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Technology in Architecture Lecture 14 Upfeed Systems Pipe Sizing Procedure Pipe Sizing Example Lecture 14 Upfeed Systems Pipe Sizing Procedure Pipe Sizing Example
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Upfeed Systems
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Pressure in Upfeed Systems Fixture pressure head Static head Friction head loss Meter pressure loss M: p. 929, F.21.13
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Pressure in Upfeed Systems Proper fixture flow pressureA +Pressure lost due to heightB +Pressure lost due to frictionC +Pressure lost through meterD Total street main pressureE
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A: Fixture Flow Pressure Pressure needed to get water through fixture M: p. 987, T.21.14
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B: Pressure lost due to height Weight of water column M: p. 929, F.21.13
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C: Pressure loss due to friction Initially unknown, must be calculated based on pressure remaining after accounting for the other factors
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D: Pressure lost through meter Make initial size assumption and then repeat to optimum size M: p. 988, F.21.63a
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E: Total Street Main Pressure Check with water company or fire department
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Pipe Sizing Procedure
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1. Determine Supply Fixture Units Fixture units take into account usage diversity M: p. 991, T.21.15
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2. Calculate Demand Flow Use curve 1 for flush valve dominated system Use curve 2 for flush tank dominated systems M: p. 992, F.21.65a
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3. Determine the “Most Critical Fixture (MCF)” Highest and farthest from inlet main Confirm pressure required (A) Identify height (B) M: p. 975, F.21.52
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4. Determine Developed Length The total length of all horizontal and vertical pipes from the main to the MCF M: p. 1014, F.22.17
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5. Determine Total Effective Length (TEL) Two approaches: 1. equivalent length or 2. multiply DL x 1.5 TEL= DL x 1.5 M: p. 993, T.21.16a
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6. Determine Street Main Pressure (E) Contact utility company or fire department
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7. Determine Pressure Available for Friction Loss Proper fixture flow pressureA +Pressure lost due to heightB +Pressure lost due to frictionC +Pressure lost through meterD Total street main pressureE or C=E-A-B-D
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Meter Loss (D) Since D is unknown, pick an initial size, do calculation, repeat as needed to optimize flow C=E-A-B-D M: p. 988, F.21.63a
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8. Determine Friction loss/100’ C=E-A-B-D Δp/100’ = 100 x C/TEL
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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 M: p. 989, F.21.64a
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10. Select final meter size When flow > Total Demand (#2) stop M: p. 989, F.21.64a
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Pipe Sizing Example
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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
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1. Determine Supply Fixture Units Fixture units take into account usage diversity M: p. 991, T.21.15
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1. Determine Supply Fixture Units ColdHotTotal 2 Flush valve toilets20.00---20.0 2 Lavatories3.003.004.0 2 Drinking fountains0.50---0.5 1 Service sink2.252.253.0 25.755.2527.5
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2. Calculate Demand Flow 20 WSFU out of 27.5 WSFU are flush valves Use curve 1 for flush valve dominated system 40 gpm M: p. 992, F.21.65a
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3. Determine the Most Critical Fixture Confirm pressure required (A) 15 psi Height above main (B) 16’ 7.0 psi S. p. 987, T.21.14
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4. Determine Developed Length Developed length 92’ M: p. 1014, F.22.17 Note: this figure for generic reference only and does not illustrate the example problem
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5. Determine Total Effective Length (TEL) TEL= DL x 1.5 = 92 x 1.5 = 138’
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6. Determine Street Main Pressure (E) 44.1 psi
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7. Determine Pressure Available for Friction Loss Proper fixture flow pressureA15.0 +Pressure lost due to heightB7.0 +Pressure lost due to frictionC? +Pressure lost through meterD? Total street main pressureE44.1
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Meter Loss (D) Pick an initial size 2” diameter… 1.4 psi M: p. 988, F.21.63a
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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’
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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) M: p. 989 F.21.64a
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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) M: p. 989 F.21.64a
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Pipe Sizing Use Δp/100’= 13.1 psi/100’ Use fixture units to determine flow M: p. 989 F.21.64a
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Pipe Sizing Use fixture units to determine flow Pay attention to flush valve domination M: p. 992 F.21.65a
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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 M: p. 989, F.21.64a
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Runout Pipe Sizing Use actual flow to size runouts Lavatory:2 gpm M: p.987, T.21.14
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Runout Pipe Sizing Use Δp/100’= 13.1 psi/100’ Lavatory: 2 gpm M: p. 989, F.21.64a
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Notation System Suggested for organizing data WSFUCurve Flow Diam. M: p. 1014, F.22.17 3.6 2 4 ¾” 2.7 2 3 ½”
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Waste & Vent Systems
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Fundamentals Siphon action can drain water Trap blocks sewer gas Vent breaks siphon M: p. 1006, F.22.8
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Air Gaps Eliminate the potential for cross contamination M: p. 1009, F.22.11
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Bathroom Design Considerations ADA compliance ANSI Standard A117.1 1986 Wheel chair access Grab bars Counter top/fixture heights Visual privacy Acoustical privacy
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Vents and Stacks Individual vents Circuit vents Soil stack Vent stack Stack vent “Wet stack” Vent through roof (VTR) M: p. 1008, F.22.10 Note: Drain fittings are 45º
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Drains & Sewers House drain House sewer Storm drain Clean outs House traps Fresh air inlet M: p. 1007, F.22.9 Note: Drain fittings are 45º
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Waste & Vent Sizing Procedure
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1. Identify waste & soil locations Clusters are more efficient M: p. 1014, F.22.17
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2. Layout system vertically & horizontally 2. Layout system vertically & horizontally Grouped fixtures can be stacked in a vertical riser M: p. 1027, F.22.31
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3. Size Traps Trap size is used when connecting to main M: p. 1017, T.22.2
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4. Calculate Drainage Fixture Units (DFU) Pipe sizes based on DFU M: p. 1017, T.22.2.2
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5. Determine loads Fixture location may control size M: p. 1022, F.22.24
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6. Determine slope and size of horizontal drains 6. Determine slope and size of horizontal drains Slope may be constrained by depth of floor cavity M: p. 1020, T.22.5
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7. Verify maximum vent length Measured from plans M: p. 1022, F.22.24
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8. Size vents according to DFU and length Calculate for each vent load and developed length M: p. 1019, T.22.4
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9. Verify space requirements and adjust design Common adjustments “Wet” walls 6” cavity Slope and ceiling exposure Cleanout access
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