Municipal water leaders who are dealing with corrosion issues seek safe and long-lasting solutions to protect their water, wastewater, and storm water systems. Municipal Water Leader spoke with Max Silva, a senior project manager at A&W Maintenance and Coatings LLC, the master applicator for Warren Environmental’s 100 percent solids, high-build epoxy products, about his company’s approach to protecting these valuable assets.
Municipal Water Leader: Please tell us about your background and how you came to be in your current position.
Max Silva: I’ve been working for A&W Maintenance and Coatings and Warren Environmental since early 2013. I graduated from Boston University with a degree in business administration in 2012 and started working for A&W and Warren right out of college. I’ve held several roles over the past 8 years. I’ve done a lot of work in the field, applying the product myself; I’ve managed crews in the field on various applications of the product; and now, I’ve transitioned into a management role as a senior project manager for A&W. I’m responsible for operations in the eastern United States. We have offices in Atlanta, Georgia, and Middleborough, Massachusetts. Those are just home bases, as we are a mobile specialty contractor with crews that travel 85 percent of the year.
Municipal Water Leader: Please introduce A&W and Warren’s products and services.
Max Silva: Warren Environmental is a manufacturer of epoxy products used in municipal potable water and wastewater applications, as well as industrial, marine, and chemical applications for protecting assets such as steel, concrete, and a variety of substrates. Warren manufactures and distributes various lines of products. The primary product is the 301 series of environmental epoxies. These are specialized epoxies that have been around since the early 1990s. The 301 series has been used across the United States and in Mexico, Europe, Australia, and Canada. A&W was founded as a painting contractor in the 1980s by the same owner who started Warren Environmental. He experimented with different resins and products and came up with the products that are now manufactured by Warren Environmental. Since then, that is all that A&W has applied. We believe that the world’s most precious resources are water and people, and we think protecting the assets that carry, treat, and hold water with a high-quality, long-lasting coating system that is safe for the environment and the life in it is extremely important.
Municipal Water Leader: Please give a sense of the range of assets that are generally rehabilitated with your epoxy coatings.
Max Silva: A&W is a coatings contractor. We work on a variety of projects, municipal and industrial, new and rehabilitation. We are frequently hired to do work at treatment plants, for example. A lot of new treatment plants are getting built, and all their clarifiers, digesters, pipelines, gravity thickeners, and so on are built with new concrete. Some owners want to be proactive in protecting that concrete because they know it’s going to erode and be exposed to chemical attack over time, so they will specify an epoxy or some other system to be applied after the concrete has cured. There are a lot of plants that have been around for 50 years with coating systems that are now completely gone, flaking off, or delaminating. In that case, we would clean the surface of the concrete tank, steel structure, or whatever it is, re‑prep it, and then apply the Warren product. Typically, the difference between new and older applications is how thickly the epoxy is applied. New assets are already structurally sound, so they just need a barrier coat and something to protect it from chemical attack, which occurs naturally in wastewater and potable distribution and treatmeant facilities. In rehab projects, there’s usually a lot of aggregate showing and concrete loss. Generally, in those cases, it is wise for an owner to apply a thicker coating—say a quarter of an inch or 250 mils.
On the industrial side, there are also many assets exposed to chemical attack or other forms of degradation. There are facilities where treated and untreated water are mixed together in a tank so that it can be diluted enough to be distributed via a water system. Those tanks often experience some level of degradation, especially if they are not coated. I’ve also seen leaching of steel holding tanks used to store chemicals in paper plants and waste management facilities. Owners also put substances in water to treat it that are also corrosive. We also put epoxy coatings on wastewater sewer manholes. Manholes in the ground need protection from hydrogen sulfide gas. So do lift stations and pump stations, both new and old, and large-diameter pipelines.
We’ve done a lot of large-diameter concrete and steel pipelines for which a trenchless solution is the best option for the owner. Whether because infrastructure has been built around the pipeline over the years or there are a lot of utilities around the pipeline, digging and replacing isn’t a great option. Using a trenchless solution, we can work from manhole to manhole without any disruption on the surface. Our applications are fast: We just need to clean the surface, apply the epoxy, test the epoxy, and then we’re done. Warren epoxy has a tenacious mechanical bond to the inside of the asset that will protect it for 75 years or more.
Municipal Water Leader: Are the potable water tanks and pipes you rehabilitate generally made of steel, or are some of them concrete?
Max Silva: We see both steel and concrete tanks. Some potable water facilities, for example, have big reservoirs and treat the water in large concrete channels with chlorine before it goes into the plant. That chlorine gas corrodes concrete.
Municipal Water Leader: What are the reasons that potable water treatment and conveyance facilities need rehabilitation?
Max Silva: These types of facilities usually require coatings because of corrosion, erosion, or age. Taking down an asset for repairs or replacement is expensive and costly to the shareholders who rely on the asset. Over time, water and chemical attack wears down concrete and steel. When aggregate gets exposed, you run the risk of developing a structural issue. Warren epoxy is a chemical barrier as well as an erosion barrier.
Municipal Water Leader: Please walk us through the process of installing a coating.
