ALUMINUM The total solution for sustainable, strong and efficient commercial building design

Framing Materials Used in Nonresidential Construction (2011)Framing Type Curtain Wall Storefront Site Fabricated Shop Fabricated Overall

Aluminum 100% 98% 100% 55%89% Wood - 1%-20%5%

Other - 1%-25%6%

Aluminumiswidelyusedinbothcommercialandresidentialconstructioninapplicationssuchaswindowanddoorframes,exteriorcladding,storefront,curtainwall,shadingdevicesandskylights.In2009,accordingtotheAluminumAssociation,thebuildingandconstructionmarketaccountedfor2.13billionpoundsof netaluminumshipments,whichrepresentsnearly12percentof totalshipmentsandisthethirdlargestNorthAmericanmarketforaluminum.

AccordingtotheAAMA/WDMA 2011/2012 Study of the U.S. Market for Windows, Doors and Skylights,aluminumaccountedfor89percentof thecommercialmarketsharein2011.(Seechartbelow.)

Aluminumframescontainingathermalbarriercontinuetogrowinpopularity(47percent)followingthetrend of increasing energy efficiency standards. In 2011, theshareof aluminumframeswithoutthermalbarriersrepresentedapproximately43percentof themarket.Althoughaluminumframeswiththermalbarrierswerehistoricallyusedmostcommonlyinnorthernregions,morestringentenergycodeshavecausedthistechnologytogainmarketshareacrosstheUnitedStates.Thermalbarriersareoftenachievedviauseof polyamideinsulatingstripsorpolyurethanepouredanddebridgedmethods.

Additionally,in2011,aluminumaccountedfornearly40percentof thenonresidentialentrydoormarketand24percentof thenonresidentialinteriordoormarket.Aluminumframedskylightswerethedominant(87percent) configuration on the market in 2011.

ALUMINUM MARKETSHARE

Framing Type Curtain Wall Storefront Site Fabricated Shop Fabricated Overall

FREEDOM OF DESIGN

Aluminumanswersthecall.Innovativeconstructionmaterialsandproductsgivearchitectsthescopeandabilitytoimplementunconventionalsolutionsinthedesignanddetailingof buildingsandotherstructures.Aluminumextrusions offer a number of benefits relative to alternative materials and processes for the architect during the designstage.

Herearesomeof thecharacteristicsinherentwhendesigningwithaluminumextrusions:

Lightweight:Aluminumisaboutone-thirdtheweightof iron,steel,copperorbrass,makingaluminumextrusionseasiertohandle,lessexpensivetoshipandanattractivematerialforuseinapplicationswhereweightreductionisapriority.

Strong:Aluminumextrusionscanbemadeasstrongasneededformostapplicationsand,duetothenatureof theextrusionprocess,thestrengthcanbeconcentratedwhereitisreallyneededbyincludingvarying wall thicknesses and internal reinforcement in the profile design.Cold-weatherapplicationsareparticularlywellservedbyextrusions,asaluminumbecomesstrongerastemperaturesfall,andinwarmweatherapplications,aluminumwillnotwarp.Also,aluminumwill not rot, peel or flake.

High strength-to-weight material:Aluminumextrusions’uniquecombinationof highstrengthandlowweightmakesthemidealforapplicationslikecurtainwall,storefrontandcommercialwindows.

Resilient: Aluminum combines strength with flexibility and can flex under loads or spring back from the shock of impact.

Corrosion resistant:Aluminumextrusionsofferexcellentcorrosionresistance.Theydonotrust,andthealuminum surface is protected by its own naturally occurring oxide film, a protection that can be enhanced by anodizing or other finishing processes.

Noncombustible and Nontoxic:Aluminumdoesnotburn,andevenatextremelyhightemperatures,doesnotproducetoxicfumes.

Reflective: Surface treatments can produce high reflectance on aluminum components, making aluminum extrusionattractivefortoday’scommercialapplications.

