Principles of Fireground Ventilation

Principles
p
of Fireground
g
Ventilation
Back to the Basics
Paul E.
E Sullivan,
Sullivan Jr.,
Jr MS,
MS CFO,
CFO CSP,
CSP CFPS
Principles of Fireground
Ventilation
OBJECTIVE:
Given information on ventilation and precautions; size-up
information; roof types
types, features
features, and openings; and
various types of ventilation devices and methods, the
student will be able to identify the principles for
removing heat, smoke, and gases from structures, so
that an attack team recognizes the need for ventilation,
determines where and when to apply
pp y ventilation,, and
follows ventilation commands.
2
Principles of Fireground
V til ti
Ventilation
Overview:
• Ventilation Introduction
• Roofs
• Ventilation Precautions
• Roof Openings
• Ventilation Size-up
p
Considerations
• Vertical Ventilation
• Performing Ventilation
• Tools Required for Ventilation
• Trench Ventilation
• Horizontal Ventilation
• Hydraulic Ventilation
• Construction Factors
3
Principles of Fireground
V til ti
Ventilation
Overview (cont’d):
• Differences
• Characteristics of Devices
• Instances for Mechanical
Ventilation
• Uses for PPV
• Contraindicators for PPV
and
d Benefits
B
fit
• Potential Hazards
Resulting from Improper
Deployment of PPV
• Care and Maintenance of
Ventilation Equipment
4
5
WHAT IS VENTILATION?
The planned and systematic removal of heated air
air, smoke
smoke,
and toxic gases from a confined area and the replacement
of these products with cooler
FRESH AIR
6
Why Are Ventilation Operations
Carried Out on the Fireground?
Increased visibility for firefighters and occupants
Reduced heat levels
Reduced chances of flashover and backdraft
Increased occupant and firefighter survivability
Increased ability to locate seat of the fire
Reduced water and smoke damage
7
Stages of a Confined Fire
R
Requiring
i i Ventilation
V til ti
Flashover
occurs
between these
stages
900 to 1,200°F
Free-Burning Fire and Decay
Intensity and Growth Fire intensifies
based on p
plume
gases, temperatures,
and fuel load
Depends on Fuel Load
High load  supports fire
Low load  decay and
diminishment
8
9
Ventilation Precautions
• Use full PPE and SCBA
• Vent from top
• Stand to windward side
• Have hoselines charged and ready because fire will
reignite
• Never place a hoseline or elevated master stream in vent
hole
• Check structural stability of roof
• Work with wind at your back
• Guard opening (if necessary)
• Coordinate with attack crews and the ventilation officer
10
Ventilation Precautions (cont’d.)
(
)
Never
Ne
er cond
conduct
ct an interior ventilation
entilation or
search and rescue operation with a
PRESSURIZED
WATER
EXTINGUISHER
This is a very
y dangerous
g
p
practice that is not
sanctioned or taught in firefighting programs.
It can also be career-ending! Think smart!
Don’t follow the pack on this one!
11
Ventilation Size-up Considerations
Wind Direction
Fire Conditions
• Size
• Stage
g of development
p
• Location in structure
Objective of Operation
• Rescue
• Suppression
Other Factors
• Weather
W th
• Personnel staffing
levels
- Numbers
- Training
- Experience
• Equipment
Building Involved
• Size
• Construction type
yp
• Location to exposures
12
Deciding to Perform Ventilation
When to ventilate??
RESCUE
IMMEDIATE
OR
SUPPRESSION
WITH INTERIOR ATTACK
Where to ventilate??
To keep
p smoke, heat,
and gases away from
victim.
Over fire to draw
smoke, heat, and
gases directly to
outside.
13
Handlight
Tools Required for Ventilation
SCBA
Bottle
Harness
PPE
Helmet
Boots
Pants
Turn-out Coat
Mask
Roof Ladder
Rescue Rope or Strap
Chain Saw
Wall Ladder
Circular Saw
Pike Pole
Axe
Portable Radio
14
CONSTRUCTION
FACTORS
Built-up Roof
Solid wood rafters
Sh thi
Sheathing
Tar paper, tar or
slag, or gravel
Shingles
Contributes
C
t ib t fuel
f l
load to fire
Most reliable
for integrity
Limits fire
spread by
channeling
Local failure will
not usually cause
system failure
15
CONSTRUCTION
FACTORS
Lightweight Wood or
Metal Truss Systems
Truss in
T
i place
l
of rafters
Otherwise same as
built-up roof
Metal decking for
metal truss
Fastt horizontal
F
h i
t l
fire spread
Total system
y
failure 5-10 minutes
after fire exposure
Usually failure
occurs before fire
department arrival
16
CONSTRUCTION
FACTORS
Heavy Steel Truss Systems
Begin to fail
at exposure to
1,000ºF
17
CONSTRUCTION
FACTORS
Wood “I” Beams
Substitute for
li ht i ht truss
lightweight
t
Contributes fuel
load to fire
System failure within
5-10
5
10 minutes’
minutes
exposure to fire
18
19
20
21
22
General Roof Precautions
• Wear full PPE with SCBA.
