Plant Integrity Management Services

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Plant Integrity Management Services

  1. 1. Asset Management Services Plant Integrity Management Services Germanischer Lloyd – Service/Product Description
  2. 2. Germanischer Lloyd – Service/Product Description Plant Integrity Management Contents Services Service Title: Asset Management Services Page 3 Service Description and Values Generated Lead Practice: GL Asset Management (UK) Pages 4 - 12 Detailed Method Statement a: Plant Integrity Management System Audits b: Corrosion Management c: Material Defect and Component Failure Investigation d: Fitness for Service Assessment e: Written Schemes of Examination f: Coatings Services g: Welding Services h: Risk Based Inspection i: Pipework Vibration Services Pages 12 - 22 Case Studies and Examples a: Corrosion Management of LNG Storage Facilities b: Integrity Management Review c: Fracture of Thermowell d: Failure of Impulse Pipework Compression Fitting e: Fitness-for-Purpose Assessment of Pressure Vessels f: Fracture Mechanics Assessment of a Defective Pig Trap g: Defect Assessment of Corroded Pipework h: Review of Integrity Management Framework i: Safety Management Audit j: Fitness for Service Assessment k: Repair of Amine Stripper l: Investigation of Coating Failure on Oil Storage Tank 2
  3. 3. SERVICE DESCRIPTION Service Description and Values Generated: Pages 23 - 32 Case Studies and Examples Germanischer Lloyd (GL) provides a range of Plant Integrity Management services to assist Operators in managing their assets in m: Corrosion Management Study a safe and efficient manner, as well as complying with all prevailing regulations and legislation. n: Weldability Testing of 48” Diameter X80 Europipe Production GL are able to tailor their services to meet client needs and can generally provide support & solutions to a range of Integrity o: Design and Qualification of Repair Management problems. Procedures for Bellows Attachment Welding Supporting each of the core services are experts with many years p: Evaluation of RBI Software experience in integrity management. q: T-OCR Risk Based Inspection r: Investigation of Double Block and Bleed Valve Vibration at a Gas Processing Facility s: Long Term Monitoring of Pipework Vibration at Gas Compressor Stations t: Assessment of Risk of Pipework Failure Due to Vibration During Offshore Plant Uprating u: Vibration Screening at an Onshore Gas Terminal 3
  4. 4. DETAILED METHOD STATEMENT a. Plant Integrity Management System Audits b. Corrosion Management In general, an audit or review of an Integrity Management System will GL’s approach to corrosion management is to consider the process, begin with a Gap Analysis. This entails a thorough review of the materials and safety aspects as an integrated whole. In most respects Operator’s activities from corporate policy and organisation through the process dictates the materials and corrosion control methods used to company procedures and work instructions, including the on plant while occasionally the materials technology available will following: shape the feasible process solutions. Ultimately, the objective is to produce a system that assures the safety of plant operations. Thus, all Compliance with national legislation and local have to be addressed when considering corrosion management. requirements The production of a corrosion management system would Integrity threats and mitigations in place generally involve the following stages: - Onshore – mechanical damage, corrosion, ground 1. Gather process data e.g. temperatures, pressures and movement etc fluid compositions during both normal operation and - Offshore – mechanical damage, stress/fatigue type upset conditions material failures, internal and external corrosion etc Quantitative risk assessments undertaken 2. Consider the safety risk assessment in order to: Engineering documentation Identify pressurised systems Plant records and fault data Identify major hazards Quality, health, safety and environmental issues Identify HAZOP actions related to corrosion and materials Plant Operations and Maintenance - Work scheduling 3. Conduct corrosion risk assessment including: - Record keeping - Routine and non routine activities Calculation of internal corrosion rates Plant Inspection Assessment of stress corrosion cracking threat Modification and repair process Assessment of erosion threat Emergency management Assessment of external corrosion including under insulation 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 assessed for compliance with prevailing regulations and compared to international “best practice”. Recommendations can be made to the Operator as to how they can improve their processes and systems. Generally in such a project there will be a Phase 2 which comprises gap closure actions. Depending on the results from the gap analysis this might entail a complete overhaul of an Operator’s Engineering Documentation System or it may involve some rationalisation and repackaging to ensure that the IMS is clear and coherent. 4
  5. 5. DETAILED METHOD STATEMENT 4. Produce corrosion management scheme c. Material Defect and Component Failure Investigation Select materials (corrosion resistant alloys or carbon GL’s approach to failure investigations is not only to use state of the steel with corrosion allowance) art methods to determine the immediate cause of the failure, but also to identify the root cause and propose solutions for eliminating the Select corrosion control methods (e.g. inhibition, problem in future. coatings, cathodic protection) There are many reasons why a material defect or failure may arise; for Select corrosion monitoring methods and locations example:- Produce corrosion data management strategy and Incorrect materials selection, select tools Materials quality issues, Devise suitable key performance indicators (KPI) for corrosion management Fabrication issues, Document change procedure for revising scheme if Operating conditions outside original design parameters, process parameters are altered (e.g. after debottlenecking) Environmental factors, Produce plant/field corrosion management guide/ Maintenance and protection issues, manual Human and procedural factors, 5. Feed back the corrosion management activities into the Third party damage. field safety case and risk assessment as mitigating factors The scope of a failure investigation depends upon the nature of the failure and also upon the results obtained as the investigation proceeds. An important first step is to ensure the failure is preserved for future examination, particularly where this may be used as evidence for litigation purposes. This may involve visits to site to assist in identifying, examining and collecting all relevant material, and stabilising and protecting as necessary for transport to the laboratory. In the event of a dynamic failure, such as an explosion resulting in extensive damage, this may be a difficult and arduous task as the majority of the failures evident will be ‘effect’ and not necessarily directly relevant to identifying the cause. In these circumstances detailed photography is essential before any material is removed from the site of the failure. It is also important to talk to site personnel to establish the circumstances surrounding the failure and operating conditions at the time. Where the failure involves a defect in a component or structure it is important that NDT (Non Destructive Testing) is carried out to determine the extent of the failure and any associated damage prior to extraction for detailed analysis. GL NDT experts offer a range of techniques, both on-site and in the laboratory, including: magnetic particle inspection (MPI), dye penetrant testing (DP), manual ultrasonic testing (MUT), alternating current potential drop (ACPD), and mechanical measurements. For characterising the defect or failure a metallurgical examination and materials testing programme is carried out. 5
