scholarly journals Evolution of Metal-Loss Severity Criteria: Gaps and a Path Forward

2021 ◽  
Author(s):  
Brian N. Leis
Keyword(s):  
Metal Loss ◽  
Loss Severity ◽  
Severity Criteria

Studi Laju Korosi Internal Pipa Baja Api 5L Grade B Berdasarkan Metode Pengukuran Metal Loss Dengan Ultrasonic Dan Polarisasi Resistance Dengan Variasi Konsentrasi Klorida

2019 ◽  
Vol 4 (2) ◽  
Author(s):  
Supriyadi Supriyadi
Keyword(s):  
Analysis Of Variance ◽  
Metal Loss ◽  
Thickness Meter ◽  
Ultrasonic Thickness

Pipa  penyalur  minyak  umumnya  menggunakan  material  baja  karbon.  Salah  satu  masalah  besar  dalam penggunaan material tersebut yang berkaitan dengan korosi yaitu terjadinya kebocoran akibat adanya pengaruh konsentrasi ion klorida yang terlarut dalam media air sehingga lingkungan bersifat korosif (asam). Oleh karena itu sebagai upaya untuk mengatasi masalah tersebut perlu diketahui besaran laju korosi material baja karbon tersebut. Dalam penelitian ini dilakukan perbandingan antara laju korosi yang diperoleh dari metode pengujian linear polarisasi resistance dan pengukuran metal loss dengan peralatan ultrasonic thickness meter. Output dari kedua metode tersebut selanjutnya diperoleh hubungan laju korosi melalui analysis of variance dengan menggunakan software. Studi pengaruh kadar klorida dilakukan untuk mengetahui korosi internal pipa baja karbon API 5L Grade B yang digunakan sebagai pipa penyalur minyak di lapangan. Metode pengujian polarisasi resistance dilakukan dalam media larutan air formasi NaCl 1%, 2% dan 3.5%. Laju korosi internal pipa baja karbon API 5L Grade B cenderung meningkat seiring dengan meningkatnya konsentrasi klorida dalam media larutan. Penelitian ini juga menunjukkan bahwa pipa baja karbon API 5L Grade B memiliki ketahanan korosi yang cukup pada fluida dengan konsentrasi klorida 1%, 2% dan 3.5%.

Computational and experimental studies of the strength of full-scale samples of pipes with defects "metal loss" and "dent with groove"

2020 ◽  
Vol 10 (3) ◽  
pp. 226-233
Author(s):  
Dmitry A. Neganov ◽  
◽  
Victor M. Varshitsky ◽  
Andrey A. Belkin ◽  
◽  
...  
Keyword(s):  
Internal Pressure ◽  
Experimental Studies ◽  
Full Scale ◽  
The Other ◽  
Metal Loss ◽  
Calculation Methods ◽  
Reliable Operation ◽  
Sufficient Stability ◽  
Comparative Results ◽  
The Moment

The article contains the comparative results of the experimental and calculated research of the strength of a pipeline with such defects as “metal loss” and “dent with groove”. Two coils with diameter of 820 mm and the thickness of 9 mm of 19G steel were used for full-scale pipe sample production. One of the coils was intentionally damaged by machining, which resulted in “metal loss” defect, the other one was dented (by press machine) and got groove mark (by chisel). The testing of pipe samples was performed by applying static internal pressure to the moment of collapse. The calculation of deterioration pressure was carried out with the use of national and foreign methodical approaches. The calculated values of collapsing pressure for the pipe with loss of metal mainly coincided with the calculation experiment results based on Russian method and ASME B31G. In case of pipe with dent and groove the calculated value of collapsing pressure demonstrated greater coincidence with Russian method and to a lesser extent with API 579/ASME FFS-1. In whole, all calculation methods demonstrate sufficient stability of results, which provides reliable operation of pipelines with defects.

Validation of the British Thoracic Society Severity Criteria for Pediatric Community-Acquired Pneumonia

2018 ◽  
Author(s):  
Lilliam Ambroggio ◽  
Cole Brokamp ◽  
Rachel Mantyla ◽  
Bradley DePaoli ◽  
Richard M. Ruddy ◽  
...  
Keyword(s):  
Community Acquired Pneumonia ◽  
British Thoracic Society ◽  
Severity Criteria

scholarly journals An Automated Pipeline for Dynamic Detection of Sub-Surface Metal Loss Defects across Cold Thermography Images

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4811
Author(s):  
Siavash Doshvarpassand ◽  
Xiangyu Wang
Keyword(s):  
Test Piece ◽  
Surface Defects ◽  
Principal Component ◽  
Specific Area ◽  
Gaussian Mixture ◽  
Metal Loss ◽  
Test Surface ◽  
Thermal Excitation ◽  
Cold Stimulation ◽  
Surface Metal

