ee5e47f9ee95bd5dc001305e82f818bd.ppt
- Количество слайдов: 42
Technology in Architecture Lecture 14 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 M: p. 858, F. 19. 13
Pressure in Upfeed Systems Proper fixture flow pressure + Pressure lost due to height + Pressure lost due to friction + Pressure lost through meter Total street main pressure A B C D E
A: Fixture Flow Pressure needed to get water through fixture M: p. 916, T. 19. 14
B: Pressure lost due to height Weight of water column M: p. 858, F. 19. 13
C: Pressure loss due to friction Initially unknown, must be calculated based on pressure remaining after accounting for the other factors
D: Pressure lost through meter Make initial size assumption and then repeat to optimum size M: p. 917, F. 19. 63
E: Total Street Main Pressure Check with water company or fire department
Pipe Sizing Procedure
1. Determine Supply Fixture Units Fixture units take into account usage diversity M: p. 919, T. 19. 15
2. Calculate Demand Flow Use curve 1 for flush valve dominated system Use curve 2 for flush tank dominated systems M: p. 919, F. 19. 65
3. Determine the “Most Critical Fixture (MCF)” Highest and farthest from inlet main Confirm pressure required (A) Identify height (B) M: p. 903, F. 19. 52
4. Determine Developed Length The total length of all horizontal and vertical pipes from the main to the MCF M: p. 941, F. 20. 17
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. 920, T. 19. 16 a
6. Determine Street Main Pressure (E) Contact utility company or fire department
7. Determine Pressure Available for Friction Loss Proper fixture flow pressure + Pressure lost due to height + Pressure lost due to friction + Pressure lost through meter Total street main pressure or C=E-A-B-D A B C D E
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. 917, F. 19. 63
8. Determine Friction loss/100’ C=E-A-B-D Δp/100’ = 100 x C/TEL
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. 918, F. 19. 64
10. Select final meter size When flow > Total Demand (#2) stop M: p. 918, F. 19. 64
Pipe Sizing Example
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: 64. 1 psi
1. Determine Supply Fixture Units Fixture units take into account usage diversity M: p. 919, T. 19. 15
1. Determine Supply Fixture Units 2 Flush valve toilets 2 Lavatories 2 Drinking fountains 1 Service sink Cold Hot 20. 00 --3. 00 0. 50 --2. 25 25. 75 5. 25 Total 20. 0 4. 0 0. 5 3. 0 27. 5
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. 919, F. 19. 65
3. Determine the Most Critical Fixture Confirm pressure required (A) 35 psi Height above main (B) 16’ 7. 0 psi M. p. 916, T. 19. 14 25 35
4. Determine Developed Length Developed length 92’ M: p. 941, F. 20. 17 Note: this figure for generic reference only and does not illustrate the example problem
5. Determine Total Effective Length (TEL) TEL= DL x 1. 5 = 92 x 1. 5 = 138’
6. Determine Street Main Pressure (E) 64. 1 psi
7. Determine Pressure Available for Friction Loss Proper fixture flow pressure + Pressure lost due to height + Pressure lost due to friction + Pressure lost through meter Total street main pressure A B C D E 35. 0 7. 0 ? ? 64. 1
Meter Loss (D) Pick an initial size 2” diameter… 1. 4 psi M: p. 917, F. 19. 63
8. Determine Friction loss/100’ C=E-A-B-D = 64. 1 -35. 0 -7. 0 -1. 4 = 20. 7 psi Δp/100’=100 x 20. 7/138 = 15 psi/100’
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. 918 F. 19. 64
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. 918 F. 19. 64
Pipe Sizing Use Δp/100’= 13. 1 psi/100’ Use fixture units to determine flow M: p. 918 F. 19. 64
Pipe Sizing Use fixture units to determine flow Pay attention to flush valve domination M: p. 919 F. 19. 65
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. 918, F. 19. 64
Runout Pipe Sizing Use actual flow to size runouts Lavatory: 2 gpm M: p. 916, T. 19. 14
Runout Pipe Sizing Use Δp/100’= 13. 1 psi/100’ Lavatory: 2 gpm M: p. 918, F. 19. 64
Notation System Suggested for organizing data WSFU Curve Flow Diam. 2. 7 2 3 ½” M: p. 941, F. 20. 17 3. 6 2 4 ¾”