Gravity drainage means the flat roof is drained via drains using an inclined pipe system. The pipes are partly filled with water. The maximum filling level may not be exceeded: h/d=0.7 for collecting and mains pipes and f=0.33 for downpipes.
The main characteristic of gravity drainage is the discharge of rainwater in a gravity system. The incline of the pipes towards the bottom serves to transport water. The outflow performance of a gravity drainage system is determined by this incline and the design of the roof drains. The shape of the drain inlet funnel leads to a corresponding increase in drainage.
Conventional internal drainage for flat roofs with gravity drainage is regulated by EN 12056 Part 3 and DIN 1986 Part 100.
Characteristics of a gravity drainage system
- Sloped pipe system
- Partly filled pipe system
- Extensive network of mains pipes
- High level of drainage due to funnel-shaped discharge pieces
- Complete drainage from the lowest point
- Inclusion of a drainage safety system
KESSEL has expanded its successful Ecoguss® drain range. In addition to parking deck, yard and roof drains the range now includes flat roof drains. Ecoguss®, a high-performance composite material based on metal, combines the advantages of cast iron and plastic without the corrosion and weight problems associated with grey cast iron.
Ecoguss® is a corrosion-free, high-performance composite material. Ecoguss® roof drains are up to 85% lighter in weight than a standard cast iron roof drain which reduces construction and installation costs. The material Ecoguss® is high temperature resistant making it ideal for use with hot asphalt / bituminous waterproof membrane installations. The shatter resistant and UV-proof material provides a long life expectancy.
KESSEL has developed a compact range of products with Ecoguss® flat-roof drains in Ø 75, Ø 110 and Ø 125. Any fitting requirements can be covered with the system accessories. There is a leaf trap and a damming ring for drainage safety. The damming ring can be retrofitted to existing drains. The spacer ring fitted with the toolless Lock & Lift system allows height adjustment of the pebble trap for the level of pebbles – as well as a retrofit for reconstruction, for example. Corresponding insulating or extension pieces for variable fitted depths are also available. The odour and rodent protection KESSEL Multistop System 200 can also be retrofitted.