NACE TM0109-2009

1.1 Aboveground Survey Techniques

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

1.1.2 This standard does not designate practices for specific situations; the complexity of some underground pipeline and environmental conditions preclude standardizing the application of some of the coating evaluation techniques. Deviation from this standard may be warranted in specific situations, provided those responsible can 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). CIS procedures are covered in NACE SP0207.3

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

1.1.5 Direct current (DC) and AC-voltage gradient surveys are used to evaluate in detail the coating condition on 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 to locate coating holidays.

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