b'Climate Durability A Framework to Determine a Climate-Dependent Durability Index for the Building Enclosure By Bas A. Baskaran, PhD, PEng, F-IIBEC; F. Shyti, MASc; and H. Yew, MEngThefollowingarticleoriginallyindex (CDDI) framework is devel- adverselyaffecttheexpectedper- forsuddenunexpectedweatheroccurinanincreasedandacceler-appeared in the September 2024 is- oped and presented in this article. formanceoftheexposedbuildingevents,wherethenumberofoc- ated manner, it can lead to strength sue of IIBEC Interface. It is reprint- enclosure components and systems.currences and magnitude are deter- reduction and rapid deterioration of ed here with permission. Background Weathershocksareoccurrencesofmined based on the future extremecomponents and systems.B uildingenclosurecompo- In Canada, design loads for therapidandsignificanttemperatureclimatic conditions. loads forEstablishingweathershockpa-nents are exposed to extremebuilding enclosure are calculated invariations, such as a hot summer dayThese future climaticrametersisimportantbecauseit weathershocks.Currently,accordance with the National Build- followed by sudden rain and a dropmainweatherparameterssuchasallowsdevelopmentofanexperi-componentpropertiesaremea- ing Code of Canada (NBCC), utiliz- in temperature, or a cold winter daywind,rainandtemperaturecanmental protocol to simulate weather sured based on existing standards.ingclimaticloadsdetermination. 1 followedbyasuddenincreaseinbefoundontheweb-basedtoolshockphenomenaincontrolled The majority of standards accountThedatalistedwithintheNBCCtemperature.Figure1showstwoClimate-RCI for a range of globallaboratoryconditions.Thisfacili-forneithertheoccurrencesofare based on historical observationsexamples of weather shocks. warmingmagnitudesfrom0.9Ftates the evaluation of how weather weather shocks nor variations in thegathered 10 to 54 years before 2010.The National Research Councilto 6.3F (0.5C to 3.5C). 4Basedshocks affect components and their climate zones. The development ofThese data do not account for futureof Canada (NRC) developed a pro- on the future climatic data, NRCsubsequent impact on systems.a protocol combining the measuredclimatic conditions for Canadian cit- tocol outlined in CSA A123.26, Per- isnowaddressingtheeffectofThe effect of weather shocks will properties of the building enclosureies or for the effect of weather shocksformance Requirements for Climateweather shocks as part of their re- be different for various components components with the climate sever- on the components and systems. Ex- ResilienceofLowSlopeMembranecent Climate Resilient Built Envi- of the systems. The components that ity can provide a single attribute astreme weather events are becomingRoofing Systems, 2to account for fu- ronment Initiative. are exposed to the weather elements anindicatorofthecomponentsmorefrequent,intenseandlongertureextremeclimaticloadsintheThese weather shocks can causewill behave differently compared to long-term performance. To addressdue to climate change. These eventsdesign and construction of roofs. 3Indeteriorationofabuildingenclo- those that are not. Thermal expan-this, a climate-dependent durabilityleadtoweathershocks,whichcanthis paper, weather shocks accountsures components, and when theysion and contraction of components Figure 1: Typical hot and cold weather shocks.10ONTARIO ROOFING NEWSISSUE 4 2024/25 THE ONLY SOURCE FOR PROFESSIONAL ICI ROOFING CONTRACTORS IN ONTARIO ORN'