Pipeline Condition Assessment Research Articles

Hydraulic transient wave separation algorithm using a dual-sensor with applications to pipeline condition assessment

Over the past two decades, techniques have been developed for pipeline leak detection and condition assessment using hydraulic transient waves (i.e. water hammer waves). A common measurement strategy for applications involves analysis of signals from a single pressure sensor located at each measurement site. The measured pressure trace from a single sensor is a superposition of reflections coming from upstream, and downstream, of the sensor. This superposition brings complexities for signal processing applications for fault detection analysis. This paper presents a wave separation algorithm, accounting for transmission dynamics, which enables the extraction of directional travelling waves by using two closely placed pressure sensors at one measurement site (referred to as a dual-sensor). Two typical transient incident pressure waves, a pulse wave and a step wave, are investigated in numerical simulations and laboratory experiments. Comparison of the wave separation results with their predicted counterparts shows the wave separation algorithm is successful. The results also show that the proposed wave separation technique facilitates transient-based pipeline condition assessment.

Ensemble learning as approach for pipeline condition assessment

The algorithms commonly used for damage condition monitoring present several drawbacks related to unbalanced data, optimal training requirements, low capability to manage feature diversity and low tolerance to errors. In this work, an approach based on ensemble learning is discussed as alternative to obtain more efficient diagnosis. The main advantage of ensemble learning is the use of several algorithms at the same time for a better proficiency. Thereby, combining simplest tree decision algorithms in bagging scheme, the accuracy of damage detection is improved. It takes advantage by combining prediction of preliminary algorithms based on regression models. The methodology is experimentally validated on a carbon steel pipe section, where mass adding conditions are studied as possible failures. Data from an active system based on piezoelectric sensors are stored and characterized through the T2 and Q statistical indexes. Then, they are the inputs to the ensemble learning. The proposed methodology allows determining the condition assessment and damage localizations in the structure. The results of the studied cases show the feasibility of ensemble learning for detecting occurrence of structural damages with successful results.

Remote pipeline assessment and condition monitoring using low-frequency axisymmetric waves: a theoretical study of torsional wave motion

Waves that propagate at low frequencies in buried pipes are of considerable interest in a variety of practical scenarios, for example leak detection, remote pipe detection, and pipeline condition assessment and monitoring. Particularly useful are the n = 0, or axisymmetric, modes in which there is no displacement (or pressure) variation over the pipe cross section. Previous work has focused on two of the three axisymmetric wavetypes that can propagate: the s = 1, fluid- dominated wave; and the s = 2, shell-dominated wave. In this paper, the third axisymmetric wavetype, the s = 0 torsional wave, is studied. Whilst there is a large body of research devoted to the study of torsional waves and their use for defect detection in pipes at ultrasonic frequencies, little is known about their behaviour and possible exploitation at lower frequencies. Here, a low- frequency analytical dispersion relationship is derived for the torsional wavenumber for a buried pipe from which both the wavespeed and wave attenuation can be obtained. How the torsional waves subsequently radiate to the ground surface is then investigated, with analytical expressions being presented for the ground surface displacement above the pipe resulting from torsional wave motion within the pipe wall. Example results are presented and, finally, how such waves might be exploited in practice is discussed.

A novel method for the remote condition assessment of buried pipelines using low-frequency axisymmetric waves

“Mapping the Underworld” is a large multi-disciplinary, multi-university research programme taking place in the UK, which aims to revolutionize the way we undertake streetworks. Within this programme, a number of vibration-based techniques for remotely detecting and locating buried pipes have been developed. Relying either on the direct excitation of a pipe as it comes up to the surface or excitation of the ground in the vicinity of a buried pipe, mapping the ground surface vibration response allows information to be gathered concerning the pipe's exact position. However, contained within this surface response is often information which could, if utilized appropriately, provide insights into the condition of the pipe as well as its location. Furthermore, critical information regarding the condition of the ground in which a pipe is buried could, in some circumstances, be gleaned. In this paper, how this additional information might be extracted, used and eventually exploited is explored. Providing the basis for work currently being undertaken in a new programme, “Assessing the Underworld”, example results are presented which demonstrate the immense potential of the proposed methods.

