Alumasc Vtherm: Vacuum Insulated System for Inverted Roofs
www.alumascroofing.co.uk
NEW WAVE INSULATION SOLUTIONS FOR PROTECTED MEMBRANE FLAT ROOFS AND GREEN ROOFS
• Rigid vacuum insulation panel with optimal performance – aged design value thermal conductivity 0.007 W/m.K
• Insulationperformanceuptofivetimesbetterthan commonly used insulation materials
• Ideal for projects with shallow construction depth
• Protectsthewaterproofingmembrane
• Minimalwaterabsorption
• Resistant to freeze / thaw cycling
• Ideal for green roof applications
• Panelsareover90%recyclable(byweight)
• Resistant to the passage of water vapour
• Idealfornewbuildandrefurbishmentprojects
• Non-deleterious material
Microporous Core
Protective Wrap
Multi-Layer Foil
1. Alumasc Separation Layer
2. Alumasc XPS Insulation
3. Kingspan Optim-R Vacuum Insulation Panel
4. Protective Rubbercrumb Layer
5. Hydrogard Protection Layers Reinforced,modifiedbitumenprotectionsheets
6. HydrotechMM6125Waterproofing Highperformancebituminousstructuralwaterproofing
7. FlexFlashReinforcementLayers OptionsforFlexFlashForFlexFlashUN
6. HydrotechMM6125Waterproofing Highperformancebituminousstructuralwaterproofing
8. Alumasc Bitumen Primer
9. Structural Concrete
TYPICAL SYSTEM BUILD UP OPTION
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INTRODUCTION
The Problem
Whetheryouaredealingwithanewbuild,orupgradingtheroofsofexistingbuildings,theremaybearequirementtoachievelowU-valueswiththethinnestpossibleroofbuild-up.
Withnewbuildapplications,regulatoryrequirementsareevermorestringent,whileeconomicfactorsandtheneedtoconserveenergymeansthatenergyefficiencyisthehighestpriority.Oneofthemoreeffectiveapproachesistoimprovethermalperformancewhilekeepingtheoverallconstructionasthinaspracticable.Highperformanceinsulationproductsareavailablethatfulfilsome,butnotall,oftheregulatoryandperformancerequirements,particularlyinapplicationswherethereiscallforathinnerinsulationproduct.
Inrefurbishmentprojects,therecanbeanevengreaterneedtokeeproofbuild-upsasthinaspossible.Internalspacemaybeatapremium,ortheremaybelittleornospaceavailableforinstallingnewroofinsulation-forexampleinbuildingswherethereareplanningheightrestrictions.
TYPICAL CONSTRUCTIONS AND U-VALUES
Assumptions
U-valuesarecalculatedunderamanagementsystemcertifiedtotheBBASchemeforAssessingtheCompetencyofPersonstoUndertakeU-valueandCondensationRiskCalculations,usingthemethoddetailed in BS / I.S. EN ISO 6946: 2007 (Building Components and buildingelements.Thermalresistanceandthermaltransmittance.Calculationmethod),andusingtheconventionssetoutinBR443(ConventionsforU-valuecalculations).ThemethoddetailedinpartD4.2ofBS/I.S.ENISO6946:2007hasbeenusedtotakeaccountoftheeffectofahighperformancenon-woven,polyethylenemembraneovertheinsulation,andan(fx)factorof≤0.012hasbeenassumed.
Theyassumeanominalselectionofpostcodes,selectedtorepresenttheinfluenceofgeographicalvariationsinrainfallonthermalperformance.
Theceiling,whereapplicable,istakentobea3mmskimcoated12.5mmplasterboardwithacavitybetweenitandtheundersideofthedeck.
Please Note:
• For the purposes of these calculations the standard of workmanship has been assumed good, and therefore the correction factor for air gaps has been ignored.
• Thefiguresquotedareforguidanceonly.AdetailedU-value calculationandacondensationriskanalysisshouldbecompleted for each project.
• Ifyourconstructionisdifferentfromthosespecified,and/orto gainacomprehensiveU-valuecalculationalongwitha condensationriskanalysisofyourproject,pleaseconsultthe AlumascTechnicalDepartmentforassistance(seerearcover).