  6. 6. DETAILED METHOD STATEMENT A metallurgical examination of a defect or failure would typically d. Fitness for Service Assessment include:- GL routinely undertakes assessments of damaged pressure vessels and Visual examination by eye and using a stereo optical pressure systems for an international clientele of asset owners/ microscope operators worldwide. We have in-depth knowledge and experience in the use of industry recognised assessment methods such as: Detailed fractography using a scanning electron microsope (SEM) API 579 Surface compositional analysis by semi-quantitative X-ray RSTRENG energy dispersive micro-analysis (EDX) in the SEM DNV RPF101 Preparation of weld sections for macro-examination and hardness surveys BS7910 Preparation of mounted and polished sections for ASME VIII microstructural analysis and to confirm crack path PD5500 Materials testing, to establish compliance with relevant standards and BS EN13445 to generate mechanical property data for supporting engineering analysis assessments, would typically involve:- GL therefore have the capability to assess the integrity of pipework Chemical composition and pressure vessels and routinely use advanced numerical techniques such as the finite element (FE) method and pipe stress analysis to Tensile testing (e.g. yield strength, ultimate tensile strength, undertake fitness for service assessments. We have excellent elongation etc, and specific tests for threaded fasteners) knowledge of the UK Pressure Systems Safety Regulations, 2000 (PSSR) and relevant US Code of Federal Regulations (e.g. CFR 192 and Hardness testing 195). Charpy impact testing For any fitness-for-purpose assessment, assumptions are required on the input parameters. These assumptions include: Fracture mechanics testing (such as CTOD and J-integral) Original equipment design data The output from the metallurgical analysis and materials testing Operational and maintenance history programme would offer the customer an opinion on the mode and likely cause of failure, and an understanding of the contribution of material Expected future service related factors. It is usual to complement the metallurgical examination and materials testing programmes with an engineering analysis to Information specific to the assessment such as defect identify and understand the contribution of mechanical factors. sizes, stress state, location of flaws, and material properties such as tensile strength and fracture Depending upon the nature and scope of the investigation further toughness. analysis may be carried out to understand the wider implications of the failure and to ensure that recommendations for preventing further Fitness for Service can be demonstrated using methods such as stress failures are implemented, for example:- analysis, defects assessment and fracture mechanics approaches. These are described as follows: Detailed fracture mechanics analysis to determine safe operating parameters Fitness for purpose assessments Remaining life analysis Review and update of operating procedures Review of asset integrity and inspection programmes (such as RBI) 6
  7. 7. DETAILED METHOD STATEMENT Stress Analysis Defect Assessment Fitness for service can be demonstrated using higher level assessment Defect assessment is a deterministic approach used to assess the methods such as FE (Finite Element Analysis). GL can undertake work integrity and fitness for service of defects found on pressure vessels or ranging from the stress analysis of individual structural components piping. Defects are features that affect the structural integrity of such as pressure vessel nozzles, full pressure vessel models to vessels, pipelines or piping, and may be located on the surface of the complete piping systems. GL consultants have the capabilities to pipe wall or actually inside the material of the pipe or shell. There are undertake advanced non-linear, static/dynamic analysis, vibration, numerous codes that can be used to assess defects and are thermal and fatigue analyses. We use these capabilities to undertake summarised in documents such as the Pipeline Defect Assessment fitness-for-service assessments of pressure systems and in conjunction Manual used for pipelines, which our consultants understand the best with full scale testing facilities to develop defect assessment methods methods to use. In addition, GL has experience in conducting for pipelines and pressure vessels. GL uses an extensive range of FE assessments to API 579 and BS 7910 used for pressure vessels and and associated software tools that are mounted on both SUN Unix piping. network and PC based Windows system. The software tools we use include: Sources for defect data include NDT methods. Using in-house expertise, appropriate assessment methods can then be chosen and ABAQUS (Standard and Explicit) FE analysis program applied to demonstrate fitness-for-service in order to satisfy regulatory requirements and operators’ integrity management strategy. MSC/PATRAN and ABAQUS CAE FE pre and post processor programs Damage assessment capabilities include the following; PC based software such as MathCad and MATLAB i) Manufacturing Damage, Manufacturing features are often a discontinuity in the geometry of the pipe or shell In addition to the above, our consultants can write customised such as a reduction in wall thickness or in the material programs, user subroutines, etc. in order to overcome the limitations itself. in proprietary software. Areas of expertise include; ii) Construction Damage, Construction defects may Linear and non-linear analysis. Where necessary, include girth weld defects or seam weld defects caused by non-linear effects can be included in the analysis; this can lack of fill or misalignment, and in the most severe case, be through the modelling of non-linear material cracking. Also, other forms of damage may occur such as behaviour, geometric non-linearity and contact indentation damage, corrosion at the girth weld, or even damage to the external coating. Buckling, postbuckling and collapse analysis of pipelines iii) 3rd party interference, 3rd party damage is often the Soil structure interaction most severe form of damage resulting in failure of the pipe or requiring immediate repair. Often this involves Steady state and transient heat transfer analysis mechanical damage such as a gouge resulting in metal loss of the pipe wall, or distortion of the pipe wall such as Fatigue and fracture mechanics; cracked body analysis a dent. Design by analysis iv) Operational damage. Defects arising from operational usage include external corrosion caused by damaged or disbonded coating where the Cathodic Protection System is not effective. Also internal corrosion caused by water in the product, and even other forms of corrosion namely ‘Sweet Corrosion’ and ‘Sour Corrosion’ may occur in pipelines. Windows is a trademark of MicrosoftTM corporation 7
  8. 8. DETAILED METHOD STATEMENT Fracture Mechanics e. Written Schemes of Examination BS7910 and similar codes such as the UK nuclear industry code R6 The Written Schemes of Examination (WSoEs) will be logically and API 579, carry out fracture assessments using the Failure structured to allow for effective monitoring and control and will show Assessment Diagram (FAD). This provides a graphical method for individual pressure systems within each of the major systems. The assessing the proximity of a loaded structure containing a defect to components that require periodic inspection in order to ensure failure by fracture and plastic collapse mechanisms. Proximity to continued fitness for purpose will be identified. fracture is characterised by the fracture ratio parameter Kr and proximity to plastic collapse is characterised by the parameter Lr. A The WSoE will ensure that all components within the plant are loaded structure can therefore be represented as an assessment point sufficiently inspected to ensure that any defects are detected at an on the FAD following calculation of Lr and Kr. early stage to prevent inoperability of the asset. Such inspections may not be limited to pressure containing components, but may also This diagram is used in levels 1 to 3 of BS7910 to determine the include access ladders, gantries, foundations, whose failure may limit acceptability of cracks by plotting a point on the diagram. When the operability of the plant or equipment. deciding which level to use, this depends on the input data available and conservatism required. These levels can be summarised as; The WSoE will be structured in such a way that will allow the User to determine the future inspection requirements for at least a 5-year Level 1 is a simplified assessment method when there is period, however, it is more likely that future inspection requirements limited data on material properties for circa 10 years will be attained. Level 2 is the normal assessment route The items of equipment covered will generally cover the following: Level 3 is based a ductile tearing resistance analysis Pressure vessels, drums, tanks etc. Heat exchangers Using the fracture mechanics approach our consultants can determine whether a defect is SAFE or UNSAFE based on the Failure Assessment Compressors Diagram. Using the fatigue assessment approaches described in BS7910, we can then determine the remaining fatigue life and future Filters integrity of the structure if subjected to cyclic loading. Onshore pipelines Offshore pipelines Relief valves Pressure safety valves Fire systems components Compressed air and nitrogen systems 8
