DesignofWaterSupplyandDrainageSystemforMulti-storeyResidentialBuildings:TechnicalNormsandPracticalSolutions

Abstract

Introduction

Multi-storeyresidentialbuildings(typically4–9floors)arewidelydistributedinurbanandsuburbanareas,andtheirwatersupplyanddrainagesystemsdirectlyaffectresidents'livingqualityandbuildingsafety.Inrecentyears,withtheimprovementoflivingstandards,usershavehigherrequirementsforwatersupplystability,drainagesmoothness,andenvironmentalprotectionofthesystem.However,problemssuchasunevenwaterpressure,drainageblockage,andinsufficientfire-fightingprotectionstillexistinactualdesignandoperation,whichneedtobesolvedbyscientificdesignmethods.Thispaperisbasedoninternationalplumbingcodes(e.g.,IAPMOUniformPlumbingCode,ISOstandards)andpracticalengineeringexperience,aimingtoprovideaprofessionaldesignguideformulti-storeyresidentialwatersupplyanddrainage.

1.WaterSupplySystemDesign

1.1WaterSourceandPressureRegulation

Municipalwatersupplyistheprimarywatersourceformostmulti-storeyresidentialbuildings.Whenthemunicipalwaterpressure(usually0.15–0.4MPa)cannotmeetthedemandofupperfloors(e.g.,thepressureatthetopfloorislessthan0.15MPa),secondarywatersupplysystemsarerequired.Forbuildingswith4–6floors,variable-frequencypumpsetsorpressure-stabilizedwatertankscanbeused.Thedesignshouldensurethatthewaterpressureofeachfloorisbetween0.15–0.35MPa:thelowerfloors(1–3floors)canbedirectlysuppliedbythemunicipalnetwork,andtheupperfloors(4–9floors)aresuppliedbysecondarypressurization.Pressurereducingvalvesareinstalledatthebranchpipesofeachfloortoavoidexcessivepressureaffectingpipelifeanduserexperience.

1.2PipeLayoutandMaterialSelection

Thewatersupplypipenetworkcanbedesignedasatree-typeorring-typelayout.Thering-typelayouthasbetterpressurestabilityandfaulttolerance(whenasectionofpipeisdamaged,otherbranchescanstillsupplywater).Forpipematerials,polypropylenerandom(PP-R)pipesarewidelyusedinlow-pressurewatersupply(≤1.0MPa)duetotheircorrosionresistance,lowthermalconductivity,andeasyinstallation.Forareaswithhighwaterpressureorspecialrequirements,cross-linkedpolyethylene(PE-X)orstainless-steelpipescanbeselected.Thepipediameterisdeterminedbyhydrauliccalculation,ensuringthattheflowvelocityisbetween0.6–2.0m/stoavoidwaterhammer(whenthevelocityexceeds2.5m/s,waterhammermayoccur,causingpipevibrationandleakage).

2.DrainageSystemDesign

2.1DrainageSystemandPipeMaterial

2.2SlopeandVentilationDesign

Thehorizontaldrainagepipeshouldhaveareasonableslopetoensuresmoothdrainagewithoutsedimentation.Forexample,theslopeofDN100pipeis0.02,andthatofDN50pipeis0.035.Theventilationsystemiscrucialtopreventsiphonageandwatersealdamage:extended-topventilationpipesaresetforeachdrainageriser,andring-typeventilationpipesareaddedforlarge-diameterhorizontalpipes(e.g.,kitchenandbathroommainpipeswithmultiplebranches)tobalanceairpressureinsideandoutsidethepipes.

2.3Anti-BackflowandOdor-ProofMeasures

Inkitchensandbathrooms,floordrainswithwaterseals(watersealheight≥50mm)andanti-backflowdevicesshouldbeinstalledtopreventsewagebackflowandodoroverflow.Forthedrainageofwashingmachinesandsinks,P-trapsorS-trapsaresettoformawaterseal,andtheconnectionbetweenthetrapandthemainpipeshouldbesmoothtoavoidblockage.

3.Fire-fightingWaterSupplyDesign

3.1IndoorFireHydrantSystem

3.2AutomaticSprinklerSystem(Optional)

4.Water-savingandEnvironmental-friendlyDesign

4.1Water-savingFixtures

4.2RainwaterHarvestingandReuse

Collectroofrainwaterthroughguttersanddownspouts,andaftersimpletreatment(filtration,disinfection),itcanbeusedforgreeningirrigation,carwashing,andtoiletflushing.A6-storeyresidentialbuildingwitharoofareaof500m2cancollectabout300m3ofrainwaterannually,reducingmunicipalwaterconsumptionbyabout20%.

4.3GreywaterTreatmentandReuse

Treatdomesticgreywater(wastewaterfromsinks,showers,etc.)throughbiologicalorphysical-chemicalmethods(e.g.,membranefiltration,activatedcarbonadsorption)andreuseitfortoiletflushingorgreening.Thegreywaterreusesystemcanreducedomesticwaterconsumptionby30%–50%,butitneedstobedesignedwithattentiontowaterqualitysafetyandsystemmaintenance.

5.TechnicalChallengesandSolutions

5.1UnevenWaterPressure

Problem:Thewaterpressureoflowerfloorsistoohigh(causingpipeleakage)orupperfloorsistoolow(insufficientwaterflow).Solution:Usevariable-frequencypumpsetswithpressuresensorstoadjustthewatersupplypressureinreal-time,andinstallpressurereducingvalvesateachfloortoensurestablepressure.

5.2DrainageBlockage

Problem:Sedimentationandblockageofdrainagepipesduetoimproperslopeorpipeconnection.Solution:Optimizethepipeslope(uselaserlevelingduringconstruction),setcleanoutsatappropriateintervals(e.g.,every10mofhorizontalpipes),andconductregularmaintenance(e.g.,annualpipedredging).

5.3DrainageNoise

Problem:High-decibeldrainagenoiseaffectsresidents'rest.Solution:Useflexible-jointcastironpipesorwrapUPVCpipeswithsound-insulationmaterials(e.g.,rubber-basedsound-insulationcotton)toreducenoisetransmission.

5.4ConstructionErrors

Problem:Pipecollisionorincorrectinstallationduetolackofoverallplanning.Solution:UseBIMtechnologytosimulatethepipelayoutbeforeconstruction,optimizethespatialarrangement,andstrengthenon-sitesupervisiontoensurethattheconstructionmeetsthedesignrequirements.

6.CaseStudy:A6-storeyResidentialProjectin[City]

6.1ProjectOverview

Theprojecthas6floors,2unitsperfloor,andatotalof48households.The