b'Technical ArticleEdge Zone could be established to below-slopegabledroofprovisions(a) equal to the Corner Zone provision.wouldbecomposedoftworoof In other words, the Edge and Cornerzones only: Perimeter and Interior Zonescouldbemergedasasingle(Fig. 6).PerimeterZone.SuchachangeThisproposedchangewould could be an important simplificationsimplifythecode.Simplicityin in the code. codification is important to make Fig.5cshowsthattheInteriortheconstructionprocesseasier Zone C p C gdata from Concordia areand reduce the risk of worker er-mostly lower than the code provision,rors during construction. The sug-whereas the data from Western andgested code change would address the field investigation are higher thanthe current underestimation of the the provision. Thus, the Western andEdgeZone(windloadupgrade) field data provide some evidence thatand would provide code simplifi- (b) thecodeprovisionfortheInteriorcation to minimize failure due to Zone is currently underestimated, butinstallation deficiencies (construc-Concordias critical values are close totability upgrade).the code provisions and suggest that the provision for the Interior Zone isAcknowledgmentsconservativeenough.Thecompari- Thepresentedresearchwas son of field and wind tunnel data iscarriedoutincollaborationwith not conclusive regarding the necessitytheSpecialInterestGroupfor to revise the Interior Zone provisions;DynamicEvaluationofRoofing therefore, no changes for these provi- Systems(SIGDERS).SIGDERS sions are indicated.wasformedbyagroupof Closing Remarks partnerswhowereinterestedin Thisarticlesummarizesresearchroofingdesign.Thesepartners(c) conductedtoverifythesuitabilityincluded:Altenloh,Brinck ofthecurrentlow-sloperoofwind&Co.,AtlasRoofingCorp., loadprovisionsinNBCC. 1 There- CanadianRoofingContractors sults from field measurements in theAssociation,CarlisleSynTec IOWA building and two independentSystems,Duro-LastRoofing, wind tunnels were consistent in dem- Element,EXPInc.,Firestone onstrating that the Edge Zone provi- Building Products Canada, GAF, sionis1 currentlyunderestimatedbyIIBEC, IKO Industries Ltd., Johns NBCC andneedstobeincreased.Manville Inc., Polyglass, RCABC, This research does not provide a spe- Rockwool,SikaCanadaInc., cificnewvaluefortheEdgeZone.SopremaCanadaandTremco However, the data show that the actu- Inc.SIGDERSmembership al wind load on the Edge Zone is closeofferstheirspecialappreciation to the wind load on the Corner Zone.toAlJanni,RyanVanWertand Therefore, the current study suggestsPaulAckermanofDuro-Last that merging the Edge and the CornerInc.forprovidingroofaccessFigure 5. NBCC provisions versus wind tunnel and field data (a) corner, (b) edge, and (c) interior. Note: Zone provisions into a single Perim- duringtheinstrumentationand eter provision is feasible. Thus, thedatacollection. NBCC = National Building Code Canada.1 Figure 5: NBCC provisions versus wind tunnel and field data (a) corner, (b) edge and (c) interior. Note: NBCC = National Building Code Canada. 1SUPPLYING QUALITY PRODUCTS THAT YOU NEEDROOFMART.CA18ONTARIO ROOFING NEWSISSUE 4 2022/23 THE ONLY SOURCE FOR PROFESSIONAL ICI ROOFING CONTRACTORS IN ONTARIO ORN'