“NUOVA” ANTI-BACKUP ROOF DRAIN IN TPO is one of the most valid systems for the connection of drainage pipes in flat roofs, in the gutters of multi-pitched roofs and in the valleys of industrial warehouses. Suitable for use on roofs made with synthetic TPO membrane. The construction is studied in detail, in fact the construction has optimal characteristics having a funnel with a diameter of 170 mm and a depth of 30 mm, and a 330 mm shank that allows to go beyond the high thicknesses of the supports, thus avoiding intermediate joints. . This construction eliminates the serious and costly problems such as clogging due to poor flow due to reduced inlet etc. created by traditional fillers on the market. The material used for the realization of the nozzle is soft and flexible UV stabilized TPO, which offers a range of chemical and physical technical characteristics that can satisfy all the needs of an elastic article, provides a high resistance to degradation caused by the sun, by ozone and other atmospheric and chemical agents. It can be used in a wide range of temperatures giving high flexibility at low temperatures and is stable over time, given its physical and mechanical characteristics. Therefore a material which, thanks to its excellent quality, ensures perfect efficiency over the years. It has been proven that this nozzle drains over 45% more than the nozzles without this particular funnel. The grille is made up of a truncated body, of variable diameter, integral with a wide and smooth flange that allows total weldability on the membrane. The insertion to the downspouts is provided on a pipe with a socket, obtaining water discharge capacity for the entire chosen diameter and can be installed before the drain pipes. The tang is provided with two or more well-positioned circular flanges, facing outwards, which, by forcing elastically on the internal surface of the exhaust pipe, ensure that the nozzle has anti-surge properties and a perfect seal. In fact, when inserting the exhaust pipe, they undergo an upward bending and consequently to the pressure exerted, they guarantee perfect adherence with any type of pipe. In this way, the passage of water vapors and any liquid masses (of regurgitation) is eliminated which, filtering under the waterproof covering, invalidate the effectiveness of the insulation, a factor which naturally constitutes one of the most serious drawbacks for the waterproof covers. We recommend using the 200 mm diameter barrier attached to the toothed ring inserted directly into the upper part of the reservoir. The ring has three seats for hooking the gravel barrier that adjust the height in the case of variable thickness of the waterproof membranes