Innovations in underground infrastructure mapping for reducing damage during construction

This is a summary of a talk I gave earlier this week at the Mapping the Underground VCX virtual event.

Context: construction productivity

The $10 trillion global construction industry is facing a crisis. For many of the world's advanced economies including Japan, Germany, U.S., South Korea, and U.K. construction productivity has been stagnant or even declining for decades. Virtually all of the funding for infrastructure was sourced from government who were looking for a social return on the investment. Since the mid 2000s, an increasing proportion of investment in infrastructure has come from private sources; pension funds, insurance companies and sovereign wealth funds which together manage over $60 trillion. These sources of investment are expecting a financial return and that is driving a growing investment in construction technology to improve productivity.

Historically, investment in research and development by the construction industry has been very low compared to other industries. Several years ago a McKinsey Global Institute study compared the degree of digitalization of nearly 30 industries and concluded that construction ranked right at the bottom with hunting. But there are signs of a change. Venture capital investment in technology startups in the construction sector is growing. 2018 was an inflection point with venture capital investment in the construction sector quadrupling.

Underground utilities contribute to low construction productivity

According to the Federal Highway Authority (FHWA) “utility-related problems are a leading cause of delays for highway construction projects, according to a recent National Cooperative Highway Research Program study.” Government agencies and construction firms are recognizing that accurate models of underground infrastructure bring practical benefits to construction projects. For example, the Alabama Department of Transportation estimated that is saved $10 million by creating an accurate 3D model of underground utilities for a major downtown highway interchange project. More importantly the 3D model was seen as responsible for helping the project remain on schedule and on budget.

Engineering consulting firms are also recognizing that an accurate 3D model prior to design can eliminate unnecessary and costly relocation of utilities. For a highway revitalization project in Cedar Falls, Iowa, a 3D model of underground utilities was created before design began and 200 utility conflicts were found and avoided or ameliorated, enabling the project to be completed on schedule and 3 percent under bid.

Underground utility damage is expensive

Every year there are injuries and fatalities attributable to underground utility damage. For comparison over a similar 20 year period the number of deaths from incidents involving major civil aviation carriers totaled 403 (excluding those associated with 9/11). Whereas the budget of the Federal Aviation Authority, which is tasked with reducing aviation incidents, is $17 billion, very little government money is devoted to reducing underground utility damage during construction.

The cost of underground utility damage to the U.S. economy is staggering. According to the Common Ground Alliance (CGA), which collects and compiles reports voluntarity submitted on incidents of underground utility damage, there are between 400,000 and 800,000 incidents annually in the U.S. The estimated direct cost per incident is about $4000. This does not include indirect costs; property damage, traffic disruption. loss of custom, environmental impacts, lawsuits, injuries, fatalities and many others costs related to utility damage. Research at the University of Birmingham in the U.K. has estimated that indirect costs are 29 X direct costs. Putting this together leads to an estimate that underground utility damage represents a $ 50-100 billion drag on the U.S. economy.

Comparing underground utility damage in Japan and the United States reveals a startling difference in the number of incidents. In 2016 about 390,000 incidents were reported in the U.S. For Japan the number of incidents was 134. Clearly this shows that something can be done to reduce underground utility damage during construction.

Innovations in detection

As a result of accelerating investment in detection technology, new developments are changing how underground utilities are located and digitally mapped.

Advances in ground-penetrating radar (GPR) have made it possible to capture scans at roadway speeds with follow-up post-processing in the office. This is a huge gain in safety because it requires no boots on the pavement. One of the important inhibitors to the broader use of GPR, among surveyors, for example, is that interpreting GPR scans has required a trained geotechnician. New GPR post-processing software combines successive scans to produce a tomographic image of underground utilities rather than the typical hyperbolas. This capability simplifies the interpretation of GPR scans, enabling surveyors and other professionals to use GPR technology effectively. In another important advance statistical averaging is being used by several GPR vendors to improve GPR depth of penetration by increasing the signal to noise ratio. The simultaneous capture of above- and below-ground scans using Lidar and GPR can create a complete 3D model of all existing infrastructure which greatly facilitates planning, design and construction.