Transient frequency response based leak detection in water supply pipeline systems with branched and looped junctions

The transient frequency response (TFR) method has been widely developed and applied in the literature to identify and detect potential defects such as leakage and blockage in water supply pipe systems. This type of method was found to be efficient, economic and non-intrusive for pipeline condition assessment and diagnosis, but its applications so far are mainly limited to single and simple pipeline systems. This paper aims to extend the TFR-based leak detection method to relatively more complex pipeline connection situations. The branched and looped pipe junctions are firstly investigated for their influences to the system TFR, so that their effects can be characterized and separated from the effect of other components and potential leakage defects in the system. The leak-induced patterns of transient responses are derived analytically using the transfer matrix method for systems with different pipe junctions, which thereafter are used for the analysis of pipe leakage conditions in the system. The developed method is validated through different numerical experiments in this study. Based on the analytical analysis and numerical results, the applicability and accuracy as well as the limitations of the developed TFR-based leak detection method are discussed for practical applications in the paper.

A theoretical study of the fundamental torsional wave in buried pipes for pipeline condition assessment and monitoring

Waves that propagate at low frequencies in buried pipes are of considerable interest in a variety of practical scenarios, for example leak detection, remote pipe detection, and pipeline condition assessment and monitoring. Whilst there has been considerable research and commercial attention on the accurate location of pipe leakage for many years, the various causes of pipe failures and their identification, have not been well documented; moreover, there are still a number of gaps in the existing knowledge. Previous work has focused on two of the three axisymmetric wavetypes that can propagate: the s=1, fluid-dominated wave; and the s=2, shell-dominated wave. In this paper, the third axisymmetric wavetype, the s=0 torsional wave, is investigated. The effects of the surrounding soil on the characteristics of wave propagation and attenuation are analysed for a compact pipe/soil interface for which there is no relative motion between the pipe wall and the surrounding soil. An analytical dispersion relationship is derived for the torsional wavenumber from which both the wavespeed and wave attenuation can be obtained. How torsional waves can subsequently radiate to the ground surface is then investigated. Analytical expressions are derived for the ground surface displacement above the pipe resulting from torsional wave motion within the pipe wall. A numerical model is also included, primarily in order to validate some of the assumptions made whilst developing the analytical solutions, but also so that some comparison in the results may be made. Example results are presented for both a cast iron pipe and an MDPE pipe buried in two typical soil types.

Evidential Reasoning–Based Condition Assessment Model for Offshore Gas Pipelines

Condition assessment of oil and gas pipelines is a significant component in pipeline operations and maintenance. Such assessments are used to ensure better decisions for repair and/or replacement to reduce pipelines’ failure possibilities. Therefore, it is essential to have an effective condition assessment model for pipelines as their failure incidents may lead to catastrophic, economical, and environmental consequences. Current practices of assessing gas pipelines condition can be considered simplified for the intended purpose. They mainly depend on experts’ opinions in interpreting inspection data, where the process is influenced by human subjectivity and reasoning uncertainty. In other words, they need detailed knowledge on the translation of raw inspection data into valuable information. This will surely lead to decisions lacking thorough and extensive review of the most influential aspects on pipelines’ conditions. To address the weaknesses of current practices, this research proposes a new fuzzy-based methodology that utilizes an integrated analytic network process (ANP) and hierarchical evidential reasoning (HER) to develop a meticulous condition assessment model for offshore gas pipelines. The proposed model is validated using historical inspection reports that are obtained from a local pipeline operator in Qatar. The model delivers satisfactory outcomes in assessing offshore gas pipelines’ conditions based on real field data.

Field study on non-invasive and non-destructive condition assessment for asbestos cement pipelines by time-domain fluid transient analysis

Asbestos cement pipelines constitute a significant portion of the potable and waste water systems in many countries in the world, including Australia. Most of the asbestos cement pipes in the developed countries were installed before 1980, and many utilities are observing that the breakage rate is increasing with the ageing of the pipe. Condition assessment for asbestos cement pipes is of important necessity for prioritising rehabilitation and preventing catastrophic pipe failure; however, few techniques are available for direct assessment of the condition of asbestos cement pipes and most of them are localised and destructive. This article outlines a pilot field study of the non-invasive and non-destructive condition assessment of asbestos cement pipelines using fluid transient pressure waves. Fluid transient analysis previously conducted by the authors for metallic pipelines is further developed and adapted to asbestos cement pipes for the detection of localised defects. A new sub-sectional condition assessment technique is proposed for determining the effective wall thicknesses of asbestos cement sub-sections within a section of pipe bounded by two measurement points. A field trial is conducted in Australia on an asbestos cement water main (which has class changes with varying wall thicknesses) to verify the proposed techniques. The wave speeds, lengths and wall thicknesses of sub-sections in different classes are determined and the results are consistent with the information in the design drawings provided by the water utility. This field study, for the first time, verifies that controlled fluid transient waves can be used as a tool for non-invasive and non-destructive condition assessment of asbestos cement pipelines.

