b'Technical ArticleTable 4: Number of drains and drain size determination for Toronto, Ontario. at 60-second intervals to a termina- authors opinion that the number ofquantitativeandqualitative, tion test pressure meeting project- tests be determined by the number offor the Silver and Gold catego-Determination of Drains specificrequirements.Whilethereroof areas defined by the direction ofries, while defaulting to current is no direct correlation between thisslope and the selection of the test areacodesandindustrypractices field test and the laboratory testingby the quality assurance inspector. for the Bronze category. How-Volume of rainwater (9,290 m 2x 25 mm = 232.25 m 3 ) 232,250 litres specified in CSA A123.21, 1the in- ever, qualitative industry prac-situtestingresultsprovideagoodSuggestions for Furtherticesvarysignificantlyacross Hydraulic load of 4-in. diameter drain/drainpipe and two- understandingoftheperformanceregions,provincesandjuris-3 5,970 litres Development of CSA per-cent slope of drainpipe per Table 7.4.10.9 in OBC of the roof assembly and may iden- A123.26 and Associateddictions.Itmaythereforebe tify non-compliant installation. prudent to revise the standard Number of 4-in. drains = 232,250 litres / 5,970 litres 39 drains Leak Detection System OptionTools todocumentqualitativepre-LeakdetectionsystemsmaybeIn general, CSA A123.26 5stream- scriptiverequirementsforthe Hydraulic load of 6-in. diameter drain/drainpipe and two- installed as an integral part of the as- linesvariousrequirementstomeetBronze category. For example, per-cent slope of drainpipe per Table 7.4.10.9 in OBC 3 17,600 litres sembly at the time of construction,the wind and rain effects of antici- the requirement for membrane or they can be installed using a non- patedclimateseveritiesonroofas- upturns at penetrations might Number of 6-in. drains = 232,250 litres / 17,600 litres 14 drains destructive technique within one orsemblies. As the first design standardbe specified.two years after completion of con- of its kind, it addresses several of theCSAA123.26 5 clearlyillus- Volume of rainwater for severe condition (9,290 m 2xstruction.CSAA123.26 5 specifiescritical issues related to roof assem- tratesthesignificanceofthe 30 mm = 278.70 m 3 ) 278,700 litres that an integral leak detection sys- blies.However,itcouldbefurtherhighwindconditionsantici-tem installed during construction isenhanced to address the following: patedattheparapetandin-suitable to reduce the Gold categoryGiventheprojectedincreasecludes some recommendationsNumber of 6-in. drains = 278,700 litres / 17,600 litres 16 drains requirementforqualityassurancein temperature due to climateforthestructuralintegrityof inspections from 100 per cent to 25change, in addition to the mea- theparapetassembly,mem-Volume of rainwater for extreme condition (9,290 m 2x 3 301,925 litres per cent of days. sures to counter the high windbraneandcladdingcompo-32.5 mm = 301.92 m ) Watertightness Testing Option conditionsandincreasedrain- nents attached to the parapet, As an alternative option to thefall,thestandardmayincludeincludingcapflashingsand Number of 6-in. drains = 301,925 litres / 17,600 litres 18 drains Gold category requirement of qual- in the future additional require- their components. This topic, ity assurance inspection for water- mentsfocusedonroofmem- particularlytherequirements Note: 1 in. = 25 mm; 1 ft. = 0.305 m; 1 gal. = 3.79 L. tightness on 100 per cent of days,branematerialperformancefor the substrate to which these partylaboratory;andmock-upsto100 per cent of the project days, in- CSAA123.26 5 allowsfortheop- countering the temperature in- components are secured, can be establish the standard of acceptance.situ negative pressure uplift testingtionofconductingfloodtesting.crease. It is recognized that ad- further detailed. Additional re-TheaboveisrecommendedtoasdescribedinAnnexBofCSAThespecifiedtestingmethodisaditional research is required inquirements could help address beconductedbyaqualifiedA123.26 5 allowsforthereductionmodified version of ASTM D5957,this regard.13 air-barriercontinuitychal-StandardGuideforFloodTestingClimate-RCI estimatesan- lenges at the base of the parapet buildingenvelopeconsultantorof quality assurance inspections to HorizontalWaterproofingInstal- ticipatedclimateseveritiesforwhere the parapet is part of the anindependentqualityassurance50 per cent of project days. A mini- lations, 18 whereinaminimumtestwind,rainandheat;thistoolmain structure.inspector. mumoftwotestsisrequiredforarea of 33 m (9.89.8 ft.) with atmay require further refinementCSAA123.26 5 mayfurther In-Situ Negative Pressure Upliftevery 5,600 m 2(60,300 ft. 2 ) of roofleast one plumbing vent or any othertoincludeadditionalmetricsdevelop the mounting require-Test Option area. The testing uses an in-situ pres- roof penetration is flooded to a min- forfreeze-thawcycles,snowmentsforrooftopadd-ons, AnnexBofCSAA123.26 5 in- surechamber,withdeflectionandimum depth of 25 mm (1 in.) for 24accumulations,hailandsospecifyingwhethertheyare cludesanalternativeoptionforpressuresensorsmountedonthehours to evaluate for water leaks. on.Similarly,CSAA123.26 5 allowedtobefloating(not PARSsandAARSstoreducetheselected roof areas. The deflection ofWhile the test area is defined, thecouldbeexpandedtoincludesecured to the roof deck, but qualityassuranceinspections,par- the roof membrane is monitored vi- CSAA123.26 5 standarddoesnotrequirementstocountersuchsupportedbyself-weightor ticularlyrelatedtowindupliftre- sually through a port and deflectionindicatethenumberofsuchtestsclimateseverities. added weight) on the roof as-sistancefortheGoldcategory.Insensor as the pressure differential isper roof or the number of tests forCSAA123.26 5 includespre- semblyorsecuredtomainlieuofconstructionreviewsforincreasedbyincrementsof720Paa certain extent of roof area. It is thescriptiverequirements,bothstructuralsystem.Iffloating, 22ONTARIO ROOFING NEWSISSUE 3 2025 THE ONLY SOURCE FOR PROFESSIONAL ICI ROOFING CONTRACTORS IN ONTARIO ORN'