Characterisation of the reliability and structural integrity of water and gas distribution infrastructure
Brief
The project’s ultimate goal is to identify a planning strategy for infrastructure improvements by defining concise parameters that represent each asset in relation to environmental, hydrogeological, seismic and intrinsic interference factors.
To this end, a comprehensive methodological approach was required, as well as the development of tools (software) for the systematic updating of results in relation to the evolution of networks and boundary conditions, and their application to the Operator’s entire area of responsibility.
Project challenge
- To enhance and supplement the preliminary studies made available by Hera concerning the area’s hazard levels and the processing of emergency data.
- To provide software tools for processing geo-referenced data (records of maintenance operations, characteristics of the infrastructure, characteristics of the territory) to be used in the study and in subsequent in-depth studies.
- To define an appropriate methodological approach to the characterisation of the infrastructure.
- To provide the results of an initial application of the methods and models proposed to the Gas network and the Hera Water network, for the entire area of competence.
Solution
The sections of the network are characterised by two “dimensions”:
- “Reliability”, which enables routes and areas of the territory to be classified in relation to the occurrence of causal events. This is useful for planning “leak detection” and “short-term” improvement work;
- “Structural Integrity”, which enables the sections and areas of the territory to be classified in relation to the occurrence of extreme natural events. This is useful for the planning of “medium-long” term safety measures and improvements.
The Network Reliability model is based on regression and classification methods and has been applied to Emergency Response records (extraordinary maintenance interventions on buried pipelines the interventions required by the scheduled leak detection).
The network “Structural Integrity” model is based on the definition and estimation of appropriate indicators and indices, and has been applied to the entire territory of competence, starting from pipeline vulnerabilities (assessed by HAZUS, FEMA methodology), and hazard maps (representing earthquakes and landslides, including satellite interferometric data) characterising the territory.
Software tools (Arcgis script) were developed for updating the Structural Integrity and Reliability models, including the necessary automatisms for assigning fractures and terrain characteristics to the sections.
A study was carried out on the interference between gas distribution infrastructure plant facilities and the territory, focusing on the possible consequences of gas releases and subsequent (immediate or delayed) release of vapour clouds.
Execution phases
- Data collection and analysis:
- infrastructure parameters,
- territory and terrain parameters,
- historical intervention records.
- Identification of models (e.g. reliability estimators, infrastructure vulnerability indices, territory hazard indices) and methods (e.g. statistical analysis on historical data, probabilistic approach).
- Development of georeferenced data processing software tools.
- Application of Reliability and Structural Integrity models on the basis of available data:
- complete infrastructure characterisation,
- complete territory and the terrain characterisation,
- Emergency Response records covering at least five years of operations.
- Analysis of network Reliability and Structural Integrity maps in support of infrastructure improvement planning.
Achieved results
The analyses were performed with ESRI-ArcGIS, using the R Environment statistical processing platform.