Seamless:Complexshapescanberealizedinone-pieceextrudedaluminumsectionswithouthavingtorelyonmechanical joining. The resultant profile is typically stronger and less likely to loosen or leak over time

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Aluminumextrusionsoffera number of benefits relative toalternativematerialsandprocessesforthearchitect

duringthedesignstage.

ALUMINUM MARKET

Easily tailored: While there are a variety of standard extrusion profiles available, the ability to design a profile to meet specific functional, aesthetic and manufacturability objectives makes aluminum extrusions a preferred element in manyproductsolutions.

Quick-to-market:Toolingforaluminumextrusionisrelativelyinexpensiveandgenerallyhasshortleadtimes,whichfacilitatesprototypedevelopment,testingandproductlaunch.

Easy to fabricate and assemble:Effectivedesignof aluminumextrusionscangreatlysimplifysubsequentfabricationandassembly,andthereareawidevarietyof fabricationprocessesthatareroutinelyemployedintheproductionof extrusion-basedcomponentsandassemblies.

Sustainable: Aluminum can be recycled infinitely with no degradationof mechanicalproperties.Aluminumextrusionsareoftenproducedwithhighrecycledcontent—withoutcompromisetoaestheticsorfunctionality.Further,extrusions’inherentpropertiesof light weight, strength and design flexibility leads to significant in-use benefit to the environment.

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FREEDOM OF DESIGN

Aluminumextrusions’uniquecombinationof highstrengthandlowweightmakesthem

idealforapplicationslikecurtainwall,storefrontandcommercial

windows.

FREEDOM OF DESIGN

FINISHES AnodizingAnodizing successfully combines science with nature to create one of the world’s most durable metal finishes.Anodizingisanelectrochemicalprocessthatthickensandtoughensthenaturallyoccurringprotectiveoxideonaluminum.Theresultingfinish is the second hardest substance known to man, second only tothediamond.Thischaracteristicmakesanodizedaluminumanexcellentchoiceforuseindoorsandrailings,storefronts,commercialwindowsandcurtainwallwherehardness,abrasionresistance,corrosionresistanceandUVresistancepropertiesarevital.

Unlike other finishes, anodizing highlights aluminum’s metallic appearance.Becauseitisanintegralpartof thesubstrate,theanodiccoatingresultsinahardanddurablesubstanceprovidingexcellentwearandabrasionresistancewithminimalmaintenance.Anodizedaluminumcanbestrippedbacktorawaluminumthroughatraditionaletchprocessandthencanbepaintedorre-anodized.Etchingisanimportantstepduringtheanodizingprocess.Etchingisdesignedtodissolveathinlayeronthesurfaceof thealuminumtodevelopa smooth uniform finish. A recent alternative to traditional caustic etchinghasbeenintroduced,whichistypicallyreferredtoas“acidetching.”Thisacidetchingprocessisamoreeco-friendlyetchprocess.Thisnewetchprocesscreatesanaestheticallyappealing,“frostier”matte finish that improves the ability to hide small defects, such as extrusiondielinesandmildscratches,thatmayoccuronthealuminumsurfaceof architecturalproducts.Althoughneitherconventionalcausticnoracidetchremovesallirregularitiesinthealuminum,acidetchdoesabetterjobof concealingthem.Thisgivesthematerialamore architecturally desirable, aesthetic finish using either primary or secondary(recycled)billet.

Thepurposeof anodizingistoformalayerof aluminumoxidethatwillprotectthealuminumbeneathit.Thealuminumoxide layer has a much higher corrosion and abrasion resistance than raw aluminum. A typical anodized finish used in the architecturalindustryiscalled“two-stepelectrolytic.”Theactualanodizingandcoloringof thealuminumoccurinseparatestepsof theprocess.Theanodizingsteptakesplaceinatankthatcontainsasolutionof sulfuricacidandwater,whilethecoloringsteptakesplaceinanotherelectrolytictank.

