Between the Poles

Major benefits of accurate location information about underground infrastructure prior to design

Blue bars - Construction spending ($millions). Red line - Reported unique damages. Yellow line - Estimated damages. Dotted lines - error bars. Source CGA 2020 DIRT Report

The stated objectives of many initiatives focussed on locating underground utilities is damage prevention. However, for those cases where reliable multi-year statistics have been compiled, the data reveals that this objective is not being realized - the annual amount of damage, when prorated to a measure of annual construction activity, in many jurisdictions has plateaued or may even be increasing.

But there are other important benefits that are being realized from these underground utility initiatives, chief among them are improved construction efficiency, greater probability of on-time and on-budget project completions, fewer and shorter utility service outages and less traffic disruption and delays for the motoring public.

An area where detailed assessments of the costs and benefits of improved information about the location of underground infrastructure have been conducted is subsurface utility engineering surveys(SUE).  SUE surveys are generally conducted prior to engineering design and in some jurisdictions such as Colorado, are now mandatory on public civil engineering projects.

For a definitive study of twenty-two projects utilizing SUE and eight non-SUE projects from Pennsylvania Department of Transportation (PennDOT) districts, eleven direct and indirect cost/benefit areas were investigated in the analysis; utility relocation, utility damage, emergency restoration, traffic delay, business impact, user service outages, environmental impact, information gathering and verification, legal and litigation, efficient utility design and construction, and other utility related costs and benefits.

On the expense side a SUE survey requires two types of expenditures; the use of geophysical techniques such as electromagnetic(EM), ground penetrating radar(GPR) and other techniques to detect the location of underground infrastructure and potholing to confirm the location of the utilities and objects detected. For this study for the projects utilizing SUE, costs detection and potholing were obtained directly from project accounting. For the projects that did not use SUE, costs were estimated from interviews, historical data, and individual project studies.

For the twenty-two projects where a SUE survey was conducted, all underground utilities and other objects were located to ASCE 38-02 Quality Level A (potholing) or B (EM or GPR). For the eight projects utilized traditional methods, the location of underground networks was estimated to ASCE quality levels C (site visit) and D (as-builts).

The study revealed that for road and highway projects $11.39 can be saved for every $1 spent on SUE. The top benefits realized as a result of conducting SUE surveys were found to be primarily improved construction efficiency and greater probability of on-time and on-budget project completions.

1. 40.33% reduction in project relocation cost by providing accurate underground information in the early stages of design
2. 29.46% reduction in construction and design costs - SUE enables designers to design efficiently and accurately with reliable information, so that design time can be saved and unnecessary construction work can be avoided or reduced.
3. 9.59% reduction in redesign costs
4. 9.08% reduction in delay costs due to relocation
5. 6.81% reduction in delay costs caused by emergencies
6. 1.41% reduction in delay costs caused by unexpected utilities
7. 1.41% reduction in information gathering and verification cost
8. 1.04% reduction in restoration cost

A ratio of 1.65% was determined as the ratio of SUE cost to total project cost. It was concluded that SUE can provide important project benefits at reasonable cost.

A reanalysis of the data collected for a 1999 USDOT Study by Purdue University found that the estimated benefit of conducting a SUE survey was a cost savings of $12.23 for every $1 spent on SUE. The largest contributors to the cost savings derived from SUE were found to be;

1. 37.1% reduced number of utility relocations
2. 19.3% reduced claims and change orders
3. 11.6% reduced accidents and injuries
4. 9.6% reduced project delays
5. 3.5% reduced right-of-way acquisition costs
6. 3.3% savings in risk management and insurance
7. 15.5% other

In Subsurface Utility Engineering for Municipalities, by James H Anspach and C. Paul Scott, the primary quantifiable benefits identified for SUE surveys are fewer and more limited utility relocations and reduced delay claims and change orders. In addition there are many benefits identified during pre-construction and construction and other benefits that accrue to network operators and the public. Important preconstruction benefits include reduced design costs through improved efficiency including avoidance of conflicts and more accurate utility relocation designs where utility conflicts are unavoidable. Construction benefits include better bids and lower bid prices,  reduced project delays resulting from utility relocations, reduced construction delays from unexpected utility conflicts, earlier project completion time, and savings in risk management and insurance. The biggest benefits for utility owners and operators are reduced revenue loss from outages and reduced costs to repair damaged facilities.  The most important benefits to the public are fewer and shorter utility service outages,  less traffic disruption and delays and for business owners reduced loss of custom.