  9. 9. DETAILED METHOD STATEMENT The WSoEs will be developed by:- GL will nominate competent, technical engineers, with long term experience in compiling WSoEs for major gas transporters, to Reviewing existing documentation pertaining to design, undertake this work. The WSoEs will be generated on Microsoft Word manufacture, construction, testing, modifications and and Excel and be provided on CDs and hard copy. The WSoEs will be repairs, past inspection reports, etc. and plant operation based on UK best practice and will not include any other national records. requirements, unless otherwise stated. Establishing safe operating limits and their protective The WSoE will be submitted to the Independent Competent Person devices. for review and/or approval. Identifying individual pressure systems. Developing examination specifications from each component group. Identifying examination frequencies on fixed time intervals for major items of equipment based upon industry practices, GL experience and information as supplied 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 of equipment, 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 to date inspection techniques for the examination of plant in the most cost effective manner. 9
  10. 10. DETAILED METHOD STATEMENT f. Coatings Services g. Welding Services Many factors dictate the protection being afforded to plant and GL staff have been involved, in many cases, in the development and equipment and these must be considered when selecting paint and qualification testing of procedures and consumables for the coating systems for providing corrosion, erosion and chemical construction of pipelines, process plant and ancillary high pressure resistance. Long term corrosion protection will generally require: equipment. GL carries out weldability studies on all candidate linepipe and components used in the UK National Transmission system in 1. Identification of appropriate coating systems accordance with the requirements of National Grid specification T/SP/MPQ/1. For line pipe this involves the production of a full scale Identify substrate type, method of preparation, girth weld under simulated field conditions, to an approved operating temperature, requirements for insulation, procedure and including such factors as lifting and manipulation to contents being processed or stored etc simulate movement of the line-up clamps following deposition of the hot pass. 2. Small-scale performance evaluation to ensure long-term protection at the new construction and maintenance Additionally, repair special procedures are tested and qualified before stage being putting into service. Application, accelerated corrosion testing, Welding consultancy services are also required when new or difficult performance assessment materials are involved, such as those employed for high temperature or sour service environments and include materials such as Inconel, 3. Development of coating application specifications for duplex stainless steels or linepipe clad with these materials. In these new construction and maintenance cases very specific welding procedure specifications are drawn up and initial production welding is carried out under the supervision of Surface preparation, application, inspection and GL expert staff. testing GL also carries out welding prequalification of high pressure 4. Coating survey and technical audits to ensure successful components produced by new suppliers, and an investigation of the application and compatibility with existing systems welding procedures and consumables employed by candidate companies is an integral part of this. Site visits are carried out and supervision of component production ensures that they meet the GL has been involved in material selection, testing, specification relevant requirements for specific companies and individual projects development and quality control issues to ensure long term protection and can be welded into the system without problems. of plant and equipment. GL also supplies expert assistance in the selection and application of Where inappropriate coating systems have been specified, or coatings methods for weld repair of pipelines, process plant and high pressure have been applied incorrectly, GL offer a consultancy service to help equipment. This is supplemented by expertise in inspection which confirm the cause of failure. Laboratory test programmes help ensures that defective areas are professionally repaired and returned establish the mechanism of failure, and to apportion blame where to service in fully reliable condition. litigation is a likely outcome. h. Risk Based Inspection The main objectives of the RBI is to derive an inspection strategy that ensures the maintenance of integrity of the plant. To establish a minimised vessel inspection programme in accordance with regulations To optimise the inspection strategy for equipment including the testing and maintenance of relief valves To establish integrity management procedures for LNG pipework To reduce, and where possible, eliminate the need for full vessel isolation and entry by utilising borescopic inspection techniques 10
  11. 11. DETAILED METHOD STATEMENT The RBI methodology combines expert judgement and probabilistic A Plant Integrity Review (PIR) is then undertaken. The PIR re-evaluates modelling. RBI software is used for the execution of criticality criticality assessments by examining process history, operating assessments and generation of inspection plans. conditions and past inspection results. The initial risk assessment is reviewed and verified against actual plant experience. This is an The methodology includes procedures to define process fluids and essential step as it provides an opportunity for the degradation systemise process streams. Within any process stream there may be mechanisms calculated by the software to be verified, by the ‘expert changes in pressure and/or temperature of the contained fluid. A panel’ and any additional failure mechanisms to be added. Changes system is defined as being that part of a process stream at similar to equipment criticality and confidence factors arising from the PIR temperature and pressure; such changes may give rise to different will produce changes to the recommended inspection corrosion regimes, or a different fluid state. Systemisation of sites is frequencies/tasks. PIR meetings should be formally recorded, using carried out using the latest version hard copies of the piping & the appropriate PIR decision record template, with details of the key instrumentation diagrams (P&IDs). decisions made and persons present. As part of the RBI process, a qualitative assessment is carried out by The competent should either be present at the PIR or receive a relevant members the RBI Project Team. This procedure uses process detailed report of any changes that are proposed, their reasons and system information, in combination with the materials