Stop Age Discrimination in Pipe Replacement Strategies

The very nature of buried pipeline assets presents a challenge to accurately access their condition, making it even harder to optimize water distribution systems by employing effective asset management strategies. To optimize pipeline renewal strategies based on actual conditions, new pipeline condition assessment techniques and technologies offer pipe‐specific evaluations that can end the water industry's reliance on desktop studies using age, or break frequency, as the primary criteria for pipeline renewal planning.

On-site non-invasive condition assessment for cement mortar–lined metallic pipelines by time-domain fluid transient analysis

Pipeline condition assessment is essential for targeted and cost-effective maintenance of aging water transmission and distribution systems. This article proposes a technique for fast and non-invasive assessment of the wall condition of cement mortar–lined metallic pipelines using fluid transient pressure waves (water hammer waves). A step transient pressure wave can be generated by shutting off a side-discharge valve in a pressurised pipeline. The wave propagates along the pipe and reflections occur when it encounters sections of pipe with changes in wall thickness. The wave reflections can be measured by pressure transducers as they are indicative of the location and severity of the wall deterioration. A numerical analysis is conducted to obtain the relationship between the degree of change in wall thickness in a cement mortar–lined pipe and the size of the corresponding pressure wave reflection. As a result, look-up charts are generated for any specific cement mortar–lined pipeline to map this relationship. The wall thickness of a deteriorated or distinct section can be determined directly and quickly from the charts using the size of the reflected wave, thus facilitating on-site pipeline condition assessment. The validity of this time-domain pipeline condition assessment technique is verified by numerical simulations and a case study using the field data measured in a mild steel cement mortar–lined water main in South Australia. The condition of the pipe as assessed by the proposed technique is generally consistent with ultrasonic measurements.

Renewal Engineering for Drinking Water Pipelines

This report presents research intended to compile and further understand the state of the technology for drinking water pipeline renewal engineering methodologies and technologies, focusing primarily on the geographic regions of the United States. Researchers performed an extensive literature review, covering conference papers, journal articles, vendor literature, and major reports. Additionally, detailed case studies describing utility drinking water pipeline condition assessment practices are outlined using information data mined directly from participating utilities. The information gathered through literature review and data mining is compiled and synthesized, resulting in the presentation of conclusions regarding the state of renewal engineering of domestic drinking water pipelines, recommendations for further research and industry needs, and a description of identified trends. Trends in technology use and practices are summarized, cost issues are discussed, and the gaps between needs and available technologies are presented. Furthermore, this report proposes a standard data structure for utilities to use for reporting purposes when performing renewal engineering efforts on drinking water pipelines. The collection of the information presented in the proposed standard data structure for utility reporting would provide the data needed to greatly improve utility operating processes and direct research toward industry needs. This title belongs to WERF Research Report Series ISBN: 9781780405667 (eBook)

Non-Destructive In-Situ Condition Assessment of Plastic Pipe Using Ultrasound

Abstract Pipelines in potable water distribution system are a vital part of modern infrastructure, providing one of the most important services for society. This vital, complex infrastructure is endemic to our urban environments but is ageing, with current average age of around 70 years and with current replacement rates an inferred serviceable asset life of hundreds of years. Hence it is important that we develop technology that will enable pipeline condition assessment without service interruption. Due to environmental and operational stresses acting upon these pipelines, the common structural health problems include stress corrosion, thermal degradation, cracks or even leaks [1] . In particular, it has been suggested that void formation external to buried pipe wall is a crucial factor in pipe breakages due to lack of structural support [1] , [2] . This paper presents the development and laboratory testing of ultrasonic non-destructive inspection technology for the condition assessment of plastic pipes, provide a measure of the structural integrity of the pipe, as well as ‘looking’ through the pipe wall to assess void formation and critical loss of support. Ultrasonic detection results are presented for grooves and cracks with two common plastic pipe materials, HDPE (High-density polyethylene) and PVC (Polyvinyl chloride) in order to simulate material loss in pipe wall. In addition, four voids in the ground external to plastics with varying shapes and dimensions were detected. Tested soils include two particle sized sands and two particle sized gravels. The study demonstrates the feasibility of developing a new technique for condition and health assessing for buried water plastic pipes

