1. Technology in Architecture
Lecture 13
Upfeed Systems
Pipe Sizing Procedure
Pipe Sizing Example

2. Upfeed Systems

3. Pressure in Upfeed Systems
Fixture pressure head Static head Friction head loss Meter pressure loss
M: p. 858, F.19.13

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: Fixture Flow Pressure
Pressure needed to get water through fixture
M: p. 916, T.19.14

6. B: Pressure lost due to height
Weight of water column
M: p. 858, F.19.13

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
M: p. 917, F.19.63

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
M: p. 919, T.19.15

12. 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

13. 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

14. 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

15. 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.19.16a

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
M: p. 917, F.19.63

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
M: p. 918, F.19.64

21. 10. Select final meter size
When flow > Total Demand (#2)  stop
M: p. 918, F.19.64

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: 64.1 psi

24. 1. Determine Supply Fixture Units
Fixture units take into account usage diversity
M: p. 919, T.19.15

25. 1. Determine Supply Fixture Units
Cold Hot Total
2 Flush valve toilets
2 Lavatories
2 Drinking fountains
1 Service sink

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
M: p. 919, F.19.65

27. 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

28. 4. Determine Developed Length
92’
Note: this figure for generic reference only and does not illustrate the example problem
M: p. 941, F.20.17

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

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

31. 7. Determine Pressure Available for Friction Loss
Proper fixture flow pressure A 35.0
+ Pressure lost due to height B 7.0
+ Pressure lost due to friction C ?
+ Pressure lost through meter D ?
Total street main pressure E 64.1

32. Meter Loss (D) Pick an initial size 2” diameter… 1.4 psi
M: p. 917, F.19.63

33. 8. Determine Friction loss/100’
C=E-A-B-D =
= 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 >
(Δp/100’= 13.1)
At 1”
Flow=13 gpm <
(Δp/100’= 5.1)
M: p. 918 F.19.64

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)
M: p. 918 F.19.64

36. Pipe Sizing Use Δp/100’= 13.1 psi/100’
Use fixture units to determine flow
M: p. 918 F.19.64

37. Pipe Sizing Use fixture units to determine flow
Pay attention to flush valve domination
M: p. 919 F.19.65

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
M: p. 918, F.19.64

39. Runout Pipe Sizing Use actual flow to size runouts Lavatory: 2 gpm
M: p.916, T.19.14

40. Runout Pipe Sizing Use Δp/100’= 13.1 psi/100’ Lavatory: 2 gpm
M: p. 918, F.19.64

41. Notation System Suggested for organizing data WSFU Curve Flow Diam.½” ¾”
M: p. 941, F.20.17