Plant Integrity Management Services

Asset Management Services

Plant Integrity Management Services

Germanischer Lloyd – Service/Product Description

Contents

Service Description and Values Generated

Detailed Method Statement

Plant Integrity Management System Audits

Corrosion Management

Material Defect and Component FailureInvestigation

Fitness for Service Assessment

Written Schemes of Examination

Coatings Services

Welding Services

Risk Based Inspection

Pipework Vibration Services

Case Studies and Examples

Corrosion Management of LNG Storage Facilities

Integrity Management Review

Fracture of Thermowell

Failure of Impulse Pipework Compression Fitting

Fitness-for-Purpose Assessment of Pressure Vessels

Fracture Mechanics Assessment of a Defective Pig Trap

Defect Assessment of Corroded Pipework

Review of Integrity Management Framework

Safety Management Audit

Fitness for Service Assessment

Repair of Amine Stripper

Investigation of Coating Failure on Oil Storage Tank

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Plant Integrity ManagementServices

Service Title: Asset Management Services

Lead Practice: GL Asset Management (UK)

Germanischer Lloyd – Service/Product Description

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Service Descriptionand Values Generated:

Germanischer Lloyd (GL) provides a range of Plant IntegrityManagement services to assist Operators in managing their assets ina safe and efficient manner, as well as complying with all prevailingregulations and legislation.

GL are able to tailor their services to meet client needs and cangenerally provide support & solutions to a range of IntegrityManagement problems.

Supporting each of the core services are experts with many yearsexperience in integrity management.

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SERVICE DESCRIPTION

Case Studies and Examples

Corrosion Management Study

Weldability Testing of 48” Diameter X80Europipe Production

Design and Qualification of RepairProcedures for Bellows Attachment Welding

Evaluation of RBI Software

T-OCR Risk Based Inspection

Investigation of Double Block and BleedValve Vibration at a Gas Processing Facility

Long Term Monitoring of PipeworkVibration at Gas Compressor Stations

Assessment of Risk of Pipework Failure Dueto Vibration During Offshore Plant Uprating

Vibration Screening at an Onshore GasTerminal

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DETAILED METHOD STATEMENT

a. Plant Integrity Management System Audits

In general, an audit or review of an Integrity Management System willbegin with a Gap Analysis. This entails a thorough review of theOperator’s activities from corporate policy and organisation throughto company procedures and work instructions, including thefollowing:

� Compliance with national legislation and localrequirements

� Integrity threats and mitigations in place

- Onshore – mechanical damage, corrosion, groundmovement etc

- Offshore – mechanical damage, stress/fatigue typematerial failures, internal and external corrosion etc

� Quantitative risk assessments undertaken

� Engineering documentation

� Plant records and fault data

� Quality, health, safety and environmental issues

� Plant Operations and Maintenance

- Work scheduling- Record keeping- Routine and non routine activities

� Plant Inspection

� Modification and repair process

� Emergency management

� Defect assessment and repair methods

� Training and competency of staff

� Safe control of operations

� Continuous improvement processes in place

The Integrity Management System under review can then be assessedfor compliance with prevailing regulations and compared tointernational “best practice”. Recommendations can be made to theOperator as to how they can improve their processes and systems.

Generally in such a project there will be a Phase 2 which comprisesgap closure actions. Depending on the results from the gap analysisthis might entail a complete overhaul of an Operator’s EngineeringDocumentation System or it may involve some rationalisation andrepackaging to ensure that the IMS is clear and coherent.

b. Corrosion Management

GL’s approach to corrosion management is to consider the process,materials and safety aspects as an integrated whole. In most respectsthe process dictates the materials and corrosion control methods usedon plant while occasionally the materials technology available willshape the feasible process solutions. Ultimately, the objective is toproduce a system that assures the safety of plant operations. Thus, allhave to be addressed when considering corrosion management.

The production of a corrosion management system wouldgenerally involve the following stages:

1. Gather process data e.g. temperatures, pressures andfluid compositions during both normal operation andupset conditions

2. Consider the safety risk assessment in order to:

� Identify pressurised systems

� Identify major hazards

� Identify HAZOP actions related to corrosion andmaterials

3. Conduct corrosion risk assessment including:

� Calculation of internal corrosion rates

� Assessment of stress corrosion cracking threat

� Assessment of erosion threat

� Assessment of external corrosion including underinsulation

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4. Produce corrosion management scheme

� Select materials (corrosion resistant alloys or carbonsteel with corrosion allowance)

� Select corrosion control methods (e.g. inhibition,coatings, cathodic protection)

� Select corrosion monitoring methods and locations

� Produce corrosion data management strategy andselect tools

� Devise suitable key performance indicators (KPI) forcorrosion management

� Document change procedure for revising scheme ifprocess parameters are altered (e.g. afterdebottlenecking)

� Produce plant/field corrosion management guide/manual

5. Feed back the corrosion management activities into thefield safety case and risk assessment as mitigating factors

c. Material Defect and Component Failure Investigation

GL’s approach to failure investigations is not only to use state of theart methods to determine the immediate cause of the failure, but alsoto identify the root cause and propose solutions for eliminating theproblem in future.

There are many reasons why a material defect or failure may arise; forexample:-

� Incorrect materials selection,

� Materials quality issues,

� Fabrication issues,

� Operating conditions outside original design parameters,

� Environmental factors,

� Maintenance and protection issues,

� Human and procedural factors,

� Third party damage.

The scope of a failure investigation depends upon the nature of thefailure and also upon the results obtained as the investigationproceeds.

An important first step is to ensure the failure is preserved for futureexamination, particularly where this may be used as evidence forlitigation purposes. This may involve visits to site to assist inidentifying, examining and collecting all relevant material, andstabilising and protecting as necessary for transport to the laboratory.In the event of a dynamic failure, such as an explosion resulting inextensive damage, this may be a difficult and arduous task as themajority of the failures evident will be ‘effect’ and not necessarilydirectly relevant to identifying the cause. In these circumstancesdetailed photography is essential before any material is removed fromthe site of the failure. It is also important to talk to site personnel toestablish the circumstances surrounding the failure and operatingconditions at the time.

Where the failure involves a defect in a component or structure it isimportant that NDT (Non Destructive Testing) is carried out todetermine the extent of the failure and any associated damage priorto extraction for detailed analysis. GL NDT experts offer a range oftechniques, both on-site and in the laboratory, including: magneticparticle inspection (MPI), dye penetrant testing (DP), manualultrasonic testing (MUT), alternating current potential drop (ACPD),and mechanical measurements.

For characterising the defect or failure a metallurgical examinationand materials testing programme is carried out.

A metallurgical examination of a defect or failure would typicallyinclude:-

� Visual examination by eye and using a stereo opticalmicroscope

� Detailed fractography using a scanning electronmicrosope (SEM)

� Surface compositional analysis by semi-quantitative X-rayenergy dispersive micro-analysis (EDX) in the SEM

� Preparation of weld sections for macro-examination andhardness surveys

� Preparation of mounted and polished sections formicrostructural analysis and to confirm crack path

Materials testing, to establish compliance with relevant standards andto generate mechanical property data for supporting engineeringanalysis assessments, would typically involve:-

� Chemical composition

� Tensile testing (e.g. yield strength, ultimate tensile strength,elongation etc, and specific tests for threaded fasteners)

� Hardness testing

� Charpy impact testing

� Fracture mechanics testing (such as CTOD and J-integral)

The output from the metallurgical analysis and materials testingprogramme would offer the customer an opinion on the mode and likelycause of failure, and an understanding of the contribution of materialrelated factors. It is usual to complement the metallurgical examinationand materials testing programmes with an engineering analysis toidentify and understand the contribution of mechanical factors.

Depending upon the nature and scope of the investigation furtheranalysis may be carried out to understand the wider implications ofthe failure and to ensure that recommendations for preventing furtherfailures are implemented, for example:-

� Detailed fracture mechanics analysis to determine safeoperating parameters

� Fitness for purpose assessments

� Remaining life analysis

� Review and update of operating procedures

� Review of asset integrity and inspection programmes(such as RBI)

d. Fitness for Service Assessment

GL routinely undertakes assessments of damaged pressure vessels andpressure systems for an international clientele of asset owners/operators worldwide. We have in-depth knowledge and experience inthe use of industry recognised assessment methods such as:

� API 579

� RSTRENG

� DNV RPF101

� BS7910

� ASME VIII

� PD5500

� BS EN13445

GL therefore have the capability to assess the integrity of pipeworkand pressure vessels and routinely use advanced numerical techniquessuch as the finite element (FE) method and pipe stress analysis toundertake fitness for service assessments. We have excellentknowledge of the UK Pressure Systems Safety Regulations, 2000(PSSR) and relevant US Code of Federal Regulations (e.g. CFR 192 and195).

For any fitness-for-purpose assessment, assumptions are required onthe input parameters. These assumptions include:

� Original equipment design data

� Operational and maintenance history

� Expected future service

� Information specific to the assessment such as defectsizes, stress state, location of flaws, and materialproperties such as tensile strength and fracturetoughness.

Fitness for Service can be demonstrated using methods such as stressanalysis, defects assessment and fracture mechanics approaches.These are described as follows:

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Stress Analysis

Fitness for service can be demonstrated using higher level assessmentmethods such as FE (Finite Element Analysis). GL can undertake workranging from the stress analysis of individual structural componentssuch as pressure vessel nozzles, full pressure vessel models tocomplete piping systems. GL consultants have the capabilities toundertake advanced non-linear, static/dynamic analysis, vibration,thermal and fatigue analyses. We use these capabilities to undertakefitness-for-service assessments of pressure systems and in conjunctionwith full scale testing facilities to develop defect assessment methodsfor pipelines and pressure vessels. GL uses an extensive range of FEand associated software tools that are mounted on both SUN Unixnetwork and PC based Windows system. The software tools we useinclude:

� ABAQUS (Standard and Explicit) FE analysis program

� MSC/PATRAN and ABAQUS CAE FE pre and postprocessor programs

� PC based software such as MathCad and MATLAB

In addition to the above, our consultants can write customisedprograms, user subroutines, etc. in order to overcome the limitationsin proprietary software. Areas of expertise include;

� Linear and non-linear analysis. Where necessary,non-linear effects can be included in the analysis; this canbe through the modelling of non-linear materialbehaviour, geometric non-linearity and contact

� Buckling, postbuckling and collapse analysis of pipelines

� Soil structure interaction

� Steady state and transient heat transfer analysis

� Fatigue and fracture mechanics; cracked body analysis

� Design by analysis

Defect Assessment

Defect assessment is a deterministic approach used to assess theintegrity and fitness for service of defects found on pressure vessels orpiping. Defects are features that affect the structural integrity ofvessels, pipelines or piping, and may be located on the surface of thepipe wall or actually inside the material of the pipe or shell. There arenumerous codes that can be used to assess defects and aresummarised in documents such as the Pipeline Defect AssessmentManual used for pipelines, which our consultants understand the bestmethods to use. In addition, GL has experience in conductingassessments to API 579 and BS 7910 used for pressure vessels andpiping.

Sources for defect data include NDT methods. Using in-houseexpertise, appropriate assessment methods can then be chosen andapplied to demonstrate fitness-for-service in order to satisfy regulatoryrequirements and operators’ integrity management strategy.

Damage assessment capabilities include the following;

i) Manufacturing Damage, Manufacturing features areoften a discontinuity in the geometry of the pipe or shellsuch as a reduction in wall thickness or in the materialitself.

ii) Construction Damage, Construction defects mayinclude girth weld defects or seam weld defects caused bylack of fill or misalignment, and in the most severe case,cracking. Also, other forms of damage may occur such asindentation damage, corrosion at the girth weld, or evendamage to the external coating.

iii) 3rd party interference, 3rd party damage is often themost severe form of damage resulting in failure of thepipe or requiring immediate repair. Often this involvesmechanical damage such as a gouge resulting in metalloss of the pipe wall, or distortion of the pipe wall such asa dent.

iv) Operational damage. Defects arising from operationalusage include external corrosion caused by damaged ordisbonded coating where the Cathodic Protection Systemis not effective. Also internal corrosion caused by water inthe product, and even other forms of corrosion namely‘Sweet Corrosion’ and ‘Sour Corrosion’ may occur inpipelines.

Windows is a trademark of MicrosoftTM corporation

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Fracture Mechanics

BS7910 and similar codes such as the UK nuclear industry code R6and API 579, carry out fracture assessments using the FailureAssessment Diagram (FAD). This provides a graphical method forassessing the proximity of a loaded structure containing a defect tofailure by fracture and plastic collapse mechanisms. Proximity tofracture is characterised by the fracture ratio parameter Kr andproximity to plastic collapse is characterised by the parameter Lr. Aloaded structure can therefore be represented as an assessment pointon the FAD following calculation of Lr and Kr.

