Transcription
For New or Replacement Sewage PumpsABSump and Sewage PumpManufacturers Association
Pump Capacity How much flow do you need? Total Dynamic Head (TDH) of the installation Solids-Handling Requirements Basin Selecting the right size Simplex or Duplex System? Sizing ExampleCopyright 2011, Sump and Sewage Pump Manufacturers Association
Refers to the rate of flow in gallons per minute(GPM) which is necessary to efficiently maintain thesystem. Most practical approach to determine this figure is theFixture Unit method. This method assigns a relativevalue to each fixture, or group of fixtures that flow intothe pump system.Copyright 2011, Sump and Sewage Pump Manufacturers Association
Pump CapacityTo determine the requiredPUMP CAPACITY,follow these 2 steps:Step 1: Determine Total Fixture UnitsStep 2: Find resulting Pump CapacityCopyright 2011, Sump and Sewage Pump Manufacturers Association
List all fixtures involved in the installation and, using Figure A, assign aFixture Unit value to each. Determine the Total Fixture Units.PUMP CAPACITYCopyright 2011, Sump and Sewage Pump Manufacturers Association
Refer to Figure B, locate the total Fixture Unit amount along thehorizontal axis of the graph.Follow vertically along until theintersecting plotted line. Follow this intersection point horizontallyand read the PUMP CAPACITY in GPM on the vertical axis.34 Fixture unitsrequire a 22 GPMcapacity.Using 34 fixture unitsas an example.Copyright 2011, Sump and Sewage Pump Manufacturers Association
TDH is a combination of Static Head and Friction Headand is expressed in feet.TDH Static Head Friction Head Static Head is the actual vertical distancemeasured from the minimum water level inthe BASIN to the point of discharge.Refer to Figure C.Copyright 2011, Sump and Sewage Pump Manufacturers Association
Static HeadCopyright 2011, Sump and Sewage Pump Manufacturers Association
The point of discharge may not be the highest point in thepiping system. A pump must be selected that has a shut-offhead greater than the highest point in the pipe system.TOTAL DYNAMIC HEADCopyright 2011, Sump and Sewage Pump Manufacturers Association
2 FT9 FTCopyright 2011, Sump and Sewage Pump Manufacturers Association
Friction Head Friction Head is the additional head created inthe discharge system due to resistance to flowwithin its components. All straight pipe, fittings,valves, etc. have a friction factor which must beconsidered.These friction factors are converted, andexpressed as equivalent feet of straight pipe,which can be totaled and translated into feet ofhead.Copyright 2011, Sump and Sewage Pump Manufacturers Association
Step 1 in calculating Friction Head First determine the discharge pipe size. 2” or 3” diameter is common on solids-handlingsewage applications in residential / light commercial In order to ensure sufficient fluid velocity to carrysolids (which is generally accepted to be 2 feet persecond), the following are minimum required flows- even if the GPM required for the fixture units isless.MINIMUM FLOW REQUIREMENTS2 feet per second 21 GPM through 2” pipe 46 GPM through 3” pipe 78 GPM through 4” pipeIf you don’t have these minimums –you won’t move the solids!Copyright 2011, Sump and Sewage Pump Manufacturers Association
Step 2 in calculating friction head The length of the discharge piping is measuredfrom the discharge opening of the pump to thepoint of final discharge, following all contours andbends.Copyright 2011, Sump and Sewage Pump Manufacturers Association
Step 3Consider all fittings - elbows, gate valves, check valves used in the installation (2) .2” 90 degree elbows 5.2 x 2 elbows in our example 10.4 feet of pipe(1) .2” check valve 17.2 feet of pipeAdded all up .27.6 feet (or 28 feet)Now add this 28’ (equivalent feet) to the existing200’ length of discharge piping for a total of 228’.Copyright 2011, Sump and Sewage Pump Manufacturers Association
Step 4Refer to Figure E. Using the required PUMP CAPCITY (GPM) in the leftcolumn, follow across to the number below the pipe size being used. Thisnumber represents the Friction Head per 100 feet of pipe. Multiply thisnumber by the number of 100ft increments to determine Friction Head.Our Example required22 GPMFRICTIONUsing a 2” line with flow of 25 GPM,we have 1.3 feet of head for every100 feet of pipe. For our examplewith 228’ of equivalent length of pipe 2.28 x 1.3 2.96 feet of head.(round up to 3’ of Friction Head)Copyright 2011, Sump and Sewage Pump Manufacturers Association
TDH Static Head Friction HeadStatic Head . 7 Feet Friction Head . 3 FeetTotal Dynamic Head 10 FeetNow look at pump curves in Figure F .At 10 feet of head, we need a pump thatcan give us a minimum of 22 GPM.Copyright 2011, Sump and Sewage Pump Manufacturers Association
Pump Selection706560E5550TDHThe pump 45is required todeliver at 40least 22 gpmat 10 feet of TDHDAt 10 Feet of TDH,Pump Bwill producemore thanA producesPump CPump& D arealso adequate.enough20gpm.ProbablyGPMBut are theytoo- large?the Tobestfit. Solids!Not EnoughMove35C302520B1510A5001020304050Gallons Per Minute6070Copyright 2011, Sump and Sewage Pump Manufacturers Association8090
