Sliplining (Relining)

1. METHOD DESCRIPTION
The rehabilitation method using segmental pipe sliplining consists in inserting short pipe segments inside the old pipeline. Depending on the type of the network and pipeline being rehabilitated, the liner is introduced through an existing manhole or an excavated insertion point.
The shape of the lining segments match the existing pipeline cross-section: they can have a circular and non-circular cross-section.

2. LINE INSTALLATION EQUIPMENT

• sewer cleaning equipment (pressure truck);
• sewer inspection camera;
• pulling machine (pipe puller);
• by-passing unit (pumps, hoses);
• platform truck for transportation of the liner (segments); ͵ hoisting crane (or container truck with a hoist);
• pumps for feeding grout;
• sewer ventilation unit;
• pneumatic fretsaw;
• pneumatic jigsaw;
• testing equipment.

3. PREPARATION TO INSTALLATION
Assessment of the sewer’s technical condition
Before starting rehabilitation, the pipeline is cleaned using a hydrodynamic sewer cleaning unit mounted on a truck. Then the pipeline is inspected using a remotely controlled camera. The video footage is used for preparing a detailed digital report on the pipeline’s technical condition. The report is a base for classifying the sewer’s technical condition.
Choice of the rehabilitation method
The rehabilitation method depends on the technical condition class and damage degree. After the assessment of the sewer’s technical condition, geodetic data have to be analyzed, including ground water level compared to the base of the sewer, motor traffic in the area, and other parameters that impact parameters of the selected liner.
Storage and transport to the site
Segmental liner is delivered to a storage yard and supplied to the site in small batches.

4. INSTALLATION OF THE LINER
Individual rehabilitation liner segments are inserted into the sewer through existing manholes (in case of segments up to 0.5 m long and DN 600 mm in diameter) or through excavated insertion points, using a hoisting device matching the weight of the segments.
Afterwards, the segments are moved to the installation point manually, using a slide or a special trolley. They are connected using a seal placed in a socket. They should be aligned with the center of the existing pipeline.
Liner segments smaller than 500 mm can be connected manually using special equipment. With larger sizes manual hoists, levers, and presses have to be used. During connection operations the segments’ connection surfaces should be protected against damage. Do not apply force to any point or small area of a bare segment end.
Before connecting two segments, mark the required spigot insertion depth on the bare end of the section. Only complete insertion of the spigot guarantees secure and tight connection. Sealing elements in the sockets are subject to high pressure forces, so mechanical devices should be used for connecting segments. Before connecting two segments, mark the required spigot insertion depth on the bare end of the section. Only complete insertion of the spigot guarantees secure and tight connection. Sealing elements in the sockets are subject to high pressure forces, so mechanical devices should be used for connecting segments.
Connecting house drains to man-accessible sewers
Using a pneumatic fretsaw, make an opening in the point where the house drain is to be connected to the segmental liner. Then, using a pneumatic jigsaw, cut an opening matching the inner diameter of the house drain pipe.

5. FILLING THE EMPTY SPACE
When the section is ready, the ends are closed and the cement mortar (after a recipe designed accordingly) is introduced to flow gently between the two walls. For ease of filling (careful not to lift the liner through floating by the mortar), you can drill holes in the inner shell wall or use existing house connections.
The mortar must be injected at a pressure that does not cause the maximum buckling tension to be exceeded for the pipe so that it does not collapse. It is especially important when rehabilitating pipes with large diameter and reduced circumferential stiffness. While sealing the pipe gap, place the spacers inside the segmented lining, preventing its distortion as a result of the mortar pressure.

6. INSPECTION
TV Inspection
After the installation and opening connections, acceptance TV inspection (including VHS or CD recording) is carried out. Inspection report is also prepared.
Tests
According to EN ISO 11296-1, 13566-5 and EN 1610

7. CORRECTION OF FLAWS
Flaws are corrected using a robot controlled via a camera or / and inserting and gluing short pipe sections.