There is an obligation on terminal and pipe line owners to ensure it is used in a safe manner and this requires an effective inspection and maintenance program. The owner is responsible for developing, documenting, implementing, executing, and assessing pipe line inspection systems and inspection procedures that will meet the relevant requirements. These systems and procedures typically include the following:
- Organization and reports of structure for inspection personnel.
- Documentation and maintenance of inspection and quality assurance procedures.
- Documentation and reports of inspection and test results.
- Corrective action for inspection and test results.
- Internal audits for compliance with the quality assurance inspection manual.
- Review and approval of drawings, design calculations, and specifications for repairs, alterations.
Types of Inspection
Different types of inspection and monitoring methods depend on the circumstances and the piping system, however the main challenge to effective inspection is ensure coverage of potential defective areas on very long pipe runs. There are two types of inspection
- Pipe screening that covers large sections of pipe quickly and gives a qualitative assessment of condition that can identify areas where defective areas exist
- Detailed examination to give a quantitative assessment, such as minimum wall thickness, which is applied to known potential “at risk” areas or areas identified by qualitative assessment
There are a number of techniques for rapid screening of pipe work, and those applied will depend on the pipe size and length to be inspected. These techniques include long range ultrasonic and Magnetic Flux Leakage. MFL, such as the Silverwing PipeScan, can be used by relatively less skilled technicians to cover large areas and identify sections for further inspection. Long range UT is a rapid method but requires a high skill level to operate.
Quantitative Inspection Solutions
The most popular method of detailed inspection is ultrasonic testing, either as a simple thickness reading, or recorded B/C-scan. The manual thickness point method gives a good accurate reading at the point measurement, but the area covered is very restricted and so probability of detection of the worst case is low. Automated methods such as the Silverwing RMS2 system significantly improve the area covered, and therefore the probability of detection for a given defect is much higher.