The following article was originally published in the October 2017 issue of Environmental Science and Engineering Magazine.
Oxidizing and neutralizing chemicals, as well as misty, wet and damp conditions, contribute to an aggressive corrosive environment in water treatment plants. In wastewater treatment plants, there is also a corrosive cocktail of bacterial decomposition of fecal and other matter and varying pH levels.
Water and wastewater systems have hundreds or even thousands of painted assets, including: pumps, valves, actuators, motors, process skids, stairways, pump stations, piping systems, elevated potable water towers, standpipes, above ground reservoirs, etc.
Slowing down and ultimately stopping the corrosion process is certainly achievable and affordable, provided sound steps are taken.
Specific coating systems selected for their bonding, overcoating and moisture-tolerant attributes must be the first priority These are somewhat more expensive, but will outperform and outlast conventional coating systems, resulting in a savings in both labour and material costs. The selection of a quality coating system will slow down the corrosion process.
If the coating system is left unattended and not periodically maintained on any and all components, hundreds of thousands of dollars will ultimately need to be spent to refurbish and restore them.
With periodic inspections, good record keeping that tracks the coating deterioration over specific time frames, and scheduled maintenance painting, there will be substantial savings. However, keeping track of coatings and corrosion issues is a daunting task of inspection, setting priorities for areas of concern, and managing costs for remediation within an annual budget.
PW Makar Coatings Inspection Ltd. has developed a coatings and corrosion assessment program, specifically tailored to water, wastewater and water transmission system facilities for municipal, private and industrial operators.
Selected areas within water, wastewater and water transmission system facilities are audited annually for their coatings and corrosion “condition levels’: The coatings and corrosion assessment program will inspect all painted assets located in the selected buildings, rooms, galleries, chambers, and elevated towers. This is a yearly program and assets inspected will be re-inspected every three to five years, depending on location and level of exposure to corrosion-causing factors.
A coatings and corrosion condition level is assigned to each painted asset. This format helps to identify assets that are in a newly painted state, ready for minor maintenance painting touchups, or a more aggressive surface preparation and the utilization of a multi-coat painting system. It will even identify safety issues, such as an asset that has lost enough metal due to corrosion to render it unsafe for further use.
The type of coating system, the colour of the top coat, the amount of dry paint film thickness and whether or not the asset has lead in its pigment can also be identified for a painted asset. Any environmental issues are noted. Is the area damp and wet? Does the area get flooded? Is the HVAC system working properly? Are there any contamination issues, i.e., oil, grease or fuel on the surface of the painted asset?
If a painted asset’s coating system has failed, an explanation as to the root cause of the failure is determined. Each asset is then photographed, which helps to visually identify the type and size of the asset and the health of its coating and corrosion tolerance.
Information gathered from the painted asset field audits are downloaded into a customized database program, where the painted assets are organized and prioritized from “pristine” to “complete failure” and requiring immediate remediation based on a percentage of deterioration. The database program assigns paint specifications to each asset based on the assigned paint condition level. The estimated labour and material cost to repaint and bring each asset to a “like new” state is also assigned.
The coatings and corrosion assessment program report package is delivered to the client, facilities managers and supervisors. It consists of hardcopy binder reports and electronic copies, which have all of the painted assets identified and categorized. A summary of the painted assets from that year’s audit is outlined in key performance indicators such as “paint health” and “general plant health”, utilizing charts and graphs.
These methods highlight where to focus resources to combat coating deterioration and corrosion issues, and demonstrate overall deterioration trends.
For the first time, water and wastewater managers have a tool to show where they have spent maintenance budget money, why they need more, and to demonstrate how well they are doing in the battle to fight corrosion and keep control of costs.
Before a coatings and corrosion assessment program can be implemented, a data collection and labeling program must be conducted. Each asset must have a specific numerical identifier assigned to it, which clearly defines one asset from another. This data collection process can be quite simple for small rural facilities in which only critical operating equipment has data and labeling assigned to it. Data collection can be much more robust for facilities which have thousands of painted assets.
A team of data collection specialists catalog and label each asset. That captured asset is then downloaded into a sophisticated computerized database program that identifies the make, model and operating parameters of that asset.
A scheduled preventative maintenance inspection plan is assigned to the labeled asset, which is routinely inspected and maintained to ensure that it is in ready-for-service condition.
With the continuing use of aging infrastructure, the “paint it and maintain it” philosophy maintains plant heath, saves maintenance dollars, frees up staff time, extends the life of the asset, and flags corrosion deterioration issues before metal failures and unsightly rust
blemishes can occur.
Paul Makar is with PW Makar Coatings Inspection Ltd.
Email: paul.makar@cogeco.ca