The most efficient part of the curve isusually in the middle of the curve,away from maximum head or flow More horsepower or flow is not alwaysbetter – especially in smaller basins. Short cycling may reduce the life ofthe pump. A longer pumping cyclewill be better for pump longevity.Copyright 2011, Sump and Sewage Pump Manufacturers Association
Solids-Handling requirements may be determinedby local codes and/or by the type of applicationand types of solids. Unless otherwise specifically stated, SSPMArecommends that a sewage pump should havethe capacity of handling spherical solids of atleast 2” diameter.Copyright 2011, Sump and Sewage Pump Manufacturers Association
Selection of the basin is best accomplished byrelating to the required Pump Capacity asdetermined by the Fixture Unit method.Figure G shows the recommended BasinDiameters assuming a pump differential of8” (Distance between pump turn-on and turnoff).Other factors such as pump size, controls, andaccessories may impact the required basinsize.Basin depth should normally be at least 24” formost pumps, and deeper where greaterpumping differentials are anticipated.Copyright 2011, Sump and Sewage Pump Manufacturers Association
Recommended BASIN DiametersOur Example required22 GPMAny Basin 18” in diameteror greater may be acceptableCopyright 2011, Sump and Sewage Pump Manufacturers Association
The question of whether to use a Simplex (one pump) orDuplex (two pump) System depends on the type ofinstallation and/or local codes requirements. Domestic/Residential Use:Simplex System is adequate inmost instances; however if entireresidence is on the system,duplex may be required.Public/Commercial Use:Duplex System is essential.Copyright 2011, Sump and Sewage Pump Manufacturers Association
Simplex or Duplex System?Duplex systems make use of special controls in orderto alternate the usage of two pumps. Duplex systemsprovide several advantages over Simplex systems: The pumps alternate and therefore share the load. The lag pump is activated in the event of failure orlockage of the lead pump. The second pump is activated along with the leadpump in instances of unusually high inflow.Copyright 2011, Sump and Sewage Pump Manufacturers Association
Using the pump curves from Figure F, fill out the SewagePump Sizing Worksheet and find a suitable pump to servea 4 bathroom home, including a dishwasher, kitchen sinkwith disposal, washing machine, laundry tray, and a watersoftener. The Static Head is 15 feet The discharge pipe is 2” diameter The discharge piping is 500 feet long The discharge piping will include (1) checkvalve, (3) 90 degree elbows, (2) 45 degreeelbows, and (1) gate valve.Copyright 2011, Sump and Sewage Pump Manufacturers Association
Example: Pump CapacityStep 1: Determine Total Fixture Units(Reference Figure A) (4) Bathroom Groups6 Fixture Units each X4 24 Fixture Units 2 Fixture Units(1) Dishwasher(1) Kitchen sink w/ disposal 3 Fixture Units(1) Washing Machine 2 Fixture Units(1) Laundry Tray 2 Fixture Units(1) Water Softener 4 Fixture UnitsTotal 37 Fixture UnitsCopyright 2011, Sump and Sewage Pump Manufacturers Association
37 Fixture unitsrequire a 23.5 GPMcapacity.37 fixture unitsper the example.Copyright 2011, Sump and Sewage Pump Manufacturers Association
Example: Pump CapacityStep 2: Find resulting Pump Capacity(Reference Figure B)37 Fixture Units 23.5 Gallons per MinuteMinimum flow for 21 Gallons per Minute2” diameter pipeMinimum GPM 23.5 Gallons per Minutefor this exampleRound up to 24Gallons per MinuteCopyright 2011, Sump and Sewage Pump Manufacturers Association
TDH Static Head Friction Head 22 feetStatic Head 15 feetFriction Head ?7 feetFriction FactorsEquivalent feet(Reference Figure D)(3) 90 degree 2” elbows 5.2 X 3(2) 45 degree 2” elbows 2.8 X 2(1) 2” Gate valve 1.4 X 1(1) 2” Swing Check valve 17.2 X 1 500’ straight pipe 15.65.61.417.239.8 equivalent ft539.8 equivalent ft539.8 ft X 1.3/per 100 ft 7.02 ft. of friction headCopyright 2011, Sump and Sewage Pump Manufacturers Association
Example: Pump Selection706560E5550TDHThe pump 45is required todeliver at 40least 24 gpmat 22 feet of TDHDPump C will be the best choice,At 22Feet ofTDH, theIt wouldperformtowardsPump Aof&theB cannotperform.middlepump curveforbest efficiency.35C302520B1510A5001020304050Gallons Per Minute6070Copyright 2011, Sump and Sewage Pump Manufacturers Association8090
Thank YouCopyright 2011, Sump and Sewage Pump Manufacturers Association
Pump CompaniesAssociate MembersBarnes Pump/Crane Pumps & SystemsAlderon IndustriesChampion Pump Co.Campbell Manufacturing, Inc.Glentronics, Inc.John Crane, Inc.Goulds Water TechnologyMetropolitan IndustriesLiberty PumpsMotor Protection Electronics, Inc.Little Giant/Franklin ElectricSJE-RhombusPentair WaterTopp Industries, Inc.Superior PumpWayne Water SystemsZoeller CompanyABWebsite:www.sspma.orgCopyright 2011, Sump and Sewage Pump Manufacturers Association
Using the pump curves from Figure F, fill out the Sewage Pump Sizing Worksheet and find a suitable pump to serve a 4 bathroom home, including a dishwasher, kitchen sink with disposal, washing machine, laundry tray, and a water softener. The Static Head is 15 feet The discharge pipe is 2” diameter
