ASTM_C_1746_-_C_1746M_-_12.pdf

Designation:C1746/C1746M12Standard Test Method forMeasurement of Suspended Sediment Removal Efficiency ofHydrodynamic Stormwater Separators and UndergroundSettling Devices1This standard is issued under the fixed designation C1746/C1746M;the number immediately following the designation indicates theyear of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method concerns measurement of the effi-ciency of hydrodynamic separators and underground settlingdevices in removing suspended sediment from simulatedstormwater runoff under conditions defined herein.This testmethod is not intended for use in determining field removalefficiency.1.2 Units tested shall be of a size commonly manufactured,not a scale model.This test method is not intended to addressproduct scaling.1.3 This test method is not for measuring the removalefficiency of filters or the scouring potential of hydrodynamicseparators and underground settling devices.1.4 In this test method,only gravity flow operation isaddressedperformance of units operating under pressurizedconditions is not addressed.1.5 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system may not be exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in non-conformancewith the standard.1.6 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D422 Test Method for Particle-Size Analysis of SoilsD854 Test Methods for Specific Gravity of Soil Solids byWater PycnometerD4959 Test Method for Determination of Water(Moisture)Content of Soil By Direct HeatingE11 Specification for Woven Wire Test Sieve Cloth and TestSieves3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 inlet(or outlet)rounding,nradius of fillet at insidepipe junction with separator structure.4.Summary of Test Method4.1 This test method describes procedures and equipment tomeasure the suspended sediment removal efficiency of hydro-dynamic separators and underground settling devices used fortreating stormwater runoff.5.Significance and Use5.1 Each device has unique flow patterns and turbulencecharacteristics and may exhibit a wide range of efficiencies asdischarge,particle-size distribution,particle density,and flowviscosity(that is,water temperature)changes.The testingprocedures described in Section 8 provide a method of mea-suring the removal efficiency of these devices under a givenflow condition,flow viscosity(water temperature),andparticle-size distribution and density.Therefore,the results oftesting represent the flow,viscosity,and particle-size distribu-tion tested.6.Apparatus6.1 The experimental setup includes an influent straight pipe(without bends or fittings)of minimum length equivalent to tenpipe diameters or 6 m 20 ft,whichever is less,upstream fromthe test unit and effluent pipe length equivalent to three pipediameters with a free-fall condition at its downstream end.Pipeshall have a Mannings roughness coefficient not greater than0.013.6.2 The test unit shall be set up to reflect actual fieldinstallation parameters to the greatest degree possible,includ-ing inlet/outlet roundings as supplied or recommended by themanufacturer.1This test method is under the jurisdiction of ASTM Committee C27 on PrecastConcrete Products and is the direct responsibility of Subcommittee C27.70 onPrecast Concrete Products for Stormwater Management.Current edition approved June 15,2012.Published July 2012.DOI:10.1520/C1746_C1746M-12.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.3 Influent and effluent pipe diameters shall be the mini-mum size recommended by the manufacturer and shall bedocumented in test results,as well as pipe orientation and pipeslopes(2 to 3%).6.4 The sediment injection point shall be at the crown of theinfluent pipe at a distance equal to 2 6 0.1 pipe diametersalong the centerline of the pipe upstream of the inlet to thetreatment device to supply the sediments in the simulatedstormwater runoff.6.5 The sediment delivery system(feeder)shall be com-prised of suitable means of sediment addition so as to provideconsistent sediment feed rate of solids(including an auger,vibratory hopper,well-mixed slurry inje