b'TECHNOLOGIEWhat are the control parameters for NBSCR design?I)Drain specifications:Les municipalits, les 1)Number of Roof Drains (N RD ): When using controlledflow roof drains, there must be at least one drain for up 2 propritaires dimmeubles, to 10,000 square feet (900 m ) of roof area, and at least two drains on roofs larger than 10,000 square feet. les assureurs et dautres 2)i ): Q iis the release rate from Release Rate per Drain (Q 3 intervenants sintressent de therooftopdetention(Q ROOF ;ft /s)dividedbythe number of drains (N RD ) in ft3/s (Eq. 1): plus en pluslutilisation de Q i = Q ROOF/ N RD Eq. 1 la vaste surface inutilise de 3)DepthofFlowatDrains(D R ):D R isdetermined toits commerciaux dans la basedontherelationshipbetweenthereleaserate and the ponding depth, as specified by the roof draincanope urbaine dense pour manufacturer. This flow depth must be less than or equal to the maximum ponding depth (D max ) (Eq. 2) where Q iis the maximum release rate from each drain (ft3/s) andattnuer les effets nfastes Q nis the release rate per inch of ponding (ft3/s/inch).des inondations urbainesD R =Q i/ Q n D max Eq. 2II) Detention time:la profondeur maximale daccumulation (D max ) (Eq. 2), Stormwater detention lag (T lag ) is calculated with metrics relatedo Q iest le taux maximum de rejet de chaque avaloirtochangesinmagnitudeortimingofdischarge,including(ft 3 /s) et Q nest le taux de rejet par pouce daccumula-the lag time that is the time between the start of a rainstormtion (ft 3 /s/pouce). and the start of discharge (Eq. 3). Detention increases with a slower discharge.D R =Q i /Q nD max Eq. 2T lag = T discharge T stormwater Eq. 3 II) Dure de rtention :Le temps de rtention des eaux pluviales (T ) est calcullagIII) Detention capacity: laide de mesures se rapportant aux changements dampleur Volumetricwaterstorage(DET),referredtoasdetentionou de moment du dversement, y compris le dlai qui secapacity, is quantified in per cent as the volume of stormwatersitue entre le dbut dun orage et le dbut du dversement detained over a period of time (W detention,t ), relative to the volume(Eq. 3). Plus lvacuation est lente, plus la rtention est forte.of stormwater event (W stormwater,t ) (Eq. 4).T = T- T Eq. 3lag coulement eau-pluvialeDET=W detention,t/ W stormwater,t 100Eq. 4III) Capacit de rtention :What are the structural specifications for Lestockagedeauvolumtrique(DET),quonappellela NBSCR performance evaluation? capacitdertention,estquantifienpourcentagedu There are three structural specifications to be determined forvolume deaux pluviales retenues sur une priode de temps NBSCR performance evaluation: (W dtention,t ),parrapportauvolumedelaverse(W eau-pluviale,t )I)volumeontheroofbycalculatingavailable(Eq. 4).Storage roof area without the equipment or structures that may interfere with stormwater storage and roof slope.DET=W dtention,t/ W eau-pluviale,t 100Eq. 4II)Load imposed on the roofing assembly by calculating1) the traditional structural loads consisting of the deadQuelles sont les spcifications permettant dvaluer le weight of the roofing structure and materials, plus anrendement des SNTC ?allowance for live load applied from snow falling on theIl y a trois spcifications structurellesdterminer :roof/rainfall events and 2) the stormwater load, whichI)Volume de stockage sur la couverture en calculant lais based on the climatic load and prediction of extremesurface disponible sans le matriel ou les structures storm fall intensity, duration and frequency. susceptibles de nuire au stockage des eaux pluviales III)Waterproofing and insulation requirements specifyingetla pente du toit.by the amount of the stormwater that is permitted to beII)Le poids imposla toiture en calculant 1) les chargesdetained to minimize unintentional adverse effects.se composant du poids normal de la charpente et des AUTOMNE/HIVER 2022 COUVERTURES CANADA 29'