5. Residential
Average consumption: 2.652 x 105 gpd
Peak day consumption: 5.304 x 105 gpd
Peak hour consumption: 1.608 x 106 gpd
Industrial
Weekday consumption: 1.44 x 106 gal/day
Peak hour consumption:1.8 x 105 gal/hr
Commercial
Average flow rate: 17.5 gpm
Peak day flow rate: 35 gpm
DEMAND
6. Fire flow is calculated based on the equation
NFF=(Oi)(Ci)[1.0+(X+P)i]
Q = 5200 gpm (10 hour duration) = 3.124 x 106 gpd
Total flow for max day and Fire flow
Qtotal = 2.38x106 + 3.124x106 = 5.50 x 106 gpd
FIRE FLOW
9. System B – Pumping station to major center of demand with
an elevated storage tank between the supply and demand
Average Day = 1.7 mgd.
Max Day = 1.7 mgd x 1.5 = 2.55 mgd
Peak hour = 2.55 mgd x 1.5 = 3.83 mgd
Max day + Fire flow = 5.5 mgd
DISTRIBUTION STORAGE
10. DISTRIBUTION STORAGE
Demand Rate Calculation Pumping Head
Average Day (1.7 mgd) 115 + (0.67 x 19) 128 ft
Max. Day. (2.55 mgd) 115 + (1.42 x 19) 142 ft
Max. Hour. (3.83 mgd) 115 + (3.0 x 19) 172 ft
Max day + fire = (5.5
mgd)
115 + (6.1 x 19) 231 ft
11. Total Length of Pipe ~ 19,000 feet
Pipe Material = ductile iron (C = 140)
Diameter: 12-14 in
Water Tower Head – 310 ft
Pump Head – 305 ft
Worst Case: Pump Failure
Pressure low: 28.84 psi, high: 40.21 psi
PIPING SYSTEM INFORMATION
16. For Commercial and Residential
25 F.U. => 40 gpm x 3 (Restaurants) = 120 gpm
10 F.U. => 30 gpm x 2 (Offices) = 60 gpm
Total = 180 gpm
For Industry = (3000gpm) x (70%) = 2100 gpm
For Residential = (Max Hourly Use) x 70% = Sewage Flow
SEWER DESIGN
17. Summary
SEWER DESIGN
Pipe Material PVC
Min. Velocity 2 ft/s
Max Velocity 10 ft/s
Roughness (n) 0.015
Min Ground Cover 6 ft
Percentage Full 50%
Min. Pipe Diameter 8 in.
Max Pipe Diameter 50 in
Max Velocity (Actual) 7.7 ft/s
Max Depth 22 ft.
20. STORM SEWER DESIGN
Design Criteria Value (Minimum) Value (Maximum)
Flow Velocity 3 ft/s 15 ft/s
Slope 0.02% 10%
Depth of Cover 5 ft below surface N/A
Diameter 1 ft N/A
Roughness Coefficient N/A N = 0.013
Capacity* N/A ¾, 0.75
Horizontal Distance from
Drinking Water Lines**
10 ft N/A
Vertical Distance from
Utilities**
1 ft
Pipe Material PVC for Diameter les
*ratio of flow depth to full depth
**from Haestad Methods, Stormwater Conveyance Modeling and Design
Design Restrictions
•Hydraulic Gradient Line should be below surface elevation at all times.
•Curved Storm Sewers are unacceptable (maintenance problems)
Depth of cover should be at least 5 ft in order to prevent crushing of pipes due to loads.
33. SUMMARY
Pipe Material PVC or Reinforced Concrete (D>1ft)
Min. Velocity 3.72fps
Max. Velocity 12.3fps
Roughness n=0.013
Min Ground Cover 5ft
Max Capacity 75% fullness
Min. Pipe Diameter 12inches
Max. Pipe Diameter 27inches
Max Depth 22ft
34. Worst Case Scenario
Pump Failure, distribution only from water tower
Water tower height 310 ft
Pump head = 0 ft
Pressure
High- 40.21 psi
Low- 28.84 psi
DISTRIBUTION DESIGN (SCENARIO 1)
35. Water Tower Failure, supply only from pump
Water tower head = 0 ft
Pump head = 305 ft
Pressure
High: 44.99 psi
Low: 30.52 psi
DISTRIBUTION DESIGN (SCENARIO 2)
36. Best Case
Elevated Storage Tank -310 ft
Pumping Reservoir- Total head about 305 ft
Pressure-
High- 45.89 psi
Low- 33.01 psi
DISTRIBUTION DESIGN (SCENARIO 3)