and contained the effect on periodicity for equipment covered by PSSR. Any changes fluid properties to allocate specific operational consequence ratings that are made to the Written Schemes of Examination (WSoE) should relating to standby, financial and location impact. This is also used to then be either made by the competent person or certified by the highlight any particular areas of concern with respect to equipment competent person before they can take effect and job plans can be deterioration. altered. i. Pipework Vibration Servicves GL offers a broad range of vibration measurement and analysis services with specialist skills and knowledge in the following areas to determine and manage the risk of vibration-induced fatigue failure of process pipework: Troubleshooting service to resolve vibration related problems Detailed screening of main pipe and small bore connections Vibration measurement and assessment Provision of advice and design guidance Following data entry, an initial criticality (risk) assessment is carried out using the current equipment design and process information. This Identification and development of optimum solutions will generate an initial relative risk (or criticality rating) for each item of equipment in the database, based on the probability and consequence. Substantial experience has been gained in the investigation of pipework vibration problems on process plant, including mechanical The RBI software includes a module program that can be used and flow-related sources, and structural and acoustic transmission of to develop detailed inspection plans. Although the RBI will determine vibration. This knowledge, coupled with an extensive range of the recommended frequency of inspection, it cannot assign an experimental and theoretical techniques which can be employed, inspection method. This must be manually selected from a list of enable a thorough investigation to be carried out. Any failure methods. The RBI project team is responsible for populating the investigation can also draw on the substantial expertise in the database with recommended inspection methods for each interim company regarding integrity issues on pipelines, pipework inspection task. However, these may be amended by site once the RBI components, rotating machinery, pressure vessels and other system is fully operational, depending on the views of site engineers, structures. In the event of a vibration related failure or identification inspectors and the competent person. of a problem, GL are able to provide a timely response, depending on the urgency of the request for support. 11
  12. 12. DETAILED METHOD STATEMENT As part of a plant integrity management programme for onshore and GL has also developed a measurement, data acquisition and analysis offshore assets, it is essential to manage the risk of potential vibration system that performs ‘long term monitoring’ of a large number of problems on piping systems and small bore tubing. This can be sensors over extended periods, for investigation of intermittent but achieved through a structured screening methodology which aims to significant pipework vibration problems associated with compression quickly identify pipework at risk, assess the relative risk, and prioritise facilities and process plant. Subsequent analysis of the data provides effort on plant areas of most concern. in-depth understanding of the operator’s specific vibration problems to enable the implementation of a cost-effective solution. GL have been active in developing strategies for reducing the threat of vibration related failures in order to target potential problems and Following collection of the measurement data from a site, vibration and demonstrate legislative compliance, resulting in a significant reduction fatigue assessment techniques are used, which have been developed in the risk of failure at many sites. and independently validated to assess dynamic stress and vibration on all aspects of pipework systems. Acceptance criteria have been derived Typically a study of this type would cover the main pipework and small from BS 7608 (Fatigue design and assessment of steel structures) for a bore connections through the following: range of common welded pipework and instrument stabbing connections and used extensively in site surveys and assessments. Visual survey Finite element modelling is used in support of assessment and analysis Basic vibration measurements activities, with detailed studies allowing pipe wall vibration modes and stress concentration effects to be investigated in depth. Assessment of risk of failure To reduce the risk of failures occurring to acceptably low levels, GL is able to provide advice on all aspects of pipework design related The screening programme aims to identify issues from the site survey to dynamic behaviour, building on the experience gained in resolving requiring immediate action, such as ineffective supports, poorly vibration related pipeline integrity issues. This advice can be applied supported pipework and vulnerable small bore connections. at any stage of a plant’s design, construction and operation. For Subsequent investigations, if required, can then focus on the highest example, specifications can be written for input to the design of an risk areas which might include assessment of vulnerable connections, installation, design reviews can be carried out, and/or an as-built monitoring of transient vibration events, and monitoring of plant over review of new or existing plant can be undertaken to identify areas of an extended period to assess the behaviour over a full range of concern. Guidance can be provided on areas such as the following: operating conditions. Main pipework configuration This assessment methodology is consistent with the process industry best practice, and has been used by operators to successfully Pipework supports demonstrate to the UK HSE that appropriate steps have been taken to manage the issue of pipework vibration on their assets. Small bore connections An additional benefit of this type of project is an increased awareness Impulse pipework of vibration issues for operational staff. This helps to avoid these problems becoming significant in the future, through recognition of Valve selection problems at an early stage, and implementation of best practice for any maintenance and replacement activities. Thermowells GL offers extensive experience of vibration surveys and on-site measurements on operating plant pipework. Methodologies and Subsequent to the identification of pipework vibration problems, and assessment methods have been developed for measuring and building on an increased understanding of the cause of the problem assessing dynamic stress and vibration on all aspects of pipework from any on-site investigation, GL’s expertise is well placed to make systems. Intrinsically safe instrumentation has been designed recommendations on the need for remedial measures to reduce the specifically for these applications, allowing vibration measurements risk of failures occurring. A variety of solutions to reduce the risk of to be carried out in hazardous areas using a combination of strain vibration-related failures are typically proposed for the client’s gauges and accelerometers as required. This includes a friction strain consideration, taking into account issues of cost, effectiveness, ease gauge for small bore pipework which was developed and patented by of implementation, operational restrictions and safety, depending on GL, and which can be easily and rapidly installed to achieve accurate the nature of the problem and site under investigation. dynamic strain measurement on most pipe sizes without the need for significant surface preparation. Solutions can range from redesign and modification of pipework and connections, and improvement of pipework supports, to identification of preferred operating regimes and recommendations for investigation of plant performance, and development of design guidance documentation for future projects. 12