Utilising cooling stimulation as a thermal excitation means has demonstrated profound capabilities of detecting sub-surface metal loss using thermography. Previously, a prototype mechanism was introduced which accommodates a thermal camera and cooling source and operates in a reciprocating motion scanning the test piece while cold stimulation is in operation. Immediately after that, the camera registers the thermal evolution. However, thermal reflections, non-uniform stimulation and lateral heat diffusions will remain as undesirable phenomena preventing the effective observation of sub-surface defects. This becomes more challenging when there is no prior knowledge of the non-defective area in order to effectively distinguish between defective and non-defective areas. In this work, the previously automated acquisition and processing pipeline is re-designed and optimised for two purposes: 1—Through the previous work, the mentioned pipeline was used to analyse a specific area of the test piece surface in order to reconstruct the reference area and identify defects. In order to expand the application of this device over the entire test area, regardless of its extension, the pipeline is improved in which the final surface image is reconstructed by taking into account multiple segments of the test surface. The previously introduced pre-processing method of Dynamic Reference Reconstruction (DRR) is enhanced by using a more rigorous thresholding procedure. Principal Component Analysis (PCA) is then used in order for feature (DRR images) reduction. 2—The results of PCA on multiple segment images of the test surface revealed different ranges of intensities across each segment image. This potentially could cause mistaken interpretation of the defective and non-defective areas. An automated segmentation method based on Gaussian Mixture Model (GMM) is used to assist the expert user in more effective detection of the defective areas when the non-defective areas are uniformly characterised as background. The final results of GMM have shown not only the capability of accurately detecting subsurface metal loss as low as 37.5% but also the successful detection of defects that were either unidentifiable or invisible in either the original thermal images or their PCA transformed results.

Investigating the Effectiveness of Techniques Used in Assessing the Integrity of Non-Piggable Pipelines

2004 ◽  
Author(s):  
Giorgio G. J. Achterbosch ◽  
Gerard A. J. Stallenberg
Keyword(s):  
Detection Threshold ◽  
Metal Loss ◽  
Substantial Part ◽  
Valuable Insight ◽  
Specific Situation ◽  
General Corrosion ◽  
Survey Techniques ◽  
Detection Probabilities ◽  
The Sixties ◽  
Coating Defect

A substantial part of the high pressure gastransport network of Gastransport Services as part of N.V. Nederlandse Gasunie in the Netherlands is not piggable. It is therefore foreseen that an ECDA approach including coating survey techniques, CP measurements and bell hole excavations, will be implemented to establish the integrity of these non-piggable lines. In order to get a better understanding of the performance of some techniques for our specific situation, a test program was carried out on a pipeline of 33 kilometres with a diameter of 8” and bitumenous coating, constructed in the sixties. DCVG, Pearson and a combination of CIPS and Pearson (CIPP) were tested in combination with 3 MFL intelligent pigruns, current attenuation measurements by the Stray Current Mapper (SCM) and bell hole excavations. Initial results for the three coating survey techniques showed that the detection probabilities for a coating defect ranged from 18% to 68% under the assumption that no false calls were generated. Using results from repeat measurements and taking into account the possibility of false calls, the detection probabilities increased to potential maximum values of 48% to 94%. Better estimations of the values could be obtained after verification of some indications from CIPP, leading to maximum values in the range of 70% to 84% for the best two techniques. Additional measurements at pre-selected locations by means of pipe-to-soil-potentials and pin-current measurements did not indicate active corrosion. Verification excavations at 14 locations indicated that in all situations a coating defect existed and that mild general corrosion was present in eight situations due to the very aggressive soil (soil resistances of several Ωm’s were measured). Current attenuation measurements by the SCM suggested a uniform distribution of coating quality. The results from the three intelligent pigruns were of relatively little use because of the detection threshold of 15% wall thickness and the fact that the suppliers often did not agree on the interpretation of metal loss. Therefore the results could not be considered to be an absolute true reference for relating the coating defects to. Although the results of the program gave very valuable insight into the characteristics of the different techniques it is recognized that not all results can be translated to other circumstances/pipelines. Therefore additional tests and surveys will be carried out in the coming year(s) to further work out the ECDA procedure for the specific situation of the non-piggable pipelines of Gastransport Services.

Corrosion Metal Loss Interaction From In-Line Inspection and How it Can Affect the Calculated Failure Pressure

2012 ◽  
Author(s):  
Lucinda Smart ◽  
Richard McNealy ◽  
Harvey Haines
Keyword(s):  
Field Measurements ◽  
Metal Loss ◽  
Data Correlation ◽  
Failure Pressure ◽  
Industry Standards ◽  
Direct Measurements ◽  
Non Destructive ◽  
Flux Leakage

In-Line Inspection (ILI) is used to prioritize metal loss conditions based on predicted failure pressure in accordance with methods prescribed in industry standards such as ASME B31G-2009. Corrosion may occur in multiple areas of metal loss that interact and may result in a lower failure pressure than if flaws were analyzed separately. The B31G standard recommends a flaw interaction criterion for ILI metal loss predictions within a longitudinal and circumferential spacing of 3 times wall thickness, but cautions that methods employed for clustering of ILI anomalies should be validated with results from direct measurements in the ditch. Recent advances in non-destructive examination (NDE) and data correlation software have enabled reliable comparisons of ILI burst pressure predictions with the results from in-ditch examination. Data correlation using pattern matching algorithms allows the consideration of detection and reporting thresholds for both ILI and field measurements, and determination of error in the calculated failure pressure prediction attributable to the flaw interaction criterion. This paper presents a case study of magnetic flux leakage ILI failure pressure predictions compared with field results obtained during excavations. The effect of interaction criterion on calculated failure pressure and the probability of an ILI measurement underestimating failure pressure have been studied. We concluded a reason failure pressure specifications do not exist for ILI measurements is because of the variety of possible interaction criteria and data thresholds that can be employed, and demonstrate herein a method for their validation.

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