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Reference Number NIA_NGN_078
Title Guided Wave Non Destructive Testing Inspection of Mains Pipelines
Status Completed
Energy Categories Fossil Fuels: Oil Gas and Coal(Oil and Gas, Refining, transport and storage of oil and gas) 100%;
Research Types Applied Research and Development 100%
Science and Technology Fields ENGINEERING AND TECHNOLOGY (Mechanical, Aeronautical and Manufacturing Engineering) 100%
UKERC Cross Cutting Characterisation Not Cross-cutting 100%
Principal Investigator Project Contact
No email address given
Northern Gas Networks
Award Type Network Innovation Allowance
Funding Source Ofgem
Start Date 01 May 2014
End Date 01 May 2016
Duration 24 months
Total Grant Value £173,158
Industrial Sectors Technical Consultancy
Region Yorkshire & Humberside
Programme Network Innovation Allowance
Investigators Principal Investigator Project Contact , Northern Gas Networks (99.999%)
  Other Investigator Project Contact , Cadent Gas (0.001%)
Web Site
Objectives The objectives are: Prove that the GUL device can be used to inspect difficult to inspect pipelines and reveal new information about asset conditionConformation that guided wave technology can be transferred from oil pipelines to UK gas pipelinesDemonstrate that the results of this version of a guided wave device can provide a valuable resource to enable the GDNs a greater ability to reclassify pipelines to conform with RIIO GD1 Confidence that the total lengths of previously uninspected pipelines can now be efficiently inspected and more objectively classified for riskEvidence that the GUL method provides a cost effective, non-obtrusive inspection techniqueEvidence that the method can reduce savings in excavation and reinstatementsConfidence that all readings obtained by this technique can be interpreted
Abstract Historically UK Gas Networks have had limited means to inspect non-piggable pipelines. Non-piggable pipelines are pipelines where an ‘inspection pig’ could not be used due to obstructions in the pipe (bends) or the lack of provision of ‘pig traps’. In such circumstances the network operator is limited to visual inspection and or localised non destructive testing with an assumption/extrapolation made from these results. These are open to error and misinterpretation and only provide limited information. Additionally the location of the pipeline (river, canal, motorway crossings, and tunnels) can make the logistics and access of any form of existing inspection technique difficult. Previous licence formulas didn’t require GDNs to classify these pipelines. They were either left uninspected or replaced when a problem occurred, but since the introduction of RIIO-GD1, GDNs have a responsibility to replace or risk score their assets. There are three methods of inspection currently available to NGN to inspect these types of non-piggable pipelines: Visual Monitoring - Sections of pipeline are exposed and visually inspected. This method can be effective for critical sections but as the pipe needs to be accessible; excavations and removal of wrap must be carried out. Only local external damage or local corrosion can be identified. Coupon Sampling - This method is a direct sampling method, where a section of pipe is exposed to the same conditions as the line pipe and weighed/examined at intervals. Coupons are usually removed at critical points in the system and should give a worst case result. They will not identify corrosion in a system caused by, for example, external damage. This process is invasive and the removal of samples can inadvertently introduce further risk. Standard Ultrasonic Wall Thickness Measurement - these measurements are very often used to determine the extent of corrosion, or depth of damage, during pipeline inspection projects. Again, the pipe surface must be exposed for the test to be carried out. Wall thickness measurements at a specific location can be misleading as the results are taken locally and these cannot really give an accurate picture of the condition of the complete length of the pipeline. An alternative method of inspection is Guided Wave technology. This is a proven technology worldwide, particularly in the oil & petrochemical industry, where it has been used extensively on long lengths of steel non piggable pipelines. However this technique is untested within the UK Gas Networks. NGN have already conducted a proof of concept trial on the gas pipelines in the Tyne Tunnel (Report No - NGN-20012014. 006), but more trials are required on a representative sample to give the networks greater evidence that this technique could be utilized by the UK Gas Networks. The Method is to use the Guided Wave technology supplied by Guided Ultrasonic Ltd (GUL) to survey non-piggable steel pipelines. The GUL system uses bursts of ultrasound that are fired into the pipe wall material. The ultrasound waves are bounced back by features of interest or faults. Specially developed software enables the user to interpret the information which gives information on the nature and location of the feature enabling information such as pipe wall thickness, corrosion, cracks or design features to be identified. To use the GUL system the ultrasound device is clamped at a convenient exposed point on the pipeline. A "shot" ultrasound wave is fired along the pipeline in both directions, (referred to as front shot and back shot). The readings are immediately recorded on to an on-site visual screen where the readings are interpreted. The readings include the length inspected assisting the operator in selecting the location along the pipeline for the equipment to be set up for the next "shot" wave. In best case scenarios one shot may cover up to a kilometre. On short pipelines only one "shot" may be required (this will be confirmed during the proposed trial) however, there may be scenarios where the condition of the pipe, existence of bolted, lead yarn or other mechanical joints will limit the distance covered. Using guided wave technology, long lengths of pipeline can be screened for corrosion or cracks, with minimal excavation. The GUL system will be complemented by the current inspection techniques (visual monitoring, coupon sampling, standard ultrasonic wall thickness measurements), such that if the GUL system identifies the locality of an issue, that assuming there is access to that specific point further local investigation can take place.Note : Project Documents may be available via the ENA Smarter Networks Portal using the Website link above
Publications (none)
Final Report (none)
Added to Database 14/08/18