  13. 13. CASE STUDIES a. Corrosion Management of LNG Storage Facilities Date: Ongoing Customer: National Grid Savings: Improved corrosion management GL has provided direct support and guidance for corrosion management initiatives at five separate sites within the UK. In recent years, this support has focused on the development of best-practice corrosion management policies and guidelines. GL assisted with the initial implementation of these guidelines by raising the profile of corrosion issues in LNG processes, and by promoting a corrosion awareness culture across the business. Specific areas of support have included: Fabric maintenance – Management and interpretation of site surveys to determine requirements for maintenance painting and insulation replacement. Definition of site-specific workscopes for ongoing fabric maintenance. Corrosion Management Policy – Drafting of policy to reflect best-practice approach to corrosion control and monitoring. Identification and definition of specific tasks to enable integration with maintenance management system. Cooling Water Treatments – Review of cooling water systems and chemical treatment service provision at all sites. Identified shortfalls in operational systems, recommendations for improved monitoring and opportunities for rationalisation of service contracts. LNG Vaporiser Life Extension – Conducted studies at two sites to confirm fitness-for-service of direct-fired vaporiser units and identify operations and maintenance to achieve required life extension. 13
  14. 14. CASE STUDIES b. Integrity Management Review Date: 2006 Customer: UK North Sea Oil Gas Operating Company Savings: Improved systems integrity GL was requested to carry out a review of integrity management The review of documentation was followed by a number of interviews procedures relating to pressure systems, pipelines and subsea with key staff within the client organisation and the lead integrity equipment ahead of an internal audit of the client company management contractor. The objective of the interviews was to management systems. As part of this review GL was asked to consider address a series of questions that were developed based on the the suitability of the following: relevant policies/procedures and integrity management “best-practice” within the oil and gas industry. Organisational relationships for delivery of effective integrity management It was found that the integrity management systems for pressure systems, subsea and pipelines were well structured and were, in Corrosion risk assessments used as a basis for integrity general, providing highly effective services. Although there had been management planning a number of relatively recent changes in terms of both staff and supporting guidelines/procedures, it was considered that these were The methods and frequency of inspection largely positive and should strengthen the understanding and control of integrity management issues in the near future. Inspection records of lead integrity management contractor The most pressing issue to be addressed concerned the fatigue of topside process plant. It was considered that the existing risk based The interpretation and analysis of inspection data inspection (RBI) plan could not be expected to manage this problem. Although it was felt that the RBI process could assist with, through Review feedback process from inspection findings into criticality assessments, the targeting of equipment a separate strategy future inspection programmes was required to manage the problem effectively. The impact of general fabric maintenance procedures on Further actions were recommended in the following areas: integrity management Management of corrosion under insulation (CUI) To carry out the review effectively, GL requested access to a number Incorporation of piping systems from vendor skids into of client and integrity management contractor documents, including: inspection plans Integrity Management Policy Consideration of performance targets or key performance indicators for the Integrity Management Policy Pressure Systems Integrity Management System Clarification of the terms of engagement between the Subsea and Pipeline Integrity Management (Draft) client and lead integrity management contractor Fabric Maintenance Philosophy Consideration of weld corrosion in risk assessments Pressure Systems Integrity Review Procedure Monitoring, Inspection and Mitigation Procedures Written Schemes of Examination (for relevant assets) 14
  15. 15. CASE STUDIES c. Fracture of Thermowell d. Failure of Impulse Pipework Compression Fitting Date: 2005 Date: 2005 Customer: Transmission Pipeline Operator Customer: Compressor Station Operator Savings: Improved use of thermowells Savings: Improved installation specifications GL were asked to investigate the failure of a stainless steel thermowell GL were asked to investigate the failure of a compression fitting on a which had been located in a dry gas transmission pipeline. A section of impulse pipework at a compressor station. The failure of circumferential crack was found at the base of the thermowell. A the fitting had caused the shutdown of the compressor unit. A metallurgical examination determined that the crack was consistent metallurgical examination determined that the failure was due to with low stress, high cycle fatigue crack propagation. An assessment three circumferential low stress, high cycle fatigue cracks which had of the process conditions indicated that the fracture was caused by initiated on the outer surface of the pipe at the point of contact with flow induced vibration produced by vortex shedding around the the back ferrule of the compression fitting. thermowell. The root cause of the problem was identified as inadequate support provided to the impulse pipework. GL suggested an improved support arrangement and, as part of a larger programme of work, GL monitored the vibration of the impulse pipework to ensure that the new support arrangements were sufficient to prevent any future failure of this pipework. Fracture highlighted using dye penetrant As a result of this failure the customer reviewed the use of thermowells across its whole network. GL assisted by providing further guidance on the susceptibility of thermowells to vortex shedding, and by identifying appropriate alternatives. Failed impulse pipework Above – scanning electron microscope images of crack surface. Left – low magnification, transgranular separation and ‘feathery’ appearance typical of austenitic stainless steel low stress high cycle Circumferential fracture fatigue failures. Right – high magnification, fine striations, a characteristic feature of low stress high cycle fatigue crack propagation. 15
  16. 16. CASE STUDIES e. Fitness-For-Purpose Assessment of Pressure Vessels Date: 2007 Customer: Centrica Savings: Cost savings to the client through a reduced frequency for repair/replacement, reduced system downtime, and life extension of high-pressure storage assets. Issue: Fracture mechanics-based fitness for purpose (FFP) assessment methods, such as those described in BS 7910, R6 and API 579 have undergone rapid developments over the past 30 years. The FFS (Fitness For Service) methodology has developed into a powerful tool that enables the analyst to assess the significance of flaws in welded structures. Although comprehensive and applicable to a wide range of engineering components, the methods contained within these guidance documents are conservative. Furthermore, the methods can be limited by, for example, the availability of stress intensity factor and reference stress solutions for specific geometries. One such limiting geometry is the nozzle, in particular the nozzle attachment welds, which is a common feature on high-pressure gas storage systems. In the UK, operators must follow legislation given in the Pressure Systems Safety Regulations (PSSR), which provides a regime with the Pressure Vessel Nozzle aim of ensuring the safety of pressure systems. One of the regulations requires that high-pressure gas storage systems must be subject to periodic inspections followed by a FFS assessment to ensure the integrity of the system. Methodology & Results: To ensure compliance with the requirements of the PSSR, GL has developed an in-house procedure that enables an FFS assessment to be undertaken for a flaw in a nozzle weld. This procedure was developed to reduce the conservatism inherent in the assessment procedures given in BS7910 while still maintaining an acceptable level of safety. Using a combination of Finite Element analysis and fracture mechanics techniques, a full FFS of pressure vessels was completed. Savings: This has resulted in substantial cost savings to the client through a reduced frequency for repair/replacement, reduced system downtime, and life extension of high-pressure storage assets. Finite Element Analysis of Pressure Vessel Nozzles 16
