REQUISITES AND TREATMENT OF KILN FUELS. 521 



In addition to the risk of explosion from coal-dust, there is always 

 the chance that coal stored in bulk will heat up and cause a disastrous 

 fire. 



The following statement regarding coal storage has been recently 

 published * by F. M. Griswold, General Inspector to the Home Insurance 

 Company, of New York: 



"The quantity stored in any one pile, heap, pocket, or bunker should 

 in no case exceed 1,500 tons. When a greater quantity must be stored 

 there should be a clear space of at least 5 feet between the piles, and that 

 space should be maintained absolutely free for ventilation and disper- 

 sion of gases from the mass. 



"No accumulation of coal of 1500 tons or less should be piled in 

 excess of 12 feet in height, when trimmed off, or squared, but where 

 such accumulation is delivered from dump-cars on a trestle over 12 

 feet in height, the extreme height of the pile formed by the natural run 

 of the coal as dumped may be 15 feet, but not more. 



"Where coal is stored under shelter, there should be perfect ventila- 

 tion, to facilitate escape of gas by circulation of the atmosphere. 



"Wet coal, especially that wetted by snow and ice, should be dis- 

 posed for immediate use; if its storage be necessary, it should be placed 

 at the top of the pile and be spread out as thinly as practicable, in order 

 to expedite drying. 



"All accumulations of coal, large or small, should be ' rod-tested ' 

 with frequency and regularity, in order to discover any tendency toward 

 dangerous heating, the danger-point being set at about 160 F. If that 

 temperature be reached, the exact locality of increasing heat may be 

 determined by inserting an iron pipe, into which a self-registering ther- 

 mometer can be lowered, allowing it to remain for sufficient time to 

 record the full intensity of the heating." 



List of references on coal drying, grinding, etc. 



Bartlett, C. D. The burning of pulverized coal. Journ. Assoc. Engineering 



Societies, vol. 31, pp. 44-48. 1903. 

 Doane, A. 0. The spontaneous ignition of coal. Engineering News, vol. 52, 



p. 141. Aug. 18, 1904. 

 Frazier, W. H. Fire hazards in Portland-cement mills. New York Journal 



of Commerce, April, 1901. 

 Griswold, F. M. Specifications for storage of bituminous coal. Engineering 



and Mining Journal, vol. 77, p. 725. 1904. Engineering News, vol. 52, 



pp. 409-410. Nov. 10, 1904. 



* Engineering and Mining Journal, vol. 77, p. 725. 1904. 



