894 report— 1884. 



TUESDAY, SEPTEMBER 2. 

 The following Reports and Papers were read . — ■ 



1. Beport of the Patent Law Committee. — See Reports, p. 293. 



2. Beport of the Screw Gauge Committee. — See Reports, p. 287. 



3. Beport of the Sea Coast Erosion Committee. — See Reports, p. 238. 



4. Some Points in Dynamo- Electric Machines. 

 By Professor S. P. Thompson, D.Sc. 



On the Heating of Conductors by Electric Currents. 

 By Professor Gr. Forbes. 



6. Automatic Sprinlders for Fire Extinction. By C. J. H. Woodbury. 



This paper gave the results of an examination of the various automatic sprinklers 

 which are operated by the melting of an easily fusible solder. These sprinklers are 

 in oeneral use iu the eastern portion of the United States, for protecting those por- 

 tions of textile mills and other industrial establishments where the nature of the 

 product or the processes used introduce extreme hazard of fire. The investigation 

 was undertaken at the instance of the Factory Mutual Insurance Companies of 

 New England, and was directed to an examination of the numerous varieties of 

 automatic sprinklers, in respect to their efficiency for purposes of mill protection, 

 including their methods of distribution and consumption of water under various 

 heads, liability to accident, and deterioration to their sensitiveness, and to all 

 matters pertaining to their practical operation. 



The conclusions based upon these tests are : — 



1. That the fusible solder which permits the operation of the sprinklers at about 

 170° Fahrenheit retains its low melting point, no change occurring in sprinlders ten 



vears old. ... 



2. They should be protected against corrosion whenever it might interfere with 

 its prompt action. A heavy mineral oil is suggested for the purpose. 



3. The distribution of water upon ceiling and floor was measured upon each 

 square foot of floor, and found to be satisfactory. 



4. The concentration of water at the beginning of a fire exceeds that of any 

 other form of inside apparatus. 



5. The minimum static head upon the sprinlders should not be less than ten 



feet. 



6. The practical value of automatic sprinkler systems is shown by a list of 131 

 fires which were extinguished by automatics, either alone or in co-operation with 

 other fire apparatus. 



7. Valves should be kept open and secured by a strap. It is important that a 

 constant head of water, ready for immediate use, rests upon the sprinklers. 



The sensitiveness of automatic sprinklers was measured by exposing them, while 

 under water-pressure, to a uniform jet of steam, and the sprinklers opened in from 

 15 to 85 seconds, according to their construction and the fusibility of the solder. 



Resistance to internal pressure was measured with a pump constructed for 

 producing the heavy pressures used in graduating the dials of hydraulic gauges. 



Those sprinklers designed with reference to elasticity became tight after the 

 bursting pressure had been reduced to a point in equilibrium with the flexure of the 

 yielding portion of the sprinkler. 



