Pipeline Safety Assessment at Inspection Time

2006 ◽  
Author(s):  
J. Alamilla ◽  
J. Garci´a-Vargas ◽  
J. Oliveros
Keyword(s):  
Failure Probability ◽  
Measurement Errors ◽  
Fluid Pressure ◽  
Corrosion Damage ◽  
Inspection Time ◽  
Pipeline System ◽  
Piping System ◽  
Pipeline Segment ◽  
Corrosion Defects ◽  
Pipeline Safety

This work presents a reliability model for determining the pipeline safety after obtaining information on the corrosion damage of the piping system by non-destructive inspection. The model is used to estimate pipeline system reliability in every region containing detected corrosion defects and the probability of either global system failure or of a given pipeline segment. The global failure probability incorporates the contribution of defects that are undetectable by the inspection tool. For this, the probability density functions of maximum depths and the number of undetected corrosion defects by the inspection tool are also determined. The failure associated to each corrosion defect is determined from the pipeline resistance and fluid pressure. The model is applied to a pipeline segment of a given length showing that defect measurement errors and the contribution of corrosion defects, undetected by inspection tool, can significantly influence the value of failure probability of the system. To calculate the failure probability of the system the directional simulation technique is utilized.

Reliability of Buried Pipeline Using a Theory of Probability of Failure

2006 ◽  
Vol 110 ◽  
pp. 221-230 ◽  
Author(s):  
Ouk Sub Lee ◽  
Dong Hyeok Kim ◽  
Seon Soon Choi
Keyword(s):  
Failure Probability ◽  
Probability Of Failure ◽  
Operating Conditions ◽  
Reliability Estimation ◽  
Design Parameters ◽  
Buried Pipeline ◽  
Safety Level ◽  
First Order ◽  
Reliability Method ◽  
Corrosion Defects

The reliability estimation of buried pipeline with corrosion defects is presented. The reliability of corroded pipeline has been estimated by using a theory of probability of failure. And the reliability has been analyzed in accordance with a target safety level. The probability of failure is calculated using the FORM (first order reliability method). The changes in probability of failure corresponding to three corrosion models and eight failure pressure models are systematically investigated in detail. It is highly suggested that the plant designer should select appropriate operating conditions and design parameters and analyze the reliability of buried pipeline with corrosion defects according to the probability of failure and a required target safety level. The normalized margin is defined and estimated accordingly. Furthermore, the normalized margin is used to predict the failure probability using the fitting lines between failure probability and normalized margin.

How Do I Ensure “Staff Competency” in My Pipeline Safety Management System?

2020 ◽  
Author(s):  
Karen Collins ◽  
Michelle Unger ◽  
Amanda Dainis
Keyword(s):  
Management System ◽  
Cognitive Biases ◽  
Safety Management ◽  
Core Competencies ◽  
Pipeline System ◽  
Safety Management System ◽  
Key Skills ◽  
Learning Programs ◽  
Knowledge Requirements ◽  
Pipeline Safety

Abstract Standards and regulations are clear: all staff who work on pipelines need to be both “competent” and “qualified.” Standards such as API 1173 are clear about competence within a safety management system: “The pipeline operator shall ensure that personnel whose responsibilities fall within the scope of the PSMS [Pipeline Safety Management System] have an appropriate level of competence in terms of education, training, knowledge, and experience.” The burden of defining and specifying competence falls on pipeline operators, but they have little guidance regarding the required skills, knowledge and levels of competency. Additionally, we are all biased — different operators will have different ideas and emphases on competencies, which will affect their decision-making. The only way to avoid these cognitive biases is to use consensus standards supported by rigorous surveys that capture the required competencies. This paper explores some of the more common biases that can affect decisions and presents the results of a controlled, independent, survey aimed at both specifying and quantifying the necessary competencies needed by a specific engineer working within a PSMS: a pipeline integrity engineer. The paper identifies and ranks these necessary competences. The survey was completed by 100 pipeline integrity engineers from 25 different countries. Its specific objective was to investigate the key skills and knowledge requirements needed in a junior engineering position (i.e., a pipeline engineer with less than three years of relevant experience) working under supervision to be ‘competent’. It listed eight core competencies (identified by subject matter experts) considered essential for a pipeline integrity engineer. Each of these core competencies contained a set of skills. Respondents were first asked to rank the eight core competences, and then rank the skills within the competency. An analysis of the data provides insights into how 100 pipeline integrity engineers view the key skills required to be “competent.” The results of the survey can assist pipeline companies in setting objective competency requirements for their engineering personnel, developing learning programs to address any gaps, and improve the overall safety of their pipeline system.

scholarly journals Experimental and Numerical Vibration Analysis of Hydraulic Pipeline System under Multiexcitations

