Quick Facts:
- One of the greatest challenges to safe pipeline operations is accidental damage to the pipe or its coating that is caused by someone inadvertently digging into a buried pipeline.
- This damage can be caused by any of the typical forms of excavation (digging, grading, trenching, boring, etc.), including road and highway maintenance, general construction, and many farming activities. Also included is new home construction and certain routine homeowner activities.
- Pipeline markers only show the general location of a pipeline or pipeline right-of-way. Markers do not show the precise pipeline location or depth of burial. Do not rely solely on markers to show where it is safe to dig.
- Prior to beginning an excavation project, EVERYONE – businesses and individuals - must call their local “One-Call” Center to report where they plan to dig so that all underground facility operators can locate and visibly mark the location of their buried facilities (free of charge) before excavation begins. If the telephone number is unknown, please call 1-888-258-0808 for your local One-Call contact information.
- State laws govern these One-Call Centers. All 50 states are now covered by One-Call programs. Calling before you dig is the law.
What is Excavation Damage and why does it occur?
Excavation damage may include damage to the external coating of the pipe, or dents, scrapes, cuts, or punctures directly into the pipeline itself. Excavation damage often occurs when required One-Call notifications are not made prior to beginning excavation, digging, or plowing activities. When the location of underground facilities is not properly determined, the excavator may inadvertently – and sometimes unknowingly – damage the pipeline and its protective coating.
Safe digging requires that the following steps be observed:
- Make the required “One-Call” before digging;
- Wait the required time for locations of all buried facilities (including pipelines) to be marked;
- Respect the location markings when digging; and
- Dig with care, avoiding contact with these underground hazards.
If digging causes a pipeline break:
- Abandon equipment and leave the area immediately;
- Warn others and keep traffic and ignition sources out of the area;
- Stay upwind of any suspected leak; and
- Immediately notify public safety officials and the pipeline company.
What are the risks from Excavation Damage?
Excavation Damage can result in both public safety and environmental hazards due to the release of petroleum and natural gas products. Injuries, and even fatalities, can and sometimes do result from excavation damage — in fact, of all pipeline failure causes, fatalities and injuries are most likely to occur with this type of failure.
Excavation Damage can cause catastrophic failures in two ways: 1) It can cause an immediate failure of the pipeline due to the contact between the excavation equipment and the pipeline; or, 2) It can result in damage to pipeline coatings or dents or scrapes to the steel pipe that can lead to catastrophic failure of the pipeline at some point in the future. (In this delayed failure mode, damage to coating can allow accelerated corrosion to occur which, when combined with the physical damage to the pipe steel from any accompanying denting or gouging, can result in an increased potential for future leaks, or in some cases, catastrophic failure.)
In any case of contact with a buried pipeline when digging, it is imperative that the pipeline company be contacted immediately to examine the pipeline even though the damage may not be apparent or may look relatively harmless at the time. (This delayed failure mode is particularly insidious, and is the reason why OPS’s Integrity Management regulations place special emphasis on “top-of-pipe” indications during inspections — indications that are located on the top 2/3rds of the pipe may be from this particular type of Excavation Damage.)
Pipeline failure rates from Excavation Damage
OPS reports that for the period 2002 through 2003, approximately 15% of incidents for hazardous liquid pipelines and approximately 18% of incidents for natural gas transmission pipelines were the result of Excavation Damage. For hazardous liquid pipelines, approximately 35,000 barrels (1.47 million gallons) of product were spilled due to Excavation Damage during this period.
What is being done to prevent Excavation Damage?
Pipeline companies have joined with other underground facility operators — providers of electricity, fiber optics, cable and telephone , and local water and sewer service — to create and finance “One-Call” Centers that serve all 50 states and the District of Columbia. While laws vary by state, they all require excavators to contact the One-Call Center responsible for their area before any digging begins.
- State One-Call Centers are established to help ensure that excavation is performed safely and to prevent damage by or to underground facilities. One-Call Centers serve as a central communication point for anyone planning to excavate (dig). The One-Call Center alerts affected underground facility operators of the excavation plans and the location of the proposed excavation. Facility operators are then responsible to locate their facilities and visibly mark their locations so that the person(s) doing the excavation will be able to dig safely over and around these buried facilities.
- By implementing the requirements of OPS’s Integrity Management regulations and through responsible maintenance programs, pipeline operators continuously inspect their pipelines for indications of Excavation Damage. Right-of-way patrols, including surveillance by airplane or helicopter, are performed by operators on a routine basis to identify areas where construction or excavation activity may adversely impact their pipeline. Operators may assign on-site personnel to observe such activities.
Excavation Damage: What more can be done?
- General Public : Be aware of pipelines located near you. Be observant for signs of pipeline damage, leakage, or security concerns. Report any concerns you have regarding pipeline safety to the pipeline operator immediately. Always respect the pipeline right-of-way. Do not dig or build on a pipeline right-of-way without first contacting your state One-Call Center.
- Industry: Pipeline operators and industry stakeholders can strengthen community and excavator awareness programs explaining the dangers of excavation damage and the steps that all excavators, including the public, must take prior to initiation of an excavation project.
- Regulators: OPS and state regulators must continue to support One-Call Centers and other damage prevention initiatives, including those of the Common Ground Alliance.
Excavation Damage: Where can I learn more?
Date of Revision: 120704