62 



BULLETIN 852, U. S. DEPARTMENT OF AGRICULTURE. 



Table 10. — Velocities, in feet per second, as computed by various formulas 

 for given sizes of pipe with given friction heads. 



Diam- 

 eter 

 (d). 



Fric- 

 tion 

 head 

 (A). 



Velocities, in feet per second, by formulas. 



Scobey. 

 Coefficient (Cj). 



3 

 0.267 



4 

 0.310 



0.345 



0.370 



Williams-Hazen. 

 Coefficient ( C w ). 



Kutter. 

 Coefficient (n). 



13 



0.014 



14 

 0.013 



15 

 0.012 



16 



0.0115 



17 

 0.011 



Moritz. 

 Coeffi- 

 cient 

 (On). 



18 

 1.24 



19 

 1.31 



Sco- 

 bey. 



Ins. 



12 

 12 

 12 



36 

 36 

 36 



72 



72 

 72 



96 

 96 

 96 



120 

 120 

 120 



144 

 144 



144 



Ft 

 2.0 

 5.0 

 9.0 



1.0 

 5.0 

 9.0 



0.2 

 1.0 

 5.0 



0.2 

 1.0 

 2.0 



0.2 



0.6 

 1.0 



0.2 

 0.6 



1.0 



0.2 

 0.6 

 1.0 



Ft. 

 1.16 



1.83 



2.46 



1.26 



2.82 

 3.79 



1.12 

 2.51 



5.61 



Ft 



1.35 



2.10 



2.85 



1.47 

 3.28 

 4.39 



1.30 

 2.91 



6.51 



Ft. 



1.63 

 3.65 



1.45 

 3.24 



7.24 



2.21 

 5.00 

 7.07 



2.67 

 4.62 

 5 



3.08 

 5.37 

 6.88 



3.45 

 5.97 

 7.71 



Ft. 



1.75 

 3.91 

 5.25 



1.55 

 3.47 

 7.77 



2.40 

 5.36 

 7.58 



2.87 

 4.91 

 6.41 



3.30 

 5.71 

 7.37 



3.70 

 6.40 



8. 26 



Ft. 

 1.11 



1.84 

 2.52 



1.19 



2.84 

 3. 



0.99 

 2.38 

 5.66 



1.54 

 3'. 68 

 5.35 



1.85 

 3.34 

 4.41 



2.13 



3.85 



2.39 

 4.32 

 5.69 



Ft. 



1.24 

 2.04 

 2.80 



1.32 

 3.15 

 4.33 



1.11 

 2. 64 

 6.30 



1.71 



4.08 

 5.94 



2.06 

 3.72 

 4.90 



2.37 



4.28 



64 



2.65 

 4.80 

 6.32 



Ft 

 1.36 

 2.25 

 3. 



1.45 

 3.47 

 4.76 



1.22 

 2.91 

 6.92 



1. 



4.49 

 6.54 



2.26 

 4.08 

 5.38 



2.60 

 4.71 

 6.20 



2.92 

 5.27 



6.96 



Ft 



1.48 

 2.45 

 3.36 



1.58 

 3.78 

 5.19 



1.33 

 3.16 

 7.55 



2.06 

 4.89 

 7.14 



2.46 

 4.46 

 5.78 



2.84 

 5.14 

 6.76 



3.18 

 5. 75 



7.58 



Ft. 



1.61 

 2.65 

 3.64 



1.72 

 4.10 

 5.62 



1.44 

 3.43 

 8.18 



2.23 

 5.31 

 7.73 



2.67 

 4.83 

 6.37 



3.08 

 5.57 

 7.32 



3.45 



6. 23 

 8.21 



Ft. 



1.85 

 4.40 

 6.06 



1.55 

 3.69 

 8.81 



2.40 

 5.71 

 8.32 



2.88 

 5. 21 

 6.86 



3.31 



3.71 

 6.70 

 8.85 



Ft. 

 1.01 

 1.61 

 2.15 



1.22 

 2.74 

 3.70 



1.19 

 2.76 

 6.20 



1.96 

 4.46 

 6.31 



2.39 

 4.18 

 5.40 



2.77 

 5.82 

 6.23 



3.13 

 5.43 



7.00 



Ft. 

 1.09 

 1.73 

 2.33 



1.35 



3.02 

 4.05 



1.34 

 3.01 

 6.74 



2.12 



4.83 



2.58 

 4.51 

 5.84 



3.00 

 5.20 

 6.73 



3.37 



5.84 

 7.55 



Ft. 

 1.24 

 1.98 

 2 



1 

 3.36 



4.50 



1.48 

 3.31 



7.48 



2.31 



5.27 

 7.47 



2.81 

 4.90 

 6.34 



3.24 

 5.65 

 7.30 



3.65 

 6.34 

 8.18 



Ft. 



1.56 

 3.54 

 4.72 



1.53 

 3.49 



7.85 



2.43 

 5.51 



7. 



2.94 

 5.11 

 6.61 



3.38 



5.89 

 7.62 



3.80 

 6.61 

 8.53 



Ft. 



1.65 

 3.75 

 5.00 



1.66 

 3.73 

 8.30 



2.59 

 5.79 

 8.20 



3.07 

 5.37 

 6.95 



3.57 

 6.18 

 7.98 



3.99 

 6.92 

 8 93 



Ft. 



1.45 

 2.37 

 3.28 



1.58 

 3.S6 

 5.36 



1.39 

 3.40 

 8.33 



2.26 

 5.52 

 8.14 



2.77 

 5.20 

 6.77 



3.24 



5. 96 

 7.92 



3.65 



6.76 

 S. 95 



Ft. 



1.53 

 2.50 

 3.47 



1.67 

 4.08 

 5.66 



1.47 



3. 59 



2.39 



2.93 

 5.39 

 7.15 



3.42 

 6.30 

 8.36 



3.85 

 7.13 

 9.45 



Ft. 

 1.52 

 2.52 

 3.50 



1.62 



3.96 



1.35 

 3.31 



2.12 

 5.19 

 7.63 



2.56 

 4.70 

 6.26 



2.96 

 5.45 

 7.24 



3.33 

 6.14 

 8.15 



1 Based on formula for velocity in average wood-stave pipe; F=1.62D ,K J?- 555 . (See Dept. Bul.376,p.7.) 

 COMPARISON OF THE VARIOUS FORMULAS. 



For the reason that there are at least four distinct classes of con- 

 crete pipes, considered from a capacity standpoint, it was not feasible 

 to make a percentage or graphical comparison between the recom- 

 mended formula, with varying coefficients and the other formulas 

 mentioned on pages 5 to 8. Of these other formulas, some con- 

 sider the influences of varying surfaces by means of coefficients, 

 while others are inelastic and were offered for "clean pipes," regardless 

 of materials. 



The point that must be kept continually in mind is that concrete 

 pipes offer a greater range of interior surfaces, due to their initial 

 construction, than pipes of any other material, considered by itself, 

 or pipes of all other materials, considered together. These concrete 

 surfaces are almost unbelievably different, aside from all fouling by 

 growths, slimes, or erosion. 



In the following discussion classes 1, 2, 3, and 4 will be considered 

 as was described on page 8, in connection Avith the new formula, the 

 latter being considered as the base from which a comparison is made. 