Max Silva: A Warren epoxy application requires a clean surface free of any loose debris or dirt. On concrete, we’ll use high-pressure water, typically 5,000–6,000 pounds per square inch (psi) with a turbo tip. That mills off any loose debris on the surface and opens the pores of the concrete to allow for a surface profile. We also need to make sure there are no salts or laitance on the surface. Laitance is a natural occurrence in concrete. It comes to the surface of concrete when it cures—it’s almost like a cream layer. We remove it with a muriatic acid solution or abrasive blasting. With steel, we perform abrasive blasting or media blasting following the Warren specification. After the surface preparation, we can spray-apply, trowel-apply, or spin-cast-apply our epoxy, depending on the application. Most of the time, we spray it through plural component spray equipment, all through a patented Warren system.
The thickness of the epoxy depends on each project. Usually, for newer applications or newer assets, you only need around a 1/8‑inch-thick coating, because you’re just protecting it from chemical attack. For more seriously deteriorated assets, we’ll use a thicker coating: 250 mils, or ¼-inch thick, or thicker. The 301 product line can be produced in different viscosities or thicknesses.
For both concrete and steel, we’ll always do post-cure testing and inspection. After we spray the epoxy, it will take 4–6 hours, depending on ambient conditions, to be hard enough to the touch for us to do our testing. We start with spark testing, also called holiday testing. The testing device sparks and makes a noise wherever there’s a void in the coating. That void could have been caused when a technician missed a spot while spraying or could be a natural defect, such as a pinhole in the coating. The spark tester allows us to locate those voids and touch them up. We also do an adhesion test. We glue a dolly onto the surface of the coating and use a testing device that pulls the dolly off and tells us the psi of adhesion the coating has to the substrate. We also use wet-film gauges to tell us how thickly we’re applying the coating during application. It is also possible to do post-cure thickness testing with ultrasonic equipment.
Municipal Water Leader: What can you tell us about the epoxy products’ safety for the environment and human health?
Max Silva: The Warren products are 100 percent solids epoxy coatings. That means that there are no solvents in the coating at all. A lot of coating systems require solvent to be added before they can be sprayed. Warren was the first to develop a system, now patented, in which you could spray 100 percent solids epoxies without solvents. Solvents in coatings can pose challenges for a few reasons. The first is that they’re flammable. A lot of our work is done in confined spaces, tunnels, and tanks. Having anything flammable in that environment poses potential safety risks for the workers. Solvents also need to evaporate out of a coating while it’s curing. That reduces its dry-film thickness, so you need to apply additional coats. The Warren system doesn’t require solvents, so you can just spray it on, and the wet-film thickness is the same as the dry-film thickness. Finally, if solvents are evaporating from a coating system in highly humid environments, the solvents have nowhere to go and can be trapped in the coating, preventing it from curing or causing other defects.
Warren products are also free from volatile organic compounds (VOCs), which are hazardous to the environment. Ours is the only epoxy that’s aquatic safe. Aquatic safe is an American Society for Testing and Materials standard that has to do with leaching harmful compounds into a water system. If you’re applying a product to a structure that’s going to carry material to a river or other waterway, you don’t want anything leaching out of the coating over time that will affect wildlife. Warren Epoxy has passed that test and does not leach anything harmful.
Municipal Water Leader: Please discuss your work on the pipe rehab project in Milton, Massachusetts.
Max Silva: The town of Milton had aggressive tuberculation in approximately 5,000 lineal feet of cast-iron water mains that went through the town. Tuberculation refers to a situation in which a 10‑inch drinking water pipe can be reduced to a 4‑inch pipe because of the buildup of rust inside. The town wanted the pipes cleaned and protected so there wouldn’t be any more buildup in the future. It opened the pipe at valves so that it could replace the valves and give us access. We were able to clean the pipes remotely and remove all the tuberculation with back-and-forth scrapers, high-pressure water, and pigging, restoring them to their original diameter. Then, we used Warren spin-casting equipment, which is a remotely operated caster of epoxy. We sent a skid down the pipe and then used a reel to retract the spinner head as it spin-cast the epoxy on the walls of the pipe. The machine is simple to operate because it’s all computerized. You essentially enter the length and diameter of the pipe and the desired epoxy thickness, and the computer does the rest of the operation. When you’re doing a spin-cast application like that in a water main, the biggest fear is that you’re going to plug the laterals that go to each house. If you did a cure-in-place liner, you’d have to go back and cut all those out individually, but when you spin-cast epoxy, it doesn’t plug them up. Once the pipe is lined, you just need to do a video inspection and you’re good to go.
Municipal Water Leader: Is there anything you would like to add about the Warren product?
Max Silva: There are always a lot of things to consider in a coating project, such as the bypassing of lines. To enable a larger-scale rehab project, the owner generally has to shut off the asset. At the same time, they need to move water, and there’s still wastewater coming in that needs to be treated. This means that the owner must install large, expensive bypass systems. The longer the systems are set up, the greater the cost to the owner and their stakeholders. One of the things that owners like about the Warren product and about A&W as a contractor is that our system is faster. Our single-coat system has fast curing times and enables a fast return to service. That is a benefit from an owner’s perspective. The other advantage is safety. There’s no odor, no VOCs, and no solvents with the Warren product, so there’s no reason that other contractors can’t work near us. We may be rehabbing a tank while other contractors are replacing the rake arms and baffle walls and putting in new handrails. That adds to the time-savings factor, which ultimately ends up saving money for the owner.