There are millions of miles of underground pipelines and other utility lines that, if damaged, can cause bodily injury, property damage, utility service outages, repair costs, and potential fines. If damage occurs, it is important to recognize it and know what to do.
When considering any activity involving any type of excavation work, no matter how minor, it is important to notify your local one-call center. This can be done by calling or submitting an online request to Call 811 (call811.com) to ensure there are no buried pipeline and utility services in the area. Most states require at least two working days’ notice prior to the project, to give utility operators the opportunity to locate and mark underground utilities. On average, seven to eight utility operators are notified for each request. Once you have confirmed that all affected utility operators have responded to the request, you can dig carefully, respecting any marked areas.
The American Public Works Association (APWA) provides a uniform color code system for identifying affected utilities (Fig 1). These colors may be used with chalk, paint or flags. White markings should be used to identify your proposed areas of excavation.
Oil and Gas Pipelines
According to the National Transportation Safety Board, pipelines are one of the safest and most efficient means of transporting oil and natural gas production. In the U.S., there are over 2.4 million miles of pipeline, with 2.1 million miles consisting of local distribution lines alone.
Three major types of pipelines are found to move oil and natural gas. Gathering pipelines are normally low pressure, small diameter systems that gather raw products from production wells and transport it to transmission systems. Transmission pipelines are typically larger and under higher pressure than gathering and distribution lines. They transport energy products across the country and to storage facilities. Distribution systems carry energy products to homes and businesses through main and service lines. These pipelines are often under low-pressure and smaller in diameter.
Pipeline markers are used to identify pipeline rights-of-way approximate locations, and are often seen where a pipeline intersects a street, highway, or railway. The markers list the pipeline operator company, product transported, and an emergency phone number. There may also be aerial markers facing skyward for patrol planes that monitor the pipeline routes and casing vent markers to indicate a pipeline passes beneath a nearby road, rail or other crossing.
Recognizing a leak
Despite best management practices and government oversight, pipeline incidents do sometimes happen. Pipeline operators have multiple safety precautions to detect leaks, from computer based leak detection systems to regular patrols of the pipeline rights-of-way. Pipeline control rooms monitor safety indicators like changes in pressure, flow, and volume along the pipeline. Pipelines can be shut down at the first sign of a leak, and notification is quickly sent to emergency responders.
The best ways for you to detect a leak in your neighborhood is to use your senses:
Sight: Liquid pools, continuous bubbling in a wet area, oily sheen on water surfaces, or a mist-like cloud over a region are some ways to recognize a leak. Other signs may be dry areas in a wet field, dead or discolored plants in an otherwise healthy area of vegetation, or frozen ground in warm weather. Blowing dirt or liquid around a pipeline region, fire from the ground, or burning above ground are other possible signs.
Sound: Another indication of a leak is uncommon hissing or loud blowing or roaring noises, varying in volume.
Smell: Unusual gasoline/diesel smells or a strong acidic, sulfur, rotten egg scent can warn people of a leak. While natural gas and highly volatile liquids are odorless in their natural state, commercial odorants such as the chemical mercaptan, are commonly added to make it easier to detect a gas release.
The Do’s and Don’ts if a leak were to occur
If a pipeline or utility line is hit when digging, it is important to extinguish all sources of ignition, and turn off any gas or electrical appliances. Leave the area immediately on foot in an upwind and uphill direction from the area if possible. Warn others to evacuate the area and call 911 from a safe distance.
You do not want to start any vehicle or equipment that could be a potential ignition source. Don’t try to turn off pipeline valves or touch any liquid or vapor cloud coming from the pipeline leak. It is important not to use anything that will create a spark, such as cell phones, pagers, flashlights, light switches, or lighting a match.
Once a company is notified of an incident, they will immediately dispatch trained personnel to the area to isolate and minimize the issue, working with public and safety officials.