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Water Distribution Systems
Distribution systems
Designed to adequately satisfy water requirements for combination of:
Domestic useCommercial UseIndustrial UseFire-fighting
Have to consider:
FlowPressureQuality
Distribution System Classifications
Branching System
Grid System
Combination system
System Type Advantages
Branching System
Grid System
Combination System
System Requirements
Commercial
Pressure greater than 60 psig typically required
Residential
Pressure of 40 to 50 psig
Tower Buildings
Intermediate booster pumps with storage tank on top
Velocities typically between 3 to 5 fps at peak flows
Select pipe sizes to avoid hig velocities
* Inch pipes recommended in areas were fire-fighting demands are expected. 6 inch pipe may be used if a grid type system is used and length between connections is lesss than 600 feet.
A typical distribution system layout
Hydraulic grade lines
Distribution Reservoirs and Service Storage
Storage reservoirs are used to meet fluctuating demands, to accommodate fire-fighting and emergency requirements, and equalize operating pressures.
Types of storage reservoirs:
Surface reservoirsStandpipesElevated storage tanks
Locate reservoirs and storage to maximize benefits. Usually near the center of use.
High enough to supply necessary pressure in the system
Modes of Operation
Demand light – pumping station will met needs in system and supply water to storage tank.
Demands high – both the tank and the pumping station will be needed to supply the flow