b'Figure 4: Conceptual illustration of the holistic approach that is the foundational concept for CSA A123.26 Performance Requirements for Climate Resilience of Low Slope Membrane Roofing Systems.CSA A123.26 Approach as an overlooked issue that must CSA A123.26 is built on thebeaddressedbecauseofitssig-foundation of a holistic approachnificant impact on the roofs per-composed of the following threeformance. 7 Figure5ashowsthe fundamental criteria: load deter- normalprobabilitydistribution mination,resistanceevaluationofload,resistanceandinstalla-andinstallationqualitycontrol.tion. For each of these probability Thisapproachensuresthatthecurves, the left segment shows theFigure 3: Examples of insured losses from extreme weather events in Canada. Note: currency shown in Canadian dollars.missing link between good codeslowestperformance.Theperfor- Figure courtesy of Reference 5.and durable roofs (quality controlmanceimprovesasonemoves duringfieldinstallation)isful- totheright,withtheexpectedtional information on the curvestiveandrepresentsthefailureisgraduallybeingusedbythe filled, leading to a more resilientmean performance at the peak ofcan be found in Reference 9. The thereliability9 buildingenclosurecommunity, area, shown in grey in Figure 5b.roof(Figure4).8 Ataninterna- thedistributioncurve.TheareaThe LRFD procedure assumes on the graph in Figure 5bwhichpreviouslyreliedonthe tional workshop held at NRCC,underthecurverepresentsthethe load and resistance to be con- representsindex,allowablestressdesign.Useof participants from various sectorstotal probability equal to 100 pertinuous probability distributions.and a larger value will correspondLRFDallowsformoreconsis-oftheroofingindustryrankedcent. The factored load and theByplottingtheloadandresis- toahighersafetyzoneforthetency in the design of buildings.alltheelementsaffectingroofs.factoredresistancecomposethetance curves in the same graph,considereddesignequation.Al- Using the LRFD approach, the Fromthisranking,installationbasis of the load resistance factorthe distribution of the differencethough LRFD is mainly used forfactored resistance must be high-qualityassurancewasidentifieddesign (LRFD) procedure. Addi- between the two values is nega- main force resistance systems, iter than the factored design load. WITH BEACON Residential Roong Commercial Roong Waterproong Insulation and MoreSERVING ROOFING CONTRACTORS ACROSS ONTARIO Cambridge | London | Whitby Ottawa | ConcordBEACON\x06CANADA.COMORN THE ONLY SOURCE FOR PROFESSIONAL ICI ROOFING CONTRACTORS IN ONTARIO ONTARIO ROOFING NEWSISSUE 4 2021/2219'