This diagram is used in levels 1 to 3 of BS7910 to determine theacceptability of cracks by plotting a point on the diagram. Whendeciding which level to use, this depends on the input data availableand conservatism required. These levels can be summarised as;

� Level 1 is a simplified assessment method when there islimited data on material properties

� Level 2 is the normal assessment route

� Level 3 is based a ductile tearing resistance analysis

Using the fracture mechanics approach our consultants can determinewhether a defect is SAFE or UNSAFE based on the Failure AssessmentDiagram. Using the fatigue assessment approaches described inBS7910, we can then determine the remaining fatigue life and futureintegrity of the structure if subjected to cyclic loading.

e. Written Schemes of Examination

The Written Schemes of Examination (WSoEs) will be logicallystructured to allow for effective monitoring and control and will showindividual pressure systems within each of the major systems. Thecomponents that require periodic inspection in order to ensurecontinued fitness for purpose will be identified.

The WSoE will ensure that all components within the plant aresufficiently inspected to ensure that any defects are detected at anearly stage to prevent inoperability of the asset. Such inspections maynot be limited to pressure containing components, but may alsoinclude access ladders, gantries, foundations, whose failure may limitthe operability of the plant or equipment.

The WSoE will be structured in such a way that will allow the User todetermine the future inspection requirements for at least a 5-yearperiod, however, it is more likely that future inspection requirementsfor circa 10 years will be attained.

The items of equipment covered will generally cover the following:

� Pressure vessels, drums, tanks etc.

� Heat exchangers

� Compressors

� Filters

� Onshore pipelines

� Offshore pipelines

� Relief valves

� Pressure safety valves

� Fire systems components

� Compressed air and nitrogen systems

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The WSoEs will be developed by:-

� Reviewing existing documentation pertaining to design,manufacture, construction, testing, modifications andrepairs, past inspection reports, etc. and plant operationrecords.

� Establishing safe operating limits and their protectivedevices.

� Identifying individual pressure systems.

� Developing examination specifications from eachcomponent group.

� Identifying examination frequencies on fixed timeintervals for major items of equipment based uponindustry practices, GL experience and information assupplied from the Client.

� Liaising with the system User.

The WSoEs will typically include :-

� Safe Operating Limits.

� Equipment to be inspected.

� Identification references of each item of equipment.

� Nature and type of inspection required (visual, NDT etc.)

� Functional testing requirements for protective devices.

� Preparatory work required prior to inspection.

� Frequency of inspection.

� Detailed written inspection procedures for each item ofequipment, based on current inspection methodologies,based upon the generic examination specifications.

� Competencies/qualifications required by inspectors.

� Standard report formats for recording examinations.

� Identification of applicable international / national codes,specs, procedures etc.

� Applicability and adaptability to utilise the most up todate inspection techniques for the examination of plant inthe most cost effective manner.

GL will nominate competent, technical engineers, with long termexperience in compiling WSoEs for major gas transporters, toundertake this work. The WSoEs will be generated on Microsoft Wordand Excel and be provided on CDs and hard copy. The WSoEs will bebased on UK best practice and will not include any other nationalrequirements, unless otherwise stated.

The WSoE will be submitted to the Independent Competent Personfor review and/or approval.

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f. Coatings Services

Many factors dictate the protection being afforded to plant andequipment and these must be considered when selecting paint andcoating systems for providing corrosion, erosion and chemicalresistance. Long term corrosion protection will generally require:

1. Identification of appropriate coating systems

� Identify substrate type, method of preparation,operating temperature, requirements for insulation,contents being processed or stored etc

2. Small-scale performance evaluation to ensure long-termprotection at the new construction and maintenancestage

� Application, accelerated corrosion testing,performance assessment

3. Development of coating application specifications fornew construction and maintenance

� Surface preparation, application, inspection andtesting

4. Coating survey and technical audits to ensure successfulapplication and compatibility with existing systems

GL has been involved in material selection, testing, specificationdevelopment and quality control issues to ensure long term protectionof plant and equipment.

Where inappropriate coating systems have been specified, or coatingshave been applied incorrectly, GL offer a consultancy service to helpconfirm the cause of failure. Laboratory test programmes helpestablish the mechanism of failure, and to apportion blame wherelitigation is a likely outcome.

g. Welding Services

GL staff have been involved, in many cases, in the development andqualification testing of procedures and consumables for theconstruction of pipelines, process plant and ancillary high pressureequipment. GL carries out weldability studies on all candidate linepipeand components used in the UK National Transmission system inaccordance with the requirements of National Grid specificationT/SP/MPQ/1. For line pipe this involves the production of a full scalegirth weld under simulated field conditions, to an approvedprocedure and including such factors as lifting and manipulation tosimulate movement of the line-up clamps following deposition of thehot pass.

Additionally, repair special procedures are tested and qualified beforebeing putting into service.

Welding consultancy services are also required when new or difficultmaterials are involved, such as those employed for high temperatureor sour service environments and include materials such as Inconel,duplex stainless steels or linepipe clad with these materials. In thesecases very specific welding procedure specifications are drawn up andinitial production welding is carried out under the supervision ofGL expert staff.

GL also carries out welding prequalification of high pressurecomponents produced by new suppliers, and an investigation of thewelding procedures and consumables employed by candidatecompanies is an integral part of this. Site visits are carried out andsupervision of component production ensures that they meet therelevant requirements for specific companies and individual projectsand can be welded into the system without problems.

GL also supplies expert assistance in the selection and application ofmethods for weld repair of pipelines, process plant and high pressureequipment. This is supplemented by expertise in inspection whichensures that defective areas are professionally repaired and returnedto service in fully reliable condition.

h. Risk Based Inspection

The main objectives of the RBI is to derive an inspection strategy thatensures the maintenance of integrity of the plant.

� To establish a minimised vessel inspection programme inaccordance with regulations

� To optimise the inspection strategy for equipmentincluding the testing and maintenance of relief valves

� To establish integrity management procedures for LNGpipework

� To reduce, and where possible, eliminate the need for fullvessel isolation and entry by utilising borescopicinspection techniques

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The RBI methodology combines expert judgement and probabilisticmodelling. RBI software is used for the execution of criticalityassessments and generation of inspection plans.

The methodology includes procedures to define process fluids andsystemise process streams. Within any process stream there may bechanges in pressure and/or temperature of the contained fluid. Asystem is defined as being that part of a process stream at similartemperature and pressure; such changes may give rise to differentcorrosion regimes, or a different fluid state. Systemisation of sites iscarried out using the latest version hard copies of the piping &instrumentation diagrams (P&IDs).

As part of the RBI process, a qualitative assessment is carried out byrelevant members the RBI Project Team. This procedure uses processsystem information, in combination with the materials and containedfluid properties to allocate specific operational consequence ratingsrelating to standby, financial and location impact. This is also used tohighlight any particular areas of concern with respect to equipmentdeterioration.

Following data entry, an initial criticality (risk) assessment is carriedout using the current equipment design and process information. Thiswill generate an initial relative risk (or criticality rating) for each itemof equipment in the database, based on the probability andconsequence.

