b'Example of ponding water on undamaged section after collapseBUILDING CODEFigure 1: Example of ponding water on undamaged section after collapse.At the building on page 28 (Figure 3), which is a hospital, there is a parapet that is approximately two feet (600 mm) high withnooverflows.Thestructuremay be designed to accommodate the weight of water, but the door into the hospital would act as an overflow if the drains were overwhelmed or blocked. Ingeneral,codecomplianceon existingbuildingsisgrandfathered, Example of ponding water on undamaged section after collapse meaning that compliance with the code of the date of the permit is adequate. grandfatheringcanworkfor While elements such as insulation, cladding or air changes per hour, ignoring updated code or climate data on roof drainage ofexistingbuildingscanresultinlife andsafetyissues.Anotherconsider-ationonnewconstructioniswhether todaysclimatedatashouldberelied onforsomethingthatisalifeand safetyissue.Whilecodesarebeing updated to consider forward-looking climate data, the current code does not requirethattobeconsidered.Inmy opinion, a designer should be allowing forincreasedintensityweatherevents, either through rethinking drainage strat- www.precisionmetals.caegies(eliminatingparapets,increasing loadcapacitiesofroofs)orincreasing drainagecapacityinexcessofcurrentYour Metal Specialists Roof Panelscode requirements. Remembercode is a minimum standard. Some approachesTested and certified byOn-Site Manufacturing - We come to youPre-Notched - Saving labour $$(removing parapets) can result in otherProudly made in Canadaimplicationswhereamunicipalityhas8081, 132nd St. Surrey B.C. rain water retention directives, including604.594.6001flow control drains and other measures. Producing quality products for the construction industry since 1975Fortunately, there is some light on the horizon.Thereareproposedchanges (ProposedChange1790)thatseekto clarify some of the issues around over-www.rcabc.orgl27'