A rough estimate of conduit pipes of a simple water service

Abstract

Correct decision of diameter of conduit pipe of a waterwork is very important for full supply of water, but very troublesome.
In many cases, the pipe line of the small scale water service such one as in farm village is simple, and it is rather easy to calculate the diameter. But, normal calculation of the diameter by means of dischage of water supplied per one person per day (q) results in very small on account of it's small population. This can'nt spply full water at peak time.
Then, writer tried an another way and estimated the diameter with Cosmogrope's Equivalent Table of pipes in order to simplify the calculation and checked after that. The diameter of small branch pipe lead to each house from the conduit pipe was taken as the basis instead of mean quantity of water (q).
The water service of T-mura, Mie-ken was taken as an example.
The result of this estimation is as follows,
1. Fig. 1 is the pipe line of this case.
2. Table 3 is the result of each interval of two cases when 13m/m and 20m/m pipe was respectively used as a small branch pipe.
3. Loss of head due to pipe friction is neglesible for mean maximum quantity of water (q″).(Table 4)
4. Discharge at each point (the beginning of branch pipe) is satisfactorily large.(Table 5) Time to full a bathtub (180 lit.) is shown at bottom of the table.
5. when large discharge and high head can be taken, hydrants must be added in this plan. In this case, water for each house is neglesibly small for calculation. (600 lit, per min, is needed for a hydrant for Japanse house).