Characteristic of Siphonic Roof Drainage System – Principles and Design Conditions

Amount and intensity of rainfalls are increasingly changing by clime changing and increasing of temperature variations. There is increase of torrential rains, which extremely burden the construction by the huge volume of rainwater and thus effect on whole building construction. It is necessary safely lead away this amount of rainfalls to remain the building construction undamaged. The method of roof drainage mostly depends on the roof construction. Flat roofs are more sensitive to torrential rains, thus there is very important to make proper design of drainage system and location of roof runoffs. There is no Standard for dimensioning the Siphonic roof drainage system in Slovakia. In this article is shown general procedure of design the siphonic roof drainage system, based on rules contained in the German technical regulation VDI 3806 - Dachentwässerung with Druckströmung.