• Place tip of ladder high enough above roof line for
firefighters to see at a distance.
• Have two paths of escape.
• Put a protective attack line in place.
• Position roof ladder(s) on roof to distribute weight.
• Pre
Pre-run
run power tools during PM checks and on the
ground before using it on the roof to prevent
malfunctioning when you need it the most.
23
General Roof Precautions (cont
(cont’d
d.))
• Be aware of “sponginess”
sponginess in the roof
roof.
• Be alert for power lines and phases.
• Keep
K
good
d communications.
i ti
U
Use a portable
t bl radio.
di
• Don’t overload roof.
24
25
Safety Rules
• Roof operations require two ladders.
• Place them on “strong” areas of the roof.
• Consider ladder placement on corners, etc.
• Place them to windward side of objective
objective.
• Work from weak areas to strong ones.
• Firefighters can’t use positioned ladders for
emergency egress if they can’t see them!
27
Visual Observation of
Possible Roof Failure
“THINK WITH YOUR FEET!”
12
Bubbling or melting tar?
3
9
Smoke or fire showing?
Elapsed time of
fire?
6
Dry spot on wet roof?
et gs
snow?
o
Melting
Sounding
g for roof
integrity?
28
29
UPSETTING
U
S
G VERTICAL
C
30
31
Trench Ventilation
Trench Cut
3- to 4-foot-wide
Outside wall to outside
wall
Tactical variation of vertical ventilation.
Designed
D i
d to
t stop
t horizontal
h i
t l progress off fire.
fi
34
37
Differences Between Negative-Pressure
Ventilation (NPV) and Positive-Pressure
Ventilation (PPV)
Placement
off Bl
Blowers
and Fans
Smoke Ejectors
((NPV))
Are Positioned
Inside a Structure
Drawing Air Out
Inside
vs.
Outside
of a
Structure
PPV Blowers
(PPV)
Are Positioned
Outside a Structure
Blowing Air
Inward
38
Positive-Pressure Ventilation Fan
Introduction of fresh air via a negative-pressure
fan or positive
positive-pressure
pressure blower into a confined
area or structure resulting in an increase in
pressure in that area.
Causes air to flow into an area of lower p
pressure or
exhaust opening because of
a pressure differential.
40
41
How Does Positive-Pressure
Ventilation Work?
Works on the VOLUME of a p
positive air system
y
in
conjunction with the VELOCITY of that air system’s
output. Operates from the outside of the structure or
contaminated area.
area
WINDOW
PPV
PPV
BLOWER
SEALED INGRESS
POINT
EXHAUST
EGRESS
POINT
Equalizes
Airflow
Pressurization
Process
POSITIVEPRESSURE
VENTILATION
Does Not Expose
Firefighters
to Contaminants
While Positioning
Blower
Requires
Minimal
Clean up of
Components
Forces
Contaminants
out of
Pre-selected
Exhaust
Openings
Does not
Block
Doorways
IS TWO TIMES MORE
EFFICIENT THAN NPV
Can Be
Affected by
Atmospheric
Conditions
NEVER
USE A PPV BLOWER AS A
SMOKE EJECTOR IN NPV MODE
43
Is
Not Efficient
in Removing
Contaminants
at the Top
of a Room
NEGATIVE
PRESSURE
VENTILATION
Exposes
Personnel
to Contaminants
While Positioning
Ejector
Harder
to Clean
Is
Not Affected
by
A
Atmospheric
h i
Conditions
Volume
Depends
Upon Size
of Ejector
Requires
Smoke Ejector
I id
Inside
Contaminated
Area
Draws
Contaminants
Through
From Interior
to Exterior
Creates
NegativePressure
Flow in
Contaminated
Area
44
4
CHARACTERISTICS OF PPV FANS
1. POWER SOURCES
•
•
•
•
2. ENGINES
• 2-cycle
• 4-cycle
Electric
Gasoline
Water or Hydraulic
Diesel, PTO, or Mobile Ventilation Unit (MVU)
4. 3 - 110
0 HORSEPOWER
O S O
3. SIZE
• Small: 18-inches
5.
