Tamada Industries, Inc.
Pollution Prevention: SF double-wall tank
Leak and Chemical Resistant Underground Tank
Tamada Industries, Inc. Ltd. is in the tank manufacturing, sales, and related installation/maintenance service business. They manufacture SF (steel and fiber reinforced plastic) double-wall tank, which is an underground tank for storing liquid fuel and chemical products. It is designed for installation at gas stations and other facilities that store hazardous materials. Utilizing proprietary technology, this double-wall structure is comprised of a primary steel tank and a secondary FRP tank.
The company has designed a detection interstice, or micro-space, between the primary steel tank and the secondary FRP tank. This is so that, even if leakage was to occur because of corrosion in the primary steel tank, soil pollution would be prohibited and the leak would be found.
The FRP in the exterior layer of the SF double-wall tank features 500 times greater insulation than the asphalt used in covering single-wall tanks. In addition, it has 50 times the tensile strength and six times the shear resistance. As such, this allows it to become a durable cover as well as prevent corrosion when it comes to the interior layer. In addition, FRP is chemical-resistant.
Many countries, including Japan, need SF double-wall tanks in order to comply with the environmental conservation regulations.
I. Leak Resistance
Unlike underground single-wall tanks formed from just steel, this double-wall tank does not leak. In fact, single walled tanks don’t even have sensors that detect when leakage has occurred.
SF double-wall tanks feature a two-layer structure comprised of a steel interior with an FRP exterior, plus they include leak sensors called Leak Monitors.
Damages arising from tank leakage can total several million yen to several billion yen, depending on amount leaked. This far outweighs the cost of simply converting to an SF double-wall tank.
II. Excellent Insulation Factor
The FRP in the exterior layer of the SF double-wall tank features 500 times greater insulation than the asphalt used in covering single-wall tanks.
The SF tank has 50 times the tensile strength and six times the shear resistance of single walled tanks. As such, this allows it to become a durable cover as well as prevent corrosion when it comes to the interior layer.
IV. Chemical Resistance
Thanks to its durability, FRP is chemical-resistant, which is integral for use at gas stations. There are various ways to form the FRP layer of SF double-wall tanks: the hand lay-up method, the spray-up method, and the sheet-molding method.
Tamada Industries makes its SF double-wall tanks by utilizing the spray-up method. A 2010 survey by the Hazardous Materials Safety Techniques Association found that just 62 tanks experienced damage to the exterior layer. This accounted for 0.15 percent of all tanks installed in Japan. However, none of these tanks with exterior-layer damage were made via the spray-up method.
This technology has already been shared in four countries: China, Thailand, Malaysia, and Vietnam.
As an underground tank for storing liquid fuel and chemical products, and that would be installed at gas station and other facilities that store hazardous materials.
The SF double-wall tank uses our proprietary technology—a double-wall structure consisting of a primary steel tank and a secondary FRP tank—to detect and prevent leakage of the liquids stored inside.
A number of countries, including Japan, require SF double-wall tanks as a part of their environmental conservation regulations.
Underground single-wall tanks formed from only steel can potentially leak, and they do not have any sensors in the tank to detect when leakage has happened.
On the other hand, SF double-wall tanks have a two-layer structure (steel interior with an FRP exterior), and they are designed to include leak sensors (Leak Monitor).
In Japan, the damages caused by tank leakage can cost from several million yen to several billion yen, depending on how much was leaked. In some cases, this compensation will cost much more than switching to an SF double-wall tank.
Various methods are available for forming the FRP layer of SF double-wall tanks: the hand lay-up method, the spray up method, and the sheet molding method. We manufacture our SF double-wall tanks using the spray up method.
According to a 2010 survey conducted by the Hazardous Materials Safety Techniques Association (sourced from 802 fire departments across Japan), only 62 tanks have been recorded to have experienced damage to the exterior layer, accounting for 0.15% of all tanks installed in Japan. However, none of these tanks with exterior-layer damage were manufactured using the spray up method.
Tamada Industries, Inc., first started to supply SF double-wall tanks across Japan in September 1994, producing over 20 years of results.
According to the Japanese Fire and Disaster Management Agency, 12,178 SF double-wall tanks were installed in gas stations from 2005 to 2013.
During this period, we supplied 10,493 of these tanks, achieving 86% of all Japan tank installations and leading to our becoming the leading manufacturer of SF double-wall tanks in Japan.
We have already shared our technology in four countries: China, Thailand, Malaysia, and Vietnam.
Currently, despite having shared our technology, there is not much progress in the spread of SF double-wall tanks in developing countries due to the low costs of common single-wall tank manufacturing.
Schematic illustration of the technology
SF double-wall tank
Installation of SF double-wall tank made in Vietnam
※This innovation seed information is reprinted with permission from UNIDO ITPO Tokyo’s STePP website.