Description of Damage

Flow obstacles are objects or materials lying in the cross section of the pipe, which project into it or cross through it in such a manner that the cross section required for a proper flow of the sewage is no longer completely available.

Properly integrated components such as reducers, throttling or back-up flaps do not constitute discharge obstructions in the sense of a damage.

Typical flow obstacles often found in practice are [ATVM143-1:1989] :

• Hardened depositing;
• Incrustation (Image 2.4.2-1) (Image 2.4.2-2) (Image 2.4.2-3) ;
• Projection flow obstacles;
• Root growth;

Image 2.4.2-1:  Incrustrations in a concrete sewer [FI-IfK]

Image 2.4.2-2:  Incrustrations in a vitrified clay sewer [FI-IfK]

Image 2.4.2-3:  Incrustrations [FI-Jtele]