Implementing Effective Corrosion Monitoring for Piping Systems

Corrosion in piping systems can lead to serious safety and operational issues. To prevent these risks and ensure the longevity of critical components, it’s essential to implement a robust corrosion monitoring program. In this article, we explore the key principles and practices for designing and executing an effective corrosion monitoring plan.

Corrosion Monitoring for Piping Systems

Corrosion monitoring is a vital aspect of asset integrity management. It involves systematically tracking the corrosion rates of critical piping systems to assess their health and predict potential failures. By doing so, organizations can make informed decisions about maintenance, repair, and replacement, ultimately enhancing safety and reducing downtime.

Designing the Corrosion Monitoring Plan

1. Early Involvement

Corrosion monitoring should be considered from the project’s inception. A philosophy and design for corrosion monitoring should be developed and reviewed during the project proposal phase. Adequate funding should also be ensured to support the plan’s implementation.

2. Submission and Review

The corrosion monitoring plan’s scope should be included in the project proposal. A detailed submission and review process must take place during the project’s detailed design phase.

3. Compliance with Standards

Corrosion monitoring should adhere to relevant industry standards. For example, 01-SAMSS-023, Intrusive Online Corrosion Monitoring, outlines specific requirements for these systems. CSD/ME&CCD serves as the Responsible Standardization Agent (RSA) for corrosion monitoring tools.

4. Timing of Installation

Corrosion monitoring end devices should not be installed more than two weeks before facility startup to prevent excessive attack in a non-process environment. Additionally, they should not be exposed to hydrotests.

5. Commissioning

While corrosion monitoring systems can be commissioned post-Mechanical Completion Certificate, sufficient funding should be allocated for their completion and start-up. This includes the provision of funds for specialist manpower from the equipment manufacturer, if required, to commission the system.

Corrosion Monitoring Fittings

6. Access and Design

Corrosion monitoring access fittings must be carefully selected and positioned. In most refinery operations, retractable fittings are preferred. Consideration should be given to compatibility with pre-existing fittings in the plant. However, on-line retrievable fittings should not be used in hydrogen service due to safety concerns.

7. Positioning Guidelines

The positioning of corrosion monitoring fittings should be determined in consultation with the facility corrosion engineer and corrosion technology experts. The following guidelines apply:

• For non-hydrocarbon-contaminated water systems where the line is completely filled with water, fittings can be mounted at 3, 9, or 12 o’clock for ease of access and serviceability.
• For hydrocarbon-contaminated water systems where both water and hydrocarbons may be present, fittings should be mounted at 3 or 9 o’clock. 12 o’clock mounting should be approved by the facility corrosion engineer in specific cases.
• For liquid hydrocarbon systems, fitting design and positioning require approval from the facility corrosion engineer and relevant authorities.
• Gas systems require special consideration based on the potential for top-of-the-line attack through condensation.
• In-line inspection (ILI) requirements should be followed for pipelines. New pipelines should be designed to accept and allow the passage of ILI tools.

8. Access and Safety

Permanent safe access must be provided for locations where corrosion probes or coupons need to be monitored, serviced, or replaced on-line. Platforms must be designed to accommodate high-pressure access tools and valves, and platforms for elevated fittings should facilitate equipment movement.

In-Line Inspection (ILI)

9. ILI Baseline Survey

New pipelines should be designed to accommodate ILI tools. A baseline ILI survey should be conducted according to the requirements of relevant standards, such as SAES-L-410 and SAES-L-420.

10. Guidance and Compliance

Guidance from standards like NACE RP0102, In-Line Inspection of Pipelines, should be followed for ILI programs. Pipeline diameters can be sized to allow ILI programs or cleaning programs, even if minimum velocity requirements are not met, to ensure effective corrosion control.

Corrosion Monitoring in Control Rooms

11. Computer Control Rooms and DCS

Corrosion monitoring for computer control rooms and distributed control systems (DCS) should adhere to the requirements of standards like SAES-J-801 and ISA 71.04.

By following these principles and practices, organizations can establish effective corrosion monitoring programs that safeguard their assets, enhance safety, and ensure the reliability of critical piping systems.