• For the purposes of these calculations, the bridging effect of the infillpanelhasbeentakentobe15%.
The Solution
TheAlumascVThermVacuumInsulatedSystemhasbeendevelopedtohelpsolvesuchproblems.AlumascVThermisaninvertedroofsystemincorporatingtheinnovativeKingspanOPTIM-Rinsulationpanelsystem.Thiscomprisesrigidvacuuminsulationpanelswithamicroporouscore,whichisevacuated,encasedandsealedinathin,gas-tightenvelope.Theresultisoutstandingthermalconductivityinthethinnestpossibleinsulationsolution.ThevacuuminsulationpanelsintheVThermSystemareaugmentedbyrigidextrudedpolystyreneinsulationinfillpanels,whichcanbecuttofitaroundproblemareassuchasrooflightsorventilatorkerbs.
Inretrofitapplications,theAlumascVThermVacuumInsulatedSystemistheidealsolutionforareaswherelackofspacecouldpreventupgradingoftheinsulation,andinnewconstruction,AlumascVThermcanenhanceU-valuesinareaswherethermalperformancewouldotherwisebediminished.
TheKingspanOPTIM-Rpanelshaveanagedthermalconductivityof0.007W/m-K,andhaveaninsulatingperformanceuptofivetimesbetterthancommonlyusedinsulationmaterials.
Aboveall,theAlumascVThermVacuumInsulatedSystemsolvestheproblemofinsulatingareaswherethereisalackofconstructiondepth.
DESIGN SERVICE
Bespoke Project Design
Alumascoffersafulldesignservice,whichmaximisestheratioofVacuumInsulationPanelstoinfillpanels.Wewilldesignthepanellayoutquicklyandeffectively,readyforclientapproval.
Eachproject-specificlayoutwillshowthesize,numberandlocationoftheVacuumInsulationPanelsandsimilardataforanyinfillpanelsthatmayberequired.
Formoredetailspleasecontactourtechnicalteamon 01744 648 400.
Kingspan OPTIM-R produced at Kingspan Insulation’s Pembridge manufacturingfacilityiscertifiedtoBES6001(FrameworkStandardfortheResponsibleSourcingofConstructionProducts)‘VeryGood’.
Linear Thermal Bridging
Makeprovisiontolimittheeffectsofcoldbridging.Ensurethatrooflightorventilatorkerbs,gutters,etc.areadequatelyinsulatedwithAlumascUpstandBoard.Similarlyinsulatearoundtheperimeteroftheroofontheinternalfaceofparapets.
Maintainaminimumdistanceof300mmbetweenthetopoftheinsulationupstandandthebottomofthehorizontalroofinsulation.Carrywallinsulationupparapetsashighastheflatroofinsulationupstand.PleasecontacttheAlumascTechnicalDepartmentforfurtheradvice(seebackcover).
Sample Specification Clause
SpecifytheVacuumInsulationPanelelementoftheVThermsystemsasfollows:
TheroofinsulationshallbetheAlumascVThermVacuumInsulationPanel……mmthick:comprisingarigidvacuuminsulationpanelwithamicroporouscore,whichisevacuated,encasedandsealedinathin,gas-tightenvelope.TheproductshallbemanufacturedunderamanagementsystemcertifiedtoISO9001:2008,ISO14001:2008, BS OHSAS 18001: 2007, and ISO 50001: 2011 and installed inaccordancewiththeinstructionsissuedbyAlumascRoofingSystems.
Protected Membrane Roofs
ThisliteraturedemonstratestheAlumascVThermVacuumInsulatedSystemusedasacomponentofprotectedmembraneroofingsystemswithagravelorpayingslabfinish,andasacomponentofgreen roofs.
Inprotectedmembraneroofingsystemstheinsulationislocatedabovethewaterproofing,aconstructionthatoffersseveraladvantagesovertraditionalwarmflatroofs.
• Becausethewaterproofingsystemisnotexposedtothe elements,itcanbeexpectedtohavealongerlifethannon- protectedmembranesystems.TheVThermSystemisprotected frommechanicaldamage,UVdegradation,anddailyandseasonal temperatureextremes.
• No condensation risk.