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Peixin Gao ◽  
Hongquan Qu ◽  
Yuanlin Zhang ◽  
Tao Yu ◽  
Jingyu Zhai
Keyword(s):  
Pressure Fluctuations ◽  
Fluid Motion ◽  
Fluid Pressure ◽  
Point Of View ◽  
Pipeline System ◽  
Base Excitation ◽  
Fem Method ◽  
Pipeline Systems ◽  
Pump Pressure ◽  
Improved Model

Pipeline systems in aircraft are subjected to both hydraulic pump pressure fluctuations and base excitation from the engine. This can cause fatigue failures due to excessive vibrations. Therefore, it is essential to investigate the vibration behavior of the pipeline system under multiexcitations. In this paper, experiments have been conducted to describe the hydraulic pipeline systems, in which fluid pressure excitation in pipeline is driven by the throttle valve, and the base excitation is produced by the shaker driven by a vibration controller. An improved model which includes fluid motion and base excitation is proposed. A numerical MOC-FEM approach which combined the coupling method of characteristics (MOC) and finite element method (FEM) is proposed to solve the equations. The results show that the current MOC-FEM method could predict the vibration characteristics of the pipeline with sufficient accuracy. Moreover, the pipeline under multiexcitations could produce an interesting beat phenomenon, and this dangerous phenomenon is investigated for its consequences from engineering point of view.

scholarly journals Brush-Holder Integrated Load Sensor Prototype for SAG Grinding Mill Motor

Electronics ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1227 ◽  
Author(s):  
Carrasco ◽  
Álvarez ◽  
Velázquez ◽  
Concha ◽  
Pérez-Cotapos
Keyword(s):  
Measurement Errors ◽  
Large Scale ◽  
Mining Industry ◽  
Data Entry ◽  
Inspection Time ◽  
Inspection System ◽  
Design Development ◽  
Internal Parameters ◽  
Inspection Tasks ◽  
Grinding Mill

One of the most widely used electro-mechanical systems in large-scale mining is the electric motor. This device is employed in practically every phase of production. For this reason, it needs to be inspected regularly to maintain maximum operability, thus avoiding unplanned stoppages. In order to identify potential faults, regular check-ups are performed to measure the internal parameters of the components, especially the brushes and brush-holders. Both components must be properly aligned and calibrated to avoid electric arcs to the internal insulation of the motor. Although there is an increasing effort to improve inspection tasks, most inspection procedures are manual, leading to unnecessary costs in inspection time, errors in data entry, and, in extreme cases, measurement errors. This research presents the design, development, and assessment of an integrated measurement prototype for measuring spring tension and other key parameters in brush-holders used in electric motors. It aims to provide the mining industry with a new, fully automatic inspection system that will facilitate maintenance and checking. Our development research was carried out specifically on the brush system of a SAG grinding mill motor. These machines commonly use SIEMENS motors; however, the instrument can be easily adapted to any motor by simply changing the physical dimensions of the prototype.

An Experimental Study on the Influence of Structural Damping on Internal Fluid Pressure During a Transient Flow

1990 ◽  
Vol 112 (3) ◽  
pp. 284-290 ◽  
Author(s):  
D. D. Budny ◽  
F. J. Hatfield ◽  
D. C. Wiggert
Keyword(s):  
Experimental Study ◽  
Transient Flow ◽  
Traditional Approach ◽  
Dynamic Pressure ◽  
Fluid Pressure ◽  
Piping System ◽  
Internal Dynamic ◽  
Structural Damping ◽  
Pipe System ◽  
Internal Fluid

The traditional approach to designing a piping system subject to internal dynamic pressure is to restrain the piping as much as possible, and the approximation made in the analysis is to assume no contribution of structural energy dissipation. To determine the validity of this concept and approximation, an experimental study of a piping system was performed to measure the influence of structural damping. A pipe system was designed with a loop that could be turned so that its natural frequency would match that of the contained liquid. It was discovered that a properly sized damper on the piping loop greatly accelerates the decay of the fluid pressure transient. The damper absorbs some energy from the piping, reducing the resulting rebound fluid pressure. When the loop is subjected to forced steady-state vibration, there is a fluid pressure response. The amplitude of that pressure can be reduced by installing an external damper: the stiffer the damper the more effective it is in reducing dynamic pressure.

