THE FLOW OF WATER IN WOOD-STAVE PIPE. 73 
The velocity in a 12-inch wood-stave pipe for a loss of head of 2.73 
feet per 1 ; 000 feet of pipe is 2.83 feet per second or 4.4 per cent less 
than that in a new cast-iron pipe for the same loss of head. 
The velocity in a 12-inch wood-stave pipe for a loss of head of 3.71 
feet per 1,000 feet is 3.33 feet per second or 12.5 per cent more than 
that in a new riveted steel or 10-year-old cast-iron pipe for the same 
loss of head. 
The velocity in a 12-inch wood-stave pipe for a loss of head of 4.43 
feet per 1,000 feet is 3.7 feet per second, or 25 per cent more than that 
in a 10-year-old riveted steel or 20-year-old cast-iron pipe, for the 
same loss of head. 
As shown by the table, the relative capacities change for various 
sizes of pipe and various velocities, but, speaking broadly, it is also 
shown that the capacity of wood-stave pipe is about 5 per cent less 
than that of new cast iron, 15 per cent more than that of new riveted 
steel or 10-year-old cast iron, and 25 per cent more than that of 10- 
year-old riveted steel or 20-year-old cast-iron pipe. 
CONCLUSIONS. 
A study of the previous pages appears to warrant the following 
general conclusions concerning the capacity of wood-stave pipes: 
1. That the new formula herein offered is the best now available 
for use in the design of wood-stave pipes, as its application meets 
(within 1 per cent) the mean of all observations and the mean capacity 
of all wood pipes upon which experiments have been made. 
2. That a very conservative factor of safety should be used where 
a guaranteed capacity is to be attained. 
3. That the Kutter modification of the Chezy formula is not well 
adapted to the design of wood-stave pipes. 
4. That the data now existing do not show that the capacity of 
wood-stave pipe either increases or decreases with age. This state- 
ment, of course, does not consider sedimentation, a purely mechanical 
process. 
5. That if silted waters are to be conveyed the pipe should be 
designed for a working velocity of from 5 to 10 feet per second. 
6. That if sand is present in the water, the design should be for a 
velocity of about 5 feet per second, which will be high enough to 
carry out a large part of the sand and at the same time not so high as 
to seriously erode the pipe. The better method, of course, is to 
remove the sand by sumps or other means. 
7. That air should be removed from the intake end of every pipe 
line, especially when the capacity load is approached. 
8. That wood pipe will convey about 15 per cent more water than 
a 10-year-old cast-iron pipe or a new riveted pipe, and about 25 per 
cent more than a cast-iron pipe 20 years old or a riveted pipe 10 
years old. 
