This file was created by scanning the printed publication. Errors identified by the software have been corrected; however, some errors may remain.

RESEARCH SUMMARYThis manual documents the procedures for estimating the rate of forward spread, intensity, flame length, and size of fires burning in forests and rangelands. It contains instructions for obtaining fuel and weather data, calculating fire behavior, and interpreting the results for application to actual fire problems. Potential uses include fire predict ion, fire planning, dispatching, prescribed fires, and monitoring managed fires.Included are sections that deal with fuel model selection, fuel moisture, wind, slope, calculations with nomograms, TI-59 calculations, point source, line fire, interpretations of outputs, and growth predictions. The use of trade, firm or corporation names in this publication is for the information and convenience of the reader. Such use does not constitute an official endorsement or approval by the US. Department of Agriculture of any product or service to the exclusion of others which may be suitable. PREFACEWhen Hal Anderson and I came to the Northern Forest Fire Laboratory in 1961, it was not yet a year old and there was a feeling that surely this lab was going to contribute. Just what would be accomplished was not entirely clear, but things were going to happen. There was also a sense of being overwhelmed, not only by all the unknowns of wildfire behavior, but also by how to use this brand new facility. There were at least two schools of thought in regard to the wind tunnels: (1) bring in boxcar loads of fuel from all over the country for burning in the wind tunnels, and (2) weld the doors shut until a logical plan for use of the facilities was developed.We did not weld the doors and we did not ship in fuel by the box-car load, but we did work hard at understanding fire spread and adapting concepts of modeling and systems to the problems of forest fire prediction. During the first 10 years a fire behavior model was produced. It took 10 more years to learn how to obtain the inputs and interpret the outputs for use by the "man on the ground," which culminated in the writing of this manual. Specialized versions of the prediction methods have been available for some time in automated forms, such as the National Fire Danger Rating System and the slash hazard appraisal system.No manual of this size, covering the diverse material needed to analyze fire conditions, can be a solo production. It could not have been done without the man who crusaded for the laboratory facilities and who was the first lab chief, Jack Barrows. His paper (Barrows 1951) showed us "industry types" how fire could be examined, but more importantly his continual optimism and confi--dence gave us the inspiration so necessary for a project that was to take 20 years to pull together.Many outstanding people have worked on this problem, as shown by the publications cited. I must single out a few for special acknowledgment, mostly members of Research Work Unit 2103 at one time or another.No one could ask for a steadier and more reliable partner in a 20-year endeavor than Hal Anderson, who started work at t...

PMS 439-1 MAY 1984 NFES 0275 This file was created by scanning the printed publication. Errors identified by the software have been corrected; however, some errors may remain.

We describe the results of 357 experimental fires conducted in an environmentally controlled large wind tunnel. The fires were burned over a range of particle sizes, fuel bed depths, packing ratios, moisture contents and windspeeds. We find that spread rate decreases with moisture content in a way which depends on the fuel type and diameter. It decreases as the square root of the packing ratio. Fuel bed depth has little elfect on spread rate, and fuel diameter has significant effect only for diameters above I mm. The relationship between rate of spread and windspeed is virtually linear.We develop a predictive model for rate of-spread based on energy transfer considerations and the laboratory results. Other laboratory-based models for spread rate are compared with our model, and tested against the laboratory data. The other models have forms similar to ours, but do not predict our data well. Our model predicts well the spread rates for fires burned in windspeeds below 3 mlsec in other laboratories. The scale of the experiments and the similarity of the dependence on windspeed to that found in the field indicate that a field model may be developed from the laboratory model with relatively few modifications.