What is ICDA?

Internal Corrosion Direct Assessment (ICDA) is a structured integrity assessment technique for use on Natural Gas Transmission and Distribution pipeline systems. ICDA is commonly used to evaluate unpiggable pipelines in lieu of alternative pipeline inspection practices such as inline inspection (ILI) or hydrostatic testing. The ICDA process, shown to the right, involves fundamentally four stages:

1. Pre-Assessment – determines if ICDA is Feasible for the specific pipeline conditions
2. Region Identification – develops data to support the pipeline behavior based on operational conditions
3. Detailed Examination – performance of non-destructive evaluations at strategically selected locations
4. Post-Assessment – critical engineering analyses that establish the integrity of the pipeline and the process

In some cases, the absence of historical failures associated with internal corrosion damage might suggest a reduced internal corrosion threat. However, until the threat has been qualified or discounted, an operator is wise to.perform a partial analysis to establish a basis for the Internal corrosion threat as part of an overall Integrity Management Program (IMP)

In addition to performing comprehensive ICDA projects, SI engineers have developed an Internal Corrosion Threat Qualification Assessment methodology based on the principals of ICDA – while minimizing the time and expense.

Implementing ICDA

SI offers integrated engineering and inspection services that guide you through the ICDA inspection process. SI utilizes state of the art GIS and data processing tools to arrive at the most informed conclusions possible. For complex piping networks, statistical techniques can be used to strategically prioritize and sample locations – greatly enhancing the inspection value.

Our engineers are available to provide everything from turnkey project management to ICDA process training – to meet the needs of your organization. Our staff has the regulatory, statistical, data management, corrosion engineering, and Guided Wave Ultrasonic Testing (GWUT) field crew expertise to execute all of your ICDA needs. See a description of the process here.

Where is ICDA Applicable?

ICDA practices are currently available for use on normally dry gas pipeline systems – systems where liquid upsets may occur periodically. ICDA can be an effective tool to screen for internal corrosion damage in:

• Gas transmission pipelines
• Gas distribution networks
• Gas gathering systems
• Steam systems
• Refineries and Chemical Processing plants

Development is underway to expand the practice of ICDA to:

• Wet Gas systems
• Hazardous Liquid pipeline systems

Is ICDA a New Inspection Process?

The ICDA process was initially conceived in 2001 and first published in the ASME B31.8S-2002 Standard, Managing System Integrity of Gas Pipelines Appendix B2. SI Associates have been actively involved in the development of industry standard practices for implementing ICDA. ICDA standards are underway in the following NACE Technology Groups:

• TG 293 Internal Corrosion Direct Assessment
• TG 305 Internal Corrosion Direct Assessment for Wet Gas Pipelines
• TG 315 Pipelines (Liquid Petroleum): Internal Corrosion—Direct Assessment

For information on the latest developments on these ICDA standards, contact SI.