Lamb wave-based experimental and numerical studies for detection and sizing of corrosion damage in metallic plates

2018 ◽  
Vol 233 (6) ◽  
pp. 2107-2120 ◽  
Author(s):  
Adel Sedaghati ◽  
Farhang Honarvar ◽  
Anthony N Sinclair
Keyword(s):  
Guided Waves ◽  
Lamb Waves ◽  
Corrosion Damage ◽  
Element Model ◽  
Thin Plates ◽  
Aluminum Plate ◽  
Arrival Times ◽  
Numerical Studies ◽  
Corrosion Defects

Lamb waves are ultrasonic-guided waves with applications in inspection and monitoring of plate-like structures. These waves can be used for detecting, locating, and sizing of defects. In this paper, a new method is proposed for in situ measurement of the location and size of circle-like corrosion defects in thin plates. A novel technique for omnidirectional generation of Lamb waves is also proposed. The probe is placed on at least three different points around the defect and the arrival times of reflected echoes are measured. An algorithm then estimates the location and size of the defect based on the arrival times of reflected echoes. A finite element model is also developed for modeling the process and studying various aspects of the method. The proposed method is then tested on an aluminum plate. The center location and radius of a 5-mm hole in a 0.5-mm thick aluminum plate is estimated with uncertainties of ±1 mm (1%) and ±0.25 mm (5%), respectively. Various aspects of the proposed method are discussed, and uncertainties in measurements are estimated. Effectiveness of the proposed method is also assessed by sizing actual corrosion defects. The proposed method is fast, flexible, and portable and shows better accuracy in comparison to similar existing methods.

Piping Fluid Transients Made Simple: Part I — Theory of the SSFFC Methodology

2005 ◽  
Author(s):  
Zakaria N. Ibrahim
Keyword(s):  
Fluid Flow ◽  
Steady State ◽  
Fluid Pressure ◽  
Piping System ◽  
Consecutive Series ◽  
Quasi Steady State ◽  
Sound Waves ◽  
Steady State Flow ◽  
State Flow ◽  
Pipe Segment

Piping systems transporting fluid between plant components are subjected to a variety of anticipated and/or postulated flow changes that disturb their steady state operations. These changes cause the fluid flow to accelerate and/or decelerate. However, consideration of fluid elasticity transforms these disturbances into weak and/or strong propagating sound waves, depending upon the abruptness level of the fluid state change. This generates dynamic forces on the pipe segments of the piping system. A simple concept for understanding the piping fluid transient phenomenon from its physical perspective is presented. The piping system consists of several pipe segments, each segment having a constant cross-sectional flow area. The pipe segment is further divided into a consecutive series of zones. Each zone comprises two or three sub-zones of quasi steady state flow. The sub-zones are separated by interface fronts at which the jump in fluid pressure and velocity occurs across them. These fronts propagate and clash with each other to create the next temporal set of sub-zones quasi steady state flow. This method is denoted in this paper as steady state flow fronts clashing ‘SSFFC’. Clashing between the incident, transmitted and/or reflected wave fronts within the zone is introduced. As a precursor to the second part of a two-part publication, the SSFFC is physically illustrated and mathematically formulated to establish the temporal fluid steady state contained within each sub-zone constituting the pipe segment. The developed formulations are comparable to those instituted by the conventional method of characteristics. The pipe segment generalized fluid flow transient forces based on SSFFC methodology are also formulated. In the concurrent publication that forms part two of this presentation [8], sample applications of SSFFC methodology are illustrated.

Designing Offshore Pipeline Safety Systems Utilising Flow and Pressure in Multi Design Pressure Pipeline Systems

2008 ◽  
Author(s):  
Gjertrud Elisabeth Hausken ◽  
Jo̸rn-Yngve Stokke ◽  
Steinar Berland
Keyword(s):  
Pressure Drop ◽  
Flow Measurement ◽  
Large Diameter ◽  
Pressure Sensors ◽  
Safety System ◽  
Pipeline System ◽  
Outlet Pressure ◽  
Pipeline Systems ◽  
Pipeline Safety ◽  
Design Pressure

The Norwegian Continental Shelf (NCS) has been a main arena for development of subsea pipeline technology over the last 25 years. The pipeline infrastructure in the North Sea is well developed and new field developments are often tied in to existing pipeline systems, /3/. Codes traditionally require a pipeline system to be designed with a uniform design pressure. However, due to the pressure drop when transporting gas in a very long pipeline, it is possible to operate multi design pressure systems. The pipeline integrity is ensured by limiting the inventory and local maximum allowable pressure in the pipeline using inlet and outlet pressure measurements in a Safety Instrumented System (SIS). Any blockage in the pipeline could represent a demand on the safety system. This concept was planned to be used in the new Gjo̸a development when connecting the 130 km long rich gas pipeline to the existing 450 km long FLAGS pipeline system. However, a risk assessment detected a new risk parameter; the formation of a hydrate and subsequent blockage of the pipeline. In theory, the hydrate could form in any part of the pipeline. Therefore, the pipeline outlet pressure could not be used in a Safety Instrumented System to control pipeline inventory. The export pressure at Gjo̸a would therefore be limited to FLAGS pipeline code. Available pressure drop over the Gjo̸a pipeline was hence limited and a large diameter was necessary. Various alternatives were investigated; using signals from neighbour installations, subsea remote operated valves, subsea pressure sensors and even a riser platform. These solutions gave high risk, reduced availability, high operating and/or capital expenses. A new idea of introducing flow measurement in the SIS was proposed. Hydraulic simulations showed that when the parameters of flow, temperature and pressure, all located at the offshore installation, were used; a downstream blockage could be detected early. This enabled the topside export pressure to be increased, and thereby reduced the pipeline diameter required. Flow measurement in Safety Instrumented Systems has not been used previously on the NCS. This paper describes the principles of designing a pipeline safety system including flow measurement with focus on the hydraulic simulations and designing the safety system. Emphasis will be put on improvements in transportation efficiency, cost reductions and operational issues.

