Information Needed for Pressure Distribution Design

PRESSURE DISTRIBUTION WORKSHEET Information needed for Pressure Distribution Design: Daily wastewater flow = ______gal/day Design loading rate = ______gal/day/sf System Configuration: 1. ______ft. system width - choose longest skinniest field that will fit the site 2. ______ft. system length Proposed Lateral Layout: 3. ______number of laterals 4. ______central or end manifold 5. ______ft. manifold length 6. ______in. orifice diameter (1/8” minimum) – the larger the hole the large the pump, 7. ______ft. distal pressure requirement (Based on orifice diameter, see Table 1) (Use a minimum of 3.0 ft – 2.3 ft required by VT regulation) force main and lateral Choose the Orifice Spacing: 8. ______in. Hole Spacing (Bed width (2(n-1)+2)) 8a ______sf area each hole covers (not to exceed 25 sf) 9. ______number of orifices per lateral (bed or trench length (in) / hole spacing (in). 10. ______ft. final lateral length ((# of orifices-1) x orifice spacing) 11. ______in. end length (bed length-lateral length)/2 Choose the Lateral Diameter: 12. ______in. (Graphs 1-6) Calculate the Lateral Discharge Rate: 13. ______gpm lateral discharge rate. (note A table 4) Hole discharge in GPM = 11.79 x Orifice Diameter2 in inches x (Pressure in Feet)1/2 Discharge rate per orifice x # of orifices per lateral = lateral discharge rate. Choose the Manifold Diameter: 14. ______in. (Table 5) Calculate the System Discharge Rate: 15. ______gpm (# of laterals x lateral discharge rate) Calculate the Force Main Friction Loss: 16. ______ft. force main length *From Site Plan 17. ______in. force main diameter (Table 6) 18. ______gpm system discharge rate (from #15)

056fc9ef1d9029769f7621f7a8902d68.doc Page 1 of 4 19. ______force main velocity (minimum 2 fps max 5 fps)(flow in cfs/area = velocity) see formula table 6

Calculate the Total Dynamic Head: 20. ______ft. Desired distal pressure 21. ______ft. Total Dynamic Head (TDH) (VTC Table 1) Pump Selection: 22. ______pump specification – draw system curve determine pump that meets minimum distal pressure (see example pump curve VTC figure 1.) Calculate the Dose Volume: 23. ______gal. based on system type. 24. ______gal. - drain back 25. ______gal. - actual dose volume (#23 + #24) Dose Chamber Sizing: 26. Septic Tank Length ______in. Width______in. Height ______in. 27 . ______gallon per inch (Length x Width / 231) 29. ______in. dose delta (dose line #25 / Line #27) 30. ______in. float off (distance from floor of tank to pump inlet +2”) 31. ______in. float on (line #30 +line #29) 32. ______in. alarm float (line #31 + 1”) 33. ______gal. storage above alarm (include all volume including volume in septic tank. Septic Tank Sizing: Less than 667 Gal/Day ……………….1,000 gallons 667 - 1500 Gal/Gay …………………. 1.5 times design flow 1,500 – 6500 Gal/Day ………… 1,125 + 75% of design flow

34. ______gallons septic tank size

056fc9ef1d9029769f7621f7a8902d68.doc Page 2 of 4 Force Main and Pump Design Number of Holes Size Design Flow C value 145 cf/s Design Distal Pressure

1 1 Pump Station 1/4" Each EPL 1/2" Each EPL 2" Each EPL 3" Each EPL 4" Each 90° Std Elbow 7.0 8.0 9.0 12.0 14.0 45° Std Elbow 3.0 3.0 4.0 6.0 8.0 Std. Tee 7.0 9.0 11.0 17.0 22.0 Check Valve 11.0 13.0 17.0 26.0 33.0 Coupling Quick Disconnect 1.0 1.0 2.0 4.0 5.0 Gate Valve 0.9 1.1 1.4 2.0 2.3 PVC Pipe Pipe Velocity - fps Pipe Volume - gallons 1 1 Force Main 1/4" Each EPL 1/2" Each EPL 2" Each EPL 3" Each EPL 4" Each 90° Std Elbow 7.0 8.0 9.0 12.0 14.0 45° Std Elbow 3.0 3.0 4.0 6.0 8.0 Std. Tee 7.0 9.0 11.0 17.0 22.0 Check Valve 11.0 13.0 17.0 26.0 33.0 Coupling Quick Disconnect 1.0 1.0 2.0 4.0 5.0 Gate Valve 0.9 1.1 1.4 2.0 2.3 PVC Pipe Pipe Volume - gallons Total Equvilent Pipe Length Force Main Friction Loss Total Force Main Friction Loss System Head (1.3 x distal pressure) Laterial Elevation Pump Inlet Elevation Vertical lift Total Dynamic Head ft @ gpm

VTC Table 1

056fc9ef1d9029769f7621f7a8902d68.doc Page 3 of 4 VTC Figure 1.

056fc9ef1d9029769f7621f7a8902d68.doc Page 4 of 4