Numerical and Experimental Study on the Effect of Signal Bandwidth on Pipe Assessment Using Fluid Transients

AbstractA non-intrusive fault detection technology for real time condition assessment of pipelines is highly desirable for pipeline operators and the use of artificially induced fluid transients for this purpose has been the topic of many studies in the past. Fluid transients are stress waves in the fluid that can propagate through pipelines at high speeds and can collect information on the pipe condition during its travel. Whilst many transient-based fault detection methods have been proposed in the literature, little work was done on the characteristics of the transient signal that is best suited for fault detection. Such a study is critical for the development of this technology as the generation of controlled pressure waves is a challenging key step of the procedure. This paper presents analytical, numerical and experimental results to illustrate the effect of signal bandwidth (frequency content) of the induced transient signals has on the spatial resolution, accuracy and range of transient based faul...

Condition Assessment for Wastewater Pipelines: Synthesis Report

The research results presented in this report were compiled to provide a clearer understanding of the state of the technology for wastewater pipeline condition assessment methodologies and technologies, focusing primarily on the geographic regions of the U.S.A. An extensive literature review was performed, covering conference papers, journal articles, vendor literature, and major reports. Additionally, approximately 50 detailed case studies describing utility wastewater pipeline condition assessment practices were created using information data mined directly from participating utilities. The information gathered through literature review and data mining was compiled and synthesized, regarding the state of condition assessment of domestic wastewater pipelines, recommendations for further research and industry needs, and a description of trends found. Trends in technology use and practices were summarized, cost issues were discussed, and the gaps between needs and available technologies were presented. Additionally, this report proposes a standard data structure for utilities to use for reporting purposes when conducting condition assessment of wastewater pipes. The collection of the information presented in the proposed standard data structure for utility reporting would provide the data needed to greatly improve utility operating processes and to more easily direct research toward industry needs. This title belongs to WERF Research Report Series . ISBN: 9781780405612 (eBook)

Condition Assessment for Drinking Water Pipelines: Synthesis Report

The research presented in this report was performed in order to compile and better understand the state of the technology for drinking water pipeline condition assessment methodologies and technologies, focusing primarily on the U.S. An extensive literature review was performed, including conference papers, journal articles, vendor literature, and major reports. Additionally, approximately 50 detailed case studies describing utility drinking water pipeline condition assessment practices were created using information data mined directly from participating utilities.The information gathered through literature review and through data mining was compiled and synthesized, resulting in the presentation of conclusions regarding the state of condition assessment of domestic drinking water pipelines, recommendations for further research and industry needs, and a description of trends found. Trends in technology use and practices were summarized, cost issues were discussed, and the gaps between needs and available technologies were presented.Furthermore, this report proposes a standard data structure for utilities to use for reporting purposes when performing condition assessment work on drinking water pipelines. The collection of the information presented in the proposed standard data structure for utility reporting would provide the data needed to greatly improve utility operating processes and to more easily direct research toward industry needs.This title belongs to WERF Research Report Series.ISBN: 9781780405605 (eBook)

Condition Assessment in Hydraulically Noisy Pipeline Systems Using a Pressure Wave Splitting Method

Abstract For the past couple of decades, researchers have been investigating the use of hydraulic transients (pressure surge waves) to investigate the condition of a pipeline system, and detect anomalies such as leaks, blockages, or pipe wall condition. The use of controlled hydraulic transients, combined with signal processing methods on measured pressure responses, have had a demonstrated utility for pipeline condition assessment, largely owing to the sensitivity of the hydraulic transient waves to the said anomalies. This paper presents a simple extension to these existing methods by proposing a technique that does not require a controlled hydraulic transient input, but utilizes existing hydraulic noise (in the form of wide-sense stationary hydraulic signals) within the system of interest to perform the diagnosis.

