Transcript Cont. - SCFA Online Training

South Carolina Fire Academy
1402 Hybrid Firefighter I
6th Edition
Chapter 13
Tactical Ventilation
Tactical ventilation is carefully
planned to achieve the best results
Planned, systematic,
coordinated removal
Performed for
Performed only when
fire attack hoselines,
teams
• Heated air
• Smoke
• Gases
• Other airborne contaminants
• Life safety
• Incident stabilization
• Property conservation
• In place
• Ready to attack
13–1
The success of tactical ventilation
depends on several factors
Careful
planning
Knowledge of
building
construction
Systematic
application of
procedures
Coordination
with other
activities
13–2
Tactical ventilation is performed
for several general reasons
Reduce interior
heat levels
Decrease rate of
fire spread
Reduce potential
of extreme fire
behavior
Improve interior
visibility
Improve
firefighter
efficiency
Improve victim
survival
Reduce smoke,
property damage
13–3
Tactical ventilation can be effective
when correctly implemented
Properly implemented
• Life safety
• Incident stabilization
• Property conservation
Improperly applied –
Can impact
• Occupants
• Firefighters
• Physical structure
13–4
Tactical ventilation can improve life
safety: The highest incident priority
Increasing oxygen concentration
Reducing concentration of toxic products
Reducing temperature
Increasing visibility
Creating smoke-free paths of egress
13–5
Incident stabilization can be
accomplished through ventilation
Stages to control, extinguish fire
Locate
Confine
Extinguish
13–6
Ventilation can influence
Property Conservation
Can remove smoke, gases, heat and
confine fire to specific area
Salvage can begin outside of immediate
fire area if enough personnel on scene
Ventilation can increase speed of fire
extinguishment
13–7
Both occupants and firefighters
are at risk during a structural fire
Occupants – Life
hazards
• Lower if awake
• Several
possibilities if
asleep
Firefighters –
Expected hazards
• Visual impairment
• Lack of oxygen
• Presence of toxic,
flammable gases
• Rapid fire
development
possible
13–8
Changes in building construction
present different risks during fires
Residential
structure and lot
size differences
Layout,
construction
material changes
Open plan
commercial
structures
Energy
conservation
measures
Use of plastics,
synthetic
materials
13–9
Knowledge of the building can help
make decisions concerning ventilation
13–10
Various building characteristics should
be considered when ventilating
Occupancy
classification
Ceiling height
Construction type
Floor area,
compartmentation
Number of stories
Number, size of
exterior windows,
doors, other wall
openings
(Cont.)
13–11
Various building characteristics should
be considered when ventilating
Number, location of
staircases, elevator
shafts, dumbwaiters,
ducts, roof openings
External exposures
Connection to
adjoining structures
Type, design of roof
Type, location of fire
protection systems
Contents
HVAC system
13–12
Several fire behavior indicators also
help with planning for ventilation
Smoke
Air flow
(Cont.)
13–13
Several fire behavior indicators also
help with planning for ventilation
Heat
Flame
13–14
CAUTION!
Do not rely solely on the presence or
location of flames to assess an incident.
13–15
First arriving units must determine
size, location, and extent of the fire
Uncoordinated
ventilation
Can spread
fire or cut off
escape
Severity,
extent of fire
depends on
several factors
Primary
consideration
Phase to
which fire has
progressed
13–16
The type of ventilation used
will depend on several factors
Coordination
with other
operations
Before orders
are given
IC
determines if
necessary
Conditions upon
arrival
Must be
appropriate for
situation
Must be capable
of exhausting
volume
13–17
The location for ventilation must be
selected based on several factors
Location of
occupants
Existing roof
openings
Desired air
flow path
Building
construction
Wind direction
Extent of fire
progress
Condition of
building,
contents
(Cont.)
13–18
The location for ventilation must be
selected based on several factors
Potential
structural
collapse
Effect on fire
Effect on
exposures
Readiness of
crew
Ability to
protect
exposures
Protecting
means of
egress, access
13–19
Weather conditions will affect what
happens inside a building as well
Building
openings
Other
conditions
Wind- most
important
13–20
CAUTION!
A strong wind can overpower the
natural convective effect of a fire and
drive the smoke and hot gases back into
the building.