  17. 17. CASE STUDIES f. Fracture Mechanics Assessment of a Defective Pig Trap Date: 2007 Customer: United Utilities Savings: Cost of temporary pig trap and system downtime due to installation Issue: GL were required to conduct a detailed assessment of a reported crack indication found on the closure casting of a pig trap located at an AGI facility in the UK. Following defect measurement in February 2007, this was recorded at approximately 3-4 mm. A number of pig runs were then subsequently conducted. The defect was then re-measured and reported to have a maximum depth of 5.3 mm. Measurements suggested that the defect had therefore grown since the pigging runs were conducted in 2007. The operator of the site facility intended to conduct further pig runs in February 2008 and hence required an assessment to determine whether the defect was safe for the intended pig runs. Methodology & Results: The approach that GL used was based on a BS7910 level 2a fracture mechanics assessment. Using fracture mechanics calculations and use of the FAD (Failure Assessment Diagram), the aim was to determine whether the current size of crack was safe under the current design conditions and safe for the intended pig runs. Finally using a BS7910 fatigue assessment of the crack, fatigue calculations were then conducted to determine the remaining fatigue life of the reported defect and whether further pressure cycles can be tolerated due to the intended pig runs. The fatigue assessment results showed that the defective area was likely to endure a large number of cycles before failure. Consequently it was concluded that the defect would endure sufficient further pressure cycles to conduct the intended pigging runs. Savings: Ultimately, the operator would have had to install a temporary pig trap to conduct the required pigging runs. Following this, the temporary trap would have been removed and a new trap installed in its place resulting in costly delays and system downtime. By conducting a fracture mechanics assessment, GL have saved the client costs associated with installing a temporary pig, inspection delays and system downtime. 17
  18. 18. CASE STUDIES g. Defect Assessment of Corroded Pipework Date: 2004 Customer: ADMA-OPCO Savings: Savings due to potential loss of containment and system shutdown Issue: ADMA-OPCO identified areas of general corrosion on the inlet pipework to separators on one of their platforms. The corrosion had occurred where clamps were fitted around vertically orientated 12” pipework, just above the girth weld that connects the pipework to 90° elbows. ADMA-OPCO requested that GL undertake an assessment of the defective area. Methodology & Results: Four assessment methodologies were used for the assessment, B31G, RSTRENG, LPC-1 and API 579 Level 1. Predicted failure pressures and safe operating pressures were calculated using the B31G, RSTRENG and LPC-1 assessment methodologies. Results showed that all failure pressures were well in excess of the design pressure, however the safe operating pressures calculated using the B31G and RSTRENG methodologies were considered to be unacceptable. In addition, the defect area was assessed to the general and local metal loss Level 1 procedures of API 579. The defects had been found to be unacceptable. These assessment results formed part of an overall opinion regarding the safety of the reported defect. Savings: Savings were made due to potential loss of containment and system shutdown. 18
  19. 19. CASE STUDIES h. Review of Integrity Management Framework i. Safety Management Audit Date: 2007 Date: 2006 Customer: Middle East Oil Producer Customer: UK LNG Terminal Operator Savings: Improved integrity management Savings: Improved safety management system A major operating company in the UAE were keen to ensure that their A UK LNG Terminal operator were expanding their storage capacity. recently implemented Integrity Management Framework was Before they were able to commission the new phase, it was imperative delivering what was intended. that a complete safety audit was undertaken to ensure that all processes currently in place were operating correctly. GL undertook a gap analysis of the current operating philosophy against the IMF, and reported on where we felt the organisation was GL sent in a team of specialists in their field to undertake this review. in relation to the IMF as well as benchmarking where we determined Interviews were undertaken with a cross section of staff, documents the IMF was in relation to international best practice. were reviewed, and site inspections were undertaken to ensure that the practice matched the document trail. This project covered:- The benefit to the client was that they were able to ensure that all Pipelines deficiencies were actioned and lessons learned before the expansion was commissioned. Pressure Equipment Critical Safety Systems Rotating Equipment Structure Civils Electrical Equipment Lifting Equipment Wells Once the gap analysis had been undertaken, a detailed list of deficiencies was prepared, and suggested improvements identified to bring the operations up to the desired level. 19
  20. 20. CASE STUDIES j. Fitness for Service Assessment Date: 2007 Customer: BG Tunisia Savings: Improved monitoring and compliance Issue: Regulatory conditions state that all pressure systems need to be inspected to ensure they are fit for purpose, and examination schedules needed to be produced. Therefore the client required an inspection schedule to be developed to make sure their assets are fit for purpose and operating within the design specifications. Methodology & Results: By working closely with the client and by taking reference from Pressure Systems Safety Regulations, the contents of the WSoE’s were agreed upon. An up to date inspection scheme was produced, scheduling inspection work to be carried out during the plant shutdown period. Inspections were identified with inspection dates and times organised and a contingency for remedial work allocated. A list of required inspection qualifications was produced and from this a list of qualified engineering staff was assembled. A Competent Person was assigned to define roles under the UK legislation that the staff would take. Savings: From the construction of the WSoE’s an extensive inspection of the client’s assets were produced. The inspection identified areas of remedial work that were required and helped setup monitoring programmes on assets that were at greatest risk of failure. The Written Scheme of Examination also provides the client with a means to demonstrate compliance with the Pressure Systems Safety Regulations 2004. 20
  21. 21. CASE STUDIES k. Repair of Amine Stripper Date: 2006 Customer: BG Hannibal Gas Processing facility Savings: Failure of processing vessel and plant shut down Issue: The client had experienced up to 40% loss in wall thickness on an amine stripper due to corrosion. Methodology and Results: The use of a coating system to isolate the vessel wall from the corrosive environment inside the amine strippers was considered to be the most cost effective solution. GL reviewed the properties of a range of different generic coatings systems to identify a material that would be compatible with the operating conditions within the amine stripper. Having identified a suitable material, a technical review of the proposed coating specification was performed and technical assistance provided during the on-site coating application process. Savings: Through wall corrosion failure and the requirement to shutdown the plant to facilitate a vessel repair. The estimated cost of a shutdown was £500,000/day. 21
  22. 22. CASE STUDIES l. Investigation of Coating Failure on Oil Storage Tank Date: 2006 Customer: Major Exploration and Operating Company Savings: Prevention of large-scale coating failure Issue: The customer was experiencing cracking and disbonding of the coating system applied to the external surfaces of a crude oil storage tank. The customer required GL to establish the mechanism of breakdown and to recommend methods of reparation. Methodology and Results: GL visited site to investigate the scale and nature of the failure. A laboratory programme of work was initiated to reproduce the coating failure under controlled conditions and to establish the failure mechanism systems for reparation of the failed coating were recommended and an application procedure prepared. Savings: This work identified the mechanism of coating failure and helped to prevent similar failures occurring in the future. 22
  23. 23. CASE STUDIES m. Corrosion Management Study Date: 2006 Customer: National Grid Savings: Development of a robust corrosion management policy to maximise asset life Issue: The client wanted to establish a robust corrosion management plan for the above ground installations that were an integral part of the high pressure gas transmission system. Methodology & Results: GL performed a review of the customer’s corrosion management policy with a view to quantifying how much should be invested on inspection and maintenance for corrosion control purposes. The review included: Inspection and maintenance policy Future maintenance requirements to reflect best industry practice The current inspection frequencies and those frequencies required to maintain plant and equipment fit-for-purpose A series of site visits were conducted to obtain an overview of the current condition of the corrosion control systems, the general requirements for maintenance painting and to identify and quantify areas which would require regular inspection and maintenance. Savings: Reduced unscheduled reductions and outages due to corrosion related issues. Reduced repair cost. Maximisation of asset life. 23
  24. 24. CASE STUDIES n. Weldability Testing of 48” Diameter X80 Europipe Production Date: 2007 Customer: National Grid (Milford Haven extension) Savings: Approved procedures of manufacturing Weldability testing entails the production of a full-scale girth weld between two 12m pipe joints under field conditions and including the manipulation of the partially-completed weld to simulate the removal and movement of the line-up clamp. Following production of the complete girth weld, the joint is subjected to X-ray inspection and must pass required codes (T/SP/P/2 or API 1104 requirements) and is then subjected to a full suite of mechanical tests. Following satisfactory results from these investigations, the welding procedure and the linepipe manufacturing route are qualified for supply to National Grid. Girth welding of 48” X80 pipe Simulation lifting of 48” joint after during weldability testing hot pass deposition. Sample welding procedure qualification record from the 48” X80 trials, showing joint design, consumables, pre-heat requirements, pass sequence and other details. 24
  25. 25. CASE STUDIES o. Design and Qualification of Repair Procedures for Bellows Attachment Welding Date: 2008 Customer: Pipeline Operator Savings: Improved welding procedure A GL report on the bellows connection concluded that the bellows on the pipeline required a weld repair to be undertaken on the cracked fillet welds. The bellows configuration is shown in Figure A of that report, reproduced below: Proposed weld procedure for the repair. Qualification of this procedure is in progress. Weld Repair instructions: Weld repairs to cracked fillet welds in bellows unit to be carried out after qualification of the attached weld repair procedure and following decommissioning and purging Consequently, according to British Standard BS 6990, prior to welding of pipeline 2. onto the live pipeline, it is necessary to qualify a procedure, simulating the cooling effect of the gas which complicates the qualification. The Ensure all necessary risk assessments and safety checks qualification set-up should simulate actual flow conditions. have been undertaken and procedures are followed, including safe control of operations (non routine The weld procedure has been developed to minimise the risk of operation) and entry into confined spaces. lamellar tearing. For weld procedure qualification, plate material representing the nearest equivalent currently available material is Prior to repair, determine chemical analysis of carrier pipe used. and box material by on-site material sampling of the carrier pipe and restraining box material in accordance with T/PM/Q/10 (ref clause 12 and appendix B). Report results to GL for assessment. Remove the two fillet weld cracks in bellows 2 by grinding in accordance with T/PM/P/11 appendix F. Confirm defect removal by visual inspection and MPI. Check carrier pipe for defects by UT & MPI below intended area of weld repair prior to welding. Perform weld repair in accordance with attached procedure: WPS/A/Tinsley/01FR (subject to qualification). Completed repair welds to be subjected to visual inspection and MPI. Cracking located in bellows attachment fillet welds. 25
  26. 26. CASE STUDIES p. Evaluation of RBI Softaware Date: 2007 Customer: Major Gas Operator Savings: Company time understanding the issues with different RBI software packages Issue: The client was in the process of evaluating bidders for provision of integrity management software (IMS) oriented risk based inspection management of pressure systems, pipelines and structure of the Miskar Assets. Five software products were evaluated: Tishuk T-OCA, DNV Orbit, Lloyds Capstone, Aver Kvarner Coabis and Credosoft Credo Pro. The client required a third party overview of the RBI systems embedded in the software and to determine the merits of the five different RBI systems. Methodology & Results: From GL experience with RBI systems, an evaluation of the RBI software was produced. The main factors GL’s experienced personnel believed 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 attributes have been captured Degradation mechanisms in the assessment and comparison with degradation mechanism in country Post RBI analysis activities (e.g. Inspection planning) Savings: An impartial third party review of software was obtained, denoting the merits and drawbacks to each system. Allows GL’s experienced personnel to put forward the best system that meets the requirements of the client, so that the investment into the system produces the best result. Also saves personnel time in trialling all the software and producing an evaluation of each. 26
  27. 27. CASE STUDIES q. T-OCR Risk Based Inspection Date: 2005 Customer: Major Natural Gas Company Savings: Reduced equipment downtime and costs due to failures Issue: Savings: The client expressed an interest in adopting a risk based inspection Main saving is on the company time and finances on determining the (RBI) scheme for integrity management of its offshore and onshore benefits and viability of implementing an RBI approach. Also identifies process plant. A feasibility study was required to determine the to the client the long term benefits of a RBI approach, as shown practicalities, outline implementation costs and potential benefits of below: applying RBI. Reduced equipment downtime and costs due to failures Methodology & Results: Reduced requirement for items to be taken offline to be inspected The initial part of the study included a review of the current integrity management systems. This was followed by an assessment of the Focusing of inspection resources on key corrosion and feasibility and requirements for the application of RBI. The final part materials degradation issues of the study comprised two RBI pilot studies centring on known areas of concern on the specific plants. The key results from this study were as follows: The report also includes recommendations for implementation of RBI, including support required and a breakdown of likely resources A feasibility of applying (risk based inspection) RBI to the requirements. facilities produced A review of existing approaches to integrity management, and any modification required to accommodate the RBI approach were identified Potential benefits of applying RBI to its facilities identified, including improvements in equipment reliability and cost reductions from optimisation of inspection planning and deployment 27
