Transcript Slide 1
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. 929, F.21.13
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
Pressure
needed to
get water
through
fixture
M: p. 987, T.21.14
B: Pressure lost due to height
Weight of water
column
M: p. 929, F.21.13
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. 988, F.21.63a
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. 991, T.21.15
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
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
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
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
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. 988, F.21.63a
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. 989, F.21.64a
10. Select final
meter size
When flow > Total
Demand (#2) stop
M: p. 989, F.21.64a
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: 44.1 psi
1. Determine
Supply
Fixture
Units
Fixture units
take into
account
usage
diversity
M: p. 991, T.21.15
1. Determine Supply Fixture Units
2 Flush valve toilets
2 Lavatories
2 Drinking fountains
1 Service sink
Cold Hot
20.00
--3.00 3.00
0.50
--2.25 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. 992,
F.21.65a
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
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
5. Determine Total
Effective Length (TEL)
TEL= DL x 1.5
= 92 x 1.5
= 138’
6. Determine Street
Main Pressure (E)
44.1 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
15.0
7.0
?
?
44.1
Meter Loss (D)
Pick an initial size
2” diameter… 1.4 psi
M: p. 988, F.21.63a
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’
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
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
Pipe Sizing
Use Δp/100’=
13.1 psi/100’
Use fixture units to
determine flow
M: p. 989 F.21.64a
Pipe Sizing
Use fixture units to
determine flow
Pay attention to flush
valve domination
M: p. 992 F.21.65a
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
Runout
Pipe Sizing
Use actual flow to size
runouts
Lavatory:
2 gpm
M: p.987, T.21.14
Runout
Pipe Sizing
Use Δp/100’=
13.1 psi/100’
Lavatory: 2 gpm
M: p. 989, F.21.64a
Notation System
Suggested for
organizing data
WSFU Curve
Flow Diam.
2.7 2
3 ½”
M: p. 1014, F.22.17
3.6 2
4 ¾”
Waste & Vent Systems
Fundamentals
Siphon action
can drain water
Trap blocks
sewer gas
Vent breaks
siphon
M: p. 1006, F.22.8
Air Gaps
Eliminate the potential for cross contamination
M: p. 1009, F.22.11
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
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
Waste & Vent Sizing Procedure
1. Identify waste & soil locations
Clusters are more
efficient
M: p. 1014, F.22.17
2. Layout system
vertically & horizontally
Grouped fixtures can
be stacked in a
vertical riser
M: p. 1027, F.22.31
3. Size Traps
Trap size is used
when connecting
to main
M: p. 1017,
4. Calculate
Drainage Fixture
Units (DFU)
Pipe sizes based
on DFU
M: p. 1017, T.22.2.2
5. Determine loads
Fixture location
may control size
M: p. 1022,
F.22.24
6. Determine slope and size of
horizontal drains
Slope may be
constrained by
depth of floor
cavity
M: p. 1020, T.22.5
7. Verify maximum vent length
Measured from
plans
M: p. 1022,
F.22.24
8. Size vents according to
DFU and length
Calculate for each
vent load and
developed length
M: p. 1019, T.22.4
9. Verify space requirements and
adjust design
Common adjustments
“Wet” walls 6” cavity
Slope and ceiling exposure
Cleanout access