Rainwater & backwater protection in accordance with DIN 1986-100
According to DIN standard 1986-100, rainwater outlets must be connected to the public sewerage system separately from domestic wastewater. If such outlets are located below the backwater level, they must therefore be protected separately against backwater. Only in a few exceptional cases may rainwater be combined with domestic wastewater and channelled through a central backwater prevention device.
Connected catchment area A in m²: 5 m²
Design rainfall intensity r 5.100 in l/(s·ha): 648 l/(s·ha)
Runoff coefficient C is not permitted for this
See figure on the left for formula and calculation
Design rainfall intensity r5 = five-minute rainfall
Rainfall duration = 300 s
Rainwater volume
= Qr x rainfall duration = 0.33 l/s x 300 s = 99 l ≙ 99 dm3
Floor area of the cellar entrance without steps
A = 1 m² = 100 dm²
Height of the required door threshold
h = Rainwater volume / Floor area = 99 dm³ / 100 dm² = 0.99 dm = 9.9 cm
The door threshold must have a minimum height of 9.9 cm so that, in the event of backwater in the sewer, the rainwater entering the cellar entrance can be retained for an assumed period of 5 minutes.
KESSEL backflow prevention products for collective protection
Backwater valves of types 2, 3 and 5, as well as hybrid drainage systems (backwater pumping stations and hybrid lifting stations) to which multiple drainage outlets can be connected, are suitable for collective protection. Suitable solutions include, for example, the Staufix, Pumpfix and Ecolift models from KESSEL.