Value:Anodizinghasalowinitialcost,pluslowmaintenancecost,offeringsuperblife-cyclevalue.Durability:Anodizingoffersexceptionalresistancetoabrasionbecausetheanodicoxideisintegraltothe

aluminumsubstrate;itsimplycannotchiporpeel.Color Stability:Anodicoxideisunaffectedbyultravioletlightraysandisresistanttosalts,makinganodizinga

colorfast finish that is repeatable and reliable. Maintenance: Anodized surfaces will not show fingerprints. It resists scratching during value-added

processingsuchasfabrication,installation,cleaningorotherhandling.Soiledanodizedaluminummaybecleanedwithsimplesoapandwater.

Aesthetics:Anodizingyieldsadeep,richmetalliclusterandisavailableinawiderangeof glossandcoloralternatives.

Environmental Safety:Anodizingisasafeprocessthatisnotharmfultohumanhealth;ithaslittleenvironmentalimpactandanodizedaluminumisfullyrecyclable.

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The benefits of anodizing are many.

Liquid and Powder CoatingLiquid and powder coating have many chemistry options that allow an almost unlimited color and gloss range as well as cost and performance qualities.

Liquidandpowdercoatingaremultistepprocessesthatcoatandprotectthealuminum.Theynotonlyprotectthealuminumsubstratebutcanenhancetheappearanceinmanydifferentways.Theprocessstartswithamultisteppretreatmentprocessbycleaningandetchingthealuminumthenusingeitherachromeconversionorchromatefreepretreatment.Thisprocessnotonlywillallowthecoatingstoadheretothealuminumbutalsohelptoprotectthealuminumfromcorrosion.Thecleaningandcoatingof thealuminumcanbeusedonextrusionsthatcontainbothprimaryandsecondary(recycled)billetandwillcovermanysmalldefectsasaresultof theextrudingprocess.

Liquid and powder coatings can be applied with technologies to meet all three performance specifications: AAMA 2603, 2604and2605.

TheprocesscanbeanythingfromasinglecoatliquidorpowdertoafourcoatPVDFliquidusingaprimer,barriercoat,colorcoatandclear.Eachof theseoptionshasadvantagesdependingontheenduseorapplication.Powdercoatingprovidesexcellenthardnessandmarresistancewhileliquidcanutilizeaprotectiveprimerandmetallictopcoatstoachievemanyuniqueappearances. Fluoropolymer systems have been the first choice in the monumental construction curtain wall market for many yearsandcontinuetobeconsideredthepremiersystemforthisapplication.

FINISHES

Durability:Paintisavailableinnearlyanydurabilityrequiredfromextremecorrosionprotectionof somechemistriestocolorandglossstabilityinotherslastingfordecades.

Color Stability: Many paint systems have durability that far exceeds the weathering specifications of AAMA 2605withminimalcolorchangeafter10years.

Maintenance: Minimal maintenance is required with only mild detergent and a clean water rinse to maintain appearance.

Aesthetics:Optionsarenearlyunlimitedfromwhitetoblack,softmutedcolorstoextremelyintensereds,brightsilverstoiridescentpearlcoatsallcanbeachievedwithpaint.

Environmental Safety:PaintingandpowdercoatingisasafeandenvironmentallysoundprocesswithoptionsrangingfromazeroVOCpowdertoalowVOCliquid.High-performancecoatinglinesusethelatesttechnologytocaptureanddestroytheVOCs,makingitamoreenvironmentallyfriendlyprocess.

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The benefits of painting are many.

THERMAL BARRIERS IN ALUMINUMFENESTRATION SYSTEMSAlthoughaluminumhasamultitudeof positiveattributes,italsohasarelativelyhighthermalconductivityrequiringtheincorporationof thermalbarriertechnologyinfenestrationsystemsinmanyclimatezones.

What is a thermal barrier?Thermalbarriersaremadefromresinsthatareincorporatedinto the aluminum profiles, separating the interior and exteriorsurfaces.Thesematerialshavethermalconductivitiesthatare500-1300timeslowerthanaluminumthuscreatinga “thermal barrier” in the profile systems in which they are used.Thisbreakinthethermalpathisnecessarytoinhibitcoldorhotexteriortemperaturesfromtransferringthroughthealuminumtotheinsideof thebuildingwhilemaintainingthe structural integrity of the aluminum profiles. While originallyusedincoldernorthernclimates,thermalbarriersareequallyimportantinhotclimatestoreduceheattransferinair-conditionedbuildings.