13–21
Exposures should be taken into
account when planning ventilation
Internal
• Affected by routing of smoke
• Ventilation can create danger
External
• Affected by radiation, direct flame
contact
13–22
Staffing and resources are both
requirements for ventilation
Resources needed
• Forcible entry tools
• Power saws
• Fans or blowers
• Smoke ejectors
• Flexible ducts
• Stacking and hanging devices
• Other support systems
• Electrical power cords
• Generators
13–23
There are two main types of tactical
ventilation that can be performed
Heat, smoke, other
parts of combustion
channeled out
through existing or
created horizontal
openings
Horizontal Ventilation
(Cont.)
13–24
There are two main types of tactical
ventilation that can be performed
Ventilating at
point above the
fire; channeling
contaminated
atmosphere out
the top
Vertical Ventilation
13–25
There are three means to accomplish
ventilation used in the fire service
Natural
Mechanical Hydraulic
13–26
There are several indicators of the need
for mechanical or hydraulic ventilation
Building or
fire dictates
other
method
Involved
area too
large for
natural
Fire below
ground
Location,
size
determined
Layout not
conducive to
natural
Natural
slows,
needs
support
13–27
Horizontal ventilation can be applied
to several types of structures
Building where fire has not involved attic, cockloft
Multi-story building with fire below top floor, or top floor if attic
uninvolved
Building so weakened would be unsafe for vertical ventilation
Building with daylight basement
Building where vertical ventilation ineffective
13–28
Natural horizontal ventilation works
with existing conditions to take
advantage of natural air flow
13–29
There are two types of mechanical
horizontal ventilation
Negative-pressure
ventilation (NPV)
Positive-pressure
ventilation (PPV)
13–30
NPV uses smoke ejectors to expel
and pull smoke from a structure
Know
placement
process
• In windows openings
• On leeward side
• Properly seal
• Flow of smoke, gases
• Avoid opening windows, doors
near ejector
• Remove obstacles
• Do not allow ejector to be
obstructed
Understand
selection
and use
• Use intrinsically safe if needed
• Turn off when carrying
• Cautions before starting
• Avoid air discharge
13–31
PPV uses a fan to create slightly
higher pressure inside a structure
than is outside
13–32
WARNING!
Improperly applied, PPV can change the
interior conditions and injure personnel
working inside the structure.
13–33
PPV has both advantages
and disadvantages
Advantages
Disadvantages
•
•
•
•
•
•
•
•
•
• Structure must be intact
• May increase interior carbon
monoxide levels if fan exhaust
enters
• May accelerate, spread hidden
fires
Set up
Effectiveness
Efficiency
Limits currents
Operate efficiently
Cleaning, maintenance less
Effective in all structure types
Able to direct
Can be pressurized
13–34
You should know the precautions
against upsetting horizontal ventilation
May pressurize
building, intensify
fire, cause fire
spread
May reduce or
eliminate positive
effects of air currents
13–35
Mechanical ventilation has both
advantages and disadvantages
Advantages
• Enhances natural ventilation
• Ensures more air flow control
• Speeds removal of contaminants
• Reduces smoke damage
• Promotes good public relations
• Benefits spaces with low oxygen levels
Disadvantages
• Can cause fire to intensify, spread
• Depends on power source
• Requires special equipment, additional
resources and personnel
13–36
Vertical ventilation occurs after the
Incident Commander considers
several factors
Need for
ventilation
Escape routes
Location for
ventilation
If it can be
done safely,
effectively
Safety
precautions
Personnel,
tools moved
Age, type of
structure
involved
Location,
duration,
extent of fire
13–37
Vertical ventilation presents
several risks the IC must assess
Risks
Determine
if offensive
or defensive
• Personnel working above
ground level on peaked, flat
surfaces
• Working above fire, on
weakened roofs
• Offensive – Aids in reaching,
extinguishing fire
• Defensive – Stop spread of
fire, contains in one area
13–38
Safety precautions should be
used during vertical ventilation
Check wind
direction,
velocity
Note
obstructions,
excessive weight
Provide
secondary
means of escape
(Cont.)
13–39
Safety precautions should be
used during vertical ventilation
Ensure main
structural
supports not cut
Guard opening
Evacuate
promptly
Prevent
personnel from
sliding, falling off
roof
Secure ladder
firmly
(Cont.)
13–40
CAUTION!
Roof ladders are only meant to prevent
slipping and are not intended to be
used on fire-weakened roofs.
13–41
Safety precautions should be
used during vertical ventilation
Caution when
around electric
wires, solar
panels, guy wires
Remain aware of
overhead
obstructions
Wear full PPE
Keep out of
range of
swinging axes,
power saws
Power tool
cautions
Extend ground
ladders above
edge of roof or
top of wall
(Cont.)
