Comparing the United States and Japan reveals a startling difference in the number of incidents of underground utility damage during construction. In the U.S. the number of incidents is between 400,000 and 800,000 per year (roughly one or two every minute). For Japan the number of incidents in 2016 was 134. Clearly something is being done differently in Japan to reduce underground utility damage.
Many jurisdictions have attempted to address the problem of damage to underground infrastructure during construction, but only a few have managed to reduce damage.
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In North America every state and most provinces have enacted one call legislation. The Common Ground Alliance (CGA) has been collecting voluntarily submitted statistics on underground utility damage in North America since 2003. The latest CGA DIRT Report for 2018 concluded that progress in the U.S. in reducing damages has plateaued. Total damages in the U.S. increased from 439,000 in 2017 to 509,000 in 2018, representing a 16% increase. Damages per 1,000 one call information requests increased by 11%, from 1.87 to 2.08, and damages per million dollars of construction spending (2017 constant dollars) went from 0.359 to 0.392.
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Number of incidents of damage (blue) and number of incidents per 1000 notifications (yellow)
Statistics on incidents of underground utility damage from the Ontario Regional Common Ground Alliance (ORCGA) 2018 DIRT Report reveals that the damage ratio - number of incidents per 1000 notifications - decreased from 2007 through 2014, but since 2014 the trend has been gradually increasing.
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The Dutch one call KLIC system is very efficient, able to produce digital maps of underground infrastructure within a day of a request from an excavator. But there are over 41,000 incidents of utility damage every year in the Netherlands and there is no sign that this is decreasing.
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Significant gas transmission pipeline incidents per 10 000 HCA miles 2004-2018
The Pipeline and Hazardous Materials Safety Administration (PHMSA) which is responsible for gas and hazardous liquids pipelines in the United States has implemented programs to reduce incidents involving underground pipelines including during construction. PHMSA’s statistics are considered reliable because incident reporting is mandatory. In spite of the regulations implemented by PHMSA to improve pipeline safety, PHMSA’s statistics have not revealed a trend toward a reduction in pipeline incidents including those attributed to excavation damage.
Two jurisdictions where historical statistics reveal a reduction in annual incidents are Japan and Heathrow International Airport. In both cases a comprehensive multi-faceted approach including policies, regulation, changes to construction practices, and new technologies have been applied to effect a reduction in the number and severity of incidents. Here we include just a few of the measures taken.
Damage prevention in Japan
In Japan the Road Administration Information Center (ROADIC) was originally created in 1986 as a result of several large-scale gas explosions that killed and injured hundreds of people and caused tremendous damage. Originally implemented in Tokyo in the mid-1980s, it has been extended to 12 major urban centres throughout Japan.
The Road Administration Information System (ROADIS), developed in the nineties under guidance of the Ministry of Land, Infrastructure and Transport (MLIT), went operational in 1998. ROADIS provides road administrators and utility network operators with data on each other's facilities in Tokyo and 11 other cities. Its data is used for road construction coordination and road occupation application / permission procedures. Its broader social responsibility is preventing accidents during road excavation and preventing indirect effects of utility damage such as injuries and deaths, traffic congestion, lost custom and delayed and over budget construction. Guidelines for construction specified in the “Construction Public Disaster Prevention Measures Summary from the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) mandate trial digging to validate the location of underground infrastructure. The Occupation Entrepreneur Liaison Council in which all utility network operators participate provides guidelines for excavation. The guidelines specify that all areas within 50 cm of underground utilities must be manually dug. In the case of new infrastructure the as-builts submitted by the contracting company to the network operator must comply with the Rules for Work Regulations Based on Article 34 of the Surveying Law. The accuracy of the as-built data is required to be ± 10-20 cm.
In 2016 a survey was carried out to determine the amount of excavation damage resulting from excavation. That year there were 263,000 requests for location information about underground utilities. Of the 180 companies contacted 107 responded by reporting incidents of damage to utilities in that year. It was found that there were 134 incidents involving underground utility elements, like cables and pipelines, and 82 incidents for above ground structures. Statistics indicate that the annual number of incidents has been declining since data was first collected in 1983.
Damage prevention at Heathrow International Airport
Airports are like cities except that they have a greater density of underground utilities and more types of underground equipment; communications cables, aeronautical ground lighting cables, gas mains, low voltage electric power cables, high voltage electric power cables, storm water mains, sanitary waste water mains, potable water mains, grey water mains, fuel mains, fire fighting water mains, and a variety of underground structures with over 50 different owners. A number of years ago Heathrow implemented a seven step process, from early design to handover, for excavations at Heathrow that continues to be followed today. Heathrow has also developed a business process for continuous improvement of the location accuracy of underground infrastructure.
Another key aspect of Heathrow’s program for reducing the risk of utility damage is training for skills development. Heathrow helped to develop National Vocational Qualifications (NVQs) relevant to underground asset management.
As a result of these and other measures service strikes (accidentally hitting a utility cable or pipe) due to inaccurate information about underground infrastructure have declined at Heathrow by a factor of 6 since 2002 while total construction activity increased significantly.
Related initiatives
Other jurisdictions have recognized the importance of adopting a more comprehensive approach to locating underground infrastructure.
In 2017 the Singapore Land Authority (SLA), Singapore-ETH Centre, and the Geomatics Department of the City of Zürich started the Digital Underground project, a comprehensive program of technologies, policies, and processes for achieving and maintaining an accurate, current, and complete map of subsurface utilities in Singapore.
In 2018 the Colorado legislature revised the state's one call legislation which now differs from other states and provinces in that it explicitly mandates subsurface utility engineering (SUE) during engineering design for public civil engineering projects to determine the location of underground utilities to ASCE 38-02 quality level B by a licensed professional engineer. (ASCE quality level B requires the application of remote sensing detection technologies such as electromagnetic detection and ground penetrating radar.)
Conclusion
Based on the experience of Japan, Heathrow and other jurisdictions, it is clear that a comprehensive approach involving policies, regulations, technologies and construction practices are required to reduce damages to underground infrastructure during construction. The available statistics show that programs such as one call centres are not sufficient by themselves to reduce utility damage, but must be complemented by other measures. An upcoming GITA white paper will provide a compilation of the measures that have been undertaken by jurisdictions in Japan, the U.K. including Heathrow, the Netherlands, Singapore, the U.S. including Colorado, Canada and other countries to reduce utility damage during construction.
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