b'Field Versus Wind TunnelThe results for the Corner Zone Versus NBCC 2020 show that the C p C gdata from Con- (a) (b)The wind loads on the roof clad- cordia and Western are mostly below ding are presented in terms of thethe code provision, except for a few combinedexternalpressurecoef- extremecasesfromWesternthat ficient and gust effect factor C p C g .were above the provisions. For the C p C g isthenondimensionalcoef- field data, the average C p C gwas -5.7, ficient used to study the forces re- whichisinfairlycloseagreement sulting from wind-building interac- withthecurrentprovision.The tions. Fig. 5 summarizes the resultsWestern results were higher than the ofthisinvestigation.ThegraphsConcordiaresults;thedifferences compare C p C gfrom the three sourc- are because the wind profiles used in(c) (d)es (field data and the two wind tun- the simulations are different. As de-nels) with NBCC code provisionsscribed previously, Western applied forthethreeroofzones(Corner,a more turbulent flow than Concor-Edge and Interior). These compari- dia, and greater turbulence implies sons allow verification of the suit- greaterflowvariabilityandgreater abilityofthecurrentprovisions.peak pressure. The greater number Tointerprettheresults,itshouldof pressure taps (or high-pressure tap be understood that the solid blackresolution) used by Western may also linesrepresentingcodeprovisionsincrease the chances to capture more are the design pressure coefficientspeak pressure. Besides the discussion as a function of the tributary arearegardingwindtunneltechniques, under consideration. It is assumedtheimportantconclusionofFig. thattheprovisionsaredeveloped5a is that, based on the results from these three approaches, there is notN Nconservativelyenoughtocover(e)0o) (f)0o clear evidence that the current provi- ( ( )the worst-case scenario in terms ofsion for the Corner Zone in NBCC 1wind load over the roof. Therefore,needs to be modified.to verify the suitability of the codeFig. 5b shows the results for the provisions, all wind load measure- Edge Zone. In contrast with the pre-ments (in the field or wind tunnel)vious case, the results show that theEshould be below the provisions. C p C gdata from the Concordia andE o W o oW ( 90 ) ( ) ( 90Fig.5ashowstheC p C g mea- Westernlaboratoriesandfromtheo 270 )270)sured by the Concordia and West- fieldmeasurementsarealmostall(ern laboratories in the wind tunnel,above the code provision. This find-and the C p C gmeasured in the IOWAingcanbeinterpretedasevidence building for the Corner Zone. ThethatthecurrentNBCCprovision cloud of data points is the result offor the Edge Zone is currently un- Smeasurements at different locationsderestimatedandneedstobeen- S o ( o )() 180withintheroofzone.Therangehanced. It can be observed that the180of those data points illustrates thatensembleofdatapointsfromthe some locations are more sensitive toWesternwindtunnelsimulationsFigure 4. Wind tunnel test setup of (a) Concordia and (b) Western. Close-up pictures of (c) Concordia wind effects (high suction) than oth- and the field measurements is similarand (d) Western models with corresponding tap layouts in (e) and (f).ers. For the field data, the bracket onto the data obtained in the CornerFigure 4: Wind tunnel testing was conducted at the Building Aerodynamics Laboratory of Concordia University and the Boundary Layer WindthedatapointshowstheinherentZone. Therefore, it seems logical toTunnel Laboratory of Western University: (a) wind tunnel test setup at Concordia; (b) wind tunnel test setup at Western; (c) close-up view of variability of field measurements. infer that the code provision for theConcordia model; (d) close-up view of Western model; (e) tap layout for Concordia model; (f) tap layout for Western model.E X P E R T S F F O R YO U RE X P E R T S O R YO U RE X P E R T S F O R YO U RB U I UIL I DI G G ENVELO P EB B L D I N N E N V E LO PEUILD NG ENVELOPEBUILT-UP ROOFINGBUILT-UP ROOFINGBUILT-UP ROOFINGBUILT-UP ROOFINGMODIFIED BITUMENMODIFIED BITUMENMODIFIED BITUMENMODIFIED BITUMENSINGLE-PLY MEMBRANESINGLE-PLY MEMBRANESINGLE-PLY MEMBRANESINGLE-PLY MEMBRANESUBGRADE MEMBRANESSUBGRADE MEMBRANESSUBGRADE MEMBRANESSUBGRADE MEMBRANESTRAFFIC COATING WITH BEACONTRAFFIC COATINGTRAFFIC COATINGTRAFFIC COATINGCOCNOENSETSOTGOAG RAO ROOFOINFIGN G CONESTOGA ROOFING COCMOMMEMRCEIRACLI,A ILN, DINUDSTURSITARLI,AL, CONESTOGA ROOFINGCO IN TITTUTIONAFL AT ROOFINGINS MERCIAL AL FLL AT STRIAL,GM TISTU ION , INDU ROOFININSTIT 1-888-518-7663conestogaroofing.comCOMMERCIAL, INDUS FINGTF:UTIONAL FLAT ROOconestogaroofing.comTF:1-888-518-7663 TRIAL, TF:1-888-518-7663conestogaroofing.comINSTITUTIONAL FLAT ROOFINGCONESTOGA WATERPROOFINGCONESTOGA WATERPROOFING(a division of Conestoga Roofing)CONESTOGA WATERPROOFING SERVING ROOFING TF:1-888-518-7663 conestogaroofing.com(a division of Conestoga Roofing)COMMERCIAL, INDUSTRIAL COMMERCIAL, INDUSTRIAL (a division of Conestoga Roofing) CONTRACTORS ACROSS ABOVE/BELOW GRADE WATERPROOFING ABOVE/BELOW GRADE WATERPROOFING COMMERCIAL, INDUSTRIAL T:CONESTOGA WATERPROOFINGONTARIO T:519-620-1515conestogawaterproofing.com519-620-1515conestogawaterproofing.comABOVE/BELOW GRADE WATERPROOFING (a division of Conestoga Roofing) Cambridge | London | Whitby T:519-620-1515conestogawaterproofing.com331 Sheldon Dr, Cambridge, ONN1T 1B1 Ottawa | Concord331 Sheldon Dr, Cambridge, ONN1T 1B1COMMERCIAL, INDUSTRIAL ABOVE/BELOW GRADE WATERPROOFING331 Sheldon Dr, Cambridge, ONN1T 1B1T:519-620-1515conestogawaterproofing.comBEACON-CANADA.COM331 Sheldon Dr, Cambridge, ONN1T 1B1ORN THE ONLY SOURCE FOR PROFESSIONAL ICI ROOFING CONTRACTORS IN ONTARIO ONTARIO ROOFING NEWSISSUE 4 2022/2317'