CONTENTS 



CONTENTS 



FOREWORD ii 



PAST RESEARCH 1 



Effects of Flame Retardants 1 



Retardants and Smoke Production 2 



Diammonium Phosphate and Ammonium Sulfate 2 



EXPERIMENTAL DESIGN 3 



The Fuel Cribs 3 



Treatment 3 



Burning Procedures 5 



Particulate Sampling 5 



RESULTS 7 



Treatment Effect on Thermal Variables 7 



Effect on Residue 7 



Effect on Particulate 12 



DISCUSSION AND CONCLUSIONS 14 



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 convenience of the reader. Such use does not constitute an official endorsement or approval 

 by the U. S. Department of Agriculture of any product or service to the exclusion of others 

 which may be suitable. 



FOREWORD 



Pressure and criticism currently are mount- 

 ing against open burning of forest debris in 

 the West because of particulate emissions and 

 their visual impact. This controversy has 

 sparked much speculation and some research 

 on alternatives to burning, including better 

 utilization and mechanical treatment of slash. 

 Because fire might be a requirement for fu- 

 ture productivity of the site, it might be im- 

 portant to look at the characteristics of fire 

 itself; specifically, in this study particulate 

 production rates and total amount of par- 

 ticulate. 



Emissions from slash fires include water 

 vapor, gases, and particulate. The particulate 

 includes both char particles and tar droplets. 

 Several variables are involved in the descrip- 



tion of particulate emissions: Time and rate 

 of production, total quantity, size distribu- 

 tion, tar composition, and color. Emissions 

 during the smoldering phases of the fire pose 

 a problem in areas of nighttime down-canyon 

 winds and early morning inversions. On the 

 other hand, if atmospheric conditions are 

 stable during the initial stages of the fire, pro- 

 duction rate might become the critical factor. 

 Because the size of the particle determines its 

 settling rate, this variable is important under 

 some conditions. Moreover, the fraction of tar 

 in the particulate becomes important when 

 considering the ramifications of smoke emis- 

 sions, because it might be related to health 

 problems. 



ii 



