CATHODIC PROTECTION -
ANNUAL STRUCTURE TO SOIL POTENTIAL SURVEY
Mountain West Services effectively and economically performs annual Structure-to-Soil Potential Surveys and enters the data electronically into the OLIMPOS program. This lowers administrative costs and also automatically keeps an electronic historical archive of previous CP Surveys. Repairs are done on site where possible so another visit is not always required, therefore decreasing expensive travel costs.
An annual potential survey is based on recording pipe-to-soil potentials at intervals over the pipeline at above ground test locations while interrupting the current source. The potentials recorded are only indicative of the level of cathodic protection at the test location.
PIPELINE SURVEYS
Mountain West Services utilizes a unique survey system designed to meet the needs of industry for the indirect inspection of pipelines, as part of External Corrosion Direct Assessment (ECDA) programs.
DEPTH OF COVER & DEPTH OF WATER
Buried pipelines can become vulnerable to third party damage and UV degradation of the coating when erosion or scouring removes the cover. Mountain West Services can accurately measure the depth of cover over buried pipelines, and when utilized with sonar and GPS can also provide elevation profiles and depth of water. This allows pipeline operators and engineers to monitor the pipeline and surrounding environment for potentially harmful geotechnical activity, pipeline exposures and erosion of cover that exceeds pipeline code requirements.
COATING SURVEY - ACVG & ACCA
Buried steel pipelines are subject to corrosion degradation unless they are protected with coatings and/or cathodic protection. The AC current attenuation (ACCA) of an applied electromagnetic field along the length of a pipeline is consistent on pipelines with homogenous coating, while coating faults will cause increased attenuations in the field. Measuring the AC voltage gradient (ACVG) above the line allows specific coating faults to be identified and quantified. By measuring and recording both the current and AC voltage gradient over intervals along the pipeline, coating faults can be identified and prioritized for repair - even before any corrosion pitting has occurred!
CATHODIC PROTECTION - CIS or CP CIPS
The CP DC current applied to the pipeline protects bare metal from corrosion damage, but only if it is able to reach the entire length of the pipeline. By logging close interval CP potentials over the entire pipeline length, the effectiveness of the CP can be determined to aid in prioritization of coating anomalies that may need repair, or to identify required adjustments and modifications to the CP system itself.
CORROSION POTENTIAL SURVEY - DCVG
DC voltage gradient surveys can also confirm the direct current interrupted (On and Off) potentials along the length of the pipeline. This survey can aid in identifying and prioritizing coating faults for repair based on the expected corrosion rate as predicted by the current discharge from soil to pipe, or vice versa.
This system allows the automatic detection and continuous secure logging of the pipeline location using an electromagnetic pipe locator and high accuracy GPS receiver. The use of a Controller that multiplexes the data streams from volt meters (DCVG, ACVG, CP/CIS, AC PSP), leak survey gas detectors, sonar and other instruments will allow multiple readings to be logged concurrently and continuously. This means all of the data can be collected in one pass over the line, saving time and money.