5 HIGH
G rpms
p s
• Large: 30- to 84 inches
6. 2 TO 10 BLADES
7. CAPACITY 3,200 cfm • 56 lbs. -
LOW
• 1,000+ lbs. HIGH
MOBILE
MOUNTED
8. CIRCULAR
30,000 cfm
ENCASEMENT SHROUD
10 DRIVE MECHANISMS
10.
12. THROTTLE and
• Belt-driven
CHOKE ASSEMBLY
• Direct drive
11. PLACEMENT FEATURES
• Anti-skid
Anti skid pads (rubber)
• Wheels
13. LUBRICATION
46
Characteristics of NPV Devices
USUALLY ELECTRIC POWERED
USUALLY 3 TO 4 BLADES
HORSEPOWER RATING
VARIES FROM 2-3 hp
16- TO 24-INCH SIZE
LOW CFM PERFORMANCE
HEAVIER THAN PPV FANS
SQUARE OR CIRCULAR ENCASEMENT
NO OIL RESERVIOR
ON/OFF SWITCH
NO PROBLEM TO
USE NEGATIVE PRESSURE FANS AS POSITIVE-PRESSURE
DEVICES.
DEVICES JUST STACK THEM ON TOP OF EACH OTHER
OTHER.
47
Conduct Size-up of Incident to Determine Best Tactical
Deployment or Application
•
Proper assessment and early deployment or PPV may eliminate
the need for roof operations because of heavy fire conditions
inside the structure.
• Location and extension of fire
• Location of victims
• Entrances and exit openings
48
Positive-Pressure
os t e essu e Ventilation
e t at o Uses
Uses:
• Single and multifamily dwellings
• Apartment buildings
• High-rise buildings
• Malls and strip stores
• Windowless buildings
g
• Mobile-conveyance fires
• Aircraft fires
• Dumpster and trash containers
Positive-Pressure Ventilation Uses (cont’d.):
• Confined space
• Trench
• Salvage operations
• Overhaul operations
p
• Marine shipboard fires
• EMS
EMS, fire
fire, and rescue
rehab areas
• Gas odor removal
• Chemical toxic vapor removal
• Tunnels and shafts
50
PPV May Not Be Appropriate on Every
Fireground
g
Incident
• Enclosed attic areas where there are no egress
vents (roof, gable, attic) for pressurized air to vent
• Too many openings in a structure preventing air
flow from effectively pressurizing interior
• An egress opening must be made in balloon
construction prior to applying PPV
51
Determine PPV Blower Size for a
Given Structure
Apply the PPV Rule of
Single family dwelling with up to 2,000 square feet:
18 to 21-inch
1821 inch blowers.
blowers
Ranchers and multistory dwellings up to 4,000
square feet: 24-inch blowers.
blowers
Larger structures (greater than 4,000 square feet)
require multiple blower application with 2 to 3 24
24inch blowers.
y use multiple blowers on high-rise
g
structures
Always
10 floors or greater.
52
Coordinated Fire Attack
• Vent as close to the point of
origin as possible when
coordinating PPV with interior
attack in a room and contents
fire.
• Hose line ready and charged while
firefighters advancing.
• Ventilation of the fire room with
outside vent person.
• Blower running and positioned while
advancing to interior.
53
Regulate Discharge Opening
PPV is most efficient when
the exhaust opening is
three-quarters to twice the
size of the entrance
opening.
54
“Pittsburgh Walter” Cover
Adjustable
Door Bar
Continuous
Roll Canvas
36" x 36"
Pry Bar
“Pittsburgh
Walter”
Cover
Exhaust
Fan
Porch 4 feet or less
Townhomes
- Rowhomes
- Apartment
T
h
R h
A
t
t Landings
L di
55
Set-up
p Per Orders of IC
EXAMPLES
PPV single unit - ingress Side 1; egress Division 1,
Side C (1 PPV blower application)
PPV series application - ingress Side 1; egress
Division 2, Side
S
D (2
( PPV blowers, 1 behind the other))
PPV parallel operation - ingress Side 1; egress
Division 1,
1 Side D (2 PPV blowers side-by-side
side by side in a
line)
Other instructions at the discretion of the IC
56
Positive-Pressure Ventilation Single Unit Application
Single-Unit
Generally, openings must be between
Generally
three-quarters to twice the size of the
entrance openings
EXHAUST
DISTANCE
5-6 feet
for seal
57
Positive-Pressure Ventilation Series (Pressure Mode) Application
EXHAUST
Positive
Pressure
5-6 feet
Smaller
Fan
DISTANCE
2-3 feet
Larger
Fan
58
Positive-Pressure Ventilation - Side-by-side
(Parallel or Volume Mode) Application
59
Can Negative Pressure Ventilation Devices
Pressure Mode?
