Effective heating of fuel ahead of spreading fire
Document Type: Report
Author(s): William H. Frandsen
Publication Year: 1973

Cataloging Information

  • combustion zone
  • effective heating number
  • fire spread
  • fuel models
  • heat effects
  • heating efficiency
  • ignition
  • isotherm
  • laboratory experiments
  • laboratory fires
  • rate of spread
Record Maintained By:
Record Last Modified: June 1, 2018
FRAMES Record Number: 14093
Tall Timbers Record Number: 6084
TTRS Location Status: In-file
TTRS Abstract Status: Okay, Fair use, Reproduced by permission

This bibliographic record was either created or modified by the Tall Timbers Research Station and Land Conservancy and is provided without charge to promote research and education in Fire Ecology. The E.V. Komarek Fire Ecology Database is the intellectual property of the Tall Timbers Research Station and Land Conservancy.


A method is presented for the evaluation of the heating efficiency required for ignition as a spreading fire closes with fuel. An array of thermocouples was implanted in the fuel ahead of the fire to obtain the heat absorbed by the fuel prior to ignition. The fraction absorbed compared to the total that would be absorbed if uniformly heated is the effective heating number. The effective heating number is represented in its final form as decreasing exponentially with the reciprocal of the surface area-to-volume ratio. The spreading fire is carried in a regular fuel crib array. Two fuel sizes are used in cross-sectional dimension: 0.6 cm. and l.3 cm. Isotherms are generated from the temperature field at ignition and presented for both fuel sizes to determine heat absorbed.

Online Link(s):
Frandsen, William H. 1973. Effective heating of fuel ahead of spreading fire. Research Paper INT-RP-140. Ogden, UT: USDA Forest Service, Intermountain Forest and Range Experiment Station. 16 p.