Other important advances are inertial mapping, which can be used to map underground pipe networks of various diameters for up to two kilometres, and acoustic locating, which has been shown to be effective in detecting underground objects down to 30 feet even in soil conditions that severely limit GPR penetration.

Innovations in digital recording

Electromagnetic (EM) detection is the industry standard for underground detection and is used by the vast majority of locators. However, a major drawback to EM is that it involves a manual process which results in marking the ground with paint or flags but does not result in a permanent record of the location of the utilities detected. Combining an EM detection wand with GNSS (and RTK for high accuracy) and digital capture on a smartphone enables the recording of an accurate digital record of the location of detected utilities.

Some jurisdictions are addressing the widespread practice of submitting inaccurate “as-designeds” at the completion of construction projects. The state of Montana has recently made it mandatory that survey-grade “as-constructeds” accurate to ± 0.3 feet and stamped by a PE or PLS be submitted after construction. This regulation is intended to ensure that accurate “as-constructed” data is being captured for all new underground infrastructure in the state right-of-way. The Montana Department of Transportation has implemented an online system for recording this information and sharing it with construction project stakeholders. It is accessible from the field using a handheld phone or other device. (For more about Montana's experience visit the talk at Mapping the Underground VCX by Matt King, Utility Supervisor at the Montana Department of Transportation.)

However, for some projects it may not be cost-efficient to conduct a traditional survey. New development in technology are providing other options. For newly installed pipelines Lidar scanning with a rig attached to a pickup truck prior to filling the trench combined with high accuracy geopositioning is being applied to efficiently capture location to millimetre precision. This enables even the position of weld points to be accurately identified back in the office. Furthermore, new reality capture solutions can generate as-builts accurate to ± five centimetres from videos taken with an Android smartphone using RTK GNSS or accurately surveyed control points for high accuracy georeferencing.

Innovations in capturing and sharing location of underground infrastructure

In the U.S. it has been estimated that $10 billion is spent annually locating existing underground utilities. This includes utilities and telecoms responding to one call notifications using either commercial locate services or their own staff and efforts by excavators to detect and verify the location of underground utilities prior to commencing digging. The result of these locate efforts is typically painted or flagged on the ground, but often it is not recorded on paper or digitally. At best this data becomes part of project documentation and is effectively lost at the completion of the project.

In Colorado new legislation mandates a subsurface engineering survey (SUE) prior to engineering design. The SUE survey must be stamped by a professional engineer (PE) and the results made available to stakeholders on public construction projects. The Colorado Department of Transportation (CDOT) has implemented a cloud and mobile system that incorporates elements of survey and GIS practice and technology. The system provides for recording and sharing the location and other information for underground utilities from SUE surveys, surveyors and other sources among CDOT, large and small construction contractors, network operators, and other stakeholders. Access to this data is provided over the web, enabling field staff to access underground utility location maps on a handheld. (For more about the Colorado program, visit the talk given by Rob Martindale, Utilities Program Manager at the Colorado Department of Transportation at Mapping the Underground VCX.)

The Scottish Vault system was implemented in 2012 as a voluntary system for sharing information about the location of underground infrastructure. Stakeholders in civil construction in Scotland have a history of working collaboratively and this tradition has enabled over 70 network operators as well as government agencies to share data about the location of underground infrastructure and planned road work. The data is accessible from laptops and on handhelds in the field. Scotland also has a dial-before-you-dig system which is gradually being superseded by Vault. In 2019 legislation was passed in the Scottish parliament to make Vault mandatory.

The Geospatial Commission, recently created by the U.K. government, has initiated the National Underground Asset Registry project with two pilots, one in the North East of England and the other in Central London. A huge achievement of the pilots was a collaborative approach that enabled 40 utility and telecom network operators and local government agencies to agree to share their data. This was facilitated by legal data sharing agreements and by strict data protection measures. The pilots resulted in a harmonized data model and symbology that allowed data from different sources to be integrated and shared on a common digital map. During the pilots a working online prototype was developed and tested. The next step is expected to be an invitation to tender (request for proposal) for a national roll out.

