Glossary – Definitions Of Drainage Problems

Below are some of the terms we use and some of the problems that we come up against when we are out on call.

CRACKS & FRACTURES:

Cracks are one of the most common conditions recorded on C.C.T.V. surveys, they fall into 3 categories. Circumferential cracks, these, of course circle a part or all of the diameter of the pipe. Longitudinal cracks, these run down the pipe. They can be seen for a part of or all a given pipe. Multiple cracks, are a mixture of both of the above conditions. Cracks become continuous when they affect more than one length of pipe, with a crack in the same position. Fractures are visibly open cracks.

DEFECTIVE CONNECTIONS:

Defective connections come in many forms; for example pipe work intruding into the drain which may have the potential to cause a blockage.

DEBRIS IN DRAIN:

Detritus matter (debris) is deposited in drains as it falls out of suspension in the transport water. The most common type of debris to identify is grease. Grease tracks itself to the side of the drain and over time builds to form a blockage.

DRAIN ENCRUSTATION:

Encrustation of drainage pipe work is caused by the build up of salts from the local water supply that is flushed down the drainage system. This condition is often more evident in hard water areas (such as cities or urban areas) where lime salts are the main cause of the encrustation. This condition can build up throughout a drainage run and cause blockage.

ROOT INGRESS:

Any root ingress usually falls into three categories. These are fine roots, tap roots or a root mass. Fine roots are self explanatory; Tap roots are about as thick as your finger and mass root is a web like build up of which clogs the drain. It is worth remembering that root ingress often starts at a single point and then tail down the drain with the flow.

COLLAPSE DRAINS:

This drain condition is self explanatory. It cannot be confused with any other condition found whilst surveying. This condition is best isolated by surveying from any downstream chamber; this allows a physical distance to be recorded for the excavational repair. A pipe is deemed to be collapsed when more than 50% of its diameter is obstructed by broken pipe.