There is a generational influx of infrastructure funding coming from the Infrastructure Investment & Jobs Act (IIJA), with over $50B allocated specifically for water and wastewater systems. This represents the single largest investment in clean water the U.S. federal government has ever made. A good portion of it will be used for water storage tanks, both for new tanks and for rehabilitation. So, how will the water sector maximize this funding to get the biggest bang for their buck? The simple answer is to utilize asset management (AM) best practices.
The American Water Works Association (AWWA) has been educating and promoting AM in the water sector for some time now. The AWWA’s “Level of Progress in Utility Asset Management”1 is a survey that measures the general progress of AM practices in North American utilities. Comparing the results of the 2015 survey to the 2020 survey, a higher percentage of utilities now have a plan for the implementation of AM, up from 7 percent to 57 percent.
The foundation of effective AM is a complete inventory of assets owned by the utility that includes the condition of each asset with an estimate of remaining service life. Only 18 percent of the utilities reported that their asset inventories are not fully developed, which improved from 26 percent in 2015. The report also said, “Fewer utilities are reporting basic attribute data, while more are reporting advanced attribute data.” As utilities continue to embrace AM best practices and conduct more asset inventories and condition assessments — collecting all relevant attributes for each asset — utility managers are going to be swimming, or drowning, in all of the condition assessment data.
Let’s review the basics of AM by looking at just one utility asset category — potable water storage tanks — and the relevant attributes for a comprehensive condition assessment. Then, we’ll discuss how to efficiently manage all of the associated critical data.
A good starting point is the AWWA’s Asset Management Definitions Guidebook (version 1.0),2 which helps make AM language understandable. Its definition for “infrastructure asset management” is “the combination of management, financial, economic, engineering, and other practices applied to physical assets with the objective of providing the required Level of Service at an acceptable level of risk at an optimal life cycle cost” (emphasis added). Note that the objective of AM is the optimization of life cycle cost, which means the lowest possible life cycle cost.
There is a very interesting nexus between AM and sustainability around life cycle costs. The Guidebooks’2 definition for “sustainability” in the context of AM is “the designing, building, operating, and funding of Infrastructure Assets in ways that do not diminish the social, economic, and ecological processes required to maintain human equity, diversity, and the functionality of natural systems. The integration of Asset Management and Sustainability is possible due to the overlap of core concepts inherent in both frameworks. Sustainability’s focus is on life cycle where a Triple Bottom Line Analysis can be performed” (emphasis added).
So, the objective of AM is to obtain the lowest life cycle cost and most sustainable solution. How is that done practically? Extending the service life of any asset as long as possible at an acceptable level of service will often yield the lowest life cycle cost.
The first step in AM is to conduct an inventory and condition assessment of the asset. Here’s what that looks like for a potable water storage tank.
A comprehensive condition assessment of a potable water storage tank will normally include the evaluation of the coatings, structural, sanitary, safety, and security conditions along with other site-specific details. There are literally hundreds of attributes to inspect to accurately assess the conditions around each of these categories, so we’re going to focus on the condition assessment of the coatings protecting the storage tank.
A key principle is to look at the interior and exterior protective coatings systems as an asset — in and of itself — protecting another asset — the steel or concrete storage tank. The AWWA M42, “Steel Water Storage Tanks,”3 states that the service life of a steel water storage tank is “indefinite” if properly maintained. How is the steel tank properly maintained? By the use of protective coatings, which, as an asset itself, has its own service life, maintenance requirements, and associated life cycle costs.
| The Outside Coating Systems (OCS) listed in AWWA D102-24 are: | |
|---|---|
| System | Generic Description |
| OCS No. 1 | Three (3) or four (4) coat Alkyd system |
| OCS No. 2 | Three (3) coat Moisture-Cure Urethane (MCU) system with a MCU Zinc-Rich Primer |
| OCS No. 3 | Three (3) coat Acrylic system with an inorganic or organic Zinc-Rich Primer |
| OCS No. 4 | Three (3) coat Fluoropolymer system with an inorganic or organic Zinc-Rich Primer and a 2-component polyurethane intermediate |
| OCS No. 5 | Three (3) coat 2-component Polyurethane system with a 2-component epoxy primer and intermediate |
| OCS No. 6 | Three (3) coat 2-component Polyurethane system with an inorganic or organic Zinc-Rich Primer and a 2-component epoxy intermediate |
| OCS No. 7 | Three (3) coat Water-Based 2-component Polyurethane system with a Water-Based 2-component Epoxy primer and intermediate |
| The Outside Coating Systems (OCS) listed in AWWA D102-24 are: | |
|---|---|
| System | Generic Description |
| OCS No. 1 | Three (3) or four (4) coat Alkyd system |
| OCS No. 2 | Three (3) coat Moisture-Cure Urethane (MCU) system with a MCU Zinc-Rich Primer |
| OCS No. 3 | Three (3) coat Acrylic system with an inorganic or organic Zinc-Rich Primer |
| OCS No. 4 | Three (3) coat Fluoropolymer system with an inorganic or organic Zinc-Rich Primer and a 2-component polyurethane intermediate |
| OCS No. 5 | Three (3) coat 2-component Polyurethane system with a 2-component epoxy primer and intermediate |
| OCS No. 6 | Three (3) coat 2-component Polyurethane system with an inorganic or organic Zinc-Rich Primer and a 2-component epoxy intermediate |
| OCS No. 7 | Three (3) coat Water-Based 2-component Polyurethane system with a Water-Based 2-component Epoxy primer and intermediate |
| The Interior Coating Systems (ICS) listed in AWWA D102-24 are: | |
|---|---|
| System | Generic Description |
| ICS No. 1 | Two (2) coat 2-component Solvent-Borne Epoxy system |
| ICS No. 2 | Three (3) coat 2-component Solvent-Borne Epoxy system |
| ICS No. 3 | One (1) or two (2) coat 2-component High-Solids Epoxy system with an optional Zinc-Rich Primer |
| ICS No. 4 | One (1) coat 100 percent Solids Aromatic Polyurethane system with an optional Zinc-Rich Primer |
| ICS No. 5 | Three (3) coat 2-component Solvent-Borne Epoxy system with an Organic Zinc-Rich Primer |
| ICS No. 6 | Two (2) coat 2-component Solvent-Borne Epoxy system with an Organic Zinc-Rich Primer |
| The Interior Coating Systems (ICS) listed in AWWA D102-24 are: | |
|---|---|
| System | Generic Description |
| ICS No. 1 | Two (2) coat 2-component Solvent-Borne Epoxy system |
| ICS No. 2 | Three (3) coat 2-component Solvent-Borne Epoxy system |
| ICS No. 3 | One (1) or two (2) coat 2-component High-Solids Epoxy system with an optional Zinc-Rich Primer |
| ICS No. 4 | One (1) coat 100 percent Solids Aromatic Polyurethane system with an optional Zinc-Rich Primer |
| ICS No. 5 | Three (3) coat 2-component Solvent-Borne Epoxy system with an Organic Zinc-Rich Primer |
| ICS No. 6 | Two (2) coat 2-component Solvent-Borne Epoxy system with an Organic Zinc-Rich Primer |
So, an effective water storage tank AM program will include an AM program for the protective coating systems with the goal of extending the service life as long as possible to yield the lowest life cycle cost and most sustainable solution.
Interior and Exterior Protective Coatings Condition Assessment
The condition assessments of both interior and exterior protective coatings systems are similar, but emphasis on certain attributes is more important for each system because of the different exposure conditions. For both new tanks and the rehabilitation of existing tanks, utilities will select and specify coating systems from AWWA D102-24, “Coating Steel Water-Storage Tanks,”4 which lists options for interior and exterior service.
Tank owners will select one of the seven exterior and one of the six interior coating systems listed. There is some helpful guidance in the AWWA D102-24 Appendix for consideration in the selection of a coating system.
In the Appendix A.1, the following comments are offered:
“Several generic types of coatings systems are included in D102 because it has been determined that no single coating systems is best suited for all service exposures or applications conditions. The coatings systems presented are not equivalent in terms of expected service life or initial and long-term costs.”