Be Used in a Positive
Positive-Pressure
YES!
If you don’t have
standard PPV blowers on
your apparatus, simply use NPV devices
2-3 FEET
- SMOKE EJECTORS -
and stack them on top of each other, then reverse their
g placing
g exhaust side in.
positioning
60
Positive-Pressure Ventilation
When properly applied, will confine a fire to
its point of origin enhancing rapid
extinguishment
Service
Porch
Bath
Kitchen
BR 2
BR 1
Living Room
61
TIPS for PPV Application
1
2
3
For odor or g
gas removal operations
p
in a residential
structure, place the blower(s) parallel pointing away
from the ingress opening, activate and reposition
pointing or coning into the ingress opening
opening.
Coordinate PPV application with an interior
advancement. This is called “positive
positive
positive--pressure
attack.” PPA usually occurs within 15 seconds.
attack
If rescue of occupants
p
is imminent and they
y are in
the stairwells of apartments, tenant housing, or other
structures, initiate PPV immediately to give them
and to clear the smoke.
smoke
FRESH AIR
62
Salvage and Overhaul Phase
• Reduced carbon
monoxide
• Safer and improved
environment
• Reduced
R d
d fire
fi gases
• Firefighter safety
• Quicker
63
PPV Enhances Firefighter Safety
• Continue to use SCBA because of CO
levels in structure during overhaul
• For quicker rescues or to find victim (s)
• Creates less water and smoke damage
• Increases firefighter safety, flexibility,
movement
• Increases visibility for interior firefighting
64
Contraindicators for PPV
• No properly trained crew
• When interior search or
rescue teams
t
or
occupants are between
the fire and exit p
point of
smoke
B1
S
Search
h&R
Rescue
BR2
• For well-involved attic
fires with no egress
venting
• Wh
When fi
fire is
i presentt in
i
the walls of balloon
construction and no
egress point is identified
BR1
B2
S
E
A
R
C
H
&
BR3
R
E
S
C
U
E
DR
Fire Area
KTN
Fire Area
LR
65
Contraindicators for PPV (cont’d.)
Backdraft
Smoke
Explosion
Rapid infusion
of oxygen to
incipient fire
phase, by fan.
• When backdraft conditions are evident.
• When the origin of fire is unknown.
• Vertically vent from the roof over the point-of-origin
first.
66
Benefits of PositivePositive-Pressure Attack
Coning/Seal
• Quicker search and rescue
operation
• Quicker removal of heat and
toxic gases
• Q
Quicker
i k attack
tt k on the
th origin
i i
of the fire
• Quicker movement of
smoke, heat, fire,
and steam
f
away from advancing attack
crews
• Quicker reduction of
flashover conditions or
potential
67
What is the bottom line with the application
off PPV/PPA?
PPV/PPA techniques do not burn the structure down.
Firefighters and officers untrained in their use,
theory, and application create the problem
If you are not trained. DON’T USE THEM!
68
Care and Maintenance of Ventilation
Equipment
q p
• PPV Blowers or Fans
- Use proper oil and fuel mixtures
- Keep belts tight and snug
- Keep shroud(s) intact
- Check fluid levels. Change fuel regularly and replace with
f
fresh
h
- Run blower
- Keep rubber feet or base intact
• NPV Blowers or Fans
- Clean blades and motor regularly
- Keep
K
electric
l t i cords
d and
d switches
it h intact
i t t
- Keep shroud(s) intact
- Be sure unit functions appropriately
- Listen for any unusual noises during operation
69
Principles of Fireground
V til ti
Ventilation
Review:
• Ventilation Introduction
• Roofs
• Ventilation Precautions
• Roof Openings
• Ventilation Size
Size-up
up
Considerations
• Vertical Ventilation
• Performing
g Ventilation
• Tools Required for Ventilation
• Trench Ventilation
• Horizontal Ventilation
• Hydraulic Ventilation
• Construction Factors
70
Principles of Fireground
V til ti
Ventilation
Review (cont’d):
• Differences
• Characteristics of Devices
• IInstances
t
ffor M
Mechanical
h i l
Ventilation
• Uses for PPV
• Contraindicators for PPV
and Benefits
• Potential Hazards
Resulting from Improper
Deployment of PPV
• Care and Maintenance of
Ventilation Equipment
71
Principles of Fireground
Ventilation
72