The RBI software includes a module program that can be usedto develop detailed inspection plans. Although the RBI will determinethe recommended frequency of inspection, it cannot assign aninspection method. This must be manually selected from a list ofmethods. The RBI project team is responsible for populating thedatabase with recommended inspection methods for each interiminspection task. However, these may be amended by site once the RBIsystem is fully operational, depending on the views of site engineers,inspectors and the competent person.

A Plant Integrity Review (PIR) is then undertaken. The PIR re-evaluatescriticality assessments by examining process history, operatingconditions and past inspection results. The initial risk assessment isreviewed and verified against actual plant experience. This is anessential step as it provides an opportunity for the degradationmechanisms calculated by the software to be verified, by the ‘expertpanel’ and any additional failure mechanisms to be added. Changesto equipment criticality and confidence factors arising from the PIRwill produce changes to the recommended inspectionfrequencies/tasks. PIR meetings should be formally recorded, usingthe appropriate PIR decision record template, with details of the keydecisions made and persons present.

The competent should either be present at the PIR or receive adetailed report of any changes that are proposed, their reasons andthe effect on periodicity for equipment covered by PSSR. Any changesthat are made to the Written Schemes of Examination (WSoE) shouldthen be either made by the competent person or certified by thecompetent person before they can take effect and job plans can bealtered.

i. Pipework Vibration Servicves

GL offers a broad range of vibration measurement and analysisservices with specialist skills and knowledge in the following areas todetermine and manage the risk of vibration-induced fatigue failureof process pipework:

� Troubleshooting service to resolve vibration relatedproblems

� Detailed screening of main pipe and small boreconnections

� Vibration measurement and assessment

� Provision of advice and design guidance

� Identification and development of optimum solutions

Substantial experience has been gained in the investigation ofpipework vibration problems on process plant, including mechanicaland flow-related sources, and structural and acoustic transmission ofvibration. This knowledge, coupled with an extensive range ofexperimental and theoretical techniques which can be employed,enable a thorough investigation to be carried out. Any failureinvestigation can also draw on the substantial expertise in thecompany regarding integrity issues on pipelines, pipeworkcomponents, rotating machinery, pressure vessels and otherstructures. In the event of a vibration related failure or identificationof a problem, GL are able to provide a timely response, dependingon the urgency of the request for support.

As part of a plant integrity management programme for onshore andoffshore assets, it is essential to manage the risk of potential vibrationproblems on piping systems and small bore tubing. This can beachieved through a structured screening methodology which aims toquickly identify pipework at risk, assess the relative risk, and prioritiseeffort on plant areas of most concern.

GL have been active in developing strategies for reducing the threatof vibration related failures in order to target potential problems anddemonstrate legislative compliance, resulting in a significant reductionin the risk of failure at many sites.

Typically a study of this type would cover the main pipework and smallbore connections through the following:

� Visual survey

� Basic vibration measurements

� Assessment of risk of failure

The screening programme aims to identify issues from the site surveyrequiring immediate action, such as ineffective supports, poorlysupported pipework and vulnerable small bore connections. Subsequent investigations, if required, can then focus on the highestrisk areas which might include assessment of vulnerable connections,monitoring of transient vibration events, and monitoring of plant overan extended period to assess the behaviour over a full range ofoperating conditions.

This assessment methodology is consistent with the process industrybest practice, and has been used by operators to successfullydemonstrate to the UK HSE that appropriate steps have been takento manage the issue of pipework vibration on their assets.

An additional benefit of this type of project is an increased awarenessof vibration issues for operational staff. This helps to avoid theseproblems becoming significant in the future, through recognition ofproblems at an early stage, and implementation of best practice forany maintenance and replacement activities.

GL offers extensive experience of vibration surveys and on-sitemeasurements on operating plant pipework. Methodologies andassessment methods have been developed for measuring andassessing dynamic stress and vibration on all aspects of pipeworksystems. Intrinsically safe instrumentation has been designedspecifically for these applications, allowing vibration measurementsto be carried out in hazardous areas using a combination of straingauges and accelerometers as required. This includes a friction straingauge for small bore pipework which was developed and patented byGL, and which can be easily and rapidly installed to achieve accuratedynamic strain measurement on most pipe sizes without the need forsignificant surface preparation.

GL has also developed a measurement, data acquisition and analysissystem that performs ‘long term monitoring’ of a large number ofsensors over extended periods, for investigation of intermittent butsignificant pipework vibration problems associated with compressionfacilities and process plant. Subsequent analysis of the data providesin-depth understanding of the operator’s specific vibration problemsto enable the implementation of a cost-effective solution.

Following collection of the measurement data from a site, vibration andfatigue assessment techniques are used, which have been developedand independently validated to assess dynamic stress and vibration onall aspects of pipework systems. Acceptance criteria have been derivedfrom BS 7608 (Fatigue design and assessment of steel structures) for arange of common welded pipework and instrument stabbingconnections and used extensively in site surveys and assessments.

Finite element modelling is used in support of assessment and analysisactivities, with detailed studies allowing pipe wall vibration modesand stress concentration effects to be investigated in depth.

To reduce the risk of failures occurring to acceptably low levels,GL is able to provide advice on all aspects of pipework design relatedto dynamic behaviour, building on the experience gained in resolvingvibration related pipeline integrity issues. This advice can be appliedat any stage of a plant’s design, construction and operation. Forexample, specifications can be written for input to the design of aninstallation, design reviews can be carried out, and/or an as-builtreview of new or existing plant can be undertaken to identify areas ofconcern. Guidance can be provided on areas such as the following:

� Main pipework configuration

� Pipework supports

� Small bore connections

� Impulse pipework

� Valve selection

� Thermowells

Subsequent to the identification of pipework vibration problems, andbuilding on an increased understanding of the cause of the problemfrom any on-site investigation, GL’s expertise is well placed to makerecommendations on the need for remedial measures to reduce therisk of failures occurring. A variety of solutions to reduce the risk ofvibration-related failures are typically proposed for the client’sconsideration, taking into account issues of cost, effectiveness, easeof implementation, operational restrictions and safety, depending onthe nature of the problem and site under investigation.

Solutions can range from redesign and modification of pipework andconnections, and improvement of pipework supports, to identificationof preferred operating regimes and recommendations forinvestigation of plant performance, and development of designguidance documentation for future projects.

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CASE STUDIES

a. Corrosion Management of LNG Storage Facilities

Date: OngoingCustomer: National GridSavings: Improved corrosion management

GL has provided direct support and guidance for corrosionmanagement initiatives at five separate sites within the UK. In recentyears, this support has focused on the development of best-practicecorrosion management policies and guidelines.

