# Optimum packing ratio

n. Packing ratio corresponding to maximum reaction velocity.

• Discussion

Optimum packing ratio is a term used in the Rothermel's (1972) surface fire spread model indicating the packing ratio that optimizes the reaction velocity term of the spread model. Optimum packing ratio is a function of the fineness of fuel particles, which is measured by the characteristic surface-area-to-volume ratio of the fuelbed. Optimum packing ratio does not optimize fire behavior (rate of spread or fireline intensity).

•

Optimum packing ratio is a dimensionless ratio.

• Rothermel, R.C. 1972. A mathematical model for predicting fire spread in wildland fuels. Res. Pap. INT-115. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 42 p.

• Notes

• Joe Scott

Systems for Environmental Management

• August 2007