Interagency Prescribed Fire Training/Fire Ecology and Management, University of Florida
Ignition Techniques (adapted from FL DOF)
Objectives
Characterize basic fire typesLink fire types to ignition patternsIdentify safety concernsDescribe when to use whatMethods of pile/windrow burningDevelop an ignition plan (you will do this later
in your Burn Plan)
Two situations requiring knowledge of ignition techniques
Prescribed Fire: “Fire applied in a knowledgeable manner to forest fuels on a specific land area under selected weather conditions to accomplish predetermined, well-defined management objectives”
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 edgePockets Inaccessible areasPre-existing control linesAreas of lesser fuel
concentrations
Learn the Basic Fire Types- Related to Wind
Characterize basic fire types1. Backing2. Head3. 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)
OBJECTIVES
What are the FACTORS TO DETERMINE FIRING TECHNIQUES?
OBJECTIVESWIND SPEED & DIRECTIONSMOKE SENSITIVE AREAS IN CLOSE PROXIMITY?
CREW EXPERIENCE/KNOWLEDGE
1. Backing Fire
Used to establish baseline Generally safestLonger residence timesSlowest R.O.S.’s (1-3 ch/hr)
ROS determined by Fuel Moisture
Excellent for heavy fuel loadsUsed to burn around valuesGenerally not the primary technique
Why not???
1. Backing Fire
1. Backing Fire
BURNS INTO THE WIND
Backing, Flanking Fire- video
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 techniqueFastest methodCan manipulate intensity with strip width and time
interval
Consider:Width of stripsChanging weather conditionsChanging fuel conditionsUsing spots where necessarySpotting potentialConvection 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
Fire- video
3. Flank Fire
REMAIN IN SIGHT
MAINTAIN
PACE
3. Flank Fire
Can be an excellent tool, burn large areas with less effort
Uniform fire intensitiesMinimal spottingGood in diverse fuel typesConsider:
Winds (Dir. & Speed.)- must be steady!Number & experience of igniters- must be experienced!Communications & visibility (in unit)Conducive burn block orientationUsing spot ignitions within the flanksVarying the flank ignition speed to control intensity
3. Flank Fire
FLANK FIRE
WIND
FIRE BURNS 90°
TO WIND
WALK INTO WIND
3. Flank Fire- pace 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 consider how to change fire intensity:Width between spotsWidth between strips
Changes in weather & fuelsLocation of spotsSpotting potentialDifficulty in maintaining gridGrid orientation to windFast burn, high convection (why?)
Point Source (Spot) Fire, initiation
Point Source (Spot) Fire- growth
5. Ring Fire
5. Ring FireTraditionally used for site-prepMinimizes short range spottingQuick & easyEarly “point-of-no-return”Traps wildlife, high intensityHigh convective heat transfer
When using ring ignition, consider:AccessObjectives (overstory, smoke plume, speed)
Where to startCrew experienceBegin 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 evaluation3. Black line4. Ignition techniques5. Contingency plans
L.C.E.S.LOOKOUTSCOMMUNICATIONS ESCAPE ROUTESSAFETY ZONES
SAFETY should always be on your mind