Thermal barriers reduce heat loss or heat gain through aluminum.Thermal barriers dramatically improve the U-value characteristics. (See chart below.)Thermal barriers dramatically improve condensation resistance. Thermal barriers are essential for energy conservation.

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Thermal Barrier Attributes

Energy-Efficient Fenestration Timeline for Thermally Improved Extrusions

AAMA 1503-09, Voluntary Test Method for Thermal Transmittance and Condensation Resistance of Windows, Doors and Glazed Wall Sectionsiscommonlyusedandwidelyacceptedinthecommercialindustryfordeterminingaproduct’scondensationresistancefactor(CRF).ACRFtoolisalsoavailableontheAAMA website.

InNorthAmerica,architects,engineers,developersandbuildingownershavetwoprimaryoptionswhenitcomestothermalbarriertechnology:polyurethaneandpolyamide.Althoughthesetwosystemsperformsimilarfunctions,theyaredifferentinthewaytheyperformandthewaytheyareincorporatedintofenestrationproducts.

Polyurethane has low thermal conductivity, maximizing thermal efficiency in the smallest possible separation.Polyurethanesystemsareverystrong,allowingforwiderspans.Polyurethanesystemsarecosteffectivetoproduce.

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This process starts with a single extruded aluminum profile.Amechanicallockmaybeaddedtotheextrusionstoimprovestructuralstrength.Structural thermal barrier polymer is placed into the thermal cavities of the aluminum profile.Once cured, the bottom of the profile is removed in a process called debridging.The result is an aluminum profile containing a structurally strong thermal barrier separating the interior and exterior surfacesof thealuminum.

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Polyurethane poured and debridged systems

Primary benefits of polyurethane systems

THERMAL BARRIER OPTIONS

Polyamide thermal barrier systems

Thisprocessbeginswithtwoseparateextrusions;oneinteriorandoneexterior.The aluminum framing members are knurled and polyamide strips are inserted into the aluminum profiles.Thecompositeextrusionsarethencrimpedtosecurethepolyamidestrips,thusproducingastructuralcomposite.

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Two-color finish options are simple and cost effective due to the fact that two separate profiles are used in the process.Flexibledesignsallowforincorporationof windowcomponentsintothethermalbarriersuchasfoam,gasketsorglassstops.Wideseparationof thealuminumallowsforlowerU-Factors.

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Primary benefits of polyamide

Thermal barrier windows, storefronts, curtain wall systems and skylightsSincetheirinceptioninthe1970s,theincorporationof thermalbarriersincommercialfenestrationsystemshasbeen instrumental in saving millions of barrels of oil and other natural resources. As energy-efficient building design continuestoplayakeyroleintheshapingof ourcities,thermalbarrierswillplayanimportantroleinthesedesignconsiderations.

SUSTAINABILITY &RECYLABILITY

Aluminumissustainable.Aluminumisanon-combustibleandnaturalmaterial.

ItisthethirdmostabundantelementintheEarth’scrust(intheformof bauxite),nexttooxygenandsilicon.

Aluminumisenvironmentallyfriendlyandnon-toxic,evenwhensubjectedtohightemperatures.Itis100 percent recyclable regardless of any applied finish andcanberecycledrepeatedlywhilestillretainingthesamematerialphysicalproperties.AccordingtoAluminumAssociationdata,75percentof allthealuminumeverproducedisstillinservicetoday.A2004studybyDelftUniversityof Technologyfoundthat“95percentof thealuminumusedinB&Cmarketisrecycledatthestructure’send-of-life.”Becauseof this,andthedesirabilityof thehighscrapprice,itreducesitsenvironmentalimpactbynotbeingdeposited into landfills. Recycling aluminum takes only five percent of the energy required to make primary aluminum,seriouslyreducingGHGemission.

