Home-Run Plumbing Systems - ToolBase Services

YOUR BLUEPRINT FOR USING ADVANCED BUILDING PEX TECHNOLOGY Home-Run Plumbing SystemsHome-RunPlumbingSystemsusingCross-LinkedPolyethylene(PEX)DOLLARS & SENSERESULTS FROM THE FIELDMAKING THE SWITCHTECH CHECKFOOD FOR THOUGHTCosts to buy, install, andoperate PEX plumbingsystems… Page 2Real-world experiences fromNE, CO, NJ and PA…Page 2What it takes to switch fromtraditional to PEXplumbing systems… Page 3Steps you need to take if youdecide to start using thisbuilding technology… Page 3What to consider to be surethat PEX plumbing is right foryou… Page 4TECH @ A GLANCEBENEFITS (+) / DRAWBACKS (-)+ AFFORDABILITY: Lower total cost (materialsplus installation)+ ENERGY EFFICIENCY: Reduced heat loss+ MARKETABILITY: More stable water pressureat fixtures during simultaneous draws of hotwater; faster hot water delivery time+ DURABILITY: Fewer joints, especially thosehidden behind walls. Piping is resistant tocorrosion and will not pit or stress corrode;Piping is resistant to freeze damage+ PERFORMANCE: The smooth interior walls ofPEX are resistant to scale build-up+ CONVENIENCE: Faster hot water deliverytime. More stable pressure at outlets duringsimultaneous flow+ ENVIRONMENTAL PERFORMANCE: In awell-design system, PEX reduces wait time forhot water at fixtures and can therefore reducethe amount of water wasted waiting– AFFORDABILITY: Higher materials cost;learning curve may add labor cost forinexperienced installersINITIAL COSTPEX plumbing system materials often cost morethan rigid pipe materials. However, labor savingscan make overall installed cost lower than rigidpipe systems. Cost will depend on the systemdesign, house size, distributor, and productavailability.OPERATIONAL COSTBecause manifolds are installed in easilyaccessible locations and have fewer connections,PEX plumbing systems can reduce maintenanceand repair costs. Due to its smaller diameter,PEX piping retains less volume of hot water in thepipe at the end of a hot water draw.Consequently, it can contribute to water andenergy savings.CODE ACCEPTANCEPEX piping has been approved by modelbuilding codes since 1993 and is accepted in allmajor building codes. Check local codes, asPEX may not be approved locally. Each modelcode outlines requirements for PEX tubing andplumbing system design, including nationalstandards to which the tubing must be testedand comply, design requirements, andacceptable connections and fittings.RESULTS FROM THE FIELDPATH field evaluations have demonstratedexcellent material and installed cost savingscompared with traditional plumbing systems.WARRANTYManufacturers typically offer a 10-year limitedwarranty on the manifold, piping, and fittings.MAKING THE SWITCH• Home-run systems can take significantly lesstime to install than traditional rigid pipeplumbing systems once the learning curve hasbeen overcome.• Trades need to receive training in properhandling and installation.• Installation requires some specialized tools.• Special care is required to eliminateconstruction and line debris from sensitivemanifolds.THE BASICSCross-linked polyethylene (PEX) is a flexiblepipe that is typically installed in a home-run,or parallel, configuration in which hot andcold supply lines originate from a centralmanifold and serve individual fixtures. PEXpiping is suitable for hot water use (up to200°F at 80 PSI) and is resistant totemperature extremes, chemical attack, anddeformation. Because the flexible piping canbe snaked through walls in a manner similarto electrical wiring installation, PEX is fasterto install than rigid piping. Home-run systemstypically only require fittings at the manifoldand the fixture, though special fittings orcouplings are available for repair or changesin direction tighter than the minimum bendradius allowed for the piping.The long-term durability and performance ofPEX piping is evident by its approval in allmodel codes. The PEX manufacturingindustry is highly regulated and piping mustundergo rigorous testing to ensure durability.Home-run systems equalize pressure,therefore allowing several fixtures to be usedsimultaneously without dramatic changes inpressure or temperature. In PEX home-runplumbing systems, less hot water is leftstanding in pipes, so less hot water energy iswasted (standing water creates energy lossto the surrounding air).PEX tubing may melt, distort or crack ifexposed to excessive heat and should not beexposed to freezing or sunlight. Abrasivesurfaces that can damage PEX pipe shouldbe avoided.continues on next pageTECH SPECS >1

