Transcript Slide 1
Ignition Techniques (adapted from FL DOF)
Interagency Prescribed Fire
Training/
Fire Ecology and Management
University of Florida
Objectives
Characterize basic fire types
Link fire types to ignition patterns
Identify safety concerns
Describe when to use what
Methods of pile/windrow burning
Develop an ignition plan (you will do
this later in your Burn Plan)
SPOT FIRE
UNBURNED
ISLAND
Surface Fire
Burning in surface fuels
▪ Grass, shrubs, litter
Ground Fire
Smoldering in ground fuels
▪ duff, peat, roots, stumps
Photo: Univ. of Toronto Fier Lab
Crown Fire
Burning in aerial fuels
▪ Crowns or canopy of the overstory
▪ May or may not be independent of surface fire
Photo: News Provider
Types of Crown Fires
When do you need to apply your
knowledge of ignition techniques?
Two situations:
Prescribed Fire: “Fire applied in a
knowledgeable manner to forest fuels on a
specific land area under selected weather
conditions to accomplish predetermined, welldefined management objectives”
“A safe way to apply a natural process, ensure
ecosystem health, and reduce wildfire risk.”
Suppression burning is the use of prescribed
fire in a wildland fire situation
2 Types of Suppression Burning
Counter Fire
Burn-out
Counter Fire
Fire applied to stop the forward spread of
uncontrolled fire
GENERALLY NOT USED IN I.A.
NEED AT LEAST 2 CREW MEMBERS
ONLY IN CERTAIN FUEL TYPES ( not blowy
leaf!)
ONLY BY EXPERIENCED firefighters
HIGH RISK
TIME CRITICAL
Burn-out: when?
Often times on
wildfires, control lines
are established some
distance from fire edge
Pockets
Inaccessible areas
Pre-existing control lines
Areas of lesser fuel
concentrations
OBJECTIVES
Learn the Basic Fire Types- Related to Wind
Characterize basic fire types
1. Backing
2. Head
3. Flanking
Link fire types to ignition patterns
Identify safety concerns
Describe when to use what
Methods of pile/windrow burning
Develop an ignition plan (you will do this
later in your Burn Plan)
What are the FACTORS TO DETERMINE FIRING
TECHNIQUES?
OBJECTIVES for your burn
Fuels consumption, wildfire control
Ecological effects
WIND SPEED & DIRECTION (why both?)
SMOKE SENSITIVE AREAS IN CLOSE PROXIMITY?
Special hazards?
CREW EXPERIENCE/KNOWLEDGE
1. Backing Fire
Used to establish baseline
Generally safest
Longer residence times
Slowest R.O.S.’s (1-3 ch/hr)
ROS determined by Fuel Moisture
Excellent for heavy fuel loads
Used to burn around values
Generally not the primary technique
Why not???
1. Backing Fire
1. Backing Fire
BURNS INTO THE WIND
1. Backing Fire- wind is important
1. Backing Fire
When backfire is the primary technique,
consider:
Windspeeds & fuel moistures
Establishing additional baselines
Orienting burn blocks
WIND
2. Strip-Head Fire
Most frequently used technique
Fastest method
Can manipulate intensity with strip width and time
interval
Consider:
Width of strips
Changing weather conditions
Changing fuel conditions
Using spots where necessary
Spotting potential
Convection activity
“Closing the door” too soon
2. Strip-Head Fire
STAY BEHIND
DOWNWIND
IGNITOR!
2. Strip-Head Fire
• Intensity is controlled by line spacing and timing
• Spread rate is sensitive to windspeed
3. Flank Fire
REMAIN IN
SIGHT
MAINTAIN
PACE
3. Flank Fire
Can be an excellent tool, burn large areas with less
effort
Uniform fire intensities
Minimal spotting
Good in diverse fuel types
Consider:
Winds (Dir. & Speed.)- must be steady!
Number & experience of igniters- must be experienced!
Communications & visibility (in unit)
Conducive burn block orientation
Using spot ignitions within the flanks
Varying the flank ignition speed to control intensity
3. Flank Fire
FIRE BURNS 90°
TO WIND
FLANK FIRE
WALK INTO WIND
WIND
3. Flank Firepace of ignition
affects fire
behavior
4. Point Source (Spot) Fire
4. Point Source (Spot) Fire
Excellent for large areas (aerial ignition)
Best technique for controlling intensities in
various weather conditions
Can be used in conjunction with strip head &
flank technique
Effective in heavy fuels
Burn manager can control where convection
occurs
Quickest way to complete ignition
Point Source (Spot) Fire
When spot firing, burn managers should consid
how to change fire intensity:
Width between spots
Width between strips
Changes in weather & fuels
Location of spots
Spotting potential
Difficulty in maintaining grid
Grid orientation to wind
Fast burn, high convection (why?)
Point Source (Spot) Fire, initiation
Point Source (Spot) Fire- growth
5. Ring Fire
5. Ring Fire
Traditionally used for site-prep
Minimizes short range spotting
Quick & easy
Early “point-of-no-return”
Traps wildlife, high intensity
High convective heat transfer
When using ring ignition, consider:
Access
Objectives (overstory, smoke plume,
speed)
Where to start
Crew experience
Begin with center point ignition
5. Ring Fire
How it’s really done:
USE A VARIETY OF TECHNIQUES
OVER A RANGE OF WEATHER
CONDITIONS FOR MOSAIC BURN
PATTERNS
SECUREING A BASE LINE…
LINE WIDTH?
>2X FLAME LENGTH
DO NOT “CLOSE THE DOOR”!
CAN CAUSE FIRE WHIRLS (VORTICES)
USE CAUTION WALKING DOWNWIND!
USE CAUTION IN HEAVY FUELS
USE CAUTION ON SLOPES
USE CAUTION WHEN FIRES CONVERGE
ALWAYS WATCH WHAT YOUR FIRE IS DOING
FIRE GENERATED WINDS
KNOW LOCATIONS OF
PERSONNEL & EQUIPMENT
Ignition steps
1. Evaluate conditions, resources, and
objectives to determine desired fire
behavior.
2. Test burn and evaluation
3. Black line
4. Ignition techniques
5. Contingency plans
SAFETY should always be on your mind
L.C.E.S.
LOOKOUTS
COMMUNICATIONS
ESCAPE ROUTES
SAFETY ZONES