13–42
Safety precautions should be
used during vertical ventilation
Ensure aerial
platform even or
slightly above
roof
Check roof
structural
integrity
Walk on loadbearing walls,
strongest parts
Penetrate ceiling
to enhance
ventilation
13–43
WARNING!
Never direct a fire stream into a vertical
exhaust opening when interior attack
crews are inside the structure because it
will force smoke, heat, and steam down
on them.
13–44
Knowing what to expect when
sounding a roof is important
13–45
CAUTION!
Work in groups of at least two, but with
no more personnel than absolutely
necessary to perform the assigned task.
13–46
Roof-cutting operations require
specific resources and skills
13–47
Roof ventilation leaders have specific
responsibilities to perform
Ensure
Roof safe
Only require openings made
Minimize secondary damage
Coordinate with firefighters inside
Ensure
Safety of personnel
Two means of
egress
Adequate exhaust
opening size
Team leaves when
assignment completed
13–48
Various types of inspection holes
can be used during ventilation
Kerf cut
Triangle cut
13–49
Offensive ventilation methods depend
on the opening and roof type
Critical points when cutting
• Square or rectangular
• Easier to repair after fire
• One opening better than several small ones
13–50
A Coffin or “7,9,8” cut is the most
common opening made in a flat roof
13–51
The 7, 9, 8 cut is a
modified Coffin cut
13–52
Different types of roofs require
different ventilation tactics
Pitched roof, shingle-covered
Pitched roof, slate or tile-covered
Arched roofs
Metal roofs
13–53
The trench cut is strictly a
defensive ventilation method
13–54
The process for making a trench
cut follows specific procedures
Opening
created
ahead of fire
• Only after
vertical
ventilation
opening made
Created by
• Two parallel
cuts
• Remove roof
material
• Push ceiling
material down
Improper
cut
• Places
firefighters in
dangerous
position
• May cause fire
spread more
rapidly
13–55
All ventilation team members
should follow safety practices
Plan ahead
Establish and maintain communication
Be aware
Have clear understanding of objectives
Have charged hoseline present
Wear full PPE and SCBA
Have two means of escape
Assign roof safety officer
Cut small inspection holes on both fire, safe working side
13–56
You should know the precautions
against upsetting vertical ventilation
Factors that
can reduce
effectiveness
Not a solution to
all ventilation
problems
13–57
WARNING!
Do not direct a fire stream into a
ventilation opening during offensive
interior operations.
13–58
Other types of ventilation situations,
such as basement fires, may arise
Heat, smoke
spread upward
Access can be
difficult without
ventilation
Basement fire
Several
ventilation
methods
13–59
Other types of ventilation situations
exist, such as windowless buildings
Windowless buildings
Complicate
operations
Problems vary
Can cause delays
Usually requires
mechanical for smoke
removal
Allow systems to
work if designed to
contain combustion
products
13–60
High-rise fires are also another type of
ventilation situation that may arise
Higher life safety
considerations
present
More personnel
required
Consider smoke
spread, hot gas
layer development
High-rise fires
13–61
Tactical ventilation must be considered
during pre-incident planning
Usually
accomplished
horizontally
Ventilation fans may
be built into top of
stairwell
Only one stairwell
may penetrate roof
PPV fans should be
located at bottom
floor
Control doors on
uninvolved floors
Ventilating draws
smoke up into
stairwell between
fire floor and roof
13–62
WARNING!
Do not use stairwells or elevator shafts
simultaneously for both evacuation and
ventilation.
13–63
Ventilation will have several
effects on building systems
Modern HVAC may
contribute to fire
spread
Systems usually
controlled from
panel in basement,
ground level
Restoring system
responsibility of
building staff
Ductwork may
create additional
fire damage
13–64
Built-in smoke control systems
are designed to confine fire
13–65
WARNING!
Do not attempt to operate building
systems that assist in ventilation.
13–66
Summary
• Tactical ventilation of a burning
building allows heat, smoke, and fire
gases to escape to the atmosphere and
also draws fresh air into the building.
• Properly applied tactical ventilation
allows firefighters to see better, locate
victims more easily, and find the seat
of the fire sooner.
(Cont.)
13–67
Summary
• Tactical ventilation limits fire spread
and channels heat and smoke away
from trapped victims; but must be
correctly coordinated.
(Cont.)
13–68
Summary
• Firefighters must understand fire
behavior, know various ventilation
methods and have knowledge of roof
construction and know how to create
exhaust openings in all types of roofs
that have a variety of openings in order
to perform ventilation correctly.
13–69