Demonstration and Evaluation of State-of-the-Art Wastewater Collection Systems Condition Assessment Technologies

AbstractCondition assessment of wastewater collection systems is a vital part of a utility’s asset management program. Reliable information on pipe condition is needed to prioritize rehabilitation and replacement projects, given the current state of our nation’s infrastructure. Although inspections with conventional closed-circuit television (CCTV) have been the mainstay of pipeline condition assessment for decades, other technologies are now commercially available. Five of these innovative technologies were selected for field trials under the U.S. Environmental Protection Agency (USEPA) demonstration program: zoom camera, electroscanning, digital scanning, laser profiling, and sonar. The goal of the field demonstration was to evaluate the technical performance and cost of these technologies. The field demonstration was conducted in August 2010 and was hosted by the Kansas City, Missouri Water Services Department. The innovative technologies were compared to CCTV inspection. Each technology identified mai...

Cost Information for Wastewater Pipelines

The research presented in this report was performed in order to compile and better understand the total costs of some commonplace wastewater pipeline condition assessment and renewal engineering methodologies and technologies in the U.S. An extensive literature review was performed, covering all pertinent sources from the body of knowledge. Additionally, detailed case studies describing utility wastewater pipeline condition assessment and renewal engineering project costs were created using information data mined directly from participating utilities.The information gathered through literature review and data mining was compiled and synthesized, resulting in the presentation of conclusions regarding the financial, social, and environmental costs of condition assessment and renewal engineering of domestic wastewater pipelines, recommendations for further research and industry needs, and a description of trends found. Trends in costs as driven by pipeline diameter, project length, and supplemental direct costs were summarized, social and environmental cost issues were discussed, and the gaps between current cost data capture practices and future needs were presented.Furthermore, a standard data structure is proposed for wastewater utilities to use for cost reporting purposes when performing condition assessment and renewal engineering work on their buried pipelines. The collection of the information presented in the proposed standard data structure for utility reporting would provide the data needed to greatly improve utility cost estimating processes and to more easily direct research toward industry needs. The standard data structure was utilized to gather the desired cost data as a pilot; once data is gathered using the standard method and structure, robust cost trend analyses can be performed.This title belongs to WERF Research Report Series.ISBN: 9781780405636 (eBook)

Cost Information for Drinking Water Pipelines

The research presented in this report was performed in order to compile and better understand the total costs of some commonplace drinking water pipeline condition assessment and renewal engineering methodologies and technologies in the U.S. An extensive literature review was performed, covering all pertinent sources from the body of knowledge. Additionally, detailed case studies describing utility drinking water pipeline condition assessment and renewal engineering project costs were created using information data mined directly from participating utilities. The information gathered through literature review and through data mining was compiled and synthesized, resulting in the presentation of conclusions regarding the financial, social, and environmental costs of condition assessment and renewal engineering of domestic drinking water pipelines, recommendations for further research and industry needs, and a description of trends found. Trends in costs as driven by pipeline diameter, project length, and supplemental direct costs were summarized, social and environmental cost issues were discussed, and the gaps between current cost data capture practices and future needs were presented. Furthermore, this report proposes a standard data structure for utilities to use for cost reporting purposes when performing condition assessment and renewal engineering work on drinking water pipelines. The collection of the information presented in the proposed standard data structure for utility reporting would provide the data needed to greatly improve utility cost estimating processes and to more easily direct research toward industry needs. The standard data structure was utilized to gather the desired cost data as a pilot; once data is gathered using the standard method and structure, robust cost trend analyses can be performed. This title belongs to WERF Research Report Series . ISBN: 9781780405629 (eBook)

Development of Synthesis Reports on Drinking Water and Wastewater Pipeline Condition Assessment Technologies and Methodologies

Development of Synthesis Reports on Drinking Water and Wastewater Pipeline Condition Assessment Technologies and MethodologiesDrinking water infrastructure and sanitation infrastructure are critical to the economic, environmental, and social health of our civilization. WATERiD (Water Infrastructure Database) is an online database created primarily for the use of utility managers and municipality decision makers that struggle with obtaining easy access to comprehensive information about available pipeline...Author(s)Nisha ThuruthySourceProceedings of the Water Environment FederationDocument typeConference PaperPublisherWater Environment FederationPrint publication date Sep, 2012ISSN1938-6478DOI10.2175/193864712811741377Volume / Issue2012 / 16Content sourceWEFTECCopyright2012Word count344