Monday, September 21, 2020

Polyurea Coatings Provide Safe, Reliable, and Flexible Waterproofing

by on September 21, 2020

Cities across the country depend on decades-old water reservoirs, ponds, and tanks to store potable water as well as for fire suppression. 

Although steel and fiberglass are mostly used for smaller tanks, the largest and most enduring outdoor tanks and reservoirs that contain millions of gallons are constructed of cement or asphalt. Unfortunately, several factors can cause these constructions to develop sizable cracks through which large quantities of liquid can escape (exfiltration) or enter the water supply.

When this happens, facility managers must decide whether to demolish and reconstruct the aging structure or find a way to extend their service time. Fortunately, advanced polyurea coatings and liners are showing ideal for the tank, pond, and reservoir restoration by presenting strong, flexible waterproofing that not only links large existing cracks but can elongate up to 400% without breaking.

Concrete/asphalt cracking

Cracks can occur in aging concrete reservoirs and tanks for numerous reasons ranging from ground movement to daily or seasonal heat changes that cause expansion and contraction. The weight of water in a big reservoir or tank can also cause concrete to move many inches. In doing so, tiny cracks in a drained tank can open to cracks 1/4" or larger when filled with water.

To address the issue, waterproof layers such as epoxies are often applied to the exterior. However, these traditional coatings lack the flexibility to budge and sway with concrete or asphalt and crack.

Instead, water facility managers turn to polyurea coatings and linings, one of the few protective coatings that can work on the expansion and contraction cycles of substrates such as asphalt, steel and concrete. Some advanced polyurea coatings have high tensile strength and the flexibility to stretch 400% and sizable bridge cracks.

Rehabilitation instead of demolition

Redstone Arsenal, a large U.S. Army base in Huntsville, Alabama, had a decision to make: demolish or repair an important, working, 5-million-gallon water tank. The tank, built-in 1941, has had a beneficial life as a water storage tank for fire suppression, as well as a back-up water supply. However, the tank had numbers of cracks and leaks and was losing water at an significant rate.

The tank was missing a significant amount of treated drinking water, which is more expensive. The Army base had attempted to use different liner types over the years, but those were not working adequately.

Redstone Arsenal's Public Works Department evaluated their options for more than ten years with no apparent solution. After the current success of a polyuria-rehabilitated water storage pond adjacent to the tank, they recognized that they could use a similar approach. The contractor on the pond was also awarded the tank project.

The spray-applied waterproof coating creates a seamless, waterproof, durable protective liner that stops leaks and strengthens the entire storage structure's integrity. It is designed to withstand decades of freeze-thaw cycling, wide variations of heat and humidity. In the late 1990s, Parsons Brinckerhoff issued a 75-year lifespan on the famed Boston Tunnel Project.

With minimal crack repair and surface preparation, the polyurea coating can be thick film-applied directly to the concrete, asphalt, or similar substrate. An alternative application method that can sometimes mitigate the need for surface or crack repairs is to pre-spray the polyurea to geotextile fabric panels placed above the onsite substrate, fusing the panel edges with more polyurea.

With either application process, the polyurea coatings exhibit preferred physical properties such as high elongation, crack bridging, hardness, and tensile strength to create a robust industrial liner that protects, strengthens, and waterproofs concrete reservoirs and vessels.

The polyurea's ability to set and cure fast also reduces water tank or reservoir downtime. This can translate into thousands of dollars per hour savings in facilities requiring potable water and a source of emergency water for fire protection.

The polyurea sets up in seconds and can be put back into service as fast as an hour. It can take days for epoxy to cure enough to do the equivalent. The time saved can provide tremendous savings to a facility. 

After repairing all cracks over 1/8″ wide with a concrete repair grout, the contractor primed the 5-million-gallon water tank's concrete surfaces with primer and applied 80-100 mils of pure polyurea. The walls were completed first. Next, they removed the heavy equipment from the floor. The tank base was re-cleaned and primed before the polyurea's last application was applied to the floor. From start to finish, the project lasted two months.

Two years later, both Redstone Arsenal's polyurea-rehabilitated 5-million-gallon water tank and the water storage pond adjacent to the tank have been investigated and remain in excellent shape, with decades of extended life expected.

Learn more about ArmorThane protective coatings here.

Popular Posts

Featured post

Enhancing Food Quality and Safety: Exploring the Role of Plant Coatings

  In the world of food production, main...


Recent Posts

Random Post

Reshaping Processing Plants Using Polyurea

With news of more food processing facilities pulling product off the market and having to shut down due to possible contamination from Listeria Monocytogenes, the concern of plant sanitation, as well as style and building structures, are at the forefront of the agenda for those in the industry.

At issue are food and meat processing plants located in aging industrial buildings with extensive ware and tear, in addition to ideal angled building. In these plants, walls and ceilings are typically built with angled steel, i-beams, concrete block, interlocking metal and fiberglass panels, double-t ceilings and tiles with concrete grout.

This supplies a virtual breeding ground for standing water, dirt, dust, mold, and pathogens such as Listeria, E. Coli, and Salmonella. With many fractures, pits, and seams, plants are at danger in spite of aggressive power cleaning and chemical sanitation strategies.

Plant Recalls from Listeria
The fallout from a public recall due to Listeria extends well beyond lost earnings and extended plant shutdown as well as a decrease in overall business value. Lawsuits, due to customer health problem and even death, along with the disastrous impact to the brand name's credibility, can put a processor out of service.

The difficulty with Listeria is that it is proficient at evading detection. It can aerosolize or connect to equipment and individuals, and will prosper in cold temperatures. As an outcome, it is difficult to control in the processing environment. To fight this pathogen, lots of centers depend on a robust sanitation program to avoid Listeria from getting in or polluting the environment. In addition, many processors participate in continuous environmental sampling programs to keep track of the efficacy of those efforts.

If any bacteria or contamination is discovered, called "testing hot," it can lead to an instant shutdown. Closing down a food processing plant that is running 24 hours a day, 7 days a week, can cost the processor millions in lost profits. There is also the danger of fines by the USDA for recurring violations.

In the majority of instances, business just react to a positive test by performing magnified cleaning and sanitization. Once the company's follow-up tasting of the affected websites is negative, the problem is normally thought about to be dealt with.

In addition to issues about bacteria, contamination likewise comes from facility maintenance concerns, such as breaking paint, spalled and broken concrete, and areas in the walls and ceilings that can gather dust, dirt, mold and other contaminants.

Perpetual Cleansing, Painting
Until now, the expensive and labor heavy solution was merely to clean up more frequently and mitigate the issues utilizing FRP panels or layer upon layer of paint to try to create a cleanable surface.

The aggressive cleaning agents like bleach and cleaning agents and heavy high pressure power cleaning cycles take a heavy toll on the paints, epoxies, concrete, fiberglass and metal surfaces eventually use them away until they need a total replacement, or even worse, they jeopardize a plant shutdown and or fines.

This is an extremely costly, labor-intensive program that duplicates itself in perpetuity at practically every food processing plant throughout the nation.

To resolve this issue, new patented techniques are being used to deliver a complete rehabilitation of the walls and ceilings, typically throughout planned maintenance weekends.

Many other coatings take 1-4 days just to treat, which is too long when you require to get the plant back online. Polyurea cures within minutes. Additionally, the space is "reshaped" through this procedure so just smooth, curved lines stay to remove areas where water, dirt, grime or pathogens can collect.

Among the key elements of the industrial process is application of an incredibly fast curing, pure polyurea coating designed for usage in food processing plants. Given that the material is spray used, it can be applied quickly by qualified applicators and constructed up to any required thickness and formed into the modified wall and ceiling design. Polyurea is the only coating system readily available that can create a monolithic surface area in the brief time frame needed to minimize plant downtime.

The majority of other coatings take 1-4 days simply to cure, which is too long when you need to get the plant back online.

Companies makes use of a special, private label formulation of pure polyurea for food contact facilities from ArmorThane, a worldwide provider of high-performance polyurea coatings, liners and joint sealants for a wide variety of industrial environments. The company uses two systems that are third-party ranked for FDA Direct Food contact.

Due to the aggressive nature of plant wash downs, a custom-made polyurea topcoat is required to finish the process., The final topcoat creates a very slick surface, making it difficult for standing water, dust, dirt, or bacteria to take hold. To finish all this work, Companies deal with the food centers to strategize and optimally time rehabilitation operations.

Before any coatings are used, there are several actions to restore an aging food facility., No quantity of cleansing will effectively prepare a surface that needs repair. So the initial step is to resolve any areas with spalled or split concrete, chipping and peeling paint, or heavy corrosion.

The next action is an intensive cleaning process to remove grease and gunk and other surface area contaminants that build-up as an outcome of meat processing, cooking, and basic facility maintenance. This involves using specially authorized wash down options and self-contained high powered water blasting techniques. All holes, voids, joints, and penetrations are filled, along with additional adjustments for the reshaping. A combination of concrete and molded foam products are utilized to transition any flat surface areas from 90 degrees to 45 degrees to avoid standing water from accumulating.

These areas usually consist of the cove joint from wall to floor, steel I beam bases, welded and frame bolted angle iron, and gaps in the existing construction or wall/ceiling fascia. Standing water is one of the numerous contributing aspects for Listeria and other pathogens, in addition to mold and corrosion. Finally, every piece of devices, pipe, flooring, and other exposed locations must be wrapped in plastic or covered prior to spraying starts.

In numerous applications, such as the within of big tanks, sprayed polyurea is not required to be cosmetically appealing.

For food processors in aging centers this type of total interior wall and ceiling rehabilitation-- regardless of the surface or substrate and level of disrepair-- might be the quickest method to break the cycle of constant degeneration and ongoing repair, while decreasing danger of pathogen-based item recalls.