GL assisted with the initial implementation of these guidelines byraising the profile of corrosion issues in LNG processes, and bypromoting a corrosion awareness culture across the business.

Specific areas of support have included:

� Fabric maintenance – Management and interpretation ofsite surveys to determine requirements for maintenancepainting and insulation replacement. Definition ofsite-specific workscopes for ongoing fabric maintenance.

� Corrosion Management Policy – Drafting of policy toreflect best-practice approach to corrosion control andmonitoring. Identification and definition of specific tasksto enable integration with maintenance managementsystem.

� Cooling Water Treatments – Review of cooling watersystems and chemical treatment service provision at allsites. Identified shortfalls in operational systems,recommendations for improved monitoring andopportunities for rationalisation of service contracts.

� LNG Vaporiser Life Extension – Conducted studies at twosites to confirm fitness-for-service of direct-fired vaporiserunits and identify operations and maintenance to achieverequired life extension.

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CASE STUDIES

b. Integrity Management Review

Date: 2006Customer: UK North Sea Oil Gas Operating CompanySavings: Improved systems integrity

GL was requested to carry out a review of integrity managementprocedures relating to pressure systems, pipelines and subseaequipment ahead of an internal audit of the client companymanagement systems. As part of this review GL was asked to considerthe suitability of the following:

� Organisational relationships for delivery of effectiveintegrity management

� Corrosion risk assessments used as a basis for integritymanagement planning

� The methods and frequency of inspection

� Inspection records of lead integrity managementcontractor

� The interpretation and analysis of inspection data

� Review feedback process from inspection findings intofuture inspection programmes

� The impact of general fabric maintenance procedures onintegrity management

To carry out the review effectively, GL requested access to a numberof client and integrity management contractor documents, including:

� Integrity Management Policy

� Pressure Systems Integrity Management System

� Subsea and Pipeline Integrity Management (Draft)

� Fabric Maintenance Philosophy

� Pressure Systems Integrity Review Procedure

� Monitoring, Inspection and Mitigation Procedures

� Written Schemes of Examination (for relevant assets)

The review of documentation was followed by a number of interviewswith key staff within the client organisation and the lead integritymanagement contractor. The objective of the interviews was toaddress a series of questions that were developed based on therelevant policies/procedures and integrity management“best-practice” within the oil and gas industry.

It was found that the integrity management systems for pressuresystems, subsea and pipelines were well structured and were, ingeneral, providing highly effective services. Although there had beena number of relatively recent changes in terms of both staff andsupporting guidelines/procedures, it was considered that these werelargely positive and should strengthen the understanding and controlof integrity management issues in the near future.

The most pressing issue to be addressed concerned the fatigue oftopside process plant. It was considered that the existing risk basedinspection (RBI) plan could not be expected to manage this problem.Although it was felt that the RBI process could assist with, throughcriticality assessments, the targeting of equipment a separate strategywas required to manage the problem effectively.

Further actions were recommended in the following areas:

� Management of corrosion under insulation (CUI)

� Incorporation of piping systems from vendor skids intoinspection plans

� Consideration of performance targets or key performanceindicators for the Integrity Management Policy

� Clarification of the terms of engagement between theclient and lead integrity management contractor

� Consideration of weld corrosion in risk assessments

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CASE STUDIES

c. Fracture of Thermowell

Date: 2005Customer: Transmission Pipeline OperatorSavings: Improved use of thermowells

GL were asked to investigate the failure of a stainless steel thermowellwhich had been located in a dry gas transmission pipeline. Acircumferential crack was found at the base of the thermowell. Ametallurgical examination determined that the crack was consistentwith low stress, high cycle fatigue crack propagation. An assessmentof the process conditions indicated that the fracture was caused byflow induced vibration produced by vortex shedding around thethermowell.

As a result of this failure the customer reviewed the use ofthermowells across its whole network. GL assisted by providingfurther guidance on the susceptibility of thermowells to vortexshedding, and by identifying appropriate alternatives.

Above – scanning electron microscope images of crack surface. Left– low magnification, transgranular separation and ‘feathery’appearance typical of austenitic stainless steel low stress high cyclefatigue failures. Right – high magnification, fine striations, acharacteristic feature of low stress high cycle fatigue crackpropagation.

d. Failure of Impulse Pipework Compression Fitting

Date: 2005Customer: Compressor Station OperatorSavings: Improved installation specifications

GL were asked to investigate the failure of a compression fitting on asection of impulse pipework at a compressor station. The failure ofthe fitting had caused the shutdown of the compressor unit. Ametallurgical examination determined that the failure was due tothree circumferential low stress, high cycle fatigue cracks which hadinitiated on the outer surface of the pipe at the point of contact withthe back ferrule of the compression fitting.

The root cause of the problem was identified as inadequate supportprovided to the impulse pipework. GL suggested an improvedsupport arrangement and, as part of a larger programme of work,GL monitored the vibration of the impulse pipework to ensure thatthe new support arrangements were sufficient to prevent any futurefailure of this pipework.

Fracture highlighted using dye penetrant

Failed impulse pipework

Circumferential fracture

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CASE STUDIES

e. Fitness-For-Purpose Assessment of Pressure Vessels

Date: 2007Customer: CentricaSavings: Cost savings to the client through a reduced frequency

for repair/replacement, reduced system downtime, andlife extension of high-pressure storage assets.

Issue:

Fracture mechanics-based fitness for purpose (FFP) assessmentmethods, such as those described in BS 7910, R6 and API 579 haveundergone rapid developments over the past 30 years. The FFS(Fitness For Service) methodology has developed into a powerful toolthat enables the analyst to assess the significance of flaws in weldedstructures.

Although comprehensive and applicable to a wide range ofengineering components, the methods contained within theseguidance documents are conservative. Furthermore, the methods canbe limited by, for example, the availability of stress intensity factorand reference stress solutions for specific geometries. One suchlimiting geometry is the nozzle, in particular the nozzle attachmentwelds, which is a common feature on high-pressure gas storagesystems.

In the UK, operators must follow legislation given in the PressureSystems Safety Regulations (PSSR), which provides a regime with theaim of ensuring the safety of pressure systems. One of the regulationsrequires that high-pressure gas storage systems must be subject toperiodic inspections followed by a FFS assessment to ensure theintegrity of the system.

Methodology & Results:

To ensure compliance with the requirements of the PSSR, GL hasdeveloped an in-house procedure that enables an FFS assessment tobe undertaken for a flaw in a nozzle weld. This procedure wasdeveloped to reduce the conservatism inherent in the assessmentprocedures given in BS7910 while still maintaining an acceptable levelof safety. Using a combination of Finite Element analysis and fracturemechanics techniques, a full FFS of pressure vessels was completed.

