HomeMy WebLinkAboutCT 2022-0003; CARLSBAD BY THE SEA SUMMERHOUSE; DOMESTIC AND FIRE WATER SYSTEM ANALYSIS; 2023-06-05
June 5, 2023
Carlos Ochoa
BWE
9449 Balboa Avenue, Ste 270
San Diego, CA 92123
SUBJECT: Front Porch Memory Care & Independent Living Facility – Domestic and Fire Water System
Analysis
Mr. Ochoa:
MCS was recently contracted to provide engineering services related to the onsite private domestic and fire
water systems for the Front Porch Memory Care & Independent Living Facility (Project) in Carlsbad, CA. The
site encompasses 5 lots totaling 0.6 ac along the southeast corner of Beech Avenue and Ocean Street. As the
site is within the Carlsbad Municipal Water District (District) service area, this letter is provided to document
proposed onsite domestic water use, meter and backflow sizing, fire flow needs, and public lateral sizing.
The proposed water use for the site was provided by others in the form of fixture units. Based on the 268
fixture units provided, the site will have a peak water demand of 80 gpm. All water uses will be supplied by
the City of Carlsbad through the District’s public water system 241 Pressure Zone.
The proposed 2-inch meter and 2-inch backflow along Beech Avenue will serve the proposed domestic water
system. The domestic connection will wet tap a 2-inch service to the existing public 6-inch main. A separate
8-inch backflow will serve the fire sprinkler system off Ocean Street through a proposed 8-inch fire service
that will connect to the existing 10-inch public main in Ocean Street. A separate 1-inch meter will supply the
irrigation system from a connection to Beech Avenue. Analysis of this connection and onsite system are not
included in this study.
A single 2-inch meter can serve the domestic water to the site with intermittent peaks. At peak flow, a 2-
inch RPPA will induce a pressure drop of 14 psi, in addition to the 3.3 psi drop caused by the meter.
Therefore, the 2-inch connection could create a maximum pressure drop of 17.3 psi across the domestic
assembly, and 14 psi for the fire sprinkler assembly.
The domestic hydraulic analysis for the onsite system shows that using the meter configuration as stated
above would allow for a 2-inch service lateral up to the building. This would include a 2-inch service
connection to Beech Avenue. Static pressure to the site based on a finished floor elevation of 33 ft as
provided is 90 psi. Minimum onsite service pressures range from 72 to 80 psi, depending on the time of day,
with velocities of 8.2 fps or less. Model output reports are included for reference. The onsite water system is
shown on Figure 1.
The proposed Project will include three floors and basement parking for a total of 52,821 sf, Type IV or VA
construction. The governing codes for this Project include the 2015 International Fire Code which, according
to Table B105.1, requires a maximum fire flow of 4,250 gpm for 4 hours before any reduction is applied for
sprinklers.
~MCS
Mission Consulting Services
WATER SYSTEMS SPECIALI STS
MOBILE: 619.851 .5178 jmael@missionconsultingsd.com www.missionconsultingsd.com
Page 2 of 2
Fire flow simulations show that with a sprinkler flow of 30 gpm (standard 2-head calculation), and Maximum
Day Demands (MDD) in the system, the public system is capable of providing the maximum required fire
flow of 4,250 gpm at the hydrant located at the intersection of Beech Avenue and Ocean Street. The onsite
pressure that occurs during this fire event is greater than the minimum 20 psi required. Velocities are also
less than the maximum 15 fps per District criteria. Model outputs are included for reference.
If you have any questions or comments, please feel free to contact me at (619) 851-5178.
Sincerely,
Jennifer R. Mael, P.E.
Project Manager
Attachment: Figure 1 – Water System
Pipe & Node Map
Hydraulic Model Output Reports
06/30/2024
MOBILE: 619.851.5178 jmael@missionconsultingsd.com www.missionconsultingsd.com
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6"
6"
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BE EC H AV
FIGURE 1 - WATER SYSTEM
Proposed 8" tee
connection Proposed 8" fire service and 8" backflow -
end publice service & begin private system
Legend
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ZONE
Ex 241 PZ
Proposed
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Project
Site
Proposed 2" wet
tap connection
Proposed 2" meter & 2"
backflow - end public service
& begin private system
Existing Hydrant
(lateral to Ocean St.)
Note: All locations approximate. Please refer to Civi Design Sheet Set for exact distances and locations.
