72 



BULLETIlSr 370, U. S. DEPARTMENT OF AGEICULTUEE. 



CAPACITY OF WOOD-STAVE PIPE COMPARED WITH THAT OF CAST- 

 IRON AND RIVETED STEEL. 



Table 8 gives the relative carrying capacities of wood, steel, and 

 cast-iron pipes. The table is based on velocities of about 1, 3, and 7 

 feet per second in the steel and cast-iron pipes of diameters ranging 

 from 4 to 144 inches. For a given velocity the loss of head for new 

 cast-iron, new riveted steel, 10-year-old cast-iron, 20-year-old cast- 

 iron, and 10-year-old-riveted steel is based on values of C^ in the 

 Williams-Hazen formula (No. 8, p. 6) of 130, 110, 110, 100 and 100, 

 respectively, these conservative values being recommended by 

 Williams and Hazen. (See Mr. Wilhams's discussion, p. 82.) 



Table 8. — Relative capacity, in per cent, of wood-stave pipe, compared with new cast 

 iron, new riveted, 10-year-old cast iron, 20-year-oJd cast iron, and 10-year-old riveted 

 steel or iron pipe; based on Williams and Hazen recommendation for values of C, in 

 their formula, of 130 for neiv cast iron, 110 for neiv riveted and 10-year-old ca^t iron, 

 and 100 for 20-year-old cast iron and 10-year-old riveted steel or iron pipe. 



Diam- 

 eter. 



Inches. 



4 



4 



4 



12 



12 



12 



36 



36 



36 



72 



72 



72 



108 



108 



108 



144 



144 



144 



Cast-iron and riveted pipes. 



Velocity 



per 

 seoend. 



Feet. 

 1.02 

 3.06 

 6.64 

 .99 

 2.96 

 6.89 

 1.09 

 3.06 

 7.00 

 .98 

 3.01 

 7.11 

 1.10 

 3.14 

 6.92 

 1.06 

 3.01 

 7.07 



Loss of head for velocity. (H) 



130. C„=110. C„=100. 



Feet. 



1.380 



10. 500 



44.000 



.360 



2.730 



13. 200 



.121 



.810 



3.740 



.044 



..349 



1.720 



.034 



.237 



1.020 



.023 



.156 



.760 



Feet. 



0.480 



3.710 



17. 900 



.164 



1.110 



5.100 

 .060 

 .476 



2.340 

 .046 

 .321 



1.380 

 .031 

 .211 



1.030 



Feet. 



2.230 



17. 100 



72. 000 



.580 



4.430 



21.300 



.196 



1.320 



6.100 



.072 



.570 



2.790 



.055 



.382 



1.650 



.037 



.252 



1.230 



Wood-stave pipes. 



Velocities correspond- 

 ing to losses in col- 

 umns 3, 4, 5, respec- 

 tively. 



Feet. 



Feet. 



0.94 





2.90 





6.50 





.92 



1.08 



2.83 



3.33 



6.80 



8.00 



1.02 



1.25 



2.90 



3.50 



6.90 



8.10 



.92 



1.10 



2.90 



3.50 



7.00 



8.30 



1.00 



1.20 



3.00 



3.60 



6.90 



8.00 



1.00 



1.20 



2.90 



3.40 



7.00 



8.30 



Feet. 

 1.24 

 3.90 

 8.70 

 1.25 

 3.70 

 8.80 

 1.34 

 3.80 

 9.00 

 1.20 

 3.80 

 9.10 

 1.35 

 4.00 

 9.00 

 1.35 

 3.80 

 9.10 



Per cent of velocity in 

 wood pipe over that 

 in metal pipe (column 

 2), corresponding to 

 columns 6, 7, 8, re- 

 spectively. 



7.8 





5.2 





2.1 





7.1 



-f- 9.1 



4.4 



+ 12.0 



1.3 



+ 16.0 



6.4 



+ 15.0 



5.2 



+ 14.0 



1.4 



+ 16.0 



6.4 



+ 12.0 



3.6 



+ 16.0 



1.4 



+ 17.0 



8.0 



+ 11.0 



4.5 



+ 15.0 



.3 



+ 16.0 



5.7 



+ 13.0 



3.7 



+ 13.0 



1.0 



+ 17.0 



+22 

 +26 

 +31 

 +21 

 +25 

 +28 

 +23 

 +24 

 +29 

 +22 

 +24 

 +28 

 +23 

 +27 

 +30 

 +21 

 +26 

 +29 



For the same sized pipe and the various losses of head the corre- 

 sponding velocities in wood-stave pipe (as shown by the new formula) 

 are compared with the velocities in the metal pipes. This comparison 

 is on a percentage basis, with the velocity of the metal pipe as the 

 base. As an example: The loss of head in a new cast-iron pipe 

 (0^=130), 12 inches in diameter, for a velocity of 2.96 feet per 

 second, is 2.73 feet per 1,000 feet of pipe. For the same velocity in 

 new riveted steel or 10-year-old cast iron (C-^= 110) the loss of head 

 in a 12-inch pipe is 3.71 feet. For the same velocity in 10-year-old 

 riveted steel or 20-year-old cast iron (C^=100) the loss of head is 

 4.43 feet. 



