Planning for water storage tanks is a crucial step early in project design. The size and type of tank will depend on several factors, including construction timelines, budget constraints, and securing funding (especially for municipalities relying on a single source). The tank design needs to meet both current and future community water needs.
Several key considerations come into play when choosing the final tank configuration: community water usage, available space, required water pressure, long-term maintenance needs, access for maintenance, and overall project cost.
For municipal water storage, there are three main types of tanks to consider: glass-coated bolted steel, welded painted steel, and concrete.
1. Manufacturing Process
What sets glass-coated bolted steel tanks apart is their factory-controlled manufacturing process. Unlike painted steel or concrete tanks, which are often built on-site, these tanks are produced in a controlled environment. This eliminates inconsistencies that can arise from factors like worker experience or varying weather conditions that can plague field-built structures. Additionally, since the tanks are pre-fabricated in the factory, they only require assembly on-site, allowing for year-round construction.
2. Coating
While paint, concrete, and glass are all common tank coating options, glass offers unique benefits due to its superior impermeability and special properties.
The process starts with glass frit, a glassy material, mixed with other minerals and water to form a liquid mixture. This mixture is carefully sprayed in precise amounts onto pre-treated steel panels that have been punched, cleaned, and roughened. Unlike other tank coatings that rely on a simple mechanical bond, glass forms a much stronger chemical bond with the steel. This chemical bond prevents a critical issue called “undercutting” – where corrosion spreads beneath the coating on the bare steel. Imagine scratching a car’s paint: if the paint only has a mechanical bond, rust would form under the scratch and spread, weakening the surrounding paint. Signs of undercutting include raised bubbles, rust stains, and a weakened tank structure. However, the strong chemical bond in glass-fused-to-steel coatings prevents corrosion from spreading even if the glass itself is scratched.
3. Tank Construction
Glass-coated bolted steel tanks are assembled using a jacking system for efficient and safe construction. First, the foundation is prepared, either by embedding a starter sheet (bottom ring) in concrete or using a pre-fabricated glass-fused floor. Then, the top ring of the tank is assembled on jacks, followed by the roof installation. Both the top ring and roof are lifted using the jacks. Workers then progressively add each new ring below the elevated top ring, bolting them together and sealing the seams with a urethane sealant.
This top-down construction approach offers several advantages. It’s safer for workers and allows for faster assembly, typically completed within a week or two, which reduces overall project costs, especially when considering labor rates. Additionally, all crews building the tank undergo factory training and certification to ensure consistent quality control throughout the on-site assembly process.
4. Maintenance
Glass-coated bolted steel tanks are built to last. The permanent glass coating eliminates the need for repainting, saving time and money on maintenance down the line. This makes them a popular choice for applications where a long-lasting, attractive appearance is important.
5. Flexibility
The bolted design and factory assembly of glass-coated bolted steel tanks offer significant advantages over field-built options. Unlike concrete or welded steel tanks that require large staging areas for on-site construction, these tanks need minimal space – typically just 6 to 10 feet around their diameter – for final assembly. This compact footprint translates to substantial cost savings on both the tank itself and the construction project. Additionally, the lightweight panels can be assembled by hand, eliminating the need for expensive cranes or specialized equipment. This makes them ideal for installation in remote locations or areas with limited access, where other tank types might be impractical.
6. Expandability
Glass-coated bolted steel tanks are designed to grow with your needs. If your community or industry experiences growth and requires more storage capacity, the tank can be easily expanded vertically. A factory-trained crew can utilize the existing jacking system to raise the entire tank. They’ll then remove the bottom ring, add new rings to meet the increased capacity, and reattach the bottom ring. The beauty of this process is that the expansion seamlessly blends with the existing tank – there’s no visual difference between the original panels and the new ones.
Conclusion
Choosing the right tank for your project goes beyond just the initial price tag. It’s important to consider the expected lifespan and ongoing maintenance costs as well. A tank with a lower upfront cost might require more frequent and expensive maintenance over time, making it a less cost-effective option in the long run. By analyzing both initial costs and future maintenance savings, communities can make the smartest financial decision for their specific needs.
Our experienced customer service team is happy to discuss these factors in more detail and help you find the perfect tank solution for your project. We offer proven services in the Houston, Texas and Longbeach, California areas.
Call NFPA 25 Inspections LA by American Tanks at +1 800 656 0167
Or email at info@nfpa25inspections.la
