# Presentation: 127595

## A comprehensive set of standard fire behavior fuel models for use with Rothermel’s spread model

- Joe H. Scott
- Systems for Environmental Management
- Missoula, MT

- Today’s presentation is brought to you by NIFTT, the National Interagency Fuel Technology Transfer Team.
- NIFTT—for your all your fuel technology needs—on the web at FRAMES.nbii.gov/niftt

## Systems

- BehavePlus
- FARSITE
- FFE-FVS
- FlamMap
- FMAplus
- NEXUS
- FSPro
- FuelCalc

## History

- Rothermel (1972) – 11 fuel models
- Albini (1976) – added two models to create the original 13
- Anderson (1982) – described each fuel model
- Many fuel inputs have always been constant for all fuel models
- 10-h and 100-h dead fuel SAV ratio
- Total and effective mineral fraction
- Ovendry fuel particle density

## Need

- Cover wider range of seasons

## Need

- Cover wider range of seasons
- Fill gaps in each fuel type

## Need

- Cover wider range of seasons
- Fill gaps in each fuel type
- Better simulate fuel treatments

## Need

- Cover wider range of seasons
- Fill gaps in each fuel type
- Better simulate fuel treatments
- Better drive crown fire initiation models

## Need

- Cover wider range of seasons
- Fill gaps in each fuel type
- Better simulate fuel treatments
- Better drive crown fire initiation models
- Reduce need for custom fuel models

## Characteristics

- Designed to stand alone

## Characteristics

- Designed to stand alone
- Original 13 still available

## Characteristics

- Designed to stand alone
- Original 13 still available
- Specifies fuelbeds not vegetation

## Naming

- Two-part naming convention

## Naming

- Two-part naming convention
- Fuel model code

## Naming

- Two-part naming convention
- Fuel model code
- Fuel model number

## Naming

## Naming

## Naming

## Naming

## Dynamic fuel models

- Transfer of herbaceous load from live to dead

## Dynamic fuel models

- Transfer of herbaceous load from live to dead
- Function of live herbaceous MC

## Dynamic fuel models

- Transfer of herbaceous load from live to dead
- Function of live herbaceous MC

- 75

- 0.5

## Dynamic fuel models

- Transfer of herbaceous load from live to dead
- Function of live herbaceous MC
- Takes on dead 1-hr MC

## Dynamic fuel models

- Transfer of herbaceous load from live to dead
- Function of live herbaceous MC
- Takes on dead 1-hr MC
- Preserves live herbaceous SAV ratio

## Dynamic fuel models

- Transfer of herbaceous load from live to dead
- Function of live herbaceous MC
- Takes on dead 1-hr MC
- Preserves live herbaceous SAV ratio
- Increases ability (and difficulty)

## Documentation

- Printed GTR

- FENWT-approved

## Documentation

- Printed GTR
- HTML tech transfer document

## Documentation

- Printed GTR
- HTML tech transfer document
- Comparison spreadsheet

## Documentation

- Printed GTR
- HTML tech transfer document
- Comparison spreadsheet
- Nomographs (new format)

## Correct for wind in upslope direction only
Complicated to use, especially for fuel models with live fuel
Head fire only

- Complicated to use, especially for fuel models with live fuel
- Head fire only

## Vectoring wind and slope

- Old nomograph – wind direction within 30 degrees of upslope, or measure slope in wind direction
- S490 – vector *wind-only spread rate* and *slope-only spread rate*; approximates mathematical solution
- Mathematical solution – vector *wind coefficient* and *slope factor*

## Nomographs

- slope vector

- wind vector

- Effective wind/slope vector

- 5.8 mi/h

- 110

- Fuel model = TL8Slope = 60%midflame wind speed = 7 mi/hwind direction = 135 degrees

## Nomographs

- slope vector

- wind vector

- Effective wind/slope vector

- Fuel model = TL8Slope = 60%midflame wind speed = 7 mi/hwind direction = downslope

- 4.7 mi/h

## Nomographs

- slope vector

- wind vector

- Effective wind/slope vector

- Fuel model = TL8Slope = 60%midflame wind speed = 7 mi/hwind direction = upslope

- 9.0 mi/h

## Modified “hauling chart”

- HPA5%

- HPA15%

- HPA25%

- Lines of equal fireline intensity

## 8 ch/h

- 3.9 ft

- Fuel model = TL8dead fuel moisture = 5%effective wind speed = 5.8 mi/h

## Non-heading fire behavior

- Assume simple ellipse
- Relative dimensions of ellipse are a function of L/B ratio
- L/B ratio is a function of effective wind speed (nomographs follow Andrews 1986)
- Location on perimeter defined by orientation of flame front with respect to direction of maximum spread

## 0.05

- 0.21

- 0.74

- 0.25

- 0.49

- 0.86

- Byram (1959)

## Fuel model = TU5dead fuel moisture = 5%effective wind speed = 5 mi/hlive woody fuel moisture = 110%

- Fuel model = TU5dead fuel moisture = 5%effective wind speed = 5 mi/hlive woody fuel moisture = 110%

## 8.6 ch/h

- 7 ft

- 7.5 ft

## NORTH

- SOUTH

## Nomographs

- The format of the nomographs facilitates development and application of fire use prescriptions, by plotting constraints on the chart.

## Nomographs

- For example, you may wish to achieve head fire flame lengths of at least 1 foot, but not greater than 4 feet.

- To minimize spotting outside the unit, you might wish to rule out low fuel moistures.

- To catch an escaped fire, you might not tolerate ROS > 6 ch/h

- And you may wish to rule out burning when eye-level winds are greater than 7 mi/h.

- What remains is the prescription window...

## Nomographs

- Don Carlton suggested the simplified “hauling chart” format
- Brad Reed coined the term “hanking fire”
- Cassie Koerner and Violet Holley, Missoula Fire Sciences Lab, labeled and error-checked the charts
- Funding from Wayne Cook, Washington Office Fire Technology Transfer Program

## Resources

- Fuel model GTR-153
- www.treesearch.fs.fed.us
- Scott and Burgan (2005)
- Fuel Model help file, CompareModels.xls, PPT
- Frames.nbii.gov
- “Fuels” subject area
- Nomograph GTR-192
- www.treesearch.fs.fed.us
- Scott (2007)
- Nomographs in PDF format
- www.fs.fed.us/fmi
- Download section
- Online fuel model course
- NIFTT, with U of Idaho

## Slide 45