What is a UV-System? A UV-System is a surface water drainage system which utilises the principle of full-bore flow. The UV-System is most frequently used for the drainage of rainwater from roofs. The title "UV" is an acronym for the Finnish word "umpivirtaus" used by its inventor, Mr Olavi Ebeling, to describe full-bore flow. History Since its invention in 1968 more than 60 million square metres of roof have been drained of precipitated rainwater by the UV-System. The first UV-System outlet (patented in 1968) provided a breakthrough in piped drainage by eliminating air-entrainment via the outlet into the connected pipework at acceptable water depths around the outlet on the roof. Thus the hydraulic principles established by eminent scientists and engineers - Bernouilli, Prandtl, Darcy, Nikuradse, Weisbach, Colebrooke et al - could be brought together to facilitate the accurate design of fully water-filled pipe systems. The benefits to the construction industry were immediately seen. The UV-System rapidly established itself throughout Scandinavia during the early 1970’s and companies such as ABB, IBM, Astra, Ericson, Pilkington, Electrolux, IKEA, Pharmacia & Upjohn, SAAB, Avesta, Volvo etc made good use of the advantages of the new technology. The UV-System gradually spread to Europe and the rest of the developed world (with the notable exception of the USA) in part due to the above companies relocating outside Scandinavia. The original concept for this technique has been continuously developed by its inventor, Mr Olavi Ebeling, since inception and in collaboration with Mr Per Sommerhein of Stockholm post 1972. Current UV-System outlets and applied UV-System dimensioning technology are the result of almost 30 years of development, study and experiment. The UV-System thus represents best practice for any project, anywhere. © 2000-2022, UV-System Nordic AB. All rights reserved.