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Why Oil and Gas Coating Projects Go Bad

SurfacePrep
 
Some of the oil and gas projects suffer huge financial loss because of premature failures of paints and coatings. The cost to repair such failures far outweighs the initial cost of painting. Additional liability may also incur if a facility must stop operation to be able to complete the necessary repairs.
Coating failure can occur due to a variety of reasons. It is typically the result of insufficient surface preparation, poor application, a defective coating or an inadequate specification. Determining the fundamental causes behind a coating failure is critical. Not only does this help in assigning financial responsibility, but knowing how a coating has failed is often the first step in planning how to fix it.
To investigate a failure and analyze the conditions that promoted the failure, important information must be collected on the failed paint or coating. Background information on the coating type and application procedure, the service history and environment, and physical evidence of the failed coating are necessary to determine why, how, when, and where a failure may have occurred. If these answers are available during the course of the investigation, one can avoid such failures in the future. Some of the obvious reasons for failure are as follows:

Not selecting the proper material

The quality of materials used in an oil and gas coating project sustain the project with a longer life cycle and lesser ongoing maintenance. However, the quality suffers when project managers specify less expensive materials, to compensate the high labor costs. It works out a losing scheme with disruptions and additional cost. Managers need to focus on specifying the right paints and coatings for the job. It takes the right materials to get the biggest payback from the investment in high-quality coating products, tools and equipment.
To be able to select the proper material it is necessary to know the conditions in which the structure is to operate, such as:

• Humidity and temperature (service temperature and temperature gradients)
• The presence of UV radiation,
• Chemical exposure, i.e., specific exposure in industrial plants,
• Mechanical damage, i.e., impact, abrasion,

Furthermore, the corrosive aggressiveness of the environment will have an effect on:

• the type of coating used for protection
• the total thickness of a coating system
• the surface preparation required
• minimum and maximum inspection and repair or recoating intervals

The more corrosive the environment, the more thorough surface preparation is required. Designing a coating system normally involves dealing with materials such as steel, hot dipped galvanized steel, spray-metalized steel, aluminum or stainless steel. It is important to consider the surface preparation depending on the constructional material that requires protection.

Not ensuring proper surface prep

Inadequate surface preparation affects the coating adhesion, which reduces the service life of oil and gas coating projects. Selection and implementation of the proper surface preparation ensures coating adhesion to the substrate and prolongs the service life of the coating system.
Most paintable surfaces such as ferrous metal and aluminum require protection to keep them from corroding in aggressive environments. Improper selection of the surface material could be due to mistaking the substrate or the environment. Any deviation from analyzing the actual surface contamination can influence the selection of incorrect surface preparation methods.
If any surface contamination is present such as oil, loose paint, rust or mold, it disables bonding to the adhering old paint. Therefore, any surface preparation short of total removal of the old coating may compromise the service life of the system. For steel, surface preparation is qualified using blasting preparation standards of surface finish profile such as those specified by the National Association of Corrosion Engineers (NACE) and the Society of Protective Coatings (SSPC).

Check for compatibility by applying a test patch of the recommended coating system, covering at least 2 – 3 square feet. Allow to dry one week before testing adhesion per ASTM D3359. If the coating system is incompatible, complete removal is required. Maintenance painting frequently does not permit or require compete removal of all old coatings prior to repainting.
Failure to provide scheduled maintenance for a protective coating system accounts for reduced service life. Maintenance must include inspection of painted areas, cleaning of surfaces to remove oils and chemicals where the damaged coatings exist. Frequently inspect the highly corrosive areas, such as those subjected to frequent chemical spillage and corrosive fumes. Areas exposed to less severe conditions, such as interiors and exteriors of potable tanks need annual inspection to assess the condition of the coating system.

Not performing proper inspection

Quality inspections are critical during the project life cycle. Before any coating materials are used, it is the responsibility of the purchasing department to ensure that the materials that arrive are of the correct quality specification. Some of the improper inspection practices are about not keeping any work documentation or performing work in an unsafe manner.
The inspector should not verbally change the requirements. The supervisor needs to be present in the loop for resolution, if any of the specifications are inadequate. Contractors must request a variant from specifications that may or may not be significant.
Regardless of variant significance, the inspector should inform the supervisor of any requested changes. If a coating applicator is not following the specifications, the inspector should not confront the applicator. Instead, approach the coating contractor to determine the non-conformity of meeting the specifications. In some cases, the coating contractor supervisor may need to correct his own worker’s practices.
Some of the roadblocks faced in the oil and gas coating projects are due to the following:

• the surface does meets specifications requirements
• all coating materials are not approved,
• storage area does not meets environmental and safety requirements,
• environmental conditions, i.e., ambient and surface temperatures, humidity and dew point do not meet specifications requirements ,
• mixing and thinning do not meet manufacturer’s requirements.

The conditions that promoted the failure are essential in identifying the underlying factors that may have initiated the failure. Other elements that may not be readily acknowledged in failure analysis, yet are no less important, are common sense, a critical and unbiased mode of thinking, experience, knowledge, and experimental observation.
 

Peter photo Peter Roosen
Peter Roosen is the CEO of Castagra Products, a storage tank and wastewater coatings manufacturing company that is highly acclaimed for its sustainable coatings, cold weather tank coating applications, and its durable frac tank coatings. Castagra is used by the world’s top oil and gas field services companies.