PEX Home-Run Plumbing SystemsDOLLARS AND SENSEInitial Cost:Considerable labor and material savingshave been documented in the field.• $300-$1,200 less than copper for moveupproduction homes (Oakwood Homes)• $200 less than conventional copper inproduction builder’s “Idea House” (K.Hovnanian)• $700 savings compared to copper for aremodeling application (ModelreMODEL)• 20% installed cost savings over copperin affordable new home (Liberty Village)Operating Cost:Moderate water and energy savingsmay be achieved; however, savingsare variable and not easily quantified.THE BASICS continuedBe sure to follow manufacturer guidelinesand codes regarding clearance from PEXpiping and plastic manifolds to heat sources,including water heaters, light fixtures, gasflues, and other heating appliances. Typically,PEX piping should have a minimum 12-inches vertical and 6-inches horizontalclearance, while manifolds need at least 36-inches vertical and 18-inches horizontal fromheat sources.Central manifolds should be installed in aconvenient and accessible location, such asa basement wall or a service closet, whichallows easy access for shut off to individualfixtures. Because each outlet from themanifold typically has its own valve, plumbingrenovations and repairs are simplified.Manifolds can be mounted between studframing, and should be secured on a flatsurface to prevent warping. A single lengthof PEX piping can run directly from a manifoldthrough studs and around obstacles. Thepipe is pulled, like a wire, from the manifoldlocation to fixture locations. Extra piping, onthe order of 1/8-inch per foot of piping, isneeded to allow for expansion andcontraction. Unrolling the pipe with a reel willprevent kinking. The pipe is then securedwith clips and cut with a plastic pipe cutterbefore fittings are applied. Piping should notbe secured too tightly to the framing, toaccount for expansion and contraction.Options for fittings include crimp orcompression; either type takes only a fewseconds to make.RESULTS FROM THE FIELDThis technology has been used by other builders in real-world building situations – learnfrom their experiences.Builders who have installed PEX home-run systems as part of PATH Field Evaluations andDemonstrations have realized material and installation savings, and have discovered tipsfor improving the transition from traditional plumbing. Full details about the Evaluationsand Demonstrations are available at the links indicated below.Lincoln, Nebraska, Liberty Village (2006 PATH Field Evaluation)www.toolbase.org/fieldevalliberty• Five side-by-side, 1500-s.f. homes with same floor plan. Three were plumbed with PEXin a manifold, home-run configuration. Two were plumbed with conventional copper in atrunk-and-branch configuration.• Average labor time for plumbing rough-in in three PEX homes was 19.3 hours; copperrough in averaged 36.1 hours. All installation was performed by the same plumbingcrew.• Material costs (years 2005-2006) for PEX were about one-third higher than that forcopper: $505 for the PEX; $378 for copper.• Using an average labor rate of $21.50 per hour (including fringe benefits), total installedcost was 20% lower for the PEX system ($920) versus the copper system ($1,154).• Pressure and flow rate were measured at each fixture. The PEX system, in most cases,maintained a steadier pressure during simultaneous flow events.• Delivery time of hot water to the fixture farthest from the water heater was cut in half forthe PEX system compared to the copper system. Delivery time to closer fixtures wasabout the same in both systems.Denver, Colorado, Oakwood Homes (2002 PATH Demonstration Site)www.toolbase.org/fieldevaloakwood• Production builder of move-up homes implemented PEX and a plastic plumbing manifoldsystem• Cost savings ranged from $300 to $1,200 less than lowest copper pricing• Open-web floor joists facilitated installation of PEX and other technologies• Flushed main street line of sand and dirt before running water through manifold toprevent damage; installed valve upstream of manifold for this purpose• To ease overhead work, plumbers used stilts commonly used by drywall contractorsFreehold, New Jersey, K. Hovnanian (2002 PATH Field Evaluation)www.toolbase.org/fieldevalkhov• Production builder incorporated several advanced technologies in its “Idea House.”System was hybrid copper/PEX• Savings were approximately $200 versus conventional copper• Plumbers did not like transitioning between copper and PEX in this hybrid system;however, they agreed that system can save installation time• Code officials were reluctant to allow this technology• Plumbers learned to unroll the tubing before pulling through walls to prevent kinking;pulling tubing may require two workers—one to push, one to pull• Other lessons learned – tubing tends to become stiff in cold weather; crimping tool canbecome cumbersome in tight spacesPhiladelphia, Pennsylvania, Model reMODEL (1999 PATH Field Evaluation)www.toolbase.org/fieldevalremodel• Remodel of a Philadelphia row home demonstrating numerous technologies including ahome-run plumbing manifold with PEX piping• Cost savings was $700 compared to conventional copper pipe• Plumbing system installation took less than half the time to install copper pipingTECH SPECS >2

PEX Home-Run Plumbing SystemsMAKING THE SWITCHWhat is required to transition from your current building practices to using this technology?Consult local codes and manufacturer specifications – Although PEX is approved by all model codes, it may be restricted by localcodes. Therefore, it is useful to consult local codes for specific requirements before designing a PEX plumbing system. Obtain a systemdesign from the manufacturer, or use manufacturer-specified design tables.Optimize home designs – By considering the plumbing layout during the house design phase, many potential problems and inefficienciescan be avoided. The best plumbing design for performance and efficiency will minimize distancefrom the water heater to the fixtures. This can be accomplished by a few basic design principlesincluding: grouping fixtures (for example, stacked or back-to-back bathrooms); centrally locating thewater heater; using common holes and chases to facilitate installing bundles of pipingsimultaneously to reduce installation time; incorporating building elements, such as open-web floortrusses, which can dramatically decrease installation time; finding a central location for themanifold.Select piping system type – PEX piping can be configured in three ways: conventional trunk-andbranch,home-run, or remote manifolds. The type selected will depend on materials and installationcost, performance, and installer preference.Plan piping routing, manifold, and valve locations – Guidelines include: minimize fittings; groupfixtures together; minimize pipe lengths; select appropriate pipe diameter; bundle runs of piping; attransitions, provide solid attachment; and use color coded piping for simplicity.Work with your trade contractors –Trade contractors must be knowledgeable about the properinstallation of PEX and about issues such as manifold proximity to water heaters and other heatsources. Trade contractors need special crimping tools to make connections; one tool is neededfor each piping diameter. Crimping tools require periodic calibration. Therefore, it is important tocheck the crimps with a gauge to ensure they are adequately compressed. Tool costs can range upto $300. Short training videos and a design guide for PEX systems are readily available (seeResources, page 4).DEFINITIONSCross-linked Polyethylene (PEX) PipingA type of flexible plastic piping, suitable forhot and cold water supply due to itsresistance to temperature extremes,chemical attack, and creep deformationCentral Plumbing ManifoldThe control center for multiple attachmentsof hot and cold water flexible plastic pipingthat run to individual fixturesPolybutylene (PB) PipingA type of flexible plastic piping that lookssimilar to PEX, but experienced failuresand caused class-action lawsuits; nolonger used in U.S. marketsTECH CHECKBelow is a checklist of steps to follow if youdecide to implement this technology in yournext building project.□ Train trades. Although home-runsystems can be installed significantlyfaster than traditional plumbing, tradesmay require additional training and timefor proper installation.□ Consider an “open building” homedesign [optional]. Home-run plumbingsystems lend themselves to “openbuilding” or “disentangled” homedesigns, where utilities are separatedfrom each other and the building’sstructure. This design offers severalbenefits, including ease of futureupgrades and repair.□ Plan placement. Planning is requiredfor optimal placement of the manifold.The manifold should be installedsecurely on a flat surface, in anaccessible area that is near the waterheater, but at a proper clearance toavoid heat damage.□ Ensure proper handling andinstallation on site. Plastic plumbingmanifolds and PEX tubing both havespecific handling and usagerequirements to avoid damage fromsunlight, heat, freezing or puncturing.When getting started with home-runsystems, site supervision may berequired to ensure that theserequirements are met.□ Conduct pressure test.TECH SPECS >3