• TheroofachievesanEXT.FAAfireratingwithgravelballastand pavingslabprotectivefinishes.
• Insulationcanbeliftedtoallowinspectionofthewaterproofing.
• Additionalinsulationcanbeaddedatalaterdateifrequired.
• Successfulinstallationoftheinsulationisnotaffectedbyweather conditions.
Design Loads & Roof Structure
Thesuitabilityofanystructuretoacceptdesignloads–includingtheincreaseddeadloadfromballast,snowandrooftraffic–shouldbeverifiedinaccordancewithBS6399-3:1988(Loadingforbuildings.CodeofPracticeforimposedroofloads).
Theadditionalloadfromballastcanbeconsiderable.
Ballast Layer Dead Load
50 mm thick paving slabs 125 kg/m2
Gravel (16–32 mm diameter) 16 kg/m2 per 10 mm depth
Intensive green roof 180 – 500 kg/m2
Semi–intensive green roof 120 – 200 kg/m2
Extensive green roof 60 – 150 kg/m2
Thelayerofballastresistsupliftfromwind,preventsflotationoftheboardsafterheavyrain,preventsUVdegradationoftheboards,andgivestherooftherequiredexternalfireperformancerating.
DESIGN CONSIDERATIONS
Wind Loads
Ensurethattheresistancetowindupliftofthewaterproofingsystem,insulationandballastisassessedinaccordancewithBS6399-2:1997(Loadingsforbuildings.CodeofPracticeforwindloads)orBS/ I.S. EN 1991-1-4: 2005 (National Annex to Eurocode 1 Actions on structures.GeneralActions.WindActions).BREDigest295givesspecificdesignguidelinesforloose-laidinsulationsystems.
Inshelteredexposurezones,oronbuildingsofupto10storeys,theself-weightofaminimum50mmgravelballastlayer(minimum80kg/m2),installedoveranon-wovenpolyethylenemembrane,isgenerallysufficienttoensurethatboththeinsulationboardsandwaterproofingsystemremainstableunderthefulldesignload.
Inmoderateexposurezones,oronbuildingsofupto10to15storeys,a50mmgravelballastspecificationisgenerallysufficient,withtheperimeteradditionallyloadedwith50mmthickpavingslabs.
Seekspecialistadviceforsevereexposurezonesortallbuildingsover 15 storeys. Refer to BRE Digest 311 (Wind scour of gravel ballast onroofs).
FlotationTheballastspecificationsdetailedinthe‘WindLoads’section(above)willbesufficienttopreventflotationoftheinsulationboardsafterheavyrain.
Falls
ProtectedmembraneroofingsystemsincorporatingtheAlumascVThermVacuumInsulatedSystemcanbelaidonroofstozerofalls,allinaccordancewithHydrotechBBAcertificate90/2431.
RAINFALL FACTORS
Rainfall Analysis
TherequirementsofBS/I.S.ENISO6946:2007partD.4.2(Correctionduetowaterflowingbeneaththeinsulationandthewaterproofingmembrane)dictatethatinvertedroofconstructionsaresubjecttoageographicalrainfallanalysis.Thecoolingeffectofrainwaterflowingbetweenandbeneaththeinsulationboards,canmeanthatgreaterthicknessesofinsulationarerequiredtomeetdesiredU-values(particularlyinlocationsthatreceivehighlevelsofrainfall).
Theuseofahighperformancenon-wovenpolyethylenemembraneovertheinsulationcandramaticallyminimiseheatlossbyreducingtheamountofrainwaterthatflowsbetweentheinsulationboards.Thisreductioninrainwaterflowisrepresentedbytheinfiltration(fx)factorofthemembrane.Thefxfactorofamembraneisfall(gradient)specific,andanfxfactormeasuredonafallcannotbeusedtorepresenttheperformanceofamembraneifinstalledhorizontally.
Drainage
Whenassessingthenumberandtypesofrainwateroutlet,refertoandensurecompliancewithBSEN12056-3:2000(Gravitydrainagesystemsinsidebuildings.Roofdrainage,layoutandcalculation).Therainwateroutletsshouldallowrainwatertobedrainedfromtheroofsurfaceatboththemembranelevelandtheuppersurfacelevel.
Types of Green Roof
Therearethreeprincipaltypesofgreenroof.
Extensive green roofs - Havearelativeshallowgrowingmedium,withlow-maintenancevegetationsuchassedumandgrass.Theyarelightweight,andsimpletodesign,constructandmaintain.Theyarenotsuitableforregularlytraffickedareasorrecreationalactivity.Extensivesystemshaveaestheticappealandofferecologicalbenefits.
Semi–intensivegreenroofs-Haveadeepergrowingmediumandsupportvegetationsuchasgrasses,perennialsandshrubs.Theycanaccommodatelimitedaccessformaintenanceandlightrecreation.
Intensive green roofs - Haveasignificantlydeepergrowingmediumandsupportawiderangeofflora,includinggrasses,shrubsandsmalltrees.Theyresemblenormalgardensasregardscareandmaintenance, and can be used for recreational activities.
Semi-intensiveandintensivegreenroofsrequirecarefuldesign,andincorporatethefollowingelements:
Growing Medium
Specialist,lightweightmixturesareavailable,incorporatingfiltration,drainage and moisture retention functions.
Drainage Layer
Normallyconsistingofacastellatedplastic(HDPE)sheeting,withfiltrationmembrane.Thislayerpromotestherapidremovalofexcessrainwaterfromtheroof,therebyavoidingsaturationofthegrowningmediumandassociatedincreaseinweight.
Root Barrier
Therootsofgrowingplantscanseriouslydamagewaterproofmembranes,bygrowingintoanysmallcracks,lapjoints,etc.Alumascroot-resistantprotectionsheetisadheredtotheHydrotechmembrane,withalljointssealedbytorching,andmustbecontinueduptheverticalfacesofupstands.
SITEWORK
Roof Waterproofing
TheAlumascVThermVacuumInsulatedSystemshouldbeusedoverthehydrotechhotliquidappliedwaterproofingsystem.
Water Vapour Control
Protectedmembraneroofsareinherentlysafeasregardscondensationrisk.Toassesstheriskofinterstitialcondensationina roof construction, refer to BS 5250: 2002 (Code of Practice for controlofcondensationinbuildings)orBS6229:2003(Flatroofswithcontinuouslysupportedcoverings.CodeofPractice).
Green Roofs
Benefits
Greenroofsareanalternativetoastandardprotectedmembraneroofandoffermanyadvantages.However,precisedesignanddetailingarerequired.
Greenroofscan:
• Reducelevelsofdustandimprovehumidity.
• Provideahabitatattractivetowildlife.
• Create areas for recreational activities.
• Retainrainfallandthereforepreventwatersurgesintothe drainage system.
• Improve sound insulation.
• Provideafinishthatisvisuallymoreattractivethangravelor paving slab ballast.
WATERPROOFING
BeforeinstallingtheAlumascVThermVacuumInsulatedSystem,itisessentialtoensurethatthewaterproofingsystemhasbeeninstalledcorrectlyandthattheroofiswatertight,cleanandleaktested.Thesurfaceofthewaterproofingshouldbesmooth,flatandfreefromprojections.
Insulation Boards
• UsearubbercrumbprotectionlayerundertheAlumascVTherm VacuumInsulatedSystem.Forfurtherinformationpleasecontact theAlumascTechnicalDepartment(seebackcover).
• LayVThermpanelsbreakbondedwherepracticable,withjoints lightlybutted.Ensuretherearenogapsatabutments.
• WhererunsofAlumascVThermVacuumInsulatedSystempanels donotaccuratelyfitthedimensionoftheroof,useinfillpanelsto makeupthedifference.Infillpanelsmustbethesamethicknessas theVThermpanels.
• InstalltheAlumascExtrudedPolystyreneoverlayassoonas possibletoavoidexposingtheAlumascVThermSystemtodirect foottraffic.
• Layanyinfillpanelstoabuttheroofperimeterandanyupstands orroofpenetrationssuchasdrainageoutlets,totakeaccountof building tolerances.
• Insulateupstandsattheroofperimeterandtheinternalfaceof parapets.