Savings:

This has resulted in substantial cost savings to the client through areduced frequency for repair/replacement, reduced system downtime,and life extension of high-pressure storage assets.

Pressure Vessel Nozzle

Finite Element Analysis of Pressure Vessel Nozzles

f. Fracture Mechanics Assessment of a Defective Pig Trap

Date: 2007Customer: United UtilitiesSavings: Cost of temporary pig trap and system downtime

due to installation

Issue:

GL were required to conduct a detailed assessment of a reported crackindication found on the closure casting of a pig trap located at anAGI facility in the UK. Following defect measurement in February2007, this was recorded at approximately 3-4 mm. A number of pigruns were then subsequently conducted. The defect was thenre-measured and reported to have a maximum depth of 5.3 mm.Measurements suggested that the defect had therefore grown sincethe pigging runs were conducted in 2007. The operator of the sitefacility intended to conduct further pig runs in February 2008 andhence required an assessment to determine whether the defect wassafe for the intended pig runs.


The approach that GL used was based on a BS7910 level 2a fracturemechanics assessment. Using fracture mechanics calculations and useof the FAD (Failure Assessment Diagram), the aim was to determinewhether the current size of crack was safe under the current designconditions and safe for the intended pig runs. Finally using a BS7910fatigue assessment of the crack, fatigue calculations were thenconducted to determine the remaining fatigue life of the reporteddefect and whether further pressure cycles can be tolerated due tothe intended pig runs. The fatigue assessment results showed thatthe defective area was likely to endure a large number of cycles beforefailure. Consequently it was concluded that the defect would enduresufficient further pressure cycles to conduct the intended piggingruns.

Savings:

Ultimately, the operator would have had to install a temporary pigtrap to conduct the required pigging runs. Following this, the temporary trap would have been removed and a new trap installed inits place resulting in costly delays and system downtime. Byconducting a fracture mechanics assessment, GL have saved the clientcosts associated with installing a temporary pig, inspection delays andsystem downtime.

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CASE STUDIES

g. Defect Assessment of Corroded Pipework

Date: 2004Customer: ADMA-OPCOSavings: Savings due to potential loss of containment and

system shutdown

Issue:

ADMA-OPCO identified areas of general corrosion on the inletpipework to separators on one of their platforms. The corrosion hadoccurred where clamps were fitted around vertically orientated 12”pipework, just above the girth weld that connects the pipework to90° elbows. ADMA-OPCO requested that GL undertake an assessmentof the defective area.


Four assessment methodologies were used for the assessment, B31G,RSTRENG, LPC-1 and API 579 Level 1. Predicted failure pressures andsafe operating pressures were calculated using the B31G, RSTRENGand LPC-1 assessment methodologies. Results showed that all failurepressures were well in excess of the design pressure, however the safeoperating pressures calculated using the B31G and RSTRENGmethodologies were considered to be unacceptable. In addition, thedefect area was assessed to the general and local metal loss Level 1procedures of API 579. The defects had been found to beunacceptable. These assessment results formed part of an overallopinion regarding the safety of the reported defect.

Savings:

Savings were made due to potential loss of containment and systemshutdown.

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CASE STUDIES

h. Review of Integrity Management Framework

Date: 2007Customer: Middle East Oil ProducerSavings: Improved integrity management

A major operating company in the UAE were keen to ensure that theirrecently implemented Integrity Management Framework wasdelivering what was intended.

GL undertook a gap analysis of the current operating philosophyagainst the IMF, and reported on where we felt the organisation wasin relation to the IMF as well as benchmarking where we determinedthe IMF was in relation to international best practice.

This project covered:-

� Pipelines

� Pressure Equipment

� Critical Safety Systems

� Rotating Equipment

� Structure

� Civils

� Electrical Equipment

� Lifting Equipment

� Wells

Once the gap analysis had been undertaken, a detailed list ofdeficiencies was prepared, and suggested improvements identified tobring the operations up to the desired level.

i. Safety Management Audit

Date: 2006Customer: UK LNG Terminal OperatorSavings: Improved safety management system

A UK LNG Terminal operator were expanding their storage capacity.Before they were able to commission the new phase, it was imperativethat a complete safety audit was undertaken to ensure that allprocesses currently in place were operating correctly.

GL sent in a team of specialists in their field to undertake this review.Interviews were undertaken with a cross section of staff, documentswere reviewed, and site inspections were undertaken to ensure thatthe practice matched the document trail.

The benefit to the client was that they were able to ensure that alldeficiencies were actioned and lessons learned before the expansionwas commissioned.

19

CASE STUDIES

j. Fitness for Service Assessment

Date: 2007Customer: BG TunisiaSavings: Improved monitoring and compliance

Issue:

Regulatory conditions state that all pressure systems need to beinspected to ensure they are fit for purpose, and examinationschedules needed to be produced. Therefore the client required aninspection schedule to be developed to make sure their assets are fitfor purpose and operating within the design specifications.


By working closely with the client and by taking reference fromPressure Systems Safety Regulations, the contents of the WSoE’s wereagreed upon. An up to date inspection scheme was produced,scheduling inspection work to be carried out during the plantshutdown period. Inspections were identified with inspection datesand times organised and a contingency for remedial work allocated.A list of required inspection qualifications was produced and fromthis a list of qualified engineering staff was assembled. A CompetentPerson was assigned to define roles under the UK legislation that thestaff would take.

Savings:

From the construction of the WSoE’s an extensive inspection of theclient’s assets were produced. The inspection identified areas ofremedial work that were required and helped setup monitoringprogrammes on assets that were at greatest risk of failure. TheWritten Scheme of Examination also provides the client with a meansto demonstrate compliance with the Pressure Systems SafetyRegulations 2004.

20

CASE STUDIES

k. Repair of Amine Stripper

Date: 2006Customer: BG Hannibal Gas Processing facilitySavings: Failure of processing vessel and plant shut down

Issue:

The client had experienced up to 40% loss in wall thickness on anamine stripper due to corrosion.

Methodology and Results:

The use of a coating system to isolate the vessel wall from thecorrosive environment inside the amine strippers was considered to bethe most cost effective solution. GL reviewed the properties of a rangeof different generic coatings systems to identify a material that wouldbe compatible with the operating conditions within the aminestripper. Having identified a suitable material, a technical review ofthe proposed coating specification was performed and technicalassistance provided during the on-site coating application process.

Savings:

Through wall corrosion failure and the requirement to shutdown theplant to facilitate a vessel repair. The estimated cost of a shutdownwas £500,000/day.

