894 



REroiiT — 1884. 



rrjjsD.iy, sKPTEMUHn i: 



Tlie followinjy Itcports and I'ajiers weru voad.— 



1. Itcport nf till} Patent Law Committee. — Sec lleport.s, p, 203, 



2. Itejjort of the Screw Gauge Committee, — See Reports, p. i2X7. 



3. Ueport of the Sea Coast Erosion Committee.-- Soe Keporl.s, p. l';)8. 



i. Some Points in Dijiiamo-Elerfric Mui-hiiws. 

 Ihj Professor S. 1*, TnoJii'soN, D.Sc. 



r». On the IL'atin(f of Coiulucturn hij Electric Currents, 

 By Professor G. Foriiks. 



G. Auto)iuttlc SpriMers for Fire Extinction. P>y C. J. H. WoODrsuitY. 



Tliia pa])t'r {jave the results of an examination of the various automatic sprinklcr.< 

 wliich art! operated ])y tlus mt'ltinjif of an easily fusible soldei'. These sprinklers an- 

 in ffeneral use in the eastern portion of the United States, for protectinj"; those por- 

 tions of textile mills and other industrial est ablislimeiits where the nature of tlie 

 product or the processes used introduce extreme hazard of lire. The invest ifratiou 

 was luidertaken at the instance of the Factory Mutual Insurance ( Jompanies (if 

 New I'lnj^land, and wa.s directed to an examination of the numerous varieties of 

 automatic spritdders, in respect to their efiiciency for pur])oses of mill protection, 

 inclndinijf their methods of distribution and consumption of water under various 

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

 matters pertaininf^' to their practical operation. 



The conclnsions based upon these tests are: — 



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

 170° Fahrenheit retains its lowmeltinj,^ ]ioint,nochan<re occurrin<,>- in sprinklers ten 

 y(!ar8 old. 



'2. They should be protected a^'ainst corrosion whenever it mif^lit interfere with 

 its prompt action. A heavy mineral oil is sufr^ested for the purpose. 



3. The distribution of Avater upon ceilinf,' and floor was measured upon each 

 square foot of floor, and found to be satisfactory. 



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

 other form of insidi! apparatus. 



6. The minimum static head upon the sprinklers should not be less than ten 

 feet. 



0. The practical value of automatic sprinkler systems is shown by a list of 1.31 

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

 other fire apparatus. 



7. Valves should bo kept open and secured by a straj). It is important that a 

 constatit head of w.ater, ready for immediate use, rests upon the sprinklers. 



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

 under water-pressure, to a uniform jet of steam, and tlie 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 fnrj 

 producing the heavy pressures used in graduating the dials ot 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 j 

 yielding portion of the sprinkler. 



