NEW STANDARD SPECIFICATIONS FOR WOOD POLES 



515 



species. For illustrative purposes a summary of part of the test re- 

 sults used in arriving at fiber stress values is shown in Table 1. A 

 detailed study of the results of these tests and of other tests made on 

 full length poles and on small clear specimens of wood of the species 



TABLE 1 



Summary of Statistical Analysis of Modulus of Rupture Values Obtained 

 FROM Tests on Full Size Poles 



2 Uncorrected for sample size. 



under investigation led to the recommendation of the following figures 

 as standard ultimate fiber stresses: 



Northern white cedar 3600 lbs. per sq. in. 



Western red cedar 5600 " " " " 



Chestnut 6000 " " " " 



Southern yellow pine (creosoted) 7400 " " " " 



The fiber stress for a given species finds application in pole line 

 engineering through the conversion of the stress value into terms of 

 moment of resistance, usually at the ground line. The poles act as a 

 series of supports for the wires. With this in mind one of the studies 

 conducted in connection with the application of the new fiber stresses, 



