Page 553 - Corrosion Engineering Principles and Practice

516 C h a p t e r 1 2 C o r r o s i o n a s a R i s k 517

ICDA
process
overview

Step one
Integrity Step two
preassessment Corrosion
Answers the questions: investigation Step three
Is there a risk of internal Answers the questions: Mitigation
corrosion in this facility? & monitoring Step four
Are actions required Answers the questions:
to control internal corrosion what must be done to Post
in this facility? mitigate internal corrosion assessment
Data collection in this facility? Answers the questions:
How is integrity of
Direct evidence
ICDA feasibility Select method this facility managed long term?
Indirect evidence
Define ICDA regions Chemical selection Remaining life
Data analysis
Corrosion growth rate
Monitoring
Evaluation criteria
Interval assessment
Back to Step one
FIGURE 12.17 Overview of the ICDA process.

monitoring, and other internal corrosion-related data. Once the
required data have been collected, the requirement to carry out the
ICDA is assessed based on the following conditions:

3
• The gas in the pipeline should contain less than 110 g/m of
water as determined by the chemical analysis of collected
fluids.
• The pipeline should not have a past history of transporting
crude oil or products.
• The pipeline has a history of inefficient coating practices.
• The pipeline is not treated with corrosion inhibitors.
• Pipeline is not subjected to regular pigging.
The ICDA regions are then classified based on changes in
temperature, pressure, and flow rate (in and out pressures).
Indirect Inspection
The main objective of the indirect inspection step is to predict regions
highly susceptible to internal corrosion. These regions are further
selected for detailed examination. For this reason, critical degree of
inclination and pipeline inclinations are calculated and compared.
This step is applicable to pipelines in which stratified flow* is the

* Stratified flow is defined as a flow pattern with liquid flowing at the bottom of
the pipe and gas at the top.