In the Netherlands in 2010 the Dutch one-call system KLIC went on-line. With the online system the turnaround time to respond to one-call information requests was reduced to hours. The largest benefit of the system is construction efficiency. KLIC is completely digital and does not require on site locate operations. For 95 % of one call information requests, maps of all underground infrastructure and the names of the utility and telecom operators with facilities in the excavation area can be accessed or downloaded within less than 24 hours. Only for major infrastructure such as gas or electric power transmission lines, is the network operator required to visit the proposed excavation site. From its beginning the KLIC one-call system was voluntary. But in 2008 the Sub soil Cables and Pipelines Information Exchange Act (WION) came into effect which made KLIC mandatory for both network operators and excavators.

Open data access

Some jurisdictions have even created open portals providing access to publicly available maps of underground infrastructure. For example, in 2019 new legislation made the Colorado Oil and Gas Conservation Commission (COGCC) responsible for regulating previously unregulated flow and gathering lines. New rules adopted by the COGCC require oil and gas companies to provide maps of their intrastate flow and gathering lines accurate to ± 25 feet. Over 7,000 miles of pipelines have been mapped, much of which had never before been documented. Remarkably COGCC created an open portal where maps of these underground lines are open to the public.

Standards are evolving

Quality standards are evolving to reflect the recent advances in technology and in business practices.

The release of the new ASCE Standard Guideline for Recording and Exchanging Utility Infrastructure Data (also referred to as the utility as-built standard) developed under the auspices of the American Society of Civil Engineers (ASCE’s) Construction Institute(CI) and Utility Engineering and Surveying Institute (UESI) is imminent. Whereas the original ASCE 38-02 standard released in 2002 did not specify precision, ASCE 38-20 does, which reflects the advances in underground detection technology and changes in business practices.

In the UK PAS 128 originally released in 2014 is also being revised and a new version will be available shortly. PAS 128 also specifies precision. Other standards including the Canadian CSA S250, Australia's 5488, the French 2012 Presidential Decree and Singapore's standard all specify precision.

At the Open Geospatial Consortium (OGC), a new Standards Working Group (SWG) has just been formed to develop the MUDDI standard for exchanging location information about the underground and to create mappings to existing standards for underground infrastructure (CityGML, buildingSMART IFC, LandInfra, CIM (Common Information Model), Multispeak, ESRI Utility Model,…) and for geotechnics (GroundwaterML, INSPIRE Geology, BGS National Geological Model, …).

(For more about evolving standards, visit the talk given Radek Grabowski and Eddie Gaytan of WGI at Mapping the Underground VCX.)

Addressing data quality

A key challenge in reducing damage to underground utilities is the low quality of the records maintained by network operators and others. Providing a mechanism for improving the quality of records is essential for reducing damage to underground utility damage. The CDOT cloud and mobile system includes an important capability that enables feedback from handhelds in the field during construction. This increases field staff engagement and enables staff to actively contribute to improving the accuracy of location and other information stored in records.

A similar capability enabling feedback from the field is provided by the prototype system developed for the National Underground Asset Registry pilots in the U.K. Referred to as “observations”, field staff can report discrepancies between what is shown by the system and what is actually observed in the field. I believe that the latest version of KLIC in the Netherlands also implements a similar capability.

Reliable metrics

If you can’t measure it, you can’t fix it. (Peter Drucker)

Reliable metrics are essential for assessing the social and economic impact of utility damage and the effectiveness of new policies, legislation, regulations, and technologies in reducing underground utility damage. Statistics available in several jurisdictions show that as a rule the trend in underground utility damage is either flat or is slowly increasing.

