Height Limitation . Where the height of elevated tanks
use ground storage tanks.
Elevated Tanks . Use elevated tanks to store water at
to allow gravity discharge from the tank into the distribution
system. Standard capacities for welded steel tanks are given in
AWWA Standard D100, Welded Steel Tanks for Water Storage. In
most cases the cost of elevated tanks limits their maximum
practical size to between 1 and 2 million gallons.
Underground Storage Tanks . Use this type of storage
as required by the following conditions:
Where economy of construction results.
Where protection against freezing is required.
Where the area above the ground is to be utilized
Where the hydraulic grade at a tank site requires
the tank to be below grade.
Where protection against sabotage and destruction
Hydropneumatic Tanks . Use Hydro pneumatic tanks at
small activities where the demand is not enough to justify any
other type of storage. Protect the tank from freezing. Design
the tank to meet pressure vessel requirements. Provide air
compressors, safety valve, and sight glass, to show the
Materials and Construction
Materials . For available material and their
characteristics, see Table 18.