WITH above-ground storage tanks numbering nearly two million — 90% of those under 300,000-gallon capacity, and with age exceeding 50 years — it's no wonder that the Steel Tank Institute/Steel Plate Fabricators Association (STI/SPFA) continually reviews and updates standards, researches new technologies, and provides education and information to the public and industry professionals.
The association has been reviewing two inspection standards that are designed for small aboveground storage tanks and for repair of shop-fabricated tanks. Review of the inspection standard began in 2000 and completion was finally expected in late 2005, said Chuck Travelstead of Brown-Minneapolis Tank and Innovative Tank Solutions.
He serves as chairman of the Above Ground Inspections Standards Committee of STI and discussed STI/SPFA actions during the 2005 Independent Liquid Terminals Association meeting in Houston, Texas. The committee is composed of a group of regulators, manufacturers, and users. “We have a wide assortment of expertise that includes major oil, petroleum marketers, inspectors, tank builders, professional engineers, and code authorities,” said Travelstead. “And everything the committee does is via a consensus process.”
STI/SPFA is comprised of over 100 fabricators of shop-fabricated and field-erected storage tanks. STI Members alone account for nearly 80% of the total shop-fabricated steel storage tank production capacity in North America.
The committee has incorporated inspection requirements for all shop-fabricated tanks and for field-erected tanks up to 30-foot diameter and with volumes of less than 300,000 gallons. This will allow one inspector to inspect all tanks at many facilities. The standard also would establish criteria for portable tanks
Travelstead pointed out that single-wall tanks sitting on soil pose the greatest risk for an incident and emphasized that tanks with evidence of high corrosion should be inspected and repaired immediately. “Tank systems with containment, elevated tanks where all surfaces of the tank can be seen, and tanks with release prevention barriers present much less risk to the environment,” says Travelstead, “and therefore necessitate a lesser inspection effort according to the STI standard.”
He advised operators to have a means of containing or detecting a release of product from the tank. The detection system should be designed with good engineering practice to divert leaked product that would provide for prompt release detection through the required owner's periodic inspection.
Among the association's other activities are tank technology development, standards and recommended practices, licensing of technologies built to STI specifications, and quality control.
Like many associations and companies in the tank storage and terminal industry, STI/SPFA has been involved in reviewing the Spill Prevention, Control and Countermeasures (SPCC) regulations that apply to facilities with aggregate capacity of 1,320-gallons in containers of 55-gallons and larger.
He pointed out that the rule (40 CFR Part 112) applies to facilities that store oil in regulated amounts such as animal and vegetable oils, natural gas condensate, transformer oils, lacquer paints/varnishes, and other petroleum-based oils.
He estimated that more than a million facilities could fall under the rule, which requires an in-depth spill plan. Compliance dates are being clarified at this time. Dates under consideration will affect new facilities and those already established.
Another storage tank issue STI/SPFA addresses is testing aboveground tanks for integrity using certified STI or API inspectors. Testing should include a regular schedule for inspection and a visual inspection combined with another testing technique, such as hydrostatic, ultrasonic, radiographic, acoustic emissions, or other nondestructive shell testing. In addition, the outside of tanks should be inspected frequently by the owner, Travelstead said.
STI/SPFA addresses many storage tank issues on its Web site at steeltank.com. Travelstead and the committee will not rest on their laurels, but plan to continue in their efforts.