PEX Home-Run Plumbing SystemsFOOD FOR THOUGHTThis section provides some things to think about before switching to this building technology –make sure it’s the right choice for you.• PEX offers many advantages and is avery durable and rigorously testedmaterial. However, be informed aboutthe differences between PEX andpolybutylene piping. Past failures ofpolybutylene piping have creatednegative perceptions among manyconsumers and contractors aboutplastic piping. A quick primer on theissue can be found atwww.plasticpipe.org/pdf/pubs/notes/TN31-2004.pdf.• Remodelers and home builders mayfind that PEX is easier to work withbecause, unlike rigid pipe, flexiblepiping can be snaked through wallsand floors.• Proper planning and design will helpensure optimal system performanceand efficiency. Consult design guidesor manufacturer information for helpwith system design.• Familiarity with local codes is vital,especially if local code officials arenot yet familiar with PEX pipingsystems.• If your plumbing contractor isunfamiliar with PEX piping, beprepared for the additional time andtraining of trades. Manifolds and PEXpiping have several restrictions forproper handling; plumbers will needtraining to ensure that piping is usedcorrectly, and site supervision may beneeded to ensure proper installation.• Although labor savings typicallyresults in a lower installed cost thantraditional plumbing, material cost ishigher than that of rigid pipe.• In a home-run configuration, it isbeneficial to have an “open-building”design in which the home’s utilitiesare built to accommodate futurechanges. By “disentangling” plumbingfrom the other utilities, the buildingstructure, and interior walls,construction and future changes aresimplified.• Home-run configurations performbest with a centrally-located waterheater. Additional remote manifoldsTIP: An open-web floor joistdesign allows greater efficiencyfor PEX installations and canresult in a lower plumbing bid.may be needed to serve very largehomes with extra plumbing fixtures.• Not all PEX piping is compatible withmanifold systems, and special pipinginstallation tools may be needed.• A tee connection on the main supplyline upstream of the manifold willallow flushing of the street line toeliminate sand or dirt that collectsduring construction before runningwater through the manifold.The Partnership for Advancing Technologyin Housing (PATH) is dedicated toaccelerating the development and use oftechnologies that radically improve thequality, durability, energy efficiency, andaffordability of America's housing.Managed by HUD, the PATH partnershipincludes the homebuilding, manufacturing,insurance and financial industries, andFederal agencies concerned with housing.PATH addresses barriers to innovation,provides information on advanced buildingtechnologies, and advances housingtechnology research; making affordable,quality American homes a reality.For more information on the PATHprogram, visit www.pathnet.org.Tech Specs are Prepared for PATH by theNAHB Research Center.RESOURCESToolBase ServicesInformation on this building technologyand many others brought to you by PATHand the building scientists at the NAHBResearch CenterOnline installation videos are available forimmediate download and viewing underthe PATH Tech Inventory on ToolBasewww.toolbase.org/techpexAlso available is the Residential PEXWater Supply Plumbing Systems DesignGuide atwww.toolbase.org/pexdesignguideAmerican Society of PlumbingEngineers (ASPE)8614 Catalpa Ave.Suite 1007Chicago, IL 60656773.695.9007www.aspe.orgPlastic Pipe and Fittings Association800 Roosevelt Road, Bldg C, Suite 20Glen Ellyn IL 60137630.858.6540www.ppfahome.orgPlastics Pipe Institute105 Decker Court, Suite 825Irving TX, 75062469.499.1044www.plasticpipe.orgTECH SPECS >4