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
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

“Wet” walls  6” cavity
Slope and ceiling exposure
Cleanout access