Protecting Excavation Public Safety through Damage Prevention
Pipeline accidents result in fewer fatalities annually than accidents in the other modes of transportation; however, a single pipeline accident has the potential to cause a catastrophic disaster that can injure hundreds of persons, affect thousands more, and cost millions of dollars in terms of property damage, loss of work opportunity, community disruption, ecological damage, and insurance liability. Excavation and construction activities are the largest single cause of accidents to pipelines. Data maintained by the U.S. Department of Transportation, Research and Special Programs Administration (RSPA), Office of Pipeline Safety, indicate that damage from outside force is the leading cause of leaks and ruptures to pipeline systems, accounting for more than 40 percent of the reported failures. According to the data, two-thirds of these failures are the result of third-party damage; that is, damage caused by someone other than the pipeline operator. Reports from the 20th World Gas Congress confirm that excavator damage is also the leading cause of accidents in other countries.
According to the Network Reliability Steering Committee (NRSC), an industry group appointed by the Federal Communications Commission, excavation damage is also the single largest cause of interruptions to fiber cable service. Network reliability data, compiled since 1993 by the NRSC, show that more than half of all facility outages are the result of excavation damage (53 percent). The Safety Board’s review of NRSC first quarter data for 1997 indicates that this relationship has not changed. In addition to being expensive and inconvenient, disruption of the telecommunications network can have significant safety implications, such as impact on traffic control systems, health services, and emergency response activities. The Federal Aviation Administration’s (FAA) study of cable cuts in 1993 documented 1,444 equipment outages or communications service disruptions resulting from 590 cable cuts nationwide over a 2-year period. The majority of cable cuts were related to construction and excavation activities. For 1995, the FAA’s National Maintenance Control Center documented cable cuts that affected 32 air traffic control facilities, including 5 en route control centers. Cable cuts for the first 8 months of 1997 affected air traffic control operations for a total of 158 hours.
The U.S. underground infrastructure comprises about 20 million miles (32.2 million kilometers) of pipe, cable, and wire. The term “underground facilities” generally refers to the buried pipelines and cables that transport petroleum, natural gas, electricity, communications, cable television, steam, water, and sewer. In addition to being categorized by product type and structural component, underground networks are further grouped according to function (gathering, transmission, distribution, service lines); owner (public utility or private industry); or jurisdiction (municipalities, State, and Federal agencies). The diverse and segmented nature of underground facilities is evident from the variety of organizational interests that work with the subsurface infrastructure: facility owners; construction crews, government authorities, insurance companies, locating contractors, and notification communication specialists.
The Safety Board has long been concerned about the number of excavationcaused pipeline accidents. In response to six serious pipeline accidents during 1993 and 1994 that were caused by excavation damage and to foster improvements in State excavation damage prevention programs, the Safety Board and RSPA jointly sponsored a workshop in September 1994. This workshop brought together about 400 representatives from pipeline operators, excavators, trade associations, and local, State, and Federal government agencies to identify and recommend ways to improve prevention programs.
This safety study was initiated to analyze the findings of the 1994 workshop, to discuss industry and government actions undertaken since the workshop, and to formalize recommendations aimed at further advancing improvements in excavation damage prevention programs. Safety issues discussed in the study include the following:
- essential elements of an effective excavation damage prevention program;
- accuracy of information regarding buried facilities; and
- system measures, reporting requirements, and data collection.
As a result of this study, safety recommendations were issued to the Research and Special Programs Administration, the American Public Works Association, the Federal Highway Administration, the Association of American Railroads, the American Short Line Railroad Association, the American Society of Civil Engineers, and the Associated General Contractors of America.
