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Home My WebLink AboutWater Size ReportSynergy Engineering and Konsulting 1 | Page Cattail Duplexes Water Design Report Project Background: • 11-unit duplex • Residential single-family use • 2.11 people per dwelling unit • Population = 11 units * 2.11 people per unit = 23.21 people • 170-gallons per capita per day • 11 units*2.11 people per unit*170 gallons per day per person = 3745.7 gallons per day o 3745.7 gallons /day *1 day/24 hours * 1 hour/60 minutes = 2.6 gallons per minute • AWWA PID instantaneous flow calculation for fixtures = 26.7 gpm o Fire flow to be provided by existing hydrant north of driveway access (Hydrant # 1454) Water Main Specifications: • Main line – 8-inch diameter Ductile Iron Pipe (DIP) • Services lines – ¾ inch diameter type “K” copper • Pressure Reduction valves required for service lines COB Standard Drawings • MPW 02660-1 Thrust Blocking for Water Main Fittings • MPW 02660-2 Water and Sewer Main Separation • COB 02660-3 Thrust Blocking for Water main Valves • COB 02660-6 Water Service Line • COB 02660-7 Typical Blowoff • COB 02660-10 Typical Valve/Tee Restraint • COB 02660-15 Water Service Line from Curb Stop to Building (Lines 2’’ and Smaller) • COB 02660-16 Water and Sewer Main and Services Location Standards • COB 020660-17 Water Service Interior Clearances • Backflow Prevention Device • Water service Meter Main Size: The water main for Cattail Duplexes has an average demand of 2.6 gpm and a peak instantaneous demand of 26.7 gpm. This water main will not provide fire flows. Fire flow are provided at the existing hydrant north of the driveway access (Hydrant #1454). Head Loss Synergy Engineering and Konsulting 2 | Page calculations indicate that 8’’ DIO with a C of 130 and a flow rate of 30 gpm will have an actual head loss of 0.002 psi and a velocity of 0.175 ft/s. COB requires that the velocity not exceed 15 ft/s. COB requires that the minimum diameter for any new main is 8 inches unless specific approval in writing Is obtained from the COB. Water main pressure at the connection point is assumed to be 123 psi based on the residual pressure at hydrant 1454 as provided by COB. Working residual water pressure is assumed to be 123 psi -0.002 psi = ~123 psi. COB requires pressure reducing valves to be installed when the anticipated average-day line pressure exceeds 120 psi. Main Extensions: The dead-end main is approximately 200 feet in length and shall end with a 2- inch blowoff valve. Services: A line serving more than one building is designated a water main. Service pipe shall be ¾’’ type “K” copper. Backflow prevention devices as required by the Water Superintendent. No service line shall be extended into townhouses until an “Application for Service” has been completed and a Plumbing Permit has been obtained from the Building Department. The Hazen-Williams calculation for a ¾ inch water pipe with a flow of 3 gpm indicates a velocity of 2 ft/s, meeting the COB standard of less than 10 ft/s for service lines. Pressure reduction valves shall be installed on service lines downstream of the shutoff valve and prior to entering the townhomes. Valves: Two valves are proposed for the Cattail Duplexes water main. One eight-inch gate valve at the connection to the existing 8-inch water main in Fen Way and 2’’ blowoff valve at the end of the extension. Hydrants: An existing fire hydrant is located along the frontage of Lot 4A and Fen Way. All proposed units are within a 350 radius of the existing hydrant. Air Relief: Air relief is provided by the 2’’ blowoff valve and eleven services. Pressure Reducing Valves: Pressure reduction valves are required for all service connections. Attachments: (1) AWWA PID Calculation (1) Hazen-Williams