136 



BuLIvETiN 86 



pipe line. In this case the loss of head must be moderate since the 

 flow of water is expanded on the top side only, the filaments of 

 water on the lower side moving in straight lines. The results of 

 all the tests are given in Table XVIII. 



TABLE XVIII. FRICTION LOSSES IN HAND-MADE CEMENT PIPE AT THE 



UNIVERSITY FARM 



The results in Table XIX will be of value to designers of pipe 

 lines. While pipe friction tables are easily available, data on the 

 effect of boxes and risers have not been published. The value ob- 

 tained in the straight pipe without risers corresponds to a value of 

 "n" in Kutter's formula of .013. This is the value most used for 

 cement and concrete surfaces. 



Tests of pipe friction were made at Continental in 1917. The 

 flow of water is northward from the pumping plant, through about a 

 mile of machine-made pipe, thence eastward across the railway and 

 through a quarter mile of 16-inch hand-made pipe. Readings were 

 taken at the several gate pits built at intervals along the line. 

 There are no outlet risers on the line of pipe as tested except in the 

 16-inch line, where the risers are 280 feet apart. A summary of the 

 tests is given in Table XIX. 