“As an aid in selecting coating systems for a particular site, it is recommended that the purchaser establish the site-specific conditions of exposure and then conduct an economic evaluation of the several coating systems using life-cycle cost analysis techniques” (emphasis added).
“Because it is impractical for an occasional purchaser of coatings to make sufficient laboratory tests to determine whether coating constituents meet requirements of this standard, it is recommended that the coatings be purchased from a manufacturer where the products have a proven performance for the intended service through in-place use or satisfactory evidence of laboratory-tested equivalency” (emphasis added).
So, consistent with AM best practices, AWWA D102 recommends using life cycle costing in the selection of coatings systems. Applying those best practices has resulted in a coalescence around just a few of the coating systems generally being used today, which are not surprisingly the systems offering the longest service life. For exteriors, the industry generally uses zinc-rich primers and the fluoropolymer finish technologies. For interiors, the trend has been to use zinc-rich primers and thicker-film epoxies. Those technologies properly maintained can offer 30+ years of service life.
A comprehensive coatings condition assessment will typically include evaluation of the following attributes:
Identification of the generic type coating and/or which AWWA D102 system was used
Date of coating systems install and name of contractor
Total dry film thickness (DFT) in mils
Coating adhesion (ASTM D4541,5 ASTM D6677,6 ASTM D7234,7 or ASTM D33598 typically performed)
Degree of blistering (ASTM D55899 )
Degree of spot failure or delamination (SSPC PA110 )
Color and gloss evaluation
Film hardness by pencil test (ASTM D336311 )
Durometer hardness testing (ASTM D224012 )
Solvent resistance of organic coatings using solvent rubs (ASTM D540213 )
As you can see, there are many coating system attributes evaluated and collected in the coating system condition assessment. Combined with all of the other condition assessment categories, there are literally hundreds of attributes associated with a comprehensive condition assessment of a water storage tank.
The challenge is now that a tank owner has taken the first step in implementing AM by conducting an inventory and a condition assessment for their potable water storage tanks, how do they efficiently store and manage all the data?
The solution is found in Managed Software as a Service (MSaaS) offerings designed specifically to help tank owners manage all of the attribute data associated with water tank AM. These software packages are not designed for AM itself but rather for the efficient management of the asset condition data utilized in AM programs. They offer a simplified approach to data management that includes a central document repository, a data visualization hub, geographic overview, and a timeline of the chronological history of all records for each tank.
Once this data is collected, owners can easily generate custom reports including required sanitary surveys, capital budget planning, and scheduling for all asset-specific tasks. Using secure cloud-based storage of the data allows multi-user access within the utility and with approved partners outside of the utility. These new MSaaS solutions will allow tank owners the ability to implement AM without drowning in all of the data.
Greg Sprinkle is the CEO of Industrial Inspection Group. Greg has been in the coatings industry for 35+ years and as a tank inspector for 20+ years. He combines his vast knowledge and experience in coatings and inspection as a true subject matter expert in both fields. He is certified as MCI #17 - PCS – AMPP Senior Inspector #N5417 - CCI – BCI. He is a frequent presenter at local AMPP chapters and currently works throughout the world with Industrial Inspection Group providing inspection and consulting services. For more information, contact [email protected].
Randy Moore is the Director of Business Development, TankPlanH2O. Randy has more than 39 years of technical sales and consulting experience in the water and wastewater industry. His experience includes 21 years of working for a coatings manufacturer and more than 17 years involved in all aspects of water storage tank asset management. Randy is involved in AMPP and AWWA as a frequent contributor to technical sessions and publications with both associations. He was co-moderator/ creator of the first joint AMPP and AWWA workshop at the last two AMPP Annual Conferences covering the topic of corrosion control for water and wastewater infrastructure. Randy is the co-chair of the newly formed AMPP TCI Municipal Water & Wastewater community and has served on the AWWA Board of Directors for six years, four of which as vice president. He holds a BS degree in Metallurgical Engineering, MS in Engineering Mgt with emphasis on corrosion theory, and an MBA, all from University of Missouri. For more information, contact [email protected].
