b'Technical ArticleFigure 4: Tested gap configurations. Figure 5: Guarded hot box.To this end, several configura- nogapbetweentheinsulationMeasuring Thermal Bypass of 75 F. Figure 5 shows the installa- withzerogapbetweenthem). tions were tested as summarizedboards, were selected by the steer- Evaluating thermal bypass wastion of staggered gap configurationThemeasureddataforthese inFigure4.Todeterminetheing committee members. accomplishedusingafour-byin the guarded hot box. testedconfigurationswereal-thermalbypassoccurringwhenInsulation boards can be installedfour-footguardedhotboxap- mostidenticaltotheopaque thetopandbottomjointsareinasingle-layerconfiguration.Al- paratus.Itwasdesigned,con- Gap Width and Height assemblies (the full board of in-isolatedfromeachother,gapsthoughtwolayersistherecom- structed and calibrated followingTounderstandtherelation- sulation).were initiated in a top and bot- mended practice, it is common toASTMC1363,StandardTestship between gap size and insu- TheR-31configurationin-tomjointorientation.Inaddi- see single-layer installation in someMethod for Thermal Performancelationthickness,apreliminary tion, staggered joints were testedparts of North America with milderseries of testing was conducted oncludedtwo-and31/3-inch-to quantify any effect the top andof Building Materials and Enve- thick insulations as indicated in bottomgapscouldpotentiallyclimates. In consultation with con- lopeAssembliesbyMeansofaR-26 and R-31 assemblies for theFigure 3. In the top gap configu-haveoneachother.Gapsweresortium members, through-gap testsHot Box Apparatus. The testingthree gap configurations: top gap,ration, the gap height was two introducedatadistanceof24also were carried out on a single-layerallows for the isolation of a com- bottomgapandstaggeredgap. insulation layout. ponent from a full-scale roof as- For the staggered gap, tests wereinches, and in the bottom gap, inches and six inches apart. More than 75 experiments weresembly and the ability to conductconducted with the gap offset 24itwas31/3inches.Thestag-In summary, two-layer configu- geredgapconfigurationisthe rations were evaluated for the topconducted on thermal bypass, andin-depthanalysisofthethermalinches.Beforeweinvestigated gap, bottom gap and staggered gapall tests included a steel deck as theperformanceofthatcomponentthedifferentgapconfigurations,combination of these two gap configurations.Twogapwidths,structuralsubstrate,fiberglass-facedand its interaction with other roofexperimentaltestingalsowasheights.Intheopaqueassem-1/4 of an inch and 1/2 of an inch,cover board and thermoplastic mem- components. All experiments weredone with insulation butt jointsbly,theinsulationboardsare in addition to a butted joint withbrane as the waterproofing layer. conducted at a mean temperature(those boards that were adjoinedcontinuous without any gaps. 87 Bakersfield St., Toronto, Ontario, M3J 1Z4 Tel: 416-787-0649Fax: 416-787-0640 Email: service@crawfordroofing.ca www.crawfordroofing.ca Think Safe,Industrial Commercial Institutional Roofing SolutionsWork Safe,since 1988Top-Line Roofing & Sheet-Metal Inc specializes in the installation, repair, and maintenance of industrial roofs throughout Southern Ontario. -PMI Programs- Modified Bitumen- Built Up SystemsOUR SERVICES:-Metal Roof Systems- Waterproofing- Restoration Commercial roofing Re-roofing-Emergency Services- Roof Anchors- Single PlyRoof maintenance Skylight installation-Roof Top Decks- Sheet Metal- InvertedRoof inspection,Sheet metal flashing evaluation & report fabrication & installationHistorical restoration Retro-fit curb installationEmergency roof repairsCommitted to Safety, Quality & Service for over 37 years(905) 602-0760Services Fully Bonded & Insured1325 Fewster DrMississauga, ONL4W 1A2toplineroofing.ca14ONTARIO ROOFING NEWSISSUE 1 2021 THE ONLY SOURCE FOR PROFESSIONAL ICI ROOFING CONTRACTORS IN ONTARIO ORN'