Interagency Prescribed Fire Training/Fire Ecology and ManagementUniversity 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)

Parts of a Fire

Wind

REAR

LEFT FLANK

RIGHT FLANK

FINGER

HEAD

SPOT FIRE

POCKET

UNBURNED ISLAND

Types of Fires

Surface Fire Burning in surface fuels

▪ Grass, shrubs, litterGround Fire

Smoldering in ground fuels▪ duff, peat, roots, stumps

Crown Fire Burning in aerial fuels

▪ Crowns or canopy of the overstory▪ May or may not be independent of surface

fire

Photo: Univ. of Toronto Fier Lab

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, well-defined 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 fireGENERALLY NOT USED IN I.A.NEED AT LEAST 2 CREW MEMBERSONLY IN CERTAIN FUEL TYPES ( not blowy

leaf!)ONLY BY EXPERIENCED firefighters HIGH RISKTIME 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?

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 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

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

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