• Maintainaminimumdistanceof300mmbetweenthetopofthe insulationupstandandthebottomofthehorizontalroof insulation.
• TakeparticularcarewheninstallingAlumascVThermSystemsin windyconditions.
Alumasc Separator Sheet
• AlwayslayAlumascSeparatorSheetovertheinsulationpanels.
• Whereonerunofseparatorsheetmembranelapsanother, maintainaminimum300mmsideandendoverlaps,inthe direction of drainage.
• Turnuptheseparatorsheetmembraneattheedgeoftheroof insulationandsecureitundertheflashing.
Gravel Ballast
• Installtheballastlayerassoonaspossibletoensurethatthe AlumascSeparatorSheetisalwaysprotectedandnotdamagedby excessiveheatbuild-uporhighwinds.
• Gravelballastshouldbewashed,roundedto20-40diameter,and laidtoaminimumofdepthof50mm.
• Thediameterofthegravelissignificantbecauseasizeof20- 40mmhasbeenfoundtoofferthemosteffectiveresistanceto windscour.RefertoBREDigest311foradvice.
General
•DonotusetheAlumascVThermVacuumInsulatedSystemin associationwithsolvent-basedadhesivesystems.Avoidexposure oftheVThermsystemtonakedflamesorexcessiveheat.
Cutting
•DonotcutorpenetratetheVacuumInsulationPanels.Ensure thesubstrateisclean,dryandlevel,andfreefromsharpobjectsor edges.
• Cuttheinfillpanelswithafine-toothedsaw,orbyscoringwitha sharpknifeandsnappingtheboardoverastraightedgeandthen cuttingthefacingontheotherside.
• Ensureaccuratetrimmingoftheinfillpanelstoachieveclose- buttingjointsandcontinuityofinsulation
Availability
•PleasecontactAlumascSalesDeptforavailabilityofthe AlumascVThermVacuumInsulatedSystem.
Packaging and Storage
•ThepackagingoftheAlumascVThermVacuumInsulatedSystem shouldnotbeconsideredadequateforoutdoorprotection.Store indoorsandraisedoffthefloor.
Health and Safety
•AlumascInsulationproductsarechemicallyinertandsafetouse.
• ASafetyDataSheetisavailableontheAlumascRoofingwebsite.
Warning–donotstandonorotherwisesupportyourweightonthisproductunlessitisfullysupportedbyaloadbearingsurface.
Pleasenotethatthereflectivesurfaceonthisproductisdesignedtoenhanceitsthermalperformance.Assuch,itwillreflectlightaswellasheat,includingultravioletlight.Therefore,ifthispanelisbeinginstalledduringverybrightorsunnyweather,itisadvisabletowearUVprotectivesunglassesorgoggles,andiftheskinisexposedforasignificantperiodoftime,toprotectthebareskinwithaUVblocksun cream.
SITEWORK
Paving Slab Ballast
•Layminimum50mmthickpavingslabs,overAlumascSeparator Sheet,onproprietarypavingslabsupportstomaintaindrainage belowtheslabsandtoensurethatmoisturevapourcanescape.
• Installthepavingslabsandsupportsassoonaspossibletoensure thattheseparatorsheetisalwaysprotectedandtoprevent excessiveheatbuild-uporhighwindsdonotdamagethe insulation panels.
• Ensurethatgapsbetweenpavingslabsandupstandsarefilled withwashedroundedgravel,nominal20-40mmdiameter.
Roof Gardens
• InstalltheAlumascVThermVacuumInsulatedSystemas described previously.
• OverlaythepanelswithAlumascSeparatorSheet–installedas described previously.
• Installafiltrationlayerorcombinedfiltrationlayer/drainage mat.
• Installthegrowingmedium,generally50-200mmdeep. Specialistspraysystemsareavailable,whichallowtheapplication ofthegrowingmediumandgrass/plantseedtobeappliedin one operation.
• Assessthedepthofthegrowingmediumwithregardtowind loadsinaccordancewithBS6399-2:1997(Loadingforbuildings. Codeofpracticeforwindloads),orBS/I.S.EN1991-1-4:2005 (NationalAnnextoEurocode1Actionsonstructures.General Actions.WindActions).
