Relining Steel Tanks: Proper Timing, Conditions and Options
Relining steel storage or processing tanks can be an economical option that prolongs the useful lifespan of an expensive piece of capital equipment. There are different types of tanks that serve a wide variety of industries; rail cars, over-the-road tanker trailers and on-site process or containment tanks. When is the right time to reline? The experts at Blair Rubber Co. offer up at least five considerations that can affect your decision:
- Condition of the steel
- Lining inspection
- Tank contents
- Size of the tank
- Environmental conditions
Condition of the steel
In most applications, the tanks themselves are made of steel. When the steel has been maintained and is in good condition, it is much more economical to reline the tanks than replace them since the steel is the most expensive portion of this piece of equipment. Tanks do get relined often since the liner will wear before the steel will.
Depending on the type of tank, inspection periods can fall under Department of Transportation regulations. Rules dictate that tanks used for over-the-road shipping must be inspected annually, and rail cars every five years.
Based on the initial results, many companies might decide to inspect more frequently as the lining ages, to prevent possible leaks.
It might be time for a tank relining if there are visible blisters or delamination of the rubber, such as lifted edges.
Depending on use and environmental conditions, Blair Rubber recommends inspection every five years. With more aggressive or corrosive contents, inspections should occur annually. For example, two harsh chemicals are sodium hydrofluoric or sodium hypochloric acid. Potent chemicals like these can cause lining failure within ten years or possibly less. Tanks that contain less aggressive contents and are properly maintained can keep the same lining from 30 to 40 years.
Smaller sized tanks make it difficult to get a person physically inside the tank for relining. In that case the best option is a new tank purchase. The minimum size for relining would be three feet in diameter by six feet tall or slightly larger.
On the other end, there is no maximum size that would prohibit relining. Blair Rubber has serviced relining projects for tanks up to 1.2 million gallons in size.
Tank Use + Environmental Conditions
Tanks that are used for storage generally will have a lining that lasts longer than tanks that are frequently filled and emptied, or hold varying amounts of content, since greater tank activity causes more stress on the lining.
Heat resistance, ozone protection, sunlight and weathering factor into lining selection as these conditions can cause greater stress on the lining. Fortunately, advances in polymer technology expand the range of options for owners and operators looking for tank relining.
Advances in Polymer Technology
Advances in the past ten years can improve the quality of the lining used in reconditioned or relined tanks.
Older rubber linings are most likely made of natural rubber polymer. Today, advanced synthetic polymers offer significantly better chemical resistance over a broader temperature range. Depending on the conditions the rubber lining will face, Blair Rubber Co. offers more than sixty recipes for the lining mixtures.
Storage tanks are relined on site to avoid the cost of moving the tank or when size would prohibit it. Project timing varies with the size of the tank and can take anywhere from a week to several months.
The key is having a qualified applicator assess the tank and perform the relining preparation and work. Blair Rubber Co. services companies across the globe Call today to find a qualified applicator in your area: (800) 321-5583