Trenchless Sewer Repair – The Future Is Here
Trenchless sewer repair is a no-dig way of repairing or replacing old and leaking underground pipes. Rather than digging a trench to fix the old pipe, this method only requires digging small holes to access the pipes if they are buried. No digging is required if the sewer line is accessible through manholes or other convenient access points.
These days, an open-cut sewer replacement is the least effective option because of the risk of damaging the extensive network of street utilities and the potentially severe negative traffic impacts.
Trenchless sewer repair is commonplace in the repair of sewer lines. Many cities are using this technology because of the significant advantages of reduced time to repair and reduced disruptions. Many repairs can be completed within 1 day.
This procedure can be used for:
- Manhole repairs
- Sewer line spot repairs
- Sewer lining rehabilitation
- Water main lining rehabilitation
Before Starting any Trenchless Sewer Repair
The problem can usually be identified by using a sewer inspection camera.
Some cities use a CCTV video sewer inspection camera system to monitor the condition of their sewer system. The system helps to determine their maintenance and rehabilitation needs.
Trenchless Sewer Repair Technologies
Lines can be repaired or replaced without damaging the surrounding infrastructure. A number of methods are available for this type of repair:
Cured-in-Place Pipe (CIPP)
One of the most widely used trenchless sewer repair methods and can be used on pipes from 3” up to 110”.
Then steam, hot water, or UV light is used to cure the resin mix to form a tight fit against the existing sewer walls. These repairs can be performed quickly and the whole procedure can take less than a day. However, this method cannot be used if the pipe has collapsed somewhere.
A new pipe is pulled through the old pipe using hydraulic machinery, completely replacing the old/broken pipe. Can be used on pipes from 2” to 36” (has been used up to 48”) . HDPE and MDPE are the most common replacement pipes used in this method. Cast iron, vitrified clay, and reinforced concrete pipes can also be used.
This method requires 2 access points.
This method can be used to replace pipes with same size diameter or larger.
Slip lining pipe can be either continuous or segmented. Lengths can be tied together using a thermal fusing machine.
Requires two access points via a small excavated entry trench to provide access to the host pipe, or to a manhole if the insertion will begin there. Also, a lubricant such as bentonite can be used to facilitate the slipping action required to insert the pipe.
It is also recommended to push and not pull the pipe through. Pulling can elongate or stretch the new pipe out of shape.
This repair always results in a smaller diameter pipe.
Grouted-in-Place Pipe (GIPP)
A patented trenchless sewer repair method by Groling in Germany called The Trolining System. This method can be used on larger pipes ranging in diameter from 2-2/3’ to 6-1/2’. It is based on high-density polyethylene (HDPE) liner components,and uses V-shaped embedment studs. The space created by the studs is filled with a specially engineered injection grout that fixes the liner permanently in place and provides the load-bearing shell of the system.
Once installed, the thermoformed pipe will not return to its original size or shape after it has cooled, nor will it shrink in length. It will take on the shape and size of the original sewer pipe.
Special sleeves or short sections of CIPP are installed inside the pipe only in the area where the pipe needs to be rehabilitated. With the help of a sewer inspection camera for proper placement, the sleeve is sealed in pace with grout or glue.
This provides a more economical way to maintain sewer lines. Instead of replacing the whole pipe section, only the damaged section is repaired. Properly done, this can provide a huge cost saving.
Which Trenchless Sewer Repair Method Do I Choose?
For most residential repair jobs, CIPP or Pipe Bursting would be used. These methods generally cost more than conventional digging, but will minimize the destruction of the homeowner’s property.
Municipal repairs are a lot more complicated and will require an evaluation by the city for each particular condition, considering the location of the pipe and the nature of the break.
From one city’s experience, CIPP is used when:
- Sewer is deep underground;
- There are abrupt changes in direction and/or grade;
- Host sewer pipe is 8 inches or smaller;
- Existing sewer laterals need to be retained – a robotic cutter makes holes in liner to connect to existing laterals. Comparatively, slip lining needs an excavation at each lateral connection.
For more information on trenchless sewer repair technologies please contact sewer contractors in your area. Please take note that technology is evolving at a rapid rate and new techniques and materials are being introduced by trenchless sewer repair manufacturers.
Related article: A Trenching and Excavation Revolution Is Underfoot