Many of our customers call us with concerns about the condition of their storage tank. They want to know if a tank with a small leak or crack can be effectively repaired, or when replacing the tank is recommended. Let’s discuss the situations where it’s possible for effective tank repair, and when tank replacement is the answer.
Repairing Polyethylene Storage Tanks
The short answer is, yes, your poly storage tank can be repaired. The effectiveness, however, depends on where the leak or crack in the tank exists, the size of the crack, and the cause of the crack. These factors will determine if the fix is quick and easy, a more challenging task, or a temporary repair until a replacement tank can be installed.
A small leak at a fitting or gasket is a simple, easy fix. It’s usually a matter of replacing the fitting or gasket. The fix is easy since it doesn’t involve a crack to the tank itself.
If you notice a leak or worn, cracked, brittle fittings or gaskets, call our Field Service Team immediately. We’re here to help, and happy to inspect your tank’s fittings and gaskets, and then make the necessary repairs.
The Protocol for Challenging Repairs
There is a common misconception about repairing cracks in polyethylene tanks. We are often asked: “Can’t you simply heat the area around the crack and do a “weld” fix?” The problem is that “welding” polyethylene compromises the molecular structure and weakens the structural integrity of the entire tank. “Welding” to repair a tank crack is not recommend to fix any type of polyethylene tank.
A crack in a polyethylene tank sidewall does present a more challenging fix. First, the damaged area of the tank must be cut out. Then a patch fitting the specific contours of the tank must be designed, fitted, and mechanically attached to the tank. Typically, a blind flange works as the patch. However, depending on the size of the crack, the location of the crack on the tank, the size of the tank, and the sidewall contours of the patch area, a standard blind flange may not work. In these situations, a certified Field Service technician will coordinate custom designing a patch piece that will do the job.
Another question we hear is: “What if the interior surface of the tank is OR-1000... can this be repaired?” Yes, tanks with OR-1000 inner surfaces can be repaired. You must make sure the inner surface patch includes the OR-1000 surface, or you risk compromising the interior protection barrier of the tank. In these tank repair situations, Poly Processing’s Field Service Team assists in installing a specially designed blind B.O.S.S. Fitting®. This provides a leak proof repair to tanks that have an OR-1000 inner surface.
Cracks in the sidewall of a poly tank up to a foot in length can be effectively repaired. A repair can last up to five years or more. The age of the tank, chemicals being stored, and the cause of the crack determine the effectiveness of the repair.
Repairing a crack or puncture from a forklift on a relatively new tank can be performed with confidence since the specific cause of the crack is known. On the other hand, repairing cracks developed from heating or pressurization of the tank raises concerns about the specific issue that is creating the crack.
Is the crack due to heating and cooling of a 15-year-old tank? Has pneumatically filling the tank over a period of time, especially of a heavy chemical such as sulfuric acid, created the crack? In these instances, a temporary repair may be needed to hold you over until you can budget to replace a problematic tank, and get guidance on changing your process to maximize tank longevity.
Temporary Repair Solutions and Tank Replacement Situations
Repairing cracks over a foot in length and cracks due to heating and pressurization, especially in older tanks, should be viewed as band-aid fixes. Poly Processing’s Field Service Team will work with you on a temporary tank repair to help you buy time to budget for tank replacement and to have your replacement tank designed, manufactured, and installed.
Any cracks in the floor of the tank, usually due to an over-pressurization issue, are not repairable. These are the types of issues that lead to taking the tank out of service immediately. Poly Processing Company manufactures tanks for different tank rental companies throughout the United States. A rental tank is an option to get through the period of time to get a replacement installed.
Polyethylene vs. Fiberglass
Any repair to a fiberglass tank compromises the interior corrosion barrier of a fiberglass tank. A poly tank repair, that fits the scenarios described above, can be effective and will not compromise the strength of the tank.