Equivalencyof about70millionbarrelsof crudeoilissaved—enoughoiltofeedU.Sconsumptionforthreedaysornearlyonedayof theworld’soilsupply.Approximately2.4millionmeters2of landissaved.More than 45 million tons of fresh and sea water use is avoided—enough watertoprovidefortheneedsof NewYorkCity’s8millionpeoplefor10days.Approximately7.5milliontonsof solidwasteisavoided.About27milliontonsof CO2greenhousegasemissionsisavoided—equivalent to eliminating five large (1,000 MW) coal-fired power plants.

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Benefits of Aluminum Recycling (Annually)

COST ADVANTAGES & TOOLING COSTS

Aluminum extruded profiles can range from simple shapes to very complex, intricate shapes. Most architectural profiles range from simple to sophisticated as well. More than 80 percent of the aluminum extrusions used in window, door store-front and curtain wall applications fit within a 10-inch circumscribing circle. The extrusion tooling required to produce these shapes is very budget friendly, ranging from $500 for simple, solid shaped profiles, up to $5,000 for a complex, multi-voidhollowshape.Typicallead-timesforthistoolingrunfromtwotothreeweeks.Aluminumextrusiontoolingcanalsoberevised, in many cases, when minor changes in the profile design require modification, which is a real advantage in manag-ingcosts.

Othertypesof toolingusedtomanufacturefenestrationshapescanbeverycostly,couldhavelongerleadtimesandmay be difficult to modify.

Vinyl Extrusion Tooling $1,500andup 6-16weeks

Injection Mold Tooling $25,000andup 20weeksorlonger

Roll Form Tooling $25,000andup 16-24weeks

Die Cast Tooling $30,000andup 20weeksormore

Stamping Tooling $10,000andup 8-20weeks

Tooling Types Cost Lead Times

Source: AEC Extrusion Manual 4th edition page 24

STRENGTH TO WEIGHTRATIOAluminumisalightweightmetal(lowdensity),weighingaboutone-thirdasmuchassteel.Thishighstrength-to-weightratiomeansthatlessof abuilding’sstructureisspentsupporting its own weight. Buildings in seismic zones benefit evenmorefromthisreducedweight,sinceseismicforcesareproportionaltotheweightof thestructure.Themechanicalpropertiesremainunchangedunder250oF,andevenimproveintemperatureslessthan0oF,intermsof elasticmodulus/stiffness.Certainalloy/tempercombinationsproducestrengths as high as 80,000 psi to 90,000 psi or more. Mild steelstrengthis44,000psi.

Aluminumisresistanttotimeandtemperature,impervioustohumidity,warpingorbecomingbrittle.Also,itdoesn’tabsorbmoisture,swell,shrink,split,crack,rotorrust,resultinginalongerservicelife.

CONCLUSIONAluminumisanexcellentconstructionmaterialforuseinwindows,storefrontsandcurtainwallaswellaswindow-wall,doorandskylightsystemsbecauseitislightweight,strongandeasytoprocess.Aluminumfenestrationsystemsareavailableinanendlessassortmentof colors,shapesandsizes to fit any design specifications. The fact that aluminum can be recycled an infinite number of times without loss of structuralproperties,andforafractionof thecostof producingvirginaluminum,it’seasytoseewhyaluminumhasbeenthematerialof choiceincommercialconstructionforsomanyyears.

AAMA/WDMA 2011/2012 Study of the U.S. Market for Windows, Doors and Skylights

AAMA 1503-09, Voluntary Test Method for Thermal Transmittance and Condensation Resistance of Windows, Doors and Glazed Wall Sections

AAMA 2603, Voluntary Specification, Performance Requirements and Test Procedures for Pigmented Organic Coatings on Aluminum Extrusions and Panels

AAMA 2604, Voluntary Specification, Performance Requirements and Test Procedures for High Performance Organic Coatings on Aluminum Extrusions and Panels

AAMA 2605, Voluntary Specification, Performance Requirements and Test Procedures for Superior Performing Organic Coatings on Aluminum Extrusions and Panels

TheAluminumAssociation

AluminumExtrudersCouncil

Aluminum Material Council Web Page

AAMA Aluminum Technical Documents

References

AMC-1-13

Additional Resources