History in the Making: Witnessing Tacoma’s First Sewer Pipe Bore
Apr 13, 2017
If you are a Tacoma local you may have noticed the commotion on S 56th St during the last couple days of March. What you might not have realized is that, while traffic was slowed for that block between Cushman and Sheridan, history was being made. Our team was working hard to orchestrate and complete Tacoma’s very first sewer pipe bore!
Pipe boring is the process of using a high powered drill to create a hole in which a new pipe can be pulled through, but there are a few steps that need to be taken before drilling can begin.
1. Utility Lines Must Be Exposed
This is done through what is called “hydro excavation.” Hydro excavation uses a high powered jet of water, along with a vacuum to essentially “pothole” a specific area. This will expose any utility lines that may be present such as gas lines, water lines, or electrical conduit. It is required by the city that all utilities must be exposed before drilling.
2. Access Holes Must Be Dug
In this particular case. We had an access hole about five feet deep on one end, and about ten feet deep in the street. This means that signs had to be placed (hence the slowed traffic) and concrete had to be cut out and removed. If you have never seen concrete removed from the middle of a main city road before, it is quite the sight.
3. The Grade Must Be Measured
In order for a sewer line to flow properly, it must be graded downward from the source. This means it must be installed at an angle. When you are working with long distances such as in pipe boring this requires the use of a grade rod, and builder’s level. The grade rod is somewhat like a measuring stick, and the builder’s level resembles a small spyglass. These are used to be sure when the drill goes through, it will go through at the proper angle.
Once all these things have been performed properly, we can begin to drill.
The process of actually getting the drill through the ground is extremely involved and tedious. First we must make sure we are able to locate the drill tip as it moves through the ground. This is done by inserting a small rod that sends a signal out to a locator. This way, we are able to measure the depth, direction, and angle of the drill head as it moves through the ground.
The person operating the locator, and the person operating the drill are in constant communication via headsets. That way, they know they are going to always be in the right place at the right time.
As the drill moves through, more rods are added to the machine. That way, we are able to reach our desired length of pipe.
In this particular case, after the hole was bored a cable was run back through the hole that was made. Because of this, we were able to pull a bursting head along with a new pipe through resulting in a brand-new sewer line.
This is especially exciting because of the possibilities of installing brand new sewer lines without having to trench at all. If you have any questions about pipe boring, or installation of new sewer lines feel free to contact us at (253) 285-1771 or click here to request appointment.