Degree of filling

For horizontal drainage pipes, the degree of filling h/d_i describes the ratio of the water depth h of the water flow to the internal pipe diameter d_i.

Sufficient aeration and ventilation is required so that the odour traps of the connected drainage objects are not sucked out and sewer gases enter the room. Filling levels that are too low as planned impair the self-cleaning ability of the pipe and should therefore be avoided. If a filling level of 1 is reached, a pressurised drainage system should be considered. Rainwater pipes may also be operated as planned when fully filled, i.e. with a filling level of 1.0, because ventilation may be interrupted in this case.