Calculation for 8-inch DIP main line 12/16/2021 Facility Name Building address or number Residential or Non-Residential Minimum Pressure (psi) Fixture Value Number of Subtotal Fixture or Appliance (at 60 psi) Fixtures Fixture Value Toilet (tank) 4 33 132 Toilet (flush valve) 35 0 Urinal (wall or stall) 16 0 Urinal (flush valve) 35 0 Bidet 2 0 Shower (single head) 2.5 11 27.5 Sink (lavatory) 1.5 33 49.5 Kitchen Sink 2.2 11 24.2 Utility Sink 4 0 Dishwasher 2 11 22 Bathtub 8 11 88 Clothes Washer 6 11 66 Hose connections (with 50 ft of hose) 1/2 in. 5 0 5/8 in. 9 11 99 3/4 in. 12 0 Miscellaneous Bedpan washers 10 0 Drinking fountains 2 0 Dental units 2 0 0 Combined Fixture Value 508.2 Demand (gpm)46 Pressure Adjustment Factor 0.58 Total Adjusted demand (gpm)26.7 Water Demand Estimate Using Fixture Values (Based on AWWA M22 Manual, Second Edition) Cattail Duplexes 12/16/21, 2:17 PM Hazen-Williams Friction Loss Equation - calculating Head Loss in Water Pipes https://www.engineeringtoolbox.com/hazen-williams-water-d_797.html 1/6 Hazen-Williams Friction Loss Equation - calculating Head Loss in Water Pipes Friction head loss (ftH2O per 100 ft pipe) in water pipes can be estimated with the empirical Hazen-Williams equation. The Darcy-Weisbach equation with the Moody diagram is considered to be the most accurate model for estimating frictional head loss for a steady pipe flow. Since the Darcy-Weisbach equation requires iterative calculation an alternative empirical head loss calculation like the Hazen-Williams equation may be preferred: h100ft = 0.2083 (100 / c)1.852 q1.852 / dh4.8655 (1) where h100ft = friction head loss in feet of water per 100 feet of pipe (fth20/100 ft pipe) c = Hazen-Williams roughness constant q = volume flow (gal/min) dh = inside hydraulic diameter (inches) Note that the Hazen-Williams formula is empirical and lacks a theoretical basis. Be aware that the roughness constants are based on "normal" conditions with approximately 1 m/s (3 ft/sec). Example - Friction Head Loss in Water Pipe 200 gal/min of water flows in a 3 inch PEH pipe DR 15 with inside diameter 3.048 inches. The roughness coefficient for PEH pipe is 140 and the length of the pipe is 30 ft. The head loss for 100 ft pipe can be calculated as h100ft = 0.2083 (100 / 140)1.852 (200 gal/min)1.852 / (3.048 in)4.8655 = 9 ft H2O / 100 ft pipe The head loss for 30 ft pipe can be calculated h30ft = h100ft (30 ft) / (100 ft) 12/16/21, 2:17 PM Hazen-Williams Friction Loss Equation - calculating Head Loss in Water Pipes https://www.engineeringtoolbox.com/hazen-williams-water-d_797.html 2/6 = 9 (30 ft) / (100 ft) = 2.7 ft H2O Related Mobile App from The Engineering ToolBox Water Pipes Head Loss Calculator App - free apps for offline use on mobile devices. Online Hazens-Williams Calculator Imperial Units The calculators below can used to calculate the specific head loss (head loss per 100 ft (m) pipe) and the actual head loss for the actual length of pipe. Default values are from the example above. 200 l - pipe or tube length (ft) 130 c - roughness coefficient determined for the type of pipe or tube 30 q - flow rate (gal/min) 8.38 dh - inside hydraulic diameter (inch) Calculate! Specific Head Loss (ft H2O / 100 ft pipe): 0.00225 Specific Head Loss (psi / 100 ft pipe): 0.000972 Actual Head Loss (ft H2O): 0.00449 Actual Head Loss (psi): 0.00194 Velocity (ft/s): 0.175 Pipe and Tube Dimensions Make Shortcut to this Calculator on Your Home Screen? SI Units 9 l - pipe or tube length (m) 140 c - roughness coefficient determined for the type of pipe or tube 10 q - flow rate (liter/sec) 76 dh - inside hydraulic diameter (mm) Calculate! Plan in advance and save more. EVEN Hotel Rochester - St Mary’s Area Book NowOne night deposit required.