Special Vent Ops Flashcards
pg 410
Physical exertion of crews to reach the fire floor will mean:
They may have less energy to perform firefighting functions
pg 411
Truck crews should never enter high rise empty handed. If they aren’t carrying forced entry tools or vent equipment they should have
Space Scba cylinders
Hose
Tools
Lights
pg 411
Moving large amounts of tools is generally coordinated by those assigned to
Lobby control
pg 411
Low rise elevators
serve the lower floors of the building
example: Floors 1-10
pg 411
Mid rise elevators
Only floors between low and high elevators ex, floor 1 and floor 10-20
pg 411
High-rise elevators
Serve only upper floors, ex.. Floor 1 and 20-30
pg 411
Express elevators
Ground floor to upper most floor. Ex. Floor 1 and 31 or whatever highest floor is
pg 411
Freight elevators
Serve some or all floors.
also designed to carry heavier loads than ordinary passenger elevators.
pg 411
Freight elevators should only be used when authorized by the officer in charge on the fire floor.
They can handle the additional weight of ff’s in full ppe along with extra tools and equipment, weighting more than a ton
pg 412
Dangers of using elevators in a fire
Malfunction or damage from heat could recall elevator car to the fire floor or strand the elevator between floors in the shaft.
pg 412
Stack effect
Natural vertical mvnt of air, or heat and smoke, in tall structures based on differences of air density inside and outside the buildings due to temp differences. Strong vertical column of mvnt.
pg 412
With the stack effect, the greater difference between the inside and outside temp and the greater the building height,
The greater the stack effect will be
pg 412
If it is hotter inside than outside the air flow will be inward at the bottom and outward at the top. In a reverse stack effect the outside air is:
Hotter.
airflow is down and out.
pg 413
Mushrooming, aka ceiling jets
Smoke rising until it hit barrier, then move horizontally until same. Then banks down and fills
pg 413
When smoke reaches the same temp as ambient air in the high rise, it loses its buoyancy and
Stratifies, forming layers of smoke in the building.
stratification can occur near the top floor and/or several floors down below.
pg 414
Most ppv positioned at street level are only effective up to how many floors up
22
more fans at the 22 floor or around there, or add smoke ejectors at the top most floor to be vented, or both
pg 414
Highrise vent options (3)
Vertical or top ventilation
Horizontal fire floor
Horizontal above and below fire floor
pg 415
If vertical vent may endanger fleeing occupants, what might have to be used
Horizontal vent
pg 415
Fire and smoke should be vented vertically through stairwells and other vertical shafts, taking advantage of
The stack effect
pg 415
Vertical venting in highrises can prevent
Mushrooming on upper floors and does not promote lapping, which is always a danger when horizontally venting multistory buildings below the top floor.
pg 415
One of the biggest challenges to vertical or top venting is
Getting ff and equipment to the roof
pg 415
If the roof is within reach of an aerial on a highrise, it is the preferred method for
Moving manpower and equipment to the roof for venting
pg 415
If an aerial does not reach the roof, how can it be used to gain access
Reach the farthest floor it can, enter through a fire escape or window and use stair and elevators the rest of the way to the roof
pg 415
Although highrises usually have more than one stairway, few have more than one that
Terminates at the roof.
pg 416
During a fire, a stairwell can be relatively free of smoke but congested with
Occupants, attack lines and ff.
therefore dedicating one stairway for evacuation and another for fire attack is critical.
pg 416
Elevators that service the fire floor or floors above should not be used unless
The officer in charge of the fire floor deems it safe to do so.
contradicts pg. 411. moving equipment is deemed safe by IC.
pg 417
If a bulkhead or penthouse is used to ventilate the stairwell that terminates at the roof, the door should be blocked open because
If it closes it could change the vent profile dangerously
pg 417
Ventilation in the stairwell that terminates at the top floor should be delayed until
All occupants have been evacuated or in an area of refuge.
FFs should be clear of the vent stairwell prior to venting. once it is opened the stairwell can be come untenable.
pg 418
If buoyancy is the only force acting on gasses within a closed compartment, then in relation to atmospheric pressure, the pressure will be what at the top
Higher at the top and lower at the bottom
pg 418
Neutral pressure plane
Point in a highrise where interior pressure equals atmospheric pressure outside, moves up or down depending on wind and temp. May be in middle of building
pg 419
The neutral plane in a building without gasses being vented or openings made is where
Between 35-50% of the building height.
pg 419
In extreme distances between the neural plane, if openings are made at the top and bottom of a structure, the escape of high pressure at the top and inward pull of air at the bottom Causes
The entire building to act as a chimney, stack effect
By dragging smoke out of a building with a smoke ejector, it causes negative pressure inside the compartment and
Forces the air out while dragging higher pressure air in from outside
What can raise or lower the neutral pressure plane
Wind
pg 421
Opening a window below the neutral pressure plane may
Draw air inside the building rather than allow smoke out of it, spreading fire
The closer ventilation takes place near the neutral plane,
The less effect, positive or negative, wind will have on it
Venting below the fire is not common but may be needed when smoke has spread to lower floors because of
Reverse stack effect
Venting floors below the fire can be facilitated by
Using ppv blowers or other fans
Venting on the fire floor first requires a knowledge of building layout because
Venting a dead end corridor or into a shaft that doesn’t exit can cause vent problems or extension
Horizontal venting on the fire floor should be done only when there is no other choice because
It can be Time consuming because of window construction, and dangerous to people on the street below
Vertical venting can be accomplished on intermediate highrise floors by
Venting smoke across the fire floor to the stairwell that reaches the roof. Maybe with assistance from fans.
