NACE TM0109 PDF

NACE TM0109 – Aboveground Survey Techniques for the Evaluation of Underground Pipeline Coating Condition

1.1 Aboveground Survey Techniques

1.1.1 This standard presents acknowledged procedures for the application of aboveground techniques toevaluate the coating condition of underground metallic pipelines.

1.1.2 This standard does not designate practices for specific situations; the complexity of some undergroundpipeline and environmental conditions preclude standardizing the application of some of the coating evaluationtechniques. Deviation from this standard may be warranted in specific situations, provided those responsiblecan demonstrate that the objectives expressed in this standard have been achieved.1.1.3 This standard does not include procedures for close-interval pipe-to-soil potential surveys (CIS). CISprocedures are covered in NACE SP0207.3

1.1.4 Alternating current (AC) attenuation surveys are used to provide an assessment of the overall quality ofthe pipe coating section by section; however, this technique is not typically effective in identifying individualholidays.

1.1.5 Direct current (DC) and AC-voltage gradient surveys are used to evaluate in detail the coating conditionon buried pipelines and identify and classify coating holidays.

1.1.6 The Pearson survey, named after J.M. Pearson (the individual who developed the technique), is used tolocate coating holidays.

1.1.7 The pipeline operator must determine which survey techniques are suitable for providing required coatingcondition assessment information for each pipeline or pipeline section.