In previous installments of this series, we discussed the philosophy of coatings program management and some of the fundamental strategies. Here, we will look at the planning requirements for condition assessment of a facility’s installed coating systems across infrastructures such as refineries or offshore operations.
Survey Types – Baseline Effort vs. Ongoing Inspections
The first consideration in planning a coating survey is determining what type or level of survey is to be performed. When initiating a new coatings management program, a comprehensive baseline survey effort will be required to:
- Determine the actual condition of the installed coating system
- Confirm the suitability of the original installed coating system
- Confirm that original coating selections are correct for service and process environments
- Evaluate the physical aspects of installed coating systems, such as degradation, dry film thickness, adhesion, etc.
The baseline survey is an extremely detailed cataloging of all of the coated assets within the facility to establish the initial condition and baseline information to move the coatings program forward. This type of survey informs future maintenance activities in order to achieve the intended level of coating performance and corrosion protection of assets, and the longest possible life cycle expectancy of the installed coatings.
An important aspect of the baseline survey effort is to determine the surface area of the coated assets. Good “as built” drawings can aid in this, but actual field observation and measurements are typically required to gain an accurate record of the assets and their relative coated surface areas. Once the baseline survey is complete, the collected data will be used for planning future maintenance efforts.
Ongoing inspections are required to continually assess performance and to plan future maintenance work. These surveys are typically done periodically, and the frequency can be based on either time, such as annually, or by utilizing a combination of time and corrosion risk/consequence analyses.
Conducting surveys can be one of the most expensive aspects of a coatings asset management program—so a key goal will be to perform them in the most cost-efficient manner possible. In some industries, annual surveys are required by regulators and/or underwriters. Generally, assets that do not have an annual requirement can be subjected to a risk-based methodology of ongoing surveys.
Determining the Data to Collect – What’s Important?
I remember reading an article years ago about coating surveys and the author’s suggestion was to “collect during the survey every imaginable data point and then let the data sort itself out with regards to its value. At that time the actual data needed can be determined and the survey efficiently streamlined”. I would have to disagree, and emphasize that this approach shows a decided lack of knowledge and experience.
As we discussed in a previous article, extensive planning should occur in the development of a coatings asset program. The initial baseline survey is probably the most expensive aspect of the program, and for this reason, a good planning process is essential.
It is important for the inspector/surveyor to fully understand and answer this question: What survey data points will help the program manager make good decisions in managing future maintenance inspections and the overall health of the facility?
Prior to the survey, the minimum data collected should ideally include:
- Installed systems manufacturers
- Installation methods
- Installation dates
During the survey itself, the minimum data points to collect should be:
- Dry film thickness
- How much of the coating is still intact?
- How much corrosion is present?
- Adhesion of the installed coatings
- Observed corrosion of the substrate
- Observed coating defects such as checking, cracking, peeling, chalking, blistering, etc.
The adherence (adhesion) of any existing coatings is important when considering over-coating of the installed coating system.
Additional survey information could include:
- Substrate types
- Operating temperatures
- Chemical environment notations
In essence, include all this plus any other information that would be deemed pertinent to making good decisions in planning the maintenance effort. Ultimately, this is what should drive the data to be collected during the baseline survey.
The collected data should comprehensively address this question: What information is required about the installed system and its observed performance to effectively plan and execute a maintenance program that maintains the integrity of the installed system and protects facility assets?
It should be obvious that this is also a great opportunity to identify any significant and potentially problematic items and locations within the facility that, due to substrate deterioration from corrosion, should be addressed immediately. These may be areas that have not previously been prioritized within the long-term maintenance program.
Facility Breakdown for Data Collection
One of the most significant challenges in performing the initial baseline survey is to organize the facility into the specific locations for assessment and evaluation. Many computerized maintenance systems catalogue assets down to the nuts and bolts. This level of detail isn’t really practical for painting efforts within a coatings maintenance program.
A more common method is to group components into paintable “units”. This method segments structural locations by column lines or levels and types of equipment such as motors and compressors.
The breakdown can also be done based on structures versus systems. For example, a single unit or system with equipment and piping could include multiple components that travel through various geographic locations, but would typically be considered a single system for refurbishment when planning maintenance painting efforts.
Always consider how the work would be accomplished during a coating refurbishment or replacement. This helps structure the survey and how the facility itself is broken down and organized into manageable components.
Extensive thought and preplanning before executing the survey will save considerable time, effort and therefore costs. The effort invested to create a good and consistent facility breakdown system and organization of the components will allow the data collection effort itself to be structured and very efficient.
The maze of systems on an offshore platform require thought and pre-planning in the execution of a baseline survey.
As we mentioned before, “as built” drawings provide an excellent starting place. However, the necessity of an actual walkthrough of the facility during the planning stage to confirm actual configuration of assets cannot be emphasized enough.
Standards for Data Collection
Collected coatings data only has value for planning and prioritizing work if it is collected in a consistent manner. During one of the first condition surveys I performed years ago, we developed written definitions for grading coating conditions—grades 1 through 5, with 5 being the best condition and 1 being the worst deterioration.
Each of the seven coating inspectors tasked with performing that survey were asked to independently evaluate the same structural coated elements using the written definitions we provided. You can imagine what happened when the individual results were reviewed as a group. It is easy for any given group of inspectors to consistently determine the best condition (grade 5) and the worst condition (grade 1).
The challenge for different individuals is determining grades 2 through 4 accurately and consistently. This is a huge problem because the “middle” condition values present the greatest coatings maintenance opportunities with regards to life-cycle extension—as we discussed in a previous installment. It is important that the 2, 3 and 4 grading values are accurate to enable the most cost-efficient maintenance decisions.
In this case, we went back as a group through the same survey exercise at the same location. This time we discussed and calibrated our evaluations so that this specific set of inspectors would essentially see things the same. Throughout the balance of that project there were no substitutions of personnel. By using careful grade definitions and group training, we were able to maintain a calibrated and standardized approach to evaluating the condition of installed coatings.
Ideally, if one person did all of the inspections on all of the assets in a particular facility, day in and day out, there would be a consistent approach to data collection. However, that is typically not the most practical approach; most surveys are performed by a team of inspectors.
It is imperative to spend time before the survey developing the program standards and grading system for coating condition evaluation. These standards can be written or photographic.
We can utilize standards such as ASTM D610 to evaluate the degree of rusting, and other standards that include degrees of chalking, checking, blistering and other physical attributes.
We can also create standards for specific industries, equipment and structural types. An example is the guide developed for the offshore oil and gas industry for evaluating atmospheric coatings condition on fixed platforms. Various structural and equipment types were photographed to demonstrate three levels of degradation and corrosion on the surface. Such visual guides are also available and published by ABS and Lloyd’s Register for ships tankage surveys and evaluations.
The time invested in planning for the survey is returned ten-fold. Planning allows the surveyor/inspector to efficiently execute the effort and the actual time spent at the facility is minimized.
In a future article, we’ll talk about data collection methodology, whether it's paper or electronic.
More in the Coatings Asset Management Best Practices series: