The URL can be used to link to this page

Home My WebLink AboutCT 16-07; RESIDENTIAL MASTER WATER METERS AND PRIVATE DOMESTIC WATER SYSTEM SIZING; 2021-11-12DEXTER WILSON ENGINEERING, INC. DEXTER S. WILSON, P.E. ANDREW M. OVEN, P.E. NATALIE J. FRASCHETTI, P.E. STEVEN J. HENDERSON, P.E. FERNANDO FREGOSO, P.E. KATHLEEN L. HEITr, P.E. MEMORANDUM 629-029 TO: Jesse Kleist, KB Home Coastal FROM: Steven Henderso4txter Wilson Engineering, Inc. DATE: November 12, 2021 SUBJECT: Marja Acres Residential Master Water Meters and Private Domestic Water System Sizing Background The Marja Acres project is located in the north-central portion of the City of Carlsbad. It is situated along El Camino Real to the southeast of Kelly Drive. The majority of the proposed 24 acre development will consist of 248 townhome residential units spread amongst several clusters where a master water meter is proposed for each cluster. The 17 different clusters vary from containing six units up to 34 units. The current site plan for the Marja Acres project is attached to the back of the memorandum. 2234 FARADAY AVENUE 0 CARLSBAD, CA 92008 • (760) 438-4422 • FAX (760) 438-0173 Jesse Kleist November 12, 2021 Page 2 Master Water Meter Sizing bvTownhome C.lusteE To size the master water meters an estimate of Water Fixture Units (WFUs) was done for each townhome residential cluster. This was achieved by calculating the typical number of WFUs for the townhome residential units. Using Chart A- 103.1(1) in the 2019 California Plumbing Code, a flow rate in gpm can be calculated from the WFUs. Using the City of Carlsbad's meter capacity ranges, a meter size and type can be determined from the flow rates in gpm. The WFU tabulation, Chart A-103.1(1) in the 2019 California Plumbing Code, and the City of Carlsbad meter flow rate range are all attached to this memorandum. The breakdown for each townhome cluster is summarized in Table 1 below. TABLE 1 WFU, MAXIMUM FLOW, AND WATER METER SIZE BY TOWNHOME CLUSTER Townhome Cluster Quantity of Units Estimated WFUs' Maximum Flow2, gpm Water Meter Size8 Cluster Supply Size 1 29 971.5 228 2" (Turbo) 6-Inch 2 32 1,072 242 21 703.5 189 1.5" (Turbo) 4-Inch 4 34 1,139 250 2" (Turbo) 6-Inch 5 22 737 197 1.5" (Turbo) 6 13 435.5 145 7 19 636.5 179 6 201 97 1.5" (PD) 9 8 268 112 1.5" (PD) 4-Inch 10 11 12 13 14 15 16 17 Total 248 8,808 1 Attached WFU Breakdown - - 2 From Chart A-103.1(1) in the 2019 California Plumbing Code (attached) plus a 26-gpm fire sprinkler allowance Per City meter flow rate range (attached e-mail) Jesse Kleist November 12, 2021 Page 3 The master water meters have been sized according to City of Carlsbad standards. The City primarily follows the AWWA standards for Cold Water Meters. As mentioned earlier, an e- mail correspondence stating this requirement from the City of Carlsbad is attached to this memorandum. The size for the master meters for the Marja Acres townhome clusters shall be either 1.5- inch positive displacement, 1.5-inch turbo, or 2-inch turbo depending on demand and unit quantities. Typical available pressures at the public water meter connections are expected to range between 60 psi and 70 psi. These 1.5-inch or 2-inch meter sizes are required based on a single meter supplying a respective townhome cluster. If a townhome cluster's private water system consists of a "looped" system with two meter connections then two smaller size meters could be utilized in lieu of the single larger meter. This two meter setup for a townhome cluster is not analyzed within this memorandum. Private Domestic Water System giziri Using the WFUs and flow rates for each townhome cluster as shown in Table 1, a worst case scenario was analyzed for the 2-inch meter and 1.5-inch meter clusters in regard to domestic demand onsite. The highest calculated domestic water demand for a 2-inch meter and 1.5- inch meter cluster respectively were inputted at the furthest distance from the public connection. This was done along the townhome cluster's main water distribution line and, to be conservative in the analysis, the entire flow was calculated across the entire piping length. Hydraulic calculations are attached to this memorandum confirming that a 6-inch diameter main cluster distribution water line can provide adequate service to the 2-inch meter clusters and 4-inch diameter main cluster distribution water line can provide adequate service to the 1.5-inch meter clusters. Residual pressure under maximum domestic demands is greater than 45 psi at the furthest unit's connection. Jesse Kleist November 12, 2021 Page 4 It is recommended to oversize the individual unit's supply laterals due to the low expected working pressures (45 to 50 psi) within the private water systems throughout the Marja Acres site. SH: cc: Mel Landy, P.E., HWL Planning & Engineering Attachment(s) Marja Acres Site Plan and Proposed Townhome Cluster Layout Marja Acres Water Fixture Unit Breakdown California Plumbing Code Appendix A Excerpt 4 - City of Carlsbad Water Meter Capacity Ranges 5 - Hydraulic Calculations for Marja Acres Private Water Systems I 1/ II . it /7, / IlL CLUSTER I WFU Calculations Townhome Maria Acres Typical Townhome Unit Job Number 736-013 Date 11/12/2021 Water Fixture Units: DESCRIPTION CLOTHES WASHER TUB/SHOWER SHOWER KITCHEN SINK BAR SINK DISHWASHER LAUNDRY SINK MOP BASIN LAVATORY WATER CLOSET (1.6 GPF, private) DRINKING FOUNTAIN HOSE BIBB EACH ADDTL HB TOTAL Typ. Townhome Unit FIXTURE TOTAL QUANTITY UNITS FIXTURE EACH UNITS 1 4 4 2 4 8 1 2 2 1 1.5 1.5 0 1 0 1 1.5 1.5 0 1.5 0 0 3 0 5 1 5 3 2.5 7.5 1 0.5 0.5 1 2.5 2.5 1 1 33.5 Cluster Quantity WFU Total 1 29 33.5 971.5 2 32 33.5 1072 3 21 33.5 703.5 4 34 33.5 1139 5 22 33.5 737 6 13 33.5 435.5 7 19 33.5 636.5 8 6 33.5 201 9 8 33.5 268 10 8 33.5 268 11 8 33.5 268 12 8 33.5 268 13 8 33.5 268 14 8 33.5 268 15 8 33.5 268 16 8 33.5 268 17 8 33.5 268 248 8308 Page 1 1) APPENDIX A TABLE A 103.1 WATER SUPPLY FIXTURE UNITS (WSFU) AND MINIMUM FIXTURE BRANCH PIPE SIZES3 APPLIANCES, APPURTENANCES, OR FIXTURES2 MINIMUM FIXTURE BRANCH PIPE SIZE'4 (Inches) PRIVATE PUBLIC ASSEMBLY5 Bathtub or Combination Bath/Shower (fill) Y2 4.0 4.0 - 3/4 inch Bathtub Fill Valve 3/4 10.0 10.0 - Bidet 1/2 1.0 - - Clothes Washer 1/2 4.0 4.0 - Dental Unit, cuspidor /2 - 1.0 Dishwasher, domestic 1/2 1.5 1.5 - Drinking Fountain or Water Cooler '/2 0.5 0.5 0.75 Hose Bibb. 1/2 25 25 - Hose Bibb, each additional7 1/2 1.0 1.0 - Lavatory 1/2 1.0 1.0 1.0 Lawn Sprinkler, each head' - 1.0 1.0 - Mobile Home, each (minimum) - 12.0 - - Sinks - - - - - Bar '/2 1.0 2.0 - Clinical Faucet '/2 - 3.0 - Clinical Flushometer Valve wib or without faucet 1 - 8.0 - Kitchen, domestic - '/2 1.5 1.5 - Laundry /2 1.5 1.5 - Service or Mop Basin '/z 15 3.0 - Washup, each set of faucets /2 - 2.0 - Shower per head '/2 2.0 20 - Urinal, 1.0 GPF Flushorneter Valve 3/4 3.0 4.0 5.0 Urinal, greater than 1.0 GPF Flushometer Valve 4.0 5.0 6.0 Urinal, flush tank /2 2.0 2.0 3.0 Wash Fountain, circular spray - 4.0 Water Closet 1.6 GPF Gravity Tank Vs 2.5 2.5 3.5 Water Closet,, 1.6 GPF Flushometer Tank 1/2 2.5 2.5 3.5 Water Closet, 1.6 GPF Flushometer Valve 1 5.0 5.0 8.0 Water Closet, greater than 1.6 GPF Gravity Tank 1/2 3.0 5.5 7.0 Water Closet, greater than 1.6 GPF Flushometer Valve 1 7.0 8.0 10.0 For SI units: 1 inch = 25 mm Notes: Size of the cold branch pipe, or both the hot and cold branch pipes. 2 Appliances, appurtenances, or fixtures rot included in this table shall be permitted to be sized by reference to fixtures having a similar flow rate and frequency of use. The listed fixture unit values represent their total load on the cold water building supply. The separate cold water and hot water fixture unit value for fixtures having both cold and hot water connections shall be permitted to be three-quarters of the listed total value of the fixture. The listed minimum supply branch pipe sizes for individual fixtures are the nominal (ID.) pipe size. For fixtures or supply connections likely to impose continuous flow demands, determine the required flow in gallons per minute (gpm) (Us) and add it sep- arately to the demand in gpm (L/s) for the distribution system or portions thereof. 6 Assembly [Public Use (see Table 422.1)]. Reduced fixture unit loading for additional hose bibbs is to be used where sizing total building demand and for pipe sizing where more than one hose bibb is supplied by a segment of water distribution pipe. The fixture branch to each hose bibb shall be sized by 2.5 fixture units, 2019 CALIFORNIA PLUMBING COLE 359 APPENDIX A CHART A 103.1 (1) ESTIMATE CURVES FOR DEMAND LOAD 500 400 E 200 z 4 No. 1 for system predominantly for Ilushometer valves No. 2 for system predominantly for flush tanks iaT. IiI•ls I1iI• sJ.Is 2!sII c!,Ii FIXTURE UNITS For SI units: 1 gallon per minute = 0.06 Us CHART A 103.1(2) ENLARGED SCALE DEMAND LOAD 100 80 . 60 cc : 40 (a a) 20 z 4 I., 6 0 20 40 60 80 100 120 140 160 180 200 220 24( FIXTURE UNITS For SI units: 1 gallon per minute = 0.06 Us 360 2019 CALIFORNIA PLUMBING CODE 100 -II )0 VaiRay Nelson From: Mario Remillard Sent: Wednesday, July 13, 2016 8:49 AM To: VaiRay Nelson Subject: Meter GPMs Hi ValRay, Below are the GPM's for the various meter sizes. 5/8 = 0.5 —20 gpm 3/4= .75-35gpm 1" = 1-55gpm 11/2 PD=2.5—l2ogpm 11/2 Turbo = 4 — 200 gpm 2PD = 2.5 — 170 gpm 2 Turbo = 4-310 gpm Mario Remillard Meter & Customer Services Supervisor/Conservation Coordinator Carlsbad Municipal Water District 5950 El Camino Real Carlsbad, Ca 92008 760-438-2722 Ext. 7153 (Carlsbad Municipal Water District 1 Project: Marja Acres r v. Water for Townhome Clusters Job: 629-029 Date: 11/11/2021 CLUSTER 4 POINT OF CONNECTION TO FURTHEST UNIT FRICTION LOSSES IN PIPING -11(f) Hazen-Williams Formula (~~ ) 1.852 I-If - D 48655 H(f) = friction losses in ft Q = 250.0 gpm C = 120 for design L= 500.00 ft D = 6 i Therefore, 11(0 = 3.33 ft MINOR LOSSES IN LATERAL PIPING- Hm H 7 =K- 2g H) = minor losses, ft sum of minor loss coefficients g = gravitational constant = 32.17 fps' Diameter = 6 in v, fps = 2.8 Minor loss coefficients Description Quantity K-value K-value, total 90 degree bend 6 0.3 1.8 45 degree bend 0 0.2 0.0 Tee-thru, flanged 0 0.3 0.0 Isolation Valve 2 1.0 2.0 Tee-branch, flanged 0 0.8 0.0 Wye 0 0.5 0.0 Check valve 1 2.5 2.5 Meter 1 1.5 1.5 Entrance/Exit Loss 2 1.0 2.0 JK = 9.8 11m 1.23 ft RESIDUAL PRESSURE AT CLUSTER 4 FURTHEST UNIT Total Fricion Losses 4.6 ft Summation of all headlosses Flow Meter and Backflow Preventer Loss = 15.0 psi 34.6 ft Total Loss = 39.2 ft 17.0 psi Available pressure at P.O.C. = 65 psi per water study, max day demand Residual Pressure at Further Unit = 48 psi \\ARTIC\Docs\629-029\2021-11-11 Hydraulic Calculations Marja Acres Pvt Water.xlsx Pg. 1 Project: Marja Acre. v t. Water for Townhome Clusters Job: 629-029 Date: 11/11/2021 CLUSTER 5 POINT OF CONNECTION TO FURTHEST UNIT FRICTION LOSSES IN PIPING - H(f) f \1.852 Hazen-Williams Formula l0.44* *L H1 - D48655 H(f) = friction losses in ft Q = 197.0 gpm C = 120 for design L= 400.00 ft D= 4 i Therefore, 11(0 = 12.31 ft MINOR LOSSES IN LATERAL PIPING- Hm H =JK v2 ,,, 2g H) = minor losses, ft sum of minor loss coefficients g = gravitational constant = 32.17 Diameter = 4 in Minor loss coefficients Description Quantity K-value 90 degree bend 2 0.3 45 degree bend 0 0.2 Tee-thru, flanged 0 0.3 Isolation Valve 2 1.0 Tee-branch, flanged 0 0.8 Wye 0 0.5 Check valve 1 2.5 Meter 1 1.5 Entrance/Exit Loss 2 1.0 JK Hm RESIDUAL PRESSURE AT CLUSTER 5 FURTHEST UNIT Total Fricion Losses = 15.7 ft Summation of all headlosses Flow Meter and Backflow Preventer Loss = 15.0 psi 34.6 ft Total Loss = 50.3 ft 21.8 psi Available pressure at P.O.C. = 67 psi per water study, max day demand Residual Pressure at Further Unit = 45 psi \\ARTIC\Docs\629-029\202 1-11-11 Hydraulic Calculations Marja Acres Pvt Water.xlsx V, fps = 5.0 K-value, total 0.6 0.0 0.0 2.0 0.0 0.0 2.5 1.5 2.0 8.6 3.38 ft Pg. 2