Localized Point Repairs and Sealing

Concept of localized repairs

A variety of localized repair systems have been developed, most for sewer rehabilitation and some for sealing joints in pressure pipelines.

Many are adaptations of full-length lining systems, particularly methods based on resin-impregnated felt or fabric cured in place.

Today these systems show a notable similarity to catheter and stent procedures used in coronary systems.

Economic feasibility

The economics of these methods must be assessed case by case.

Where damage is confined to only part of a pipeline, repairing individual defects can be more economical than rehabilitating the entire length.

As a broad rule, localized repairs are often considered economically viable when structural defects affect less than about 25% of a sewer length, although the balance varies with specific circumstances.

Cleaning and pre-inspection

Cleaning and pre-inspection are essential for localized repair systems, just as they are for full-length rehabilitation methods.

For point repairs that require bonding to the existing pipe, all traces of grease and debris must be removed.

System categories

Five principal categories of localized repair systems can be identified: sleeve or impregnated-felt repairs, resin injection systems, robotic repairs, restoration of circular section and joint sealing.

Comparing these approaches also raises the question of what should or should not be regarded as a structural repair.

Joint sealing

Available systems include localized joint testing and sealing using inflatable packers to treat specific points in the pipeline.

These techniques make it possible to address isolated defects and joints while reducing the need for intervention along the full network.