CC007 Pipeline coating inspection and assessment

Competency ID
and title

CC007 Pipeline coating inspection and assessment

Competency area

Corrosion Control

Stream/s

Operations

Level

Elective

Knowledge

The principles of corrosion mitigation and the corrosion mitigation strategies being applied (AS 2885.1 Mitigation of Corrosion).

AS 2885.3 – pipeline coating system and its application.

The types of coatings in use, their application, testing and inspection and common failure modes / types of degradation for each coating type including:

·         Line pipe coatings including coal tar enamel, extruded PE, FBE, trilaminate etc.

·         Field joint coatings including heat shrink sleeves, tape wrap, liquid epoxy, powder coat etc.

The sources and nature of coating damage.

The consequences of coating failures:

·         general corrosion

·         pitting corrosion

·         stress corrosion cracking

·         cathodic disbondment.

The concept and consequences of CP shielding

Corrosion mechanisms and CP limitations for protecting coating defects in acidic soils.

The indicators of poor coating condition:

·         CP system measurements (current draw, potential gradients along pipeline test points etc.).

·         Metal loss surveys identify corrosion.

The methods of detecting coating faults (including capabilities and limitations):

·         direct current voltage surveys (DCVG)

·         alternating current voltage gradient (ACVG)

·         close-interval potential surveys (CIPS)

·         EMAT ILI.

Exposed pipe coating defect assessment:

·         Visual field joint coating inspection.

·         Visual linepipe coating inspection techniques.

·         Holiday detection techniques – including appropriate settings and safe operation.

The direct assessment process for investigating coating defect indications:

·         DCVG or ACVG survey

·         screening of results based on %IR readings of indications

·         selection of sites

·         dig-up planning

·         investigate and document findings,

·         anomaly assessment (ref AM033)

·         repair any metal loss if required

·         repair coating, including surface preparation

·         reinstate.

·         update PIMP.

Experience

Experience (under the supervision of an experienced engineer) in detection and assessment of coating degradation that could include participation on a team whose responsibilities are coating assessment and repair that cover a number of coating investigations and repairs, playing a significant role in a program of inspection, defect survey, defect assessment, dig up and repair.

Expertise

Develops and runs a pipeline coating inspection and assessment program.

Interprets the results contained in a coating survey report (e.g. DCVG) and identify sites for investigation.

Identifies and oversee the appropriate survey method for a particular pipeline or pipeline segment.

Identifies and assesses coating defects on exposed pipe.

Able to determine the type of coating repair required (ref: OP021).