ISBL Buried Piping Integrity Management

TAG has the capability to determine the suitability for service and if required conduct fitness for service analysis of buried piping that cannot be inspected using in line inspection tools.

• API 570 covers buried piping inspection but leaves a lot of the detail to the end user.
• API 580 provides the governing requirements for use and application of risk based inspection technology.
• API 579 provides guidance for establishing the fitness for service for buried piping.

Bottom line is all potential degradation mechanisms are required to be identified and evaluated for piping systems within a facility, including external and internal mechanisms.

Internal degradation mechanisms will be largely similar in nature to those attacking above grade piping and work done there can be extrapolated to below grade.  External degradation mechanisms require special consideration with soil to air interfaces providing trending data for the project.

Technology exists today that can be utilized to determine the additional locations within a complex piping system that possess the highest potential for external corrosion.  It is commonly recognized that for external corrosion to gain a foothold on a buried piping system the coating must have a defect and the cathodic protection system not be functioning as designed.  In a plant environment with complex piping configurations, locating areas of failed coating is the key to analyzing the system for external corrosion.

If the coating is in good condition and bonded to the pipe, corrosion is not a concern.  TAG can locate areas of coating that have failed and integrate that information with cathodic protection potentials to establish excavation locations that have the highest possibility of external corrosion.

Many factors are evaluated using state of the art tools to determine where to excavate within a plant environment — from depth of cover to safe excavation considerations; with all indirect inspection tools considered to perform this work.  Our modified External Corrosion Direct Assessment (ECDA) approach will provide the plant operator with the valuable factual information required to make prudent cost effective maintenance decisions for the future.

TAG is not an inspection company, our job is to make sure the project is done right by qualified personnel, meeting the engineering criteria we agree to.

• TAG will work with you to establish a solid plan and ensure execution is correct.
• We have the experienced personnel to assist in making the critical excavation selections.
• We have the analysis skills to evaluate your suitability for service and integrate all results within the context of risk to ensure safe and efficient operations

Probably the most crucial skill set for conducting a successful ISBL buried piping evaluation is knowing the capability and limitations of the indirect inspection tools.  TAG has the experience required to ensure that the tools used will achieve successful project implementation.  Inexperience with the capability of an indirect inspection procedure is a pitfall that must be avoided in order to perform a successful modified ECDA piping analysis.

As we are identifying potential areas on the piping for investigation, the process will also evaluate effectiveness of the existing cathodic protection system.  Cathodic protection system refinements or improvements if required are an inherent benefit of an ECDA evaluation, which may very well be the best method available for analyzing the cathodic protection system in a plant setting.  The piping system will also be tested for internal corrosion metal loss and other possible defects during the excavations.  In addition to providing calibration of the ECDA evaluation, all data needed for an effective suitability for service determination will be obtained while the pipe is excavated.

Excavation results will confirm that external corrosion is a manageable issue at the present time or if additional resources will need to be allocated in the future to assure long term reliable facility operation.  Evaluation of the results considering all possible degradation mechanisms will establish a firm plan for the future.

Our goal is to elevate the operator’s confidence in the reliability of the plant’s buried piping and provide you with informed information as to the actual situation concerning external corrosion damage.  Combining this information with a determination of the probability of failure due to process variables will complete the risk profile.  The process will allow your plant management team to make informed decisions as to the path forward for buried piping maintenance whether it is establishing a re-inspection interval or something more drastic such as a piping section replacement project.

TAG would like to discuss your specific project further with you.  We are convinced that with our commitment to detail, ability to integrate the various technologies, and understanding of the state of the art assessment process; we can save your company significant effort as you begin to execute this project.  By obtaining a more accurate assessment of the extent of any external corrosion and determining the influence it has on the overall mechanical integrity of your ISBL buried piping; we can save you money.