Rainplus® represents the most modern technology in the constructions sector and in the drainage of rainfall from the roofs of medium and large size buildings. The system makes use of the building height as the driving force, which together with the effect of negative pressure, allows high speed flow rates to be reached thus maximising drainage efficiency. Rainplus® allows the entire flow of water to be directed to any part of the building whatsoever, thus enabling the most modern rainwater harvesting systems to be installed as required by the Green Buildings Program. The Rainplus® siphonic drainage system is made up of special outlets that are patented, designed and tested to American Standard ASME A112.6.9 and European Standard EN 1253 and connected to HDPE® high density polyethylene pipes. The outlets also incorporate special components that allow installation on any type of roof and waterproofing sheet.