Whether you work directly with the installation or cleaning of sewer lines, or indirectly in a related business or in an ancillary capacity, it is important that you have an awareness of this safety issue. You also need to know how to respond should a hazardous condition occur.
Utilities use a trenchless technology called horizontal directional drilling (boring) to pull cables, conduit and pipe underground. This installation method causes less impact to the surrounding area and minimizes environmental disruption. It also saves time, allowing utility crews to work more efficiently. Before Chattanooga Gas begins directional drilling, precautionary safety measures are taken to determine the location of all underground facilities, including sewer lines. Unfortunately, there are instances when sewer lines cannot be properly identified and our gas pipe is inadvertently pulled through existing infrastructure, leaving the opportunity for accidental damage to the gas pipe in the future.
The presence of a gas pipe in a sewer line is known as a “cross bore.” A cross bore can remain undetected for months, even years. The typical way they are discovered is when the sewer line becomes clogged and a blockage needs to be removed. While it is common practice to use a mechanical rotary device to root out the blockage, this process could damage the gas pipe that has been bored through the sewer line, resulting in a loss of service and a potentially hazardous leak condition.
Prior to working on a sewer line, important precautionary steps should be taken to prevent possible damage to the infrastructure:
If you discover a natural gas pipe in a sewer line, stop all work immediately, call Chattanooga Gas at 866.643.4170 and report it as a natural gas emergency. Be sure to let the customer service representative know that you have discovered a cross bore. We will take the appropriate steps to remove the gas pipe and make the area safe.
Should you be working on, or in the vicinity of a sewer line, you need to know the signs of a natural gas leak:
If you believe you have damaged a gas pipe in a sewer line by pulling, nicking or breaking it: