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Environmental Controls I/IG

Environmental Controls I/IG. Lecture 7 Upfeed Systems Pipe Sizing Procedure Pipe Sizing Example. Upfeed Systems. Pressure in Upfeed Systems. Fixture pressure head Static head Friction head loss Meter pressure loss. S: p. 913, F.21.13. Pressure in Upfeed Systems.

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Environmental Controls I/IG

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  1. Environmental Controls I/IG Lecture 7 Upfeed Systems Pipe Sizing Procedure Pipe Sizing Example

  2. Upfeed Systems

  3. Pressure in Upfeed Systems Fixture pressure head Static headFriction head lossMeter pressure loss S: p. 913, F.21.13

  4. Pressure in Upfeed Systems Proper fixture flow pressure A + Pressure lost due to height B + Pressure lost due to friction C +Pressure lost through meter D Total street main pressure E

  5. A: FixtureFlow Pressure Pressure needed to get water through fixture S: p. 970, T.21.14

  6. B: Pressure lost due to height Weight of water column S: p. 913, F.21.13

  7. C: Pressure loss due to friction Initially unknown, must be calculated based on pressure remaining after accounting for the other factors

  8. D: Pressure lost through meter Make initial size assumption and then repeat to optimum size S: p. 971, F.21.63a

  9. E: Total Street Main Pressure Check with water company or fire department

  10. Pipe Sizing Procedure

  11. 1. Determine Supply Fixture Units Fixture units take into account usage diversity S: p. 974, T.21.15

  12. 2. Calculate Demand Flow Use curve 1 for flush valve dominated system Use curve 2 for flush tank dominated systems S: p. 975, F.21.65a

  13. 3. Determine the “Most Critical Fixture (MCF)” Highest and farthest from inlet main Confirm pressure required (A) Identify height (B) S: p. 958, F.21.52

  14. 4. Determine Developed Length The total length of all horizontal and vertical pipes from the main to the MCF S: p. 995, F.22.17

  15. 5. Determine Total Effective Length (TEL) Two approaches: 1. equivalent length or 2. multiply DL x 1.5 TEL= DL x 1.5 S: p. 976, T.21.16a

  16. 6. Determine Street Main Pressure (E) Contact utility company or fire department

  17. 7. Determine Pressure Available for Friction Loss Proper fixture flow pressure A + Pressure lost due to height B + Pressure lost due to friction C +Pressure lost through meter D Total street main pressure E or C=E-A-B-D

  18. Meter Loss (D) Since D is unknown, pick an initial size, do calculation, repeat as needed to optimize flow C=E-A-B-D S: p. 971, F.21.63a

  19. 8. Determine Friction loss/100’ C=E-A-B-D Δp/100’ = 100 x C/TEL

  20. 9. Verify flow for meter size If flow > Total Demand (#2)  repeat 7-9 at smaller diameter If flow < Total Demand (#2)  repeat 7-9 at larger diameter S: p. 972, F.21.64a

  21. 10. Select finalmeter size When flow > Total Demand (#2)  stop S: p. 972, F.21.64a

  22. Pipe Sizing Example

  23. Given Information Small Office Building  public numbers 2 Flush valve toilets 2 Lavatories 2 Drinking fountains 1 Service sink DL: 92’ MCF: Flush Valve Toilet, 16’ above water main Street Main Pressure: 44.1 psi

  24. 1. Determine Supply Fixture Units Fixture units take into account usage diversity S: p. 974, T.21.15

  25. 1. Determine Supply Fixture Units Cold Hot Total 2 Flush valve toilets 20.00 --- 20.0 2 Lavatories 3.00 3.00 4.0 2 Drinking fountains 0.50 --- 0.5 1 Service sink 2.25 2.25 3.0 25.75 5.25 27.5

  26. 2. Calculate Demand Flow 20 WSFU out of 27.5 WSFU are flush valves Use curve 1 for flush valve dominated system 40 gpm S: p. 975, F.21.65a

  27. 3. Determine the Most Critical Fixture Confirm pressure required (A) 15 psi Height above main (B) 16’  7.0 psi S. p. 970, T.21.14

  28. 4. Determine Developed Length Developed length 92’ Note: this figure for generic reference only and does not illustrate the example problem S: p. 975, F.22.17

  29. 5. Determine Total Effective Length (TEL) TEL= DL x 1.5 = 92 x 1.5 = 138’

  30. 6. Determine Street Main Pressure (E) 44.1 psi

  31. 7. Determine Pressure Available for Friction Loss Proper fixture flow pressure A 15.0 + Pressure lost due to height B 7.0 + Pressure lost due to friction C ? +Pressure lost through meter D ? Total street main pressure E 44.1

  32. Meter Loss (D) Pick an initial size 2” diameter… 1.4 psi S: p. 971, F.21.63a

  33. 8. Determine Friction loss/100’ C=E-A-B-D = 44.1-15.0-7.0-1.4 = 20.7 psi Δp/100’=100 x 20.7/138 = 15 psi/100’

  34. 9. Verify flow for meter size At 2” Flow=150 gpm > Total Demand 40 gpm At 1-1/2” Flow=60 gpm > Total Demand 40 gpm (Δp/100’= 13.1) At 1” Flow=13 gpm < Total Demand 40 gpm (Δp/100’= 5.1) S: p. 972 F.21.64a

  35. 9. Verify flow for meter size When flow > Total Demand (#2)  stop At 1-1/2” Flow=60 gpm > Total Demand 40 gpm (Δp/100’= 13.1) S: p. 972 F.21.64a

  36. Pipe Sizing Use Δp/100’= 13.1 psi/100’ Use fixture units to determine flow S: p. 972 F.21.64a

  37. Pipe Sizing Use fixture units to determine flow Pay attention to flush valve domination S: p. 972 F.21.65a

  38. Pipe Sizing Use Δp/100’= 13.1 psi/100’ Use fixture units to determine flow Select size which does not exceed 13.1 psi/100’ 20 gpm, use 1” 10 gpm, use ¾” Use runout sizes at each fixture S: p. 972, F.21.64a

  39. Runout Pipe Sizing Use actual flow to size runouts Lavatory: 2 gpm S: p.970, T.21.14

  40. Runout Pipe Sizing Use Δp/100’= 13.1 psi/100’ Lavatory: 2 gpm S: p. 972, F.21.64a

  41. 2.7 2 3 ½” 3.6 2 4 ¾” Notation System Suggested for organizing data WSFU Curve Flow Diam. S: p. 995, F.22.17

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