pg 424
Smoke dampers
Control airflow in hvac units, usually activated by fire alarm signaling system
pg 424
The actual manipulation of hvac system for smoke control should be left to
The building engineer, who much be available to IC for consultation and for actual manipulation of the HVAC system under fd direction
pg 424
Guidelines for effectively using hvac system to control smoke mvnt
Operated only by building engineer
Used to assist locating seat of fire
Use to limit fire extension and smoke to smallest area possible
Should not be allowed to spread fire or smoke beyond area of origin
Provide fresh air to trapped occupants in refuge areas
pg 424
To accomplish manual shut down of smoke dampers with the least delay, building engineer should be contacted when
As soon as the fd arrives
pg 427
Curtain boards
Vertical boards, fire resistive half walls that extend down from roof to limit spread of fire and smoke
pg 425
Because automatic roof vents work on their own, it may reduce or eliminate the need for
Additional vertical venting
under some conditions, previaling winds may prevent heat and smoke from exiting through automatic roof vents.
pg 425
Automatic roof vents may be activated by smoke detectors but otherwise, most still operate using
Spring loaded or counterweight cover assembly with fusible link activator
pg 427
Sprinklers operating near roof vents may not allow heat to activate them, firefighters should not try to force open vents because it can damage them, but rather they should
Be familiar with manual controls
pg 410
Highrise fires present numerous challenges, including (8)
Limited access Large number of offices or apartments Heavy occupant loads Falling glass or debris Rapid smoke and fire spread through shafts Locked interior doors Low water pressure Climbing a lot of stairs
pg 426
Monitors are primarily intended to increase natural light in a building but may also provide
Natural ventilation
pg 426
Most monitors have wires glass or glass panels sloping down from their ridge as a roof and rely on what for ventilation
Rely on the glass breaking for vent
note: monitors with solid walls may be hinged at the bottom and held closed at the top with a fusable link.
pg 426
Monitors with solid walls may have panels hinged at the bottoms with fusible links to
allow them to fall open by gravity in case of fire.
427
Curtain boards are intended to confine the fire to an area over its source, the walls generally extend how far
A distance of at least 20 percent the vertical distance from the floor to roof but no lower than 10 feet
pg 427
Curtain board may help accelerate the activation of
Sprinkler heads over the area of origin
pg 428
Usually but not always, cellars will have no windows and basements will have
Small windows between grade level and first floor
pg 428
Early ventilation of fire below grade is critically important to firefighting operations because
Pipe chases, shafts, chutes etc can contribute to fire spread on upper floors
pg 428
To prevent or reduce the upward spread of smoke and fire from an involved basement or cellar, it must be vented as quickly as possible. If an opening of adequate size can be made opposite into interior point of entry into the space the fastest way to ventilate the compartment may be:
to set up a positive-pressure blower at the entry point.
pg 428
If no openings can be made in a cellar how do you vent
Cut a hole on the first floor near a window and position a smoke ejector to facilitate vent
pg 429
Windowless building require what type of vent
Fast vertical vent to prevent backdraft
p.412 Warning
+Elevators that serve the fire floor or above should not be used unless?
-This includes freight elevators
The officer in charge on fire floor has deemed safe to do so
p.412
+Elevators that do not serve the fire floor or above may be used to evacuate occupants and for shuttling FF’s and equipment party way to the fire floor ONLY if it is equipped with?
Manual Fire Department Controls
p.412
+The greater the difference between outside and inside temps and the greater the building height, the greater the___ will be.
Stack effect
p.413
+____ of smoke can create a highly toxic atmosphere many floors above the fire, even when there is little heat.
Stratification
p.415
+___ can prevent or reduce mushrooming on the upper floors and does not promote lapping.
Top Ventilation
p.415
+When able to reach the roof of a high rise, using it is the preferred method of getting firefighters to the roof because it is the fastest, safest and most direct route and avoids the congestion of occupants and firefighters and their equipment entering the interior stairways.
Aerial Device
p.419
+Assuming the structure is closed, with little or no gases being vented to the atmosphere, a neutral pressure plane exists at the level of ambient atmospheric pressure, which is usually between__ and__ percent of the building height.
35 and 50 percent
p.421
+The closer that ventilation takes place to the__ __ ___, the less positive or negative effects wind will exert.
Neutral pressure plane
p.423
+When only cold smoke is left, vertically venting eliminates the need for breaking windows for horizontal vent, also opening floors up near the neutral pressure plane only minimally affects smoke removal unless __ ventilation is added.
Mechanical
p.428
+Basements that have both interior stairwell access and access from the exterior of the building are called?
(FULL ACCESS)
Daylight Basements
p.429 Windowless Buildings
+These walls may appear fragile but can be as resistant to being breached as masonry and are of little value to tactical ventilation.
Translucent glass walls
