Since 2013 France has implemented a national damage prevention system that requires achieving 40 cm accuracy for the location of all critical underground network infrastructure prior to beginning construction. Annual statistics reveal a decreasing trend in the amount of underground utility damage since 2013.
The DT DICT system has some superficial similarities to a North American one call system, but is fundamentally different in that the DT DICT process actually improves the quality of the underground location data as it operates. The Guichet Unique (Téléservice réseaux et canalisations) contains a list of all utility and telecom operators in France, maps of their services areas, and contact information. At the beginning of each construction project, the project manager must prepare a DT (Déclaration de projet de Travaux), a notification of planned construction work. Using the information provided by the Guichet Unique, the DT is forwarded to each network operator with equipment in or near the proposed construction site.
All network operators are obliged to respond to the DT within 9 business days. Operators are required to provide all the information in their possession on the location of their existing networks at the proposed site. Network operators can respond in two ways. They can provide maps of their underground infrastructure compliant with Class A (accurate to 40 cm). But if they are not able to provide compliant maps, they can request that the project manager carry out one or more investigations complémentaires (IC). In this case the project manager will contract a locate service provider to conduct locate operations with the objective of ensuring Class A compliance for all noncompliant underground utility facilities. The cost of the investigations complémentaires are borne by the network operator or operators. The important outcome of this process is that when the project manager is ready to begin excavation, he/she knows the location of all underground infrastructure at the project site to 40 cm or better.
The IC process also results in improvements to network operators records, because the regulations require that the results of the investigations complémentaires be sent to the relevant network operators within 15 days. The network operators are required to update their network records with the information provided in the investigations complémentaires.
Underground damage in France
The DT DICT regulations make reporting incidents of underground damage during construction mandatory for network operators. The National Observatory DT DICT compiles these reports annually and issues a network operator dashboard summarizing the damage statistics for the year.
| Year | Damage incidents | Year over year change | Total DTs | Damage rate (% of DTs) | % DTs submitted digitally |
| 2013 | 24,441 | 3,437,274 | 0.71 % | 29 % | |
| 2014 | 19,317 | -21 % | 3,263,725 | 0.59 % | 35 % |
| 2015 | 18,382 | - 5 % | 3,349,224 | 0.55 % | 85 % |
| 2016 | 16,994 | - 8 % | 3,516,665 | 0.48 % | 89 % |
| 2017 | 16,698 | - 2 % | 3,750,933 | 0.45 % | 92 % |
| 2018 | 16,344 | - 2 % | 3,966,390 | 0.41 % | 93 % |
| 2019 | 16,025 | - 2 % | 4,181,769 | 0.38 % | 93 % |
The annual damage statistics reveal that although the number of DTs submitted is growing every year, the trend in underground utility damage is decreasing, currently by 2 % per year.
The decreasing trend in underground utility damage in France is in contrast to North America and the Netherlands where the latest statistics reveal little progress in reducing underground utility damage over the past five years in spite of one call and other measures that have been implemented.
Background
I have blogged previously about the French presidential decree in 2012 that mandated that all of France's critical underground utility infrastructure should be mapped to an accuracy of 40 cm (about 16 inches). Critical infrastructure according to the decree includes buried electric power cables, pipelines, and public transport infrastructure, but not buried water and telecommunications infrastructure. The deadline for urban areas was January 1, 2019 and for non-urban areas January 1, 2026.
The national regulation requiring mapping of subsurface infrastructure titled Decree relating to excavations near underground, overhead or underwater transmission or distribution networks was promulgated on 15 February 2012. The "anti-network damage" reform, known as "DT-DICT", came into effect on 1 July 2012. The responsibility for implementing the decree lies with a "competent local authority". Across France different departmental organizations have taken responsibility for implementing the decree.
Location accuracy classes
The location accuracy classes apply to planimetry (x, y) and altimetry (z). They are defined as follows: -
Class A: structure for which the maximum location uncertainty is less than or equal to 40 cm if it is rigid or 50 cm if it is flexible; the maximum uncertainty is increased to 80 cm for underground civil engineering structures attached to installations intended for the circulation of rail transport vehicles when these structures were built prior to January 1, 2011;
Class B: structure of which the maximum location uncertainty is greater than class A and less than or equal to 1.5 m; the maximum uncertainty is lowered to 1 m for connections to critical underground structures for safety purposes and from January 1, 2021, for connections to non-critical underground structures.
Class C: structure for which the maximum location uncertainty is greater than 1.5 m, or 1 m for connections to critical underground structures for safety purposes and from January 1, 2021, for connections to non-critical underground structures, or for which the operator is unable to provide accuracy information.
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