WATER CONDUCTORS 



137 



For large size pipes and high pressures the stress due to the 

 swelling action is relatively small and may be neglected, in which 

 case the equation can be written, 



U ~W 



The friction losses may be obtained from Hazen and Williams' 

 formula on page 116, and the Table XXXIV 1 gives the discharge, 

 velocity and loss of head per 100 feet for pipes of different di- 

 ameters. 



Concrete Pipe. Reinforced concrete pipes (Figs. 66 and 67) 

 for power work are used to a limited extent for low-pressure con- 



FIG. 66. Concrete Pipe, Showing Steel Forms for Pouring. 



duits, but there is every indication that they may in the future 

 be extensively used in place of open flumes and canals. This will 

 not only tend to increase the total head of the plant, but it will 

 prevent leaves, branches, etc., from falling into the conduit, which 

 is often the case when they are of the open type. 



1 As given by Washington Pipe and Foundry Company. 



