i UNITED STATES DEPARTMENT OF AGRICULTURE 
CARL L. ALSBERG, Chief, and the 
Office of Public Roads and Rural Engineering 
LOGAN WALLER PAGE, Director 
Washington, D. C. Vv August 4, 1916 
DUST EXPLOSIONS AND FIRES IN GRAIN SEPA- 
RATORS IN THE PACIFIC NORTHWEST. 
By Davin J. PRICE, Engineer in Charge of Grain Dust Explosion Investigations, 
Bureau of Chemistry, and E. B. McCormick, Chief, Division of Rural Engi- 
neering, Office of Public Roads and Rural Engineering. 
—EE————EE 
CONTENTS. 
Page. Page 
Introduction: = 2223 = = s ea ee 1 | Experimental field and laboratory 
Plan of investigation aA a od 2 SV CTE ee A 11 
Classification of explosions_________ 3 | Nature of dust explosions_________ 17 
Results of field investigation_______ 6 | Methods developed for preventing ex- 
Static electricity as a cause of ex- plosions or extinguishing fires____ 19 
TOLOST OT) Sees eee ee SE eS 9 | Special acknowledgments —~_________ 22 
INTRODUCTION. 
The large number of fires and explosions in grain separators 
during the threshing process has awakened unusual interest in the 
Pacific Northwest during the last two seasons. These fires and ex- 
plosions were most frequent in the wheat-growing territory in east- 
ern Washington and northern Idaho, although occasional occurrences 
were reported in adjoining territory in northeastern Oregon. From 
reports received from various sources it is apparent that similar 
explosions and fires have occurred in scattered localities throughout 
the territory west of the Mississippi River. 
The Department of Agriculture had for some time been conducting 
studies relative to the causes and prevention of dust explosions in 
grain mills, elevators, and similar plants. The close relation of 
thresher explosions to the general study of grain-dust explosions led 
to the inauguration of a special study of this allied problem in the 
northwestern field during the 1915 season. As a result of this study 
166 occurrences were investigated and reported. It is probable that 
many other explosions and fires took place which were not brought 
to the attention of the department. 
43454°—Bull, 379—16——1 
