scope:

Foreword

In-line inspection is an important tool in the investigation of the condition of a pipeline. It is a significant part of pipeline integrity management and, as such, complements a quality integrity management program and promotes safe, efficient, and cost-effective pipeline operation. In-line inspection (ILI) tools, popularly called "intelligent" or "smart" pigs, are devices designed to survey the condition of the pipeline wall without disrupting the operation of the pipeline. Pigs are inserted into the pipeline and travel through it, driven by the transported fluid. Their operation is based on technologies of nondestructive evaluation (NDE) (a more general term than nondestructive testing [NDT]).

The purpose of this technical committee report is to analyze available and emerging technologies in the field of in-line pipeline inspection tools and review their status with respect to characteristics, performance, range of application, and limitations. It is intended as a practical reference for both new and experienced users of ILI technology.

It is aimed at assisting in the provision of an understanding of the practical aspects of using the tools, highlighting the implications, and helping assess the benefits.

The section titled "Types of In-Line Inspection Tools" provides a brief explanation of available technologies and tools. The procedures and rationale behind decisions leading to the use of in-line inspection tools and the associated cost and benefits are discussed in the sections titled "Decision Making Process" and "Cost/Benefit." The procedures related to inspections are discussed in "Operational Issues," and finally, the sections titled "Results of ILI" and "Data Management" deal with the outcome and use of results of in-line inspection. A glossary of terms commonly used in the in-line nondestructive inspection of pipelines is included in Appendix A. A list of abbreviations and acronyms commonly used in the industry is given in Appendix B. Appendixes C, D, and E provide generic specifications of tools and lists of activities connected to performing in-line inspections.

This NACE technical committee report was prepared by Task Group (TG) 039 (formerly T-10E-6) on In-Line Nondestructive Inspection of Pipelines, which is administratively sponsored by Specific Technology Group (STG) 35 on Pipelines, Tanks, and Well Casings. This report is issued by NACE International under the auspices of STG 35.