21

CASE STUDIES

l. Investigation of Coating Failure on Oil Storage Tank

Date: 2006Customer: Major Exploration and Operating CompanySavings: Prevention of large-scale coating failure

Issue:

The customer was experiencing cracking and disbonding of thecoating system applied to the external surfaces of a crude oil storagetank. The customer required GL to establish the mechanism ofbreakdown and to recommend methods of reparation.

Methodology and Results:

GL visited site to investigate the scale and nature of the failure. Alaboratory programme of work was initiated to reproduce the coatingfailure under controlled conditions and to establish the failuremechanism systems for reparation of the failed coating wererecommended and an application procedure prepared.

Savings:

This work identified the mechanism of coating failure and helped toprevent similar failures occurring in the future.

22

CASE STUDIES

m. Corrosion Management Study

Date: 2006Customer: National GridSavings: Development of a robust corrosion management

policy to maximise asset life

Issue:

The client wanted to establish a robust corrosion management planfor the above ground installations that were an integral part of thehigh pressure gas transmission system.


GL performed a review of the customer’s corrosion managementpolicy with a view to quantifying how much should be invested oninspection and maintenance for corrosion control purposes. Thereview included:

� Inspection and maintenance policy

� Future maintenance requirements to reflect best industrypractice

� The current inspection frequencies and those frequenciesrequired to maintain plant and equipmentfit-for-purpose

A series of site visits were conducted to obtain an overview of thecurrent condition of the corrosion control systems, the generalrequirements for maintenance painting and to identify and quantifyareas which would require regular inspection and maintenance.

Savings:

� Reduced unscheduled reductions and outages due tocorrosion related issues.

� Reduced repair cost.

� Maximisation of asset life.

23

CASE STUDIES

n. Weldability Testing of 48” Diameter X80 EuropipeProduction

Date: 2007Customer: National Grid (Milford Haven extension)Savings: Approved procedures of manufacturing

Weldability testing entails the production of a full-scale girth weldbetween two 12m pipe joints under field conditions and includingthe manipulation of the partially-completed weld to simulate theremoval and movement of the line-up clamp. Following production ofthe complete girth weld, the joint is subjected to X-ray inspection andmust pass required codes (T/SP/P/2 or API 1104 requirements) and isthen subjected to a full suite of mechanical tests. Followingsatisfactory results from these investigations, the welding procedureand the linepipe manufacturing route are qualified for supply toNational Grid.

24

CASE STUDIES

Girth welding of 48” X80 pipeduring weldability testing

Simulation lifting of 48” joint afterhot pass deposition.

Sample welding procedure qualification record from the48” X80 trials, showing joint design, consumables,pre-heat requirements, pass sequence and other details.

o. Design and Qualification of Repair Procedures for BellowsAttachment Welding

Date: 2008Customer: Pipeline OperatorSavings: Improved welding procedure

A GL report on the bellows connection concluded that the bellows onthe pipeline required a weld repair to be undertaken on the crackedfillet welds. The bellows configuration is shown in Figure A of thatreport, reproduced below:

Consequently, according to British Standard BS 6990, prior to weldingonto the live pipeline, it is necessary to qualify a procedure, simulatingthe cooling effect of the gas which complicates the qualification. Thequalification set-up should simulate actual flow conditions.

The weld procedure has been developed to minimise the risk oflamellar tearing. For weld procedure qualification, plate materialrepresenting the nearest equivalent currently available material isused.

Proposed weld procedure for the repair. Qualification of thisprocedure is in progress.

Weld Repair instructions:

� Weld repairs to cracked fillet welds in bellows unit to becarried out after qualification of the attached weld repairprocedure and following decommissioning and purgingof pipeline 2.

� Ensure all necessary risk assessments and safety checkshave been undertaken and procedures are followed,including safe control of operations (non routineoperation) and entry into confined spaces.

� Prior to repair, determine chemical analysis of carrier pipeand box material by on-site material sampling of thecarrier pipe and restraining box material in accordancewith T/PM/Q/10 (ref clause 12 and appendix B). Reportresults to GL for assessment.

� Remove the two fillet weld cracks in bellows 2 by grindingin accordance with T/PM/P/11 appendix F.

� Confirm defect removal by visual inspection and MPI.

� Check carrier pipe for defects by UT & MPI belowintended area of weld repair prior to welding.

� Perform weld repair in accordance with attachedprocedure: WPS/A/Tinsley/01FR (subject to qualification).

� Completed repair welds to be subjected to visualinspection and MPI.

25

CASE STUDIES

Cracking located in bellows attachment fillet welds.

26

CASE STUDIES

p. Evaluation of RBI Softaware

Date: 2007Customer: Major Gas OperatorSavings: Company time understanding the issues with

different RBI software packages

Issue:

The client was in the process of evaluating bidders for provision ofintegrity management software (IMS) oriented risk based inspectionmanagement of pressure systems, pipelines and structure of theMiskar Assets. Five software products were evaluated: Tishuk T-OCA,DNV Orbit, Lloyds Capstone, Aver Kvarner Coabis and Credosoft CredoPro. The client required a third party overview of the RBI systemsembedded in the software and to determine the merits of the fivedifferent RBI systems.


From GL experience with RBI systems, an evaluation of the RBIsoftware was produced. The main factors GL’s experienced personnelbelieved to be important in determining an effective RBI system are:

� Determine whether the RBI is qualitative, quantitative,semi-quantitative or combination of both

� Evaluate how the software derive Probability of Failure(PoF)

� Evaluate how the software derives Consequence of Failure(CoF) and whether important consequence attributeshave been captured

� Degradation mechanisms in the assessment andcomparison with degradation mechanism in country

� Post RBI analysis activities (e.g. Inspection planning)

Savings:

An impartial third party review of software was obtained, denotingthe merits and drawbacks to each system. Allows GL’s experiencedpersonnel to put forward the best system that meets the requirementsof the client, so that the investment into the system produces the bestresult. Also saves personnel time in trialling all the software andproducing an evaluation of each.

27

CASE STUDIES

q. T-OCR Risk Based Inspection

Date: 2005Customer: Major Natural Gas CompanySavings: Reduced equipment downtime and

costs due to failures

Issue:

The client expressed an interest in adopting a risk based inspection(RBI) scheme for integrity management of its offshore and onshoreprocess plant. A feasibility study was required to determine thepracticalities, outline implementation costs and potential benefits ofapplying RBI.


