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【求塑料给水管材英文文献】

Plasticwatersupplytubing

byAldenSmith

Polyvinylchloridepipe(PVC)hasmadeatremendousimprovementinplumbing.Itreplacescastironandgalvanizedpipeinalmostallsituations.Lightweightandeasytoworkwith,PVCisavailableinmanydifferentsizes.Fittingsandrelatedmaterialsarereadilyavailableatallplumbingandhardwarestores.ThisarticlediscussesPVCpipe,itsusesandinstallation.

WhatisPVC?

PVCpipeismadefrompolyvinylchloride.Itisusedindrains,asventsandtohandlewasteinbuildings.Itisrigid,lightweight,andstrong.BecauseofPVCpipe’seaseofinstallation,itisidealfordrainapplicationsunderkitchensinksandbathroomvanities.ThemanyfittingsavailableforattachingPVCmakeituniversalinallsettingsexceptveryhightemperatureapplications.Itworksmuchbetterforplumbingthantheoldstandardcastironpipebecauseitdoesnotneedtobehotsoldered,isresistanttoalmostanyalkalineortoxicsubstance,andiseasytoinstall.Therearetwotypes,whicharedefinedinstandards—type40forpersonalhomesandtype80,sedinindustrialsettings.

SomeAdvantages

PVChasmanyadvantages,aslistedhere:

Itisveryeasytoinstall.

Itischemicalresistant

Itisstrong

Itisfireresistant

Ithasahighinternalcorrosionresistance.

Itisimmunetogalvanicorelectrolyticattack.

Itisfreefromtoxicity,isodorlessandtasteless

Ithaslowfrictionloss

Ithaslowthermalconductivity

Thereisalowinstallationcost

Itisvirtuallymaintenancefree.

CuttingandFitting

PVCcanbecuteasily.Youcancutitwithahacksaw,butabrasivedisksaremadeformitersawsthatworkbettertogetastraightedge.Remember,ajointthatisskewedduetopipenotbeingcutstraightcanthrowofftheentirerunofpipe.

Measuretwice,cutonce.Aftercutting,cleanallshavingsoutofthepipeandburrtheinsideedges.Whenthepipeiscuttotheproperlength,layitoutonthefloorwithfittingsinplacetodetermineiflengthiscorrect.Ifitistheproperlength,proceedtoinstallation.

PVCCleanersandCements

PVCisjoinedwithaspecialtypeofcement.First,thepipemustbecleanedwithall-purposepipecleaner.Thecementsetsupveryquickly,soyoumustbereadytogoassoonasitisapplied.Coattheinnersurfaceofthejointwiththecement,insertthePVCpipe,andturnit1/4turntoinsurethatthecementcompletelycoversthepipe.Becertainthatthepipeisseatedcorrectlyinthejoint.

OncethePVCpipeisinplaceandyouhavedeterminedthatitisofproperlength,installpipehangerstosupportthepipe.Thiseasesstrainonthejointsthatcouldleadtopossibleleakage.Followrecommendationsforthedistancesfromhangertohanger,allowingformovementinexpansionandcontraction.Besuretoprotectthepipefromnails,screwsorabrasivematerials.

SomeFAQ’s

WhatisthedesignlifeofPVCpipe?

PVC,becauseofitscomposition,willlastforthedesignlifeofthehomeinwhichitisinstalled.Becauseitisrustproofandchemicalresistant,adesignlifeof100yearsistypical.

IsPVCpiperecyclable?

Yes.Thepipecanbepulverizedandreturnedtotheextrusionprocesstomanufacturenewpipe.Therearecurrentlynostandardsforthis.Becauseofitslonglife,PVChasn’thadalotofexposuretorecycling.

IsPVCresistanttoUVrays?

BecauseofitsinherentdesignPVCpipecontainsstabilizersthatprotectthepipeagainstattackbyUVrayspresentinsunlight.Somediscolorationmayoccur.Severalyearsofexposuremayseeslightreductionintheimpactresistanceofthematerial.Bypaintingtheexposedpipewithalatexpaint(don’tuseoilbased)thisproblemisvirtuallyeliminated.

IsPVCpipefireproof?

Likeanyplastic,PVCpipewillmeltifsubjectedtohightemperatures.However,itstopsthatprocessimmediatelywhenthefiresourceisremoved.StudiesshowthatPVCpipeinatypicalinstallationislessthan1%ofallcombustiblematerialsinabuilding.

PVCpipeiseasytoinstall.Itslightweightmakesiteasyfortheplumbertohandle.Whendoinganyplumbingreplacementinabuilding,givePVCpipeatry.

AldenSmithisanawardwinningauthorandregularcontributortoDoItYourself.com.Hewritesonavarietyofsubjects,andexcelsinresearch.

Comments(2)

April9,2009·FiledunderUncategorized

WorkingwithPlasticPipe

Plasticpipinganddo-it-yourselfplumbinggotogetherlikehammersandnails.Plasticpipeiseasytocutandjointoitsmanyfittings,anditiswidelyacceptedbyplumbingcodes.Insidethisdocumentyouwillfindinformationabout:

MeetthePlastics

SolventWelding

MechanicalCouplings

InstallingPlasticPiping

MEETTHEPLASTICS

Plastic(morecorrectlythermoplastic)forplumbingcomestwoways:inpipesizesandintubingsizes.Whilebotharesizednominallyaccordingtoinsidediameter,pipesgobyiron-pipesizesandtubesgobycopper-tubesizes.Pipesandtubesandtheirfittings,eveninthesamedesignatedsizes,shouldnotbeinterchanged.Withplasticpiping,youchoosefromawideselectionofmaterials.TableAshowstheplasticplumbingmaterialsavailableanddescribeswhateachisusedfor.

Rapidtechnologicaladvancesinplasticplumbingmayleavelocalplumbingcodesoutdated.So,beforepurchasingyourmaterials,it’sagoodideatoconsultyourcityorcountybuildingofficials.

DWVstandsforthedrain-waste-ventsystemusedtocarrywastesawayfromyourhome’sfixturesandtoventthesystemabovetheroof.Sewerpipesaremadetocarryhouseholdwastesbelowgroundtoapublicsewerorprivatedisposalsystem.Drainagepipesareusedbelowground,too,butarethinner-walledandlowerincost.They’reusuallyusedwithnon-septicwater,suchasroofrunoff.Tubulargoodsarethethin-walledfixturedrainandtrappartsusedbeneathsinksandwashbasins.

Onlytwokindsofplastictubescanwithstandhotwaterunderpressure:rigidCPVCandflexiblePB.Thetwomaybeusedsinglyortogethertobuildcorrosion-free,non-electrolytichouseholdwatersupplysystems.Becauseplasticpipeisnon-conducting,itcannotbeusedforelectricalgrounding.

PVCpressurepipeshouldbeusedonlyforcoldwateroutdoors.Itisidealforbuildinglawn-wateringandirrigationsystems.PEpipeservesasimilarpurposebutisflexibleandcannotbesolventwelded.PEisespeciallyusefulasdeep-wellpipe.

Risertubesarethehighlyflexible,small-diametertubeslinkingawatersupplysystemandfaucets,makingthefaucetseasiertoconnect.Risertubesoftenfitdirectlyintoanadapteronafixtureshutoffvalve.

Plasticpipesformostuses(excepttubularproducts)areratedbytheAmericanSocietyforTestingandMaterials(ASTM).LookfortheASTMdesignationoneachpipe,tubeandfittingthatyoubuy,signifyingthatitmeetsASTMstandards.WatersupplypipingshouldcarrytheNationalSanitationFoundation’s“NSF-pw”approval,meaningthepartsaresuitedforcarryingpotable,ordrinkable,water.

SOLVENTWELDING

Thesimplesolvent-weldingprocessusedtojoinmanyplasticpipesmustbedoneproperlytopreventleaks.

Here’show.

Usethetwo-stepmethod–employingcleaner/primerandsolvent–exceptwithABSandstyrene,withwhichtheone-stepmethod(solventonly)isusuallyenough.1.Inspectthepipeendandfittingsocketforcracks,gouges,dirtandabrasion.Ifthepipeendisimperfect,itcanbecutbacktoexposegoodmaterial.Discardadamagedfitting.2.It’sagoodideatopurchasepipeandfittingsmadebythesamemanufacturer.Ifthisisn’tthecase,test-fitthem.Thepipeshouldenterthefittingbutmeetresistancepart-wayin.Heldupsidedown,thepipeshouldnotfalloff.

3.Cuttingpipes.Cutthepipeoffsquarelytotheproperlengthusingafine-toothsaworplasticpipecutter(ahacksawworkswell).Flexibleplasticpipesaremoreeasilyseveredwithasharpknife,butbecarefulnottocutyourself.Ifyouhavealargeamountofcuttingtodo,youcangetatubingcutterwithaspecialwheelforuseonrigidplasticsorashear-typecutterforPVC.Then,usingaknife,removeanyburrsandchamfertheouterendofthepipeslightly.Donotusesandpaperonplasticpipes.Itmayremovetoomuchmaterialforsuccessfuljoining.

4.Cleaning.Now,usingaqualitycleaner/primer,cleanthepipeendandfittingsocket(omitthisentirestepwithABSandstyrene).Applythecleaner/primerwithadauber,brushorcleanclothtoremovegrease,oilanddirt,andtopreparetheplasticmatingsurfacesforsolventcementaction.Thesurfacestobejoinedshouldbecleanandfreeofdirtandgrease.Thepipeshouldbedrybeforeapplyingcement.

5.Solventwelding.BrushonacoatofanASTM-ratedsolventcementthatismatchedtothetypeofpipeandfittingyouareusing.Itisimportanttousetherighttypeofsolventcement.TableBshowsthevariouscementsandthekindsofplastictheyaresuitedto.Liberallyapplycementfirsttothepipeend,thenapplyitsparinglytothefittingsocket.Leavenobarespots.Withchemical-resistantPVCandCPVCpressurizedpiping,givethepipetwoapplicationsofcement–onebeforeandoneaftercoatingthefittingsocket.Withallsolventwelding,useadauberorbrushthat’satleastone-thirdtoone-halfthepipe’sdiametertoapplythecement.

6.Immediatelyjointhepipeandfittingfull-depthwithaslighttwisttobringitintocorrectalignment.Thetwistbreaksupinsertionlinesinthesolventcement.Holdthefittingonuntilthesolventcementgrabstightly.Afilletofcementaroundthefittingindicatesthatyouusedenoughsolventcementtoensurealeak-freejoint.WithPVCandCPVC,donotwipeoffthefillet.Ontheotherhand,theone-stepsolvent-weldingmethodforABSandstyrenecallsforwipingoffanyexcesscementaroundthefitting.Thejointshouldbereadyforuseinanhour.

Safetyprecaution.Avoidprolongedbreathingofsolventcementandcleaner/primervapors.Workinawell-ventilatedarea,andcapthecansaftereachuse.Keepsolventandcleanerawayfromanyopenflame.Readandfollowtheprecautionsthatappearonthelabels.Removeanycementonyourhandswithhandcleaner.

Correctingerrors.Solventweldingisnormallyaone-wayprocess–youcaninstallthefitting,butyoucannotgetitoffagain.Whenyouaccidentallyputthewrongfittingonapipe,youmustcutitoutandreplaceitwiththecorrectfitting.

MECHANICALCOUPLINGS

Somefittingsaremadeforjoiningpipesandtubesthatcannotbesolventwelded.

PEpipe.Simplebarb-typeplasticormetalfittingsareusedwithflexiblePEpipe.Tomaketheconnection,slideacorrectlysizedworm-driveclampoverthepipeendandpushthepipeallthewayontothebarbedfitting.Positiontheclampabout1/4〃fromtheendofthepipeandtightenit.

Withanyflexibletube,becarefulnottobenditintootightacurve.Itcankinkthetubeanddiminishorcompletelyshutoffthewaterflow.

PBtubing.FlexiblepolybutylenetubingforhotandcoldwatersupplysystemsisjoinedbypatentedO-ring-sealedmechanicalcouplings.Eachsystemusesitsowncoupling,andthey’reoftennotinterchangeablewiththoseofothersystems.Followtheinstructionsforthekindyouareusing.

Flaringplastic.BothCPVCandPBtubingcanbejoinedtoeachotherortometalpipingwiththeuseofflareorcompressioncouplingsandadapters.Flaringisdonewithaflaringtool.TopreventcrackingofaCPVCtubewhenflared,cuttheendoffsquarelyandsmoothlywithapipeortubingcutter.Soaktherigidtube’sendinboilingwaterjustbeforeflaring.

Slip-jam-nutcouplings.Tubulardrainagepipesarejoinedbyslip-jam-nutcouplings.Tomakeupsuchacoupling,firstinstallthenutfacingitsthreads.Theninstallthecorrect-sizedslipwasherwithitsflatfacetowardthenut.IfyouaresurethatnoneofthepartsaremadeofABSplastic,whichisadverselyaffected,youmayuseplumber’sputtyorsiliconerubbersealantaroundtheinsideoftheslipjamnuttopreventleaks.Adjustthelengthanddirectionofthetubularparts,thenstartthenut’sthreadswithitsfittingandtighten.

Mostplastictubularcouplingswilltightenleak-freebyhand,butyoumaywanttogivethemanextraquarter-turnwithapairofchannel-lockingpliers.

Transitionunions.Foradaptingplasticwatersupplytubingtothreadedmetalparts,suchasatwaterheatersandbathtub/showervalves,useafittingcalledatransition.Transitionunionsallowthermalmovementsbetweenmetalandplasticwithoutleaks.Useamale-threadsadapterfornon-pressurizedconnectionsatspotssuchasshowerrisersandwaterheaterreliefvalvetappings.

SomemechanicalcouplingsmadeforPBwatersupplytubingalsoworkwithcoppertubingsincethetwoarethesamesize.Theseallowyoutojointplastictocopperwithoutsweat-soldering.Thesefittingsmakeeffectivetransitionunions.

Flexiblefittings.Flexiblereplacementdrain-waste-ventandsewer/drainpipefittingsaremadeofsoftvinyl.Thesecomewithlargeworm-drivebandclampsthatenablethemtobefastenedsecurelytoplasticormetalpipes.Aflexiblefittingcanbeshoehornedintoplace,eventhoughthepipesitfitsoverareimmovable.

Clickondrawingabovetoviewanimation.

INSTALLINGPLASTICPIPING

Plasticpipingistheeasiesttoinstall,buttherearespecialthingstolookfor.

Securing.Mountplasticpipessotheycanexpandandcontractwithoutdamage.LargerDWVpipesarehungbyperforatedmetalstrappingcalled“plumber’stape”spacedamaximumof48〃apart.Smallerwatersupplytubesareattachedtotheframingbytubinghangersthatholdittightlytotheframingwhilepermittingback-and-forthmovement.Usehangersamaximumof32〃apart(onehangerateveryotherjoist).Also,besurenottobindrigidpipesinattheends.Leaveabout1/4′forevery10′ofpipe,asshown.

Provideprotectionfromnailswithpre-punched,nailed-onsteelstrapsfromyourdealer.Thestrapsalsohelptobraceoveranynotchesmadeintheframingforpiping.Besuretoinstallairchambersorwaterhammerarrestersateveryfixtureandapplianceexcepttoilets.

Joiningtoexistingdrain.Toleadanewdrainintoanolderplasticdrain,useslipcouplings.First,marktheportionoftheoldpipetobecutoutwherethenewpipewilljoinit.Next,sawoutthelengthofpipebetweenthemarks.Slideashoulder-lessslipcouplingontobothendsofthecutpipe,leavingabout1-1/2〃exposedforsolventwelding.Positionthenewfittingreadyforcouplingontotheoldpipe.Therewillbepipestubsonbothsidesofthejointsforsolventwelding.Dopethepipeendsallaroundwithaheavycoatingofsolventcement.Immediatelyslidetheslipcouplingintoplace,halfwayastridethejoint.Giveitaslighttwistasyouputitinplace.Holdthealignmentfor10secondsbeforeworkingontheotherendofthefittinginthesameway.