scholarly journals Fluid Mixing Nonequilibrium Processes in Industrial Piping Flows

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6364
Author(s):  
Mikhail Sukharev
Keyword(s):  
Measurement Errors ◽  
Quadratic Function ◽  
Component Composition ◽  
Pipeline System ◽  
Mixing Processes ◽  
Component Mixture ◽  
Nonequilibrium Processes ◽  
Arbitrary Configuration ◽  
Multicomponent Fluid ◽  
Computational Procedures

The flow of a multicomponent fluid through a pipeline system of arbitrary configuration is considered. The problem consists in determining the component composition of the fluid for each pipeline of the system based on the values of the concentration of the components throughout the entire set of measuring points, provided that there are no phase transitions. To solve the problem, mathematical models have been developed that, in principle, are suitable for pipeline systems of various functional purposes, the presentation is concretized and carried out in relation to gas transmission systems. The models are stochastic in nature due to measurement errors, which are considered random variables. The solution of the problem is reduced to the optimization of a quadratic function with constraints in the form of equalities and inequalities. The considered mixing processes do not depend on the regime parameters of the fluid flow. The processes are irreversible and non-equilibrium. A criterion is introduced that characterizes the degree of closeness of a multicomponent mixture to an equilibrium state. The criterion is analogous to entropy in thermodynamic processes. A numerical example of calculating the distribution of a three-component mixture is given. The example illustrates the feasibility of the proposed computational procedures and gives an idea of the distribution of the component composition and the change in «entropy» along the directions of pumping of the gas supply system.

A New Probabilistic Methodology for Undertaking External Corrosion Direct Assessment

2006 ◽  
Author(s):  
Andrew Francis ◽  
Marcus McCallum ◽  
Menno T. Van Os ◽  
Piet van Mastrigt
Keyword(s):  
Surface Characteristics ◽  
Survey Techniques ◽  
Direct Assessment ◽  
Ground Survey ◽  
Pressure Test ◽  
Integrity Management ◽  
Corrosion Defects ◽  
Low Probability ◽  
External Corrosion ◽  
Pipeline Safety

External Corrosion Direct Assessment (ECDA) has now become acknowledged, by the Office of Pipeline Safety (OPS) in North America, as a viable alternative to both in-line inspection (ILI) and the hydrostatic pressure test for the purpose of managing the integrity of high pressure pipelines. Accordingly an ECDA standard is now in existence. The essence of ECDA is to use indirect above ground survey techniques to locate the presence of coating and corrosion defects and then to investigate some of the indications directly by making excavations. However, one of the problems of above ground survey techniques is that they do not locate all defects and are susceptible to false indication. This means that the defects will not be present at all indications and that some defects will be missed. In view of the limitations of above ground survey techniques the ECDA standard requires that at least two complimentary survey techniques should be used. The selected survey techniques will depend on the nature of a particular ‘ECDA segment’, taking account of the surface characteristics. However, in many situations the surveys will include a coating survey and a corrosion survey. In general the outcome from these two surveys will be NH locations at which just the coating survey gives an indication, NC locations at which just the corrosion survey gives an indication and NHC locations at which both surveys give an indication. This paper presents a new probabilistic methodology for estimating the distributions of the actual numbers of coating and corrosion defects, taking account of the outcomes of the surveys and the probabilities of detection and false indication of both techniques. The method also shows how the probabilities of detection and false indication are updated depending on what is found during the excavations and the distributions of the numbers of remaining corrosion and coating defects are subsequently modified. Based on a prescribed repair criterion the analysis is used to determine the probability that at least one remaining corrosion defect will exceed the repair criteria. As excavations are sequentially performed the probability naturally reduces. The attainment of an acceptably low probability is used as a trigger to terminate the excavation programme. A detailed description of the development of the method is given in this paper and the application is illustrated through a simple numerical example. A description of how the method is used to build a Direct Assessment module for a pipeline integrity management system is described in an accompanying paper.

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