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J316
J314
J310
J306
3125
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J312
PIPE AND NODE MAP
Project
Site
J308
J306
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5
9
Existing Hydrant
(lateral to Ocean St.)
J304
3130
4 135
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Junction Report: Peak Flow
ID Demand
(gpm)
Elevation
(ft)
Head
(ft)
Pressure
(psi)
3125 32.63 50.00 246.53 85.16
3130 26.04 44.00 246.57 87.78
J304 0.00 44.03 246.57 87.76
J306 0.00 48.69 246.53 85.72
J308 80.00 33.00 198.05 71.51
J310 0.00 33.00 241.65 90.41
J312 0.00 33.00 201.43 72.98
J314 0.00 44.96 246.57 87.36
J316 0.00 33.00 246.57 92.54
Date: Friday, April 28, 2023, Time: 11:16:19, Page 1
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Pipe Report: Peak Flow
ID From
Node To Node Length
(ft)
Diameter
(in)Roughness Flow
(gpm)
Velocity
(ft/s)
Headloss
(ft)
HL/1000
(ft/k-ft)
4355 3240 3130 704.5 10.0 114.0 53.9 0.2 0.0 0.0
4135 3125 3115 348.4 6.0 112.0 -31.9 0.4 0.1 0.2
4140 J306 3130 141.1 6.0 112.0 -42.9 0.5 0.0 0.3
4360 3245 3125 608.6 6.0 114.0 22.7 0.3 0.1 0.1
4145 3130 J304 5.4 10.0 114.0 -2.9 0.0 0.0 0.0
P4153 J304 J314 179.4 10.0 114.0 -2.9 0.0 0.0 0.0
P4155 3125 J306 39.5 6.0 112.0 37.1 0.4 0.0 0.2
P4157 J306 J310 28.9 2.0 120.0 80.0 8.2 4.9 168.7
P4159 J310 J312 5.0 2.0 120.0 80.0 8.2 40.2 8,044.9
P4161 J312 J308 20.0 2.0 120.0 80.0 8.2 3.4 168.7
P4163 J314 3135 581.9 10.0 114.0 -2.9 0.0 0.0 0.0
P4165 J314 J316 35.9 8.0 120.0 0.0 0.0 0.0 0.0
Date: Friday, April 28, 2023, Time: 11:12:57, Page 1
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Junction Report: MDD + 4,250gpm Fire
ID Demand
(gpm)
Elevation
(ft)
Head
(ft)
Pressure
(psi)
3125 25.80 50.00 165.21 49.92
3130 20.59 44.00 156.57 48.78
J304 4,250.00 44.03 156.42 48.70
J306 0.00 48.69 162.99 49.53
J308 80.00 33.00 114.51 35.32
J310 0.00 46.37 158.11 48.42
J312 0.00 45.93 117.89 31.18
J316 30.00 44.03 162.86 51.49
J314 0.00 44.99 162.86 51.07
Date: Monday, June 05, 2023, Time: 10:22:32, Page 1
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Pipe Report: MDD + 4,250gpm Fire
ID From Node To Node Length
(ft)
Diameter
(in)Roughness Flow
(gpm)
Velocity
(ft/s)
Headloss
(ft)
HL/1000
(ft/k-ft)
4355 3240 3130 704.5 10.0 114.0 1,368.7 5.6 9.9 14.1
4135 3125 3115 348.4 6.0 112.0 -577.2 6.5 12.3 35.3
4140 J306 3130 141.1 6.0 112.0 661.5 7.5 6.4 45.5
4360 3245 3125 608.6 6.0 114.0 190.1 2.2 2.7 4.4
4145 3130 J304 5.4 10.0 114.0 2,009.7 8.2 0.2 28.6
P4153 J304 J314 184.1 10.0 114.0 -2,240.3 9.2 6.4 35.0
P4155 3125 J306 39.5 6.0 112.0 741.5 8.4 2.2 56.2
P4157 J306 J310 28.9 2.0 120.0 80.0 8.2 4.9 168.7
P4159 J310 J312 5.0 2.0 120.0 80.0 8.2 40.2 8,044.9
P4161 J312 J308 20.0 2.0 120.0 80.0 8.2 3.4 168.7
P4165 J314 J316 48.4 10.0 112.0 30.0 0.1 0.0 0.0
P4163 J314 3135 577.2 10.0 114.0 -2,270.3 9.3 20.7 35.9
Date: Monday, June 05, 2023, Time: 10:21:41, Page 1