Directburial.Whenplasticseweranddrainagepipesareburiedintheground,followafewcommon-senserules.First,laythepipesonunexcavatedtrenchbottom,notonsoftfill.Fillcouldsettleunevenly,makinglowspotsinthepipeline.Digoutdepressionsforthecouplingssothatlengthsofpipearefullybedded,notbridgedbetweencouplings.Backfillaroundthepipesshouldbefreefromrocksthatcoulddamagethepipewalls.Packedsandisagoodinitialbackfill.Oncethepipesarewellcovered,useordinarybackfilltherestoftheway.

TABLEChoosingaCement

Typeof

CementTypeofPipe

ABSPVCCPVStyreneAll-Purpose

ABSRRRRR

PVCNRRRNRR

CPVCNRNRRNRR

StyreneRRRRR

R-RecommendedNR-NotRecommended

TABLEAMeetthePlasticPipes

PlasticCharacteristicsJoinsbyColorsUses

PVC(polyvinylchloride)RigidwithhighchemicalresistanceSolventweldingWhite,gray,beige,andmanyothersDWV,sewer,anddrainpipe;cold-waterburiedpressurepipe;tubulargoods

ABS(acrylonitrile-butadiene-styrene)RigidSolventweldingBlackDWV,sewer,anddrainpipe;tubularparts

CPVC(chlorinatedpolyvinylchloride)Rigid,heat-resistantSolventweldingBeigeHotandcoldwatersupplytubes,indoorsandburied

PB(polybutylene)Flexible,heat-resistantMechanicalcouplingsBeige,grayHotandcoldwatersupplytubes,indoorsandburied;risertubes

PE(polyethylene)Flexible,low-costClampedcouplingsBlack,milkyColdwateronlyoutdoorpiping,buried

SorRS(styreneorrubber-styrene)Rigid,low-costSolventweldingBlack,milky,orwhiteDrainpipeoutdoorsandburied

PP(polypropylene)Semi-rigidwithhighheatandchemicalresistanceSlip-jam-nutcouplingsBeigeTubulardrainageproductsforfixtures

TOOLANDMATERIALCHECKLIST

Pipes,Tubes,Fittings

Cleaner/Primer

MiterBox

Paintbrush

PTFEPlumber’sTape

Screwdriver

Channel-LockingPliers

SiliconeRubberSealant(RTV)orPlumber’sPutty

SolventCement

Fine-ToothSaw

Knife

CleanCloths

PlasticPipeCutter

Nut-Driver

FlaringTool

HandCleaner

Checkyourstateandlocalcodesbeforestartinganyproject.Followallsafetyprecautions.InformationinthisdocumenthasbeenfurnishedbytheNationalRetailHardwareAssociation(NRHA)andassociatedcontributors.Everyefforthasbeenmadetoensureaccuracyandsafety.NeitherNRHA,anycontributornortheretailercanbeheldresponsiblefordamagesorinjuriesresultingfromtheuseoftheinformationinthisdocument.AskforOther“Show-How”InstructionSheets

Additionaleasy-to-useinstructionsheetsforhomedo-it-yourselfprojectsareavailablefromyourlocalsupplierofmaterials.Comeinandaskfor“Show-How”instructionswhenyougetreadyforthatnexthandymanproject!

Comments(3)

April9,2009·FiledunderUncategorized

PVCPIPES

PVCpipe,orPolyVinylChloridepipe,isarelativelymoderntypeofpiping,usedmostoftenindrinkingwatersystems,andothercoldwaterinstallations.Whenthereisaneedforfoodstuffsorultra-pureliquidsinmanufacturingapplications,PVCpipeorstainlesssteelpipeisusuallyused.

PVCpipeisplasticpipeandhasbeeninuseintheUnitedStatessincethe1960’s,whenitwasfirstintroduced.PVCpipeoftenreplacesmetalpipeinkitchensandbathroomsthesedays.

HealthConcernsofPVCPipe

TherehasbeensomecontroversyoverthehealthissuesofPVCinrecentyears.SomeofthechemicalsintheplasticusedinPVCpipehavebeenreportedtoleechoutovertime,andmayaffectthewatersupply,ifdrinkingwaterorshowerwaterissuppliedviaaPVCpipe.

FlexibilityofPVCPipe

PVCpipecanwithstandvigorousmovementandacertaindegreeofbendingwithoutcracking.PVCpipeisthereforeoftenusedinearthquakeproneareas,orinareaswherethereisperiodicland