Wheeled / Foot Traffic
• TakecarenottowalkontheVThermvacuuminsulatedinsulation panels.Useaprotectivefootorcrawlboardduringtheinstallation process.
• TheinfillpanelsandtheAlumascExtrudedPolystyreneOverlay maybewalkedon.
PRODUCT DETAILS
Composition
TheVacuumInsulationPanelscomprisearigidvacuuminsulationwithamicroporouscore,whichisevacuated,encasedandsealedinathin,gas-tightenvelope.
Theinfillpanelscompriseahigh-performancerigidextrudedpolystyrene insulation.
Standards and Approvals
TheVIP PanelismanufacturedtothehigheststandardsunderamanagementsystemcertifiedtoISO9001:2008(QualityManagementSystems.Requirements),ISO14001:2004(EnvironmentalManagementSystems.Requirements),BSOHSAS18001:2007(HealthandSafetyManagementSystems.Requirements)andISO50001:2011(EnergyManagementSystems.RequirementswithGuidanceforUse).
Standard Dimensions
TheVacuumInsulationPanelsareavailableinthefollowingstandardsize(s):
Nominal Dimension Availability
Length 300 - 1200 mm
Width 300 - 600 mm
Insulant Thickness 20 - 60 mm
Othersizesmaybeavailabledependentonorderquantity.PleasecontactAlumascRoofingformoredetails.
Compressive Strength
ThecompressivestrengthoftheKingspanOPTIM-Rpanelstypicallyexceeds150kPaat10%compressionwhentestedtoBS/I.S.ENISO826:1996(Thermalinsulatingproductsforbuildingapplication.Determinationofcompressionbehaviour).
Durability
If installed correctly and protected from damage and penetration, theAlumascVThermVacuumInsulatedSystemcanprovidereliablelong-termthermalperformanceoverthelifetimeofthebuilding.
Resistance to Solvents, Fungi & Rodents
TheAlumascVThermVacuumInsulatedSystemshouldnotbeusedinassociationwithsolvent-basedadhesivesystems.Damagedboardsorboardsthathavebeenincontactwithsolventsoracidsshouldnotbeused.
TheinsulationcoreandfacingsusedinthemanufactureoftheAlumascVThermVacuumInsulatedSystemresistattackbymouldandmicrobialgrowth,anddonotprovideanyfoodvaluetovermin.
Fire Performance
TheAlumascVThermVacuumInsulatedSystem,whensubjectedtotheBritishStandardfiretestspecifiedinthetablebelow,willachievetheresultshown,whenthesurfacefinishiseitherminimum50mmgravel ballast or minimum 40 mm paving slabs.
Test Result
BS 476–3: 2004 (External fire exposure roof
test)
Ext. FAA rating
FurtherdetailsonthefireperformanceofproductsmaybeobtainedfromtheAlumascTechnicalServiceDepartment(seebackcover).
Aminimumdistanceof300mmshouldbemaintainedbetweenthetopoftheinsulationupstandandthebottomofthehorizontalroofinsulation.Wallinsulationshouldalsobecarriedupintoparapetsashighastheflatroofinsulationupstand.PleasecontacttheAlumascTechnicalDepartment(seebackcover)forfurtheradvice.
Thermal Properties
ThevaluesdetailedbelowarequotedinaccordancewithBS/I.S.EN12667:2001(Thermalperformanceofbuildingmaterialsandproducts.Determinationofthermalresistancebymeansofguardedhotplateandheatflowmetermethods.Productsofhighandmediumthermalresistance),withallowanceforageingandedgeeffectoftheencapsulatingfilmtoformthedesignvalue.
Thermal Conductivity
TheVacuumInsulationPanelsachieveathermalconductivity(K-value)of0.007W/mK(ageddesignvalueallowingforedgeeffect).
Thermal Resistance
Thermalresistance(R-value)oftheVacuumInsulationPanelsvarieswiththicknessandiscalculatedbydividingthethicknessofthepanel(expressedinmetres)bythethermalconductivity(K).
Insulant Thickness (mm) R ValueThermal Resistance (m2-K/W)
20 2.857
25 3.571
30 4.285
40 5.714
50 7.143
60 8.571
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