  28. 28. CASE STUDIES r. Investigation of Double Block and Bleed Valve Vibration at a Gas Processing Facility Date: 2004 Customer: Onshore Operator, Kazakhstan Savings: Management of the risk of failures reduce the occurrence of failures and the associated costs of plant shutdown and remedial work Issue: During the commissioning and early operational life of a large gas processing facility, failures were experienced of a significant number of small bore connections across the plant. This was determined to be due to the poor design of these connections. Replacing all these fittings would have been extremely costly, and a programme of bracing of the large double block and bleed valves was therefore undertaken. However, it was not known how effective this bracing was in reducing the dynamic stresses to acceptable levels. Methodology & Results: GL undertook a study across the processing plant to characterise the vibration of the small bore connections with large mass double block and bleed valves. Dynamic stress measurements were taken on a selection of connections, including a range of different designs and bracing arrangements. This knowledge was used to develop a screening method which could be used by Client staff to assess all the connections on the plant to implement a prioritised replacement plan. Savings: Management of the risk of failure of these connections reduced the occurrence of failures, and the associated costs of plant shutdown and remedial work. 28
  29. 29. CASE STUDIES s. Long Term Monitoring of Pipework Vibration at Gas Compressor Stations Date: 2003 to 2008 Customer: UK Onshore Operator Savings: Detailed understanding of the risk of pipework vibration problems across operating range of compression plant Issue: Earlier work programmes had carried out an initial assessment of small bore connections at compressor stations, from which a large programme of replacement and removal had been instigated. However, some pipework vibration problems were known to occur at operating conditions that were experienced only occasionally and had not been assessed. Methodology & Results: 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 the twenty-six UK compressor stations for a period of at least three months in each case, and has provided a comprehensive assessment of the pipework vibration over the full station operating range. For example, at several stations, pipework vibration problems were identified which were a result of the interaction of the gas flow from adjacent units, phenomena that would not have been picked up by carrying out measurements on each unit separately. This equipment has also been used to investigate vibration problems following specific incidents on compressor stations and on seal and lubrication oil system pipework. Savings: Detailed understanding of the occurrence of pipework vibration problems across the operating range of the plant ensures that full consideration is given to the causes, directing any remedial action and confirming safe operating ranges. 29
  30. 30. CASE STUDIES t. Assessment of risk of pipework failure due to vibration dur- ing offshore plant uprating Date: 2007 Customer: UK Offshore Operator Savings: Eliminated need for major changes to main pipework, and allowed uprating to be achieved within available timescales Issue: Upgrade of two offshore compressor trains was planned to increase gas flow rates. A preliminary study by the Client suggested that the risk of vibration related failure of the main pipework was already unacceptable and would be increased by uprating. The available outage period was insufficient for significant design changes to the pipework to be implemented. Methodology & Results: GL undertook a study to assess the dynamic stresses experienced by the main pipework and small bore connections during operation of the compressor units in their original configuration. Assessment of the dynamic behaviour was carried out over a range of operating conditions on both compressor trains. Knowledge gained of the relationship between vibration and gas flow was subsequently used to predict the likely behaviour of the pipework at the current maximum and uprated conditions. The study concluded that there was no need for major changes to the main pipework prior to the uprating, allowing effort to be concentrated on issues related to small bore connections. Savings: The findings of this work eliminated the need for major changes to the main pipework, achieving significant cost savings for the project and allowing the uprating to be achieved within the available timescales. 30
  31. 31. CASE STUDIES u. Vibration screening at an onshore gas terminal Date: 2005 to 2008 Customer: UK Operator Savings: Demonstrated management of risk of vibration related failure of pipework to regulatory bodies Issue: To manage the risk of vibration related pipework fatigue failures a structured vibration screening and assessment methodology was required by the Client, to identify problem areas and define subsequent actions. Methodology & Results: A phased approach was employed by GL to identify potential problem areas on the main pipework and small bore connections. The initial site survey consisted of a walk-round visual review of the site processes and pipework, basic vibration measurements, and assessment of the likelihood of failure of any connections. This exercise identified key problem areas for immediate remedial action and further investigation, allowing effort to be focused on the highest risk areas in subsequent stages. Recommendations included identification of pipework support design and maintenance issues, changes to the design of small bore connections that were identified to be at risk of failure, and identification of areas of the plant to be assessed in greater detail to develop an understanding of any problems identified and to develop solutions. This subsequent detailed assessment work has included installation of monitoring equipment to assess the behaviour of the plant over its full operating range. This methodology is now being deployed for the Client’s offshore facilities. Savings: This project successfully demonstrated to the UK Health and Safety Executive that the issue is being adequately managed across the Client’s facilities. 31
  32. 32. Asset Management Services Germanischer Lloyd Plant Integrity Management Services Industrial Services GmbH Pipeline Integrity Management Services Oil and Gas Production Optimisation (Includes RAM and Gas Processing) Steinhöft 9 20459 Hamburg, Germany Dynamic and Steady State Simulation Phone +49 40 36149-7700 Rotating Equipment Performance & Fax +49 40 36149-1781 Condition Monitoring including glis@gl-group.com Emissions Reporting Gas Quality and Interchangeability www.gl-group.com/glis Germanischer Lloyd does not warrant or assume any kind of liability for the up-to-date nature, accuracy, completeness or quality of the information provided. Liability claims against Germanischer Lloyd arising out of or in connection with material or non-material loss or damage caused by the use or non-use of information provided, including the use of incorrect or incomplete information, are excluded unless such loss or damage is caused by the proven wilful misconduct or grossly negligent conduct of Germanischer Lloyd. All offers are subject to alteration and are non-binding. Germanischer Lloyd expressly reserves the right without notice to change, supplement or delete parts of the pages or the entire offer or to stop the publication temporarily or definitively. Issue no.001 15.05.2008

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