58 



BULLETIN 376, TJ. S. DEPARTMENT OF AGBICULTURE. 



EFFECT OF AGE UPON THE CARRYING CAPACITY OF WOOD-STAVE PIPE. 



Some manufacttirers and hydraiilicians have contended that wood- 

 stave pipe becomes smoother with length of use, and that therefore 

 the capacity of the pipe increases with its age. 



In order to study this question the writer prepared figure 5. This 

 chart shows that, judging by available experimental data, there is 

 no definite law between age and change in capacity, but unfor- 

 tunately the results of but one test are accessible on any pipe older 

 than 7 years. That pipe (No. 31, Ogden, Utah), although 24 years 



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36 



Fig. 5.— Diagram showing lack of relationsliip between age and carrying capacity. Numbers correspond 

 with those in column 1, Tables 2 and 3. Ages taken from column 4, Table 3. Relative capacities taken 

 from column 18, Table 3. 



old at time of test, shows a capacity only about 3 per cent greater 

 than the discharge computed by the new formida. 



CAPACITY OF WOOD-STAVE PIPES. 



In the following pages the design of wood-stave pipes is con- 

 sidered with reference to carrying capacity alone. Such structural 

 features as thickness of staves, banding, cradles, etc., do not come 

 within the scope of this paper. 



The total loss of head necessary in the conveyance of a given 

 quantity of water will be the sum of the velocity head, hy; the entry 

 head, he; and the friction head, hf, or its equivalent per unit length; 



