b'Technical ArticleWinds Are Changing in Canada:By Mauricio Chavez, PhD, and Bas A. Baskaran, PhDVerifying wind load code provisions on a low-slope gabled roof with field measurements and wind tunnel dataThefollowingarticleoriginallyhasbeenrequired.Recently,a)appeared in IIBEC Interface and isKoppandMorrison 5 revisitedthe reprinted with permission. provisionsforlow-sloperoofsand T hewindloadprovisionsforcompleted an extensive wind tunnelN low-sloperoofsinthe2020simulationusingmoderndigital NationalBuildingCodeoftechniques to verify the provisions Canada(NBCC), 1 aswellastheinASCE7-10.Theresearchers provisions in the American Societyconcluded that both design pressure ofCivilEngineers2010editioncoefficients and the size of the roof ofMinimumDesignLoadsforzonesneededenhancements.The BuildingsandOtherStructuresrecommendationswereconsidered (ASCE7-10), 2 wereestablishedby ASCE, and the provisions were inthe1970sbasedonfindingspartially increased as well as the roof fromboundarylayerwindtunnelzonesmodifiedinASCE-7-16. 6 In experimentsbyStathopoulos 3 Canada, NBCC did not adopt the andSurryetal. 4 Windpressureproposedchangesforlow-slope measurement tools have significantlyroofs,andthereforethepressure improved during the past 50 years,coefficientsandroofzoningwere andverificationofthosepressureunchanged.coefficientsusingexperimentalThe changes to wind load provi-dataobtainedbymoderndevicessions in ASCE 7-16 motivated the andcomplementaryapproachesNational Research Council of Can- SAFETY RAILINGS MEET STYLEInstrumented area: b)NW and SW corners Accu-Fit Fall Protection Railings from Safety Rail Company are the perfect solutionforcombiningformand function with distinctive styling that complementsbuildingarchitecture,H=23 offeringcleansightlines,upscale styling, and a non-penetrating design.PROTECT LIVESCO MPLIANTBECALL TODAY SAFETYRAILCOMPANY.COM I 888.434.2720 Figure 1a: The building selected to verify the code provisions for low-slope roof.Figure 1. (a) Building (240 ft x 24 ft x 23 ft) and surroundings and (b) Instrumented area. Note: 1 = 1 ft = Figure 1b: Building dimensions and instrumented area: NW and SW corner. Note: 1 = 1 ft = 0.3048 m.0.3048 m. 14ONTARIO ROOFING NEWSISSUE 4 2022/23 THE ONLY SOURCE FOR PROFESSIONAL ICI ROOFING CONTRACTORS IN ONTARIO ORN'