Where its construc tion is economically justified.
capacity to meet the following requirements.
(1) Domestic and General Uses. Plan for the
maximum daily demand plus reserve capacity for the estimated
load not less than 20 years in the future, unless this growth
factor has already been used in computing the maximum daily
demand. Evaluate effect of long detention time on decay of
(2) Essential to Defense. The basis of design
should be the maximum daily demand plus reserve capacity for the
estimated load 20 to 40 years in the future.
Temporary Installations. Use the maximum daily
demand plus a reasonable reserve capacity for the expected life
of the installation.
Design Velocity. Velocities above 5 ft per second
should not be used because of high friction losses. Where
excess head is available, limit the velocities as follows:
TYPE OF STRUCTURE
MAXIMUM VELOCITY (fps)
Steel and ductile iron
Size . Determine the hydraulic details from cost
studies. Allowance should be provided for the loss of carrying
capacity during the expected service life.
Arrangements . Where there is only one major source of
supply, and little or no transmission storage, multiple conduits
should be provided, whenever possible, so that delivery of water
need not be interrupted during repairs. If feasible, the
conduits should be arranged to enter the Military activity from