b'Figure 2. Photo showing an incorrect drain TECHNICAL & RESEARCHsump configuration, improper installation of a metal drain pan, and foreign material adhered to drain pan.Figure 3. This photo illustrates incorrect flashing of a drain sump with thermoplastic roof membrane.ria for this item. The force exerted on the roof membrane from installing the drain clamping ring can pull tension onadjacentfieldseams,whichcould weaken or damage the field splice. The tension could cause wrinkles and voids inadjacentfieldseamsiftheyarein close proximity to the drain assembly.Theverticalsufacesofthesump areaarebare/exposedpolyisocyanu-rate (polyiso) insulation, which means there is no insulation facer to adhere to, resulting in loose flashing and, poten-tially, damage to the polyiso insulation from the solvents in the bonding adhe- tical transitions is not installed per thedrain is not functioning properly. The sive. manufacturerspecifications,andtheoverflow drain lines are generally not A metal drain pan is installed, whichroofcontractorhasnotinstalledtheconnected to the plumbing system.isnotrequiredbycodeandnotrec- manufacturerrequiredunreinforcedAdditionally, for this particular project, ommended by the roof manufacturer,thermoplastic flashing detail membrane. theinsulationsystemisspecifiedto above the roof insulation as shown inTherearenoinsideoroutsidecornerbeadheredwithfoamadhesiveand Fig. 3. The metal drain pan, if specified,detail flashings installed in this example. is intended to receive a hail coverage shouldbeinstalledagainstthestruc- The primary roof drain and the over- riderwiththewarranty.Theuseof tural deck, not on top of the insulationflowdrainareinstalledatthesameinsulation fastening plates is generally assembly. A sump pan (or sump receiv- elevation.Thecompletedoverflowprohibited by the roof manufacturer on er)isasquare,approximately-in.- drainclampingringdidnotincludeprojects where a hail coverage warranty thick (3 mm), flat piece of steel (unlessan overflow drain collar adapter. Theis specified because the metal attach-itsadualpan).Itshouldfittheroofoverflow drain will function the samement plates introduce a very hard pinch drain bowl, and its purpose is to assistas a primary drain, channeling waterpointfortheroofmembraneathail in securing the drain bowl to the roofintotheoverflowdrainoutletsatallimpact points.deck. Sump pans are manufacturer spe- times. Overflow drains are intended toTheinsulationiscuppedandloose, cific,sotheycannotbeinterchangedactively remove water in the event theand the fasteners and insulation plates with other manufacturers roof drains.primary drain becomes clogged. As thethathavebeeninstalledtocompen-Metaldrainpansarenottypicallyoverflow drain begins to remove watersateforinadequatelyadheredinsula-installed in conjunction with single-plyfromtheroof,itgenerallydischarg- tion introduce thermal bridging to the roof systems in many areas of US butes (also known as daylights) onto theroof assembly. Because the metal fas-can be incorporated by the designer. grounds of the facility, thereby provid- teners and plates are secured into the The inside corner detailing at the ver- ing a visual indication that the primarymetaldeck,theywilleasilytransmit www.mrca.orgMidwest Roofer 19 7'