In North America the Common Ground Alliance (CGA) has been collecting voluntarily submitted incident reports since 2003. About 400,000 incident reports are submitted each year, but the CGA estimates that this may only about 50 % of all incidents of underground utility damage. The CGA compiles statistics in their annual DIRT report. To analyze trends over several years, the CGA looks at incidents reported by “consistently reporting sources”. These are sources that have consistently reported incidents over a consecutive three year period. By compiling and analyzing these incidents and comparing the results with a measure of total construction activity in the U.S., the CGA is able to detect trends over several years. For the years 2015 to 2017 the analysis revealed a gradual increase in underground utility damage per million dollars of construction.

In Ontario an affiliate of the CGA,the Ontario Regional Common Ground Alliance (ORCGA), collects and compiles voluntarily submitted incident reports and also issues an annual DIRT report. In the 2018 ORCGA DIRT report annual statistics, reported for 2007 through 2018, of the damage ratio (number of incidents per 1000 one call notifications) revealed that the damage ratio has been trending upward since 2014.

For federally regulated pipeline operators in the U.S. it is mandatory to report incidents of pipeline damage to the Pipeline and Hazardous Materials Safety Administration (PHMSA) which is the federal agency responsible for regulating pipelines. In 2002 in response to several serious pipeline incidents PHMSA required companies operating pipelines carrying hazardous materials to identify high consequence areas (HCAs) and implement higher integrity standards within those areas. Legislation passed in 2011 requires PHMSA to maintain a map of HCAs, originally with a locational accuracy of ± 500 feet which was later tightened up to ± 50 feet. Incident reports must include location, volume of gas or fluid released, and other information. PHMSA compiles these incidents and releases annual statistics. To identify trends over time PHMSA prorates annual pipeline damage to the total mileage of HCAs. This analysis has not revealed a trend toward a reduction in pipeline incidents.

In the Netherlands, where the KLIC online one-call system has been implemented, reporting incidents of utility damage, of which there are about 41,000 every year, is mandatory. The Dutch Kadaster, the Dutch land registry and mapping agency, compiles and analyzes incident reports. The statistics show that while construction efficiency has improved, no trend toward reducing underground utility damage has been discerned.

There are exceptions to this general trend. In Japan and at Heathrow International Airport where programs of continuous improvement have been implemented, statistics reveal a sustained long term reduction in underground utility damage.

At Heathrow statistics have been compiled since 2001, when a comprehensive program to reduce the risk of damage to underground utilities was initiated. Comparing the annual incidents of underground utility damage and a proxy for the amount of construction activity at Heathrow reveals a consistent downward trend in the incidents of damage to underground services.

Among the critical measures that have been implemented at Heathrow is a seven step process, from preliminary design to handover, that must be followed for all excavations at Heathrow. Among other objectives the process ensures that at the completion of construction accurate “as-constructeds” are captured. Another important measure at Heathrow is the mandatory reporting of all underground services strikes. Thirdly, where different types of excavation equipment are permitted to dig is restricted at Heathrow. Exclusion zones based on the PAS 128 quality standard have been defined. For example, within 3 meters of an underground service assigned QL A or B(1,2 or 3) only hand-digging, vacuum or hydraulic extraction are allowed. Another important Heathrow requirement is that all people involved in detecting and mapping underground infrastructure must be trained. To support this Heathrow has helped to develop National Vocational Qualifications (NVQs) relevant to underground asset management.

Wrap up

This review of a few recent innovations in legislation, regulations, and business processes as well as technical innovations reveals that over the past few year there have been remarkable advancements in detecting, recording, sharing and updating information about the location of underground assets. Furthermore, this trend appears to be accelerating.

However, the evidence suggests that there is no silver bullet and that a successful program for reducing utility damage requires a comprehensive program over many years. But there is a big payoff from such a program for the construction industry, fewer injuries and fatalities and less risk of project delays and budget overruns. Reducing risk can reduce insurance premiums for contractors in an industry where margins are typically low. Furthermore, developing and maintaining an accurate 3D map of underground infrastructure has potential benefits for other use cases beyond construction such as planning, utility outage management, disaster planning, emergency response, urban digital twins and smart cities.

For more information about underground utility damage, see the article “The Underground” in the July issue of xyHt magazine.