Plans for maintenance protective coatings

Protective coatings are an investment by facility owners to protect plant assets from corrosion and deterioration. As with any investment, periodic maintenance provides the longest life and the lowest cost per year of service. However, deferring maintenance can be costly. Protective coatings, if left unattended, will deteriorate to the point of nonexistence. There are no "forever" coatings. And once the coating system has deteriorated, the asset that is being protected by the coatings will be subject to corrosion, potentially to the point of loss of integrity. Weakness or holes in substrates can occur, which can lead to leaks in piping

or the collapse of structures.

A good maintenance plan for protective coatings will prevent these worst-case scenarios. Preventive maintenance of protective coatings can be performed at a relatively low cost, but if they're allowed to deteriorate, costs to repair or replace the protective coatings will increase. The most time-consuming of protective coating tasks is surface preparation, which makes it the task with the highest cost. There are many levels of surface preparation, from hand cleaning to abrasive blasting, and the effectiveness of each varies, as does the cost and the equipment required. Hand cleaning has the lowest cost, with only hand tools or sandpaper required, but does not clean as well as other methods, and it is slow. This method is usually limited to smaller areas of less deteriorated coating systems. Power tool cleaning is more aggressive and quicker and can provide a better surface for maintenance coatings to be applied. Because of contaminants and fallout that could affect the adhesion of the applied coatings, these two preparation methods are generally accompanied with a pressure-wash cleaning or, in some cases, a higher-pressure water blasting or water jetting system.

Abrasive blast cleaning provides the best surface for applying a protective coating because, dependent on the level of blast, it

removes the existing coating and provides a profile for the new coating to bond. However, it is a more costly method because it requires an abrasive, which must be picked up after blasting and disposed of, and more protection of areas that are not to be blasted (i.e., insulated surfaces, nonmetallic surfaces and nonferrous surfaces). The equipment for abrasive blasting is also much more costly than non-blast preparation tools. Depending on the location of the substrate that is protected, the dust generated from the abrasive blasting may require a containment to be built, and all of the requisites associated with containments (confined- space training, confined-space attendants, ventilation, etc.) will add to the cost. The cost of an abrasive blasting protective coatings project can easily be double that of a pressure washing and power tool cleaning project. This, in turn, limits the surface area to receive a maintenance protective coating system to half as much footage for the same dollar. If the surface to receive a protective coating for maintenance purposes requires a full abrasive blast to prepare the surface, then the maintenance plan for protective

coatings is either nonexistent or ineffective.

When discussing a plan for maintenance coatings, choosing the proper coatings material for the environment will have as much impact on the longevity and performance of the coatings system as the surface preparation. Coatings will have varying degrees of chemical resistance, ultraviolet (UV) resistance, high heat resistance and even impact resistance. The coating system specified for a tank farm with low chemical but high UV exposure should be different than the coating system for piping and structure near a cooling tower, which douses the surrounding area with a constant mist of chemically treated water. The right coating system for an environment will perform as designed, as long as the surface preparation is adequate and there are no influences on the coating that are outside of the coating's design parameters, such as spills, spikes in temperatures, mechanical damage, etc.

The choice of the coating systems will also have an impact on which surface preparation technique is required. While virtually every coating system will perform better over a blasted surface than one that is not blasted, there are coatings that are specifically designed to be applied to a less clean surface. These are often referred to as "surface tolerant" coatings and have been embraced by the maintenance coating industry as a cost-effective prime coat selection for most protective coatings systems for maintenance. As mentioned before, when a coating system can be applied and performs well over a surface that is not abrasive blasted, the cost will be lower and more square footage can be coated for the same maintenance dollar.

Another consideration in developing a maintenance plan for protective coatings is the service life of the protective coating between maintenance applications. A preventive maintenance protective coating requiring only pressure washing and power tool cleaning will not last as long between maintenance as a new protective coating system applied over a blasted surface, but the preventive maintenance cost will be considerably lower. The key to a successful, cost-effective maintenance plan for protective coatings is to find the point on a protective coatings timeline that will maximize the surface area to be coated for the maintenance dollar available while also maintaining the protection and integrity of the assets.

An assessment of conditions and environments, relevant data for managing protective coatings, and an understanding of the impact of scheduling at the most cost-effective time are all integral to a good plan. Many times, when setting up a maintenance plan for protective coatings in a facility that has allowed the protective coatings to deteriorate, there will be a period of "catch-up" required before a maintenance coatings plan can be fully implemented. In these cases, cost-effective protective coatings work does not necessitate scheduling the worst conditions first or exclusively but is based on the consequences of deferring coating projects. If the consequence of extensive corrosion left unattended is metal loss, the surfaces should be addressed first, mitigating the need for steel replacement. However, if the consequence of extensive corrosion left unpainted is not metal loss, then deferring will have little cost impact, as blasting is already required. If the consequence of surfaces with less corrosion being left unpainted is an upgrade in surface preparation (from hand/power tool cleaning to abrasive blast), then the project should have a higher priority for scheduling than the project with extensive corrosion that will not lead to metal loss. A balance of preventing metal loss and preventing preparation upgrade is the goal. This approach will provide a longterm solution to asset protection through protective coatings while also maximizing limited budgets.

Another positive but unintended benefit of a good maintenance plan for protective coatings is improved aesthetics of the plant. Studies have shown that a well-kept, aesthetically pleasing work environment provides improved employee morale, which leads to better productivity and safer work practices. In addition, improved aesthetics of a facility can lead to the positive perception that the facility is well run, which is important for community relations as well as to the business customers of the facility.

A good maintenance plan for protective coatings that considers the consequences of deferring coatings, surface preparation options, the design of the coatings, and the environments they will be exposed to will provide improved conditions for the facility and lower spends. Protective coatings contribute to the integrity of the assets in a facility and are an investment by the facility that, if maintained, will provide protection for extended periods at reasonable costs.

For more information, visit www. brockgroup.com or call (281) 807-8200.

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