The initial part of the study included a review of the current integritymanagement systems. This was followed by an assessment of thefeasibility and requirements for the application of RBI. The final partof the study comprised two RBI pilot studies centring on known areasof concern on the specific plants. The key results from this study wereas follows:

� A feasibility of applying (risk based inspection) RBI to thefacilities produced

� A review of existing approaches to integrity management,and any modification required to accommodate the RBIapproach were identified

� Potential benefits of applying RBI to its facilities identified,including improvements in equipment reliability and costreductions from optimisation of inspection planning anddeployment

Savings:

Main saving is on the company time and finances on determining thebenefits and viability of implementing an RBI approach. Also identifiesto the client the long term benefits of a RBI approach, as shownbelow:

� Reduced equipment downtime and costs due to failures

� Reduced requirement for items to be taken offline to beinspected

� Focusing of inspection resources on key corrosion andmaterials degradation issues

The report also includes recommendations for implementation of RBI,including support required and a breakdown of likely resourcesrequirements.

28

CASE STUDIES

r. Investigation of Double Block and Bleed Valve Vibration ata Gas Processing Facility

Date: 2004Customer: Onshore Operator, KazakhstanSavings: Management of the risk of failures reduce the

occurrence of failures and the associated costs ofplant shutdown and remedial work

Issue:

During the commissioning and early operational life of a large gasprocessing facility, failures were experienced of a significant numberof small bore connections across the plant. This was determined tobe due to the poor design of these connections. Replacing all thesefittings would have been extremely costly, and a programme ofbracing of the large double block and bleed valves was thereforeundertaken. However, it was not known how effective this bracingwas in reducing the dynamic stresses to acceptable levels.


GL undertook a study across the processing plant tocharacterise the vibration of the small bore connections with largemass double block and bleed valves. Dynamic stress measurementswere taken on a selection of connections, including a range ofdifferent designs and bracing arrangements. This knowledge wasused to develop a screening method which could be used by Clientstaff to assess all the connections on the plant to implement aprioritised replacement plan.

Savings:

Management of the risk of failure of these connections reduced theoccurrence of failures, and the associated costs of plant shutdownand remedial work.

29

CASE STUDIES

s. Long Term Monitoring of Pipework Vibration at GasCompressor Stations

Date: 2003 to 2008Customer: UK Onshore OperatorSavings: Detailed understanding of the risk of pipework

vibration problems across operating range ofcompression plant

Issue:

Earlier work programmes had carried out an initial assessment ofsmall bore connections at compressor stations, from which a largeprogramme of replacement and removal had been instigated. However, some pipework vibration problems were known to occur atoperating conditions that were experienced only occasionally and hadnot been assessed.


GL developed a data acquisition and analysis system that would per-form long term monitoring of a large number of sensors over ex-tended periods. To date this has been installed on nine of thetwenty-six UK compressor stations for a period of at least threemonths in each case, and has provided a comprehensive assessmentof the pipework vibration over the full station operating range. Forexample, at several stations, pipework vibration problems wereidentified which were a result of the interaction of the gas flow fromadjacent units, phenomena that would not have been picked up bycarrying out measurements on each unit separately. This equipmenthas also been used to investigate vibration problems following specificincidents on compressor stations and on seal and lubrication oilsystem pipework.

Savings:

Detailed understanding of the occurrence of pipework vibrationproblems across the operating range of the plant ensures that fullconsideration is given to the causes, directing any remedial action andconfirming safe operating ranges.

t. Assessment of risk of pipework failure due to vibration dur-ing offshore plant uprating

Date: 2007Customer: UK Offshore OperatorSavings: Eliminated need for major changes to main

pipework, and allowed uprating to be achievedwithin available timescales

Issue:

Upgrade of two offshore compressor trains was planned to increasegas flow rates. A preliminary study by the Client suggested that therisk of vibration related failure of the main pipework was alreadyunacceptable and would be increased by uprating. The availableoutage period was insufficient for significant design changes to thepipework to be implemented.


GL undertook a study to assess the dynamic stressesexperienced by the main pipework and small bore connections duringoperation of the compressor units in their original configuration. Assessment of the dynamic behaviour was carried out over a range ofoperating conditions on both compressor trains. Knowledge gainedof the relationship between vibration and gas flow was subsequentlyused to predict the likely behaviour of the pipework at the currentmaximum and uprated conditions.

The study concluded that there was no need for major changes tothe main pipework prior to the uprating, allowing effort to beconcentrated on issues related to small bore connections.

Savings:

The findings of this work eliminated the need for major changes tothe main pipework, achieving significant cost savings for the projectand allowing the uprating to be achieved within the availabletimescales.

30

CASE STUDIES

u. Vibration screening at an onshore gas terminal

Date: 2005 to 2008Customer: UK OperatorSavings: Demonstrated management of risk of vibration

related failure of pipework to regulatory bodies

Issue:

To manage the risk of vibration related pipework fatigue failures astructured vibration screening and assessment methodology wasrequired by the Client, to identify problem areas and definesubsequent actions.


A phased approach was employed by GL to identify potential problemareas on the main pipework and small bore connections. The initialsite survey consisted of a walk-round visual review of the siteprocesses and pipework, basic vibration measurements, andassessment of the likelihood of failure of any connections. Thisexercise identified key problem areas for immediate remedial actionand further investigation, allowing effort to be focused on the highestrisk areas in subsequent stages.

Recommendations included identification of pipework support designand maintenance issues, changes to the design of small boreconnections that were identified to be at risk of failure, andidentification of areas of the plant to be assessed in greater detail todevelop an understanding of any problems identified and to developsolutions. This subsequent detailed assessment work has includedinstallation of monitoring equipment to assess the behaviour of theplant over its full operating range.

This methodology is now being deployed for the Client’s offshorefacilities.

Savings:

This project successfully demonstrated to the UK Health and SafetyExecutive that the issue is being adequately managed across theClient’s facilities.

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CASE STUDIES

Germanischer Lloyd does not warrant or assume any kind of liability for theup-to-date nature, accuracy, completeness or quality of the information provided.Liability claims against Germanischer Lloyd arising out of or in connection withmaterial or non-material loss or damage caused by the use or non-use of informationprovided, including the use of incorrect or incomplete information, are excludedunless such loss or damage is caused by the proven wilful misconduct or grosslynegligent conduct of Germanischer Lloyd.All offers are subject to alteration and are non-binding. Germanischer Lloyd expresslyreserves the right without notice to change, supplement or delete parts of the pagesor the entire offer or to stop the publication temporarily or definitively.

Germanischer LloydIndustrial Services GmbH

Oil and Gas

Steinhöft 9

20459 Hamburg, Germany

Phone +49 40 36149-7700

Fax +49 40 36149-1781

[email protected]

www.gl-group.com/glis

Issue no.001 15.05.2008

Asset Management Services

� Plant Integrity Management Services

Pipeline Integrity Management Services

Production Optimisation (Includes RAMand Gas Processing)

Dynamic and Steady State Simulation

Rotating Equipment Performance &Condition Monitoring includingEmissions Reporting

Gas Quality and Interchangeability

Documents

Plant Integrity Management Services