Allied Corrosion Industries, Inc.


Dry Gas-Internal Corrosion Direct Assessment

Quick Facts:

  • Internal Corrosion is caused by exposure to water and other contaminants/organic acids in the pipeline transmission materials.
  • Pipeline failure can cause adverse effects on human health, environmental degradation, and damage to personal and commercial property.
  • Internal Corrosion is one of the leading causes of pipeline failure.
  • Internal Corrosion Direct Assessment are used to gauge internal corrosion and its impact on pipelines.
  • Allied Corrosion combines ICDA with other assessment processes in order to provide you wil a complete pipeline integrity program.

Key Benefits:

Internal Corrosion Direct Assessment (ICDA) is a process designed to gauge internal corrosion and its impact on natural gas pipelines, and other transmission pipeline systems. An intricate part of Pipeline Integrity Management is the verification that internal corrosion does not exist in your transmission pipeline system. Our field-proven pipeline Direct Assessment specialists effectively combine the internal corrosion direct assessment process with other corrosion assessment processes, providing a complete and cost effective pipeline integrity management program. Allied Corrosion has assembled an experienced staff of proven Direct Assessment professionals, along with investing in state-of-the-art equipment required to identify and assess potential internal corrosion locations on dry gas transmission pipelines. Our direct assessment staff consists of NACE certified Corrosion Specialists, Cathodic Protection Specialists and Internal Corrosion for Pipeline Technologists.

The DG-ICDA Process

Dry Gas- Internal Corrosion Direct Assessment (DG-ICDA): As defined in the NACE Standard SP0206-2006 Dry Gas Internal Corrosion Direct Assessment (DG-ICDA) for gas lines is a detailed examination of locations along a pipeline where liquids could first accumulate, allowing inferences to be made about the integrity of the remaining downstream length of pipe. The DG-ICDA process consists of four steps:

1. Pre-Assessment

The pre-assessment phase requires historical and current data collection, which is used to determine feasibility and identify regions for DG-ICDA. To minimize the interference with the operator's day to day operations, we normally provide a list of the minimum data elements required, along with a list of additional data elements requested if available. The actual collection of data, though normally performed by the operator, can be performed by our staff if requested.

2. Indirect Inspection

Utilizing sub-foot accurate GPS and a depth recording digital pipe locator, all connected to a data logger utilizing Utilimapper software, a pipeline elevation profile is created from data collected over the operator´s pipeline. This data, in conjunction with the multi-phase flow modeling calculations determined by our liquid hold-up software is presented in both graphical and tabular form.

Mapping and Survey Solutions


3. Direct Examination

The objective of the direct examination step is to identify three consecutive potential liquid hold-up locations that are free of internal corrosion. The best case being, that no internal corrosion is found at the first three locations examined. The direct examination is accomplished by excavating the pipeline at predetermined intervals along the entire segment identified as a potential liquid hold-up location. Utilizing Long Range Guidedwave Ultrasonic equipment, the pipe segment between excavations is inspected for anomalies. All anomalies indicated by the GUL inspection are then excavated and examined utilizing our Automated Ultrasonic Corrosion Mapping System.

This system provides documented results verifying the existence or nonexistence of internal, midwall, or external anomalies. It performs the inspection using raster scan technology at sample intervals as fine as every .04 of an inch with speeds reaching 10 inches per second. In addition to examining the condition of the pipeline at each excavation, our pipeline integrity management team can design and install internal corrosion monitoring systems, ranging from permanently installed GUL transducer belts to coupons. These types of installations can ultimately save the operator large expenditures in excavation cost.






4. Post Assessment

The objective of this step is to determine the effectiveness of the whole DG-ICDA process and to determine reassessment intervals. Utilizing all of the information collected throughout the entire process, we can provide the operator with written documentation discussing the functions performed during each step of the DG-ICDA methodology. The effectiveness, along with suggested improvements to the applications of DG-ICDA are included in this documentation.

Our Pipeline Integrity Management Staff is ready to provide turn-key DG-ICDA services or any portion of the methodology an operator requires. Our goal is to provide you with the highest quality of professional customized Direct Assessment Services that you require. We are available to meet all of your DA needs. Please contact one of our Pipeline Integrity Management Specialists to discuss how we can assist you in meeting your requirements.

The Allied Corrosion Difference

Our strong understanding of the potential destruction from a compromised pipeline allows us to deliver detailed DG-ICDA to complement any operator's Integrity Management program. Our comprehensive pipeline integrity and cathodic protection engineering services will keep your pipeline assets protected throughout its life-cycle.

Person working on mapping blueprints at a desk.

Contact Allied Corrosion Today


1550 Cobb Industrial Dr.  |  P.O. Box 9098  |  Marietta, GA 30065-2098

770-425-1355 (Phone) | 770-425-1354 (Fax) | info@alliedcorrosion.com (Email)

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Voltage Range
Relative Position
Least Noble (More Anodic)
-1.60V to -1.67V
-1.00V to -1.07V
-0.93V to -0.98V
Aluminum Alloys
-0.76V to -0.99V
-0.66V to -0.71V
Mild Steel
-0.58V to -0.71V
Cast Iron
-0.58V to -0.71
Low Alloy Steel
-0.56V to -0.64V
Austenitic Cast Iron
-0.41V to -0.54V
Aluminum Bronze
-0.31V to -0.42V
Brass (Naval, Yellow, Red)
-0.31V to -0.40V
-0.31V to -0.34V
-0.31V to -0.40V
50/50 Lead/Time Solder
-0.29V to -0.37V
Admiralty Brass
-0.24V to -0.37V
Aluminum Brass
-0.24V to -0.37V
Manganese Bronze
-0.24V to -0.34V
Silicon Bronze
-0.24V to -0.30V
Stainless Steel (410, 416)
-0.24V to -0.37V
(-0.45V to -0.57V)
Nickel Silver
-0.24V to -0.30V
90/10 Copper/Nickel
-0.19V to -0.27V
80/20 Copper/Nickel
-0.19V to -0.24V
Stainless Steel (430)
-0.20V to -0.30V
(-0.45V to -0.57V)
-0.17V to -0.27V
70/30 Copper Nickel
-0.14V to -0.25V
Nickel Aluminum Bronze
-0.12V to -0.25V
Nickel Chromium Alloy 600
-0.09V to -0.15V
(-0.35V to -0.48V)
Nickel 200
-0.09V to -0.20V
-0.09V to -0.15V
Stainless Steel (302, 304, 321, 347)
-0.05V to -0.13V
(-0.45V to -0.57V)
Nickel Copper Alloys (400, K500)
-0.02V to -0.13V
Stainless Steel (316, 317)
0.00V to -0.10V
(-0.35V to -0.45V)
Alloy 20 Stainless Steel
0.04V to -0.12V
Nickel Iron Chromium Alloy 825
0.04V to -0.10V
0.04V to -0.12V
0.20V to 0.07V
0.20V to 0.07V
0.36V to 0.19V
Most Noble (More Cathodic)

Primary voltage range for material
Voltage range in crevices or stagnant and poorly aerated water