b'BUILDING CODEshallbedeterminedinaccor- describesitsscope,andsentence(2)CAN/CSA-A123.21. I will discuss the dance with the requirements oflinks Part 5 to the load requirements inapplication side of sentence (5) in detail CAN/CSA-A123.21,DynamicPart 4. Sentence (3) is an escape hatchlater in this article, but it needs a little WindUpliftResistanceofthe designer can use if an aspect of thecontext first.Membrane-RoofingSystems.buildingenclosurewillnotbesubjectWhat is CAN/CSA-A123.21? It is (See Note A-5.2.2.2. (4).) to the full extent of the loads covereda test method developed by the CSA 5) Membraneroofingassembliesby Part 4 (specifically, Article 4.1.7.1.).GroupunderthedirectionofthewithprovenpastperformanceHowever, since a roof is never subjectNational Research Council of Canada for the anticipated wind loadsto less than 100 per cent of the speci- (NRC),usedtotestsheetmembrane need not comply with sentencefied wind load, we will ignore sentenceroof assemblies in a controlled labora-(4). (See Note A-5.1.4.1. (5).) (3). Sentence (4) tells us that membranetory environment, under dynamic wind Aquickstudyofthearticletellsroofassembliesmustbecapableofconditions (Figure 1). A test is termi-usallweneedtoknow.Sentence(1)resistingSWLsusingthetestmethodnated when the system remains intact underpredictedmaximumloading (referredtoassustainedpressure), or when it fails. The results of the test are published in a report for the roof system manufacturer, who then makes the report available to the roofing design WITH BEACON community. Dynamic Uplift Resistance (DUR)valuesmaybeexpressedinResidential Roong a report as either a positive or nega- Commercial Roong tive number, but they always refer to Waterproong uplift pressures. Insulation and More The standardized test method was developedafteryearsofstudyand SERVING ROOFING collaborativeworkbyaconsortium CONTRACTORS ACROSSofindustrypartnersformedin1994 CANADANova Scotia | Quebecunder the direction of the NRC. The Alberta | Saskatchewan SpecialInterestGroupontheDynamic British Columbia | Ontario Evaluation ofRoofing Systems (SIGDERS) isstillactivetoday.Thestandardis BEACON\x04CANADA.COM managed by a task group that operates under the mandate of the CSA-A123 Technical Committee for Roofing and is published by the CSA Group. It was grantednationalstandardstatusin CanadabytheStandardsCouncilof Canada. The research and development of revisions continues to rest with the NRC and SIGDERS.Beforethe2018BuildingCode, www.precisionmetals.ca Article5.2.2.2.simplyendedwith sentence (3); to comply with the Code, Your Metal Specialists designershadtoaccountforsuch Roof Panels loads and effectsin the design based onthemostcurrentandapplicable Tested and certified byOn-Site Manufacturing - We come to you 1Pre-Notched - Saving labour $$ informationavailable. Todothis, Proudly made in Canada designers commonly relied on the suite 8081, 132nd St. Surrey B.C.of standards published by FM Global. 604.594.6001 Specificationscalledthemeverything Producing quality products for the construction industry since 1975 fromFMApprovalStandard4470 to 1-90 or I-90, shorthand for the wind resistance component of several FMGlobalapprovalstandardsfor Class 1 roofs.20lROOFINGBC l SPRING 2022'