General Rotationally Molded Polyethylene Tank Sizes:
Many sizes are available for single walled vertical tanks. The range is from 5 gallons to 15,000 gallons, as well as hundreds of sizes for horizontal, rectangular and conical bottom configurations. There are in general two styles of double walled containment systems ranging in sizes from 15 to 10,500 gallons.
Polyethylene tanks are just apt for applications storing a very wide variety of liquids up to 120 degree Fahrenheit.
Life Expectancy of Plastic Tanks-
There is no substantial way to determine the life expectancy of a polyethylene tank. There are a number of variables which can effect the tank, such as:
- Mixed chemicals in tank
- Reaction of chemical in tank
- Temperature of chemicals
- Weight of chemical
- Number of processes fittings installed in tank
- Other features or accessories attached to tank walls
- Mechanical agitation in tank
- External loading in tank
- Usage of tank indoors or outdoors
- Stationary or Transport related usage of tank
It has been nearly 40 years since rotationally molded plastic tanks have been in the market. Let’s talk about the life expectancy of a rotationally molded polyethylene tank. Many applications could be termed as ‘tank friendly’ and hence tanks would have a longer service life in this case. The applications that are categorised as demanding result in a short service life of the tank. A tank may fail in just 2 years or might go up to 20years.
Although no guarantee can be made on how long a polyethylene tank will actually last, we know from our inspection and experience, that the moderate plastic storage tank will last anywhere from 10 to 20 years. This would depend upon the kind of chemicals the tank is holding and the conditions of the environment it is exposed to. There are exceptions to this, like 12-1/2% sodium hypochlorite, which normally lead tanks to pre-maturely age after only 5 to 7 years. This occurs on all HD Linear Polyethylene Tanks.
General Tank Warranties:
There are standard guaranties on tanks if they are used in applications that have been approved. This kind of commitment is 3 years for standard weight tanks and 5 years for heavy duty tanks. The warranty covers repair work or replacement of a tank that fails due to faulty material and workmanship.
How Do You Determine If Tank Is Still Safe For Use?
If a plastic tank is starting to show its age, you will be able to notice fine fissures or hairline cracks also known as crazing. See carefully for crazing on the dome of a vertical tank in the area where sunlight is most acute or around the nozzles on the sidewall of the tank, especially where mechanical loading from pipe and valves are joint. The top of a transport tank, which has been permitted to set out all year, is a good place to look as well. These fine cracks will become fiercer and clearly visible as time goes on and will become stress cracks. Dropping a ray of light inside the tank can do wonders in visual examinations, as any stress cracks will be easier to spot with the internal light source in place. The flexibility of a good tank is obvious.
When a tank starts to wear and tear or is otherwise determined to be unsafe, it is best to replace it.