Advances in capturing and sharing location information about underground infrastructure in Europe

I was invited to participate in a meeting of the European Underground Infrastructure Community this morning.  I heard about very important advances in capturing, capturing and sharing location information (maps) about underground infrastructure that are relevant to any jurisdiction attempting to reduce underground damage and improve construction efficiency.

France

In 2012 a presidential decree mandated that the location of underground infrastructure had to be accurate to 40 cm or better (Quality Level A) for all critical infrastructure in urban areas by 2019.  In France critical infrastructure refers to infrastructure that is dangerous for excavators.  It excludes telecom and most water distribution networks. At this point the target date has slipped a bit, but it is estimated that about 80% of the location of urban underground infrastructure is known to QL A.

It is important to note that this applies not only to new infrastructure but existing infrastructure as well.  One of the contributors to the improvement in the quality of existing infrastructure data is a shared responsibility model.  As a contractor I am expected to request information through the DICT system about the location of underground infrastructure in the areas of a proposed excavation.  If the information supplied by the network owners operating in that area is poorer than QL A, I can invoice the network operator for the work I have to do to achieve QL A.  This system motivates network owners to work toward improving the quality of their data to reduce the cost of paying invoices. Furthermore, the cost for a contractor to do this work is probably significantly higher than if the network operator undertakes the work themselves.

Netherlands and Flanders

Studies from the 1940s through today have shown that incorrect or incomplete knowledge about the location of underground utilities is the leading reason for project delay claims.  A study of ten  Pennsylvania Department of Transportation (PennDoT) projects that involved a subsurface utility engineering (SUE) survey prior to engineering design found significant business benefits with an ROI of $22.21 saved for every dollar invested in SUE. Most one call centers are designed to provide underground utility information just prior (in North America about three days in advance, in the Netherlands up to 20 days in advance) to shovels going in the ground.  What this means is that planning and engineering design are conducted blind about the location underground utilities. The result is increased risk of utility damage, unnecessary but expensive utility relocations and construction delays.  In the Netherlands the KLIC system now can respond to three types of information requests, safe digging requests (80% of all requests), emergencies (5%), and planning requests (15%).  In Flanders similarly about 16-17 % of information request to the KLIP system are study requests.  This means that areas of high risk from underground infrastructure or where areas where utilities relocates would be expensive can be avoided during the design process.  Nobody would begin engineering design for a civil engineering project without a (above-ground) survey by a registered professional land surveyor.  Having accurate, reliable information about underground utilities is just as important.  In addition to the Netherlands and Flanders other jurisdictions are recognizing this as well.  In Colorado a SUE survey prior to civil engineering work in the public right of way is now mandatory.

In both Flanders and the Netherlands data is shared using an open standard harmonized data model (IMKL) that allows all data for a proposed excavation to be downloaded as a ZIP file and visualized on a single layered map using a free and open basic, commercial, and in-house developed viewers, supporting both offline and online viewing,

Germany

Red - inquiries handled conventionally. Green - inquiries handled by BIL system

In Germany there has been rapid growth in the number of request for information about the location of underground pipelines.  BIL is the Germany-wide information system for pipeline inquiries. Since February 2016 BIL has provided a cost-free digging request portal to a the national information system for pipeline inquiries. The foundation for BIL was laid in 2015 by 17 German pipeline companies from the chemical, high-pressure gas and mineral oil sectors. To date the BIL system has been able to automate 80% of these requests, with the result that  turnaround times are faster and require less staff.

It is interesting that 30.36 % of requests to the BIL system were for planning purposes (pre-construction) and the remainder for excavations.  This varies considerably for different sectors from about 20 % for civil for different sectors. While civil engineering and pipeline construction predominantly inquired about excavation, significantly more planning inquiries were made in the area of ​​energy generation and special measures (railway infrastructure, hydraulic structures, tunnels, industrial areas)

Spain

Two regions in Spain, Catalonia and Navarre, have developed non-governmental industry consortia for sharing information about the location of underground infrastructure,  These consortia are industry-supported, primarily by large utility and telecom operators such as Telefonica, ENEL, and Iberdrola.  Excavators pay a fee to retrieve this information which is provided as vector data, in AutoCAD, Microstation or shape file formats.

Thanks to Holger Kessler for the opportunity to participate.