equipment: UST or AST?: A Steel Tank Survey Helps You Decide

Bob Deierlein

Aboveground storage tanks (ASTs) are said to have grown in popularity by 100 percent in the last five years. But are ASTs best for your fleet? The following outline from the Steel Tank Institute, Lake Zurich, Ill., can help you make the decision: 1. What impact will fire codes or regulations have on your decision? National model fire codes generally dictate AST design and installation criteria for flammable and combustible liquids storage. The four major codes are: * Uniform Fire Code (UFC) Appendix II-F, published by the International Fire Code Institute;

* 30 and 30A of the National Fire Protection Association (NFPA);

* National Fire Prevention Code of the Building Officials and Code Adminstrators (BOCA); and

* Standard Fire Prevention Code of the Southern Building Code Congress International (SBCCI).

Check with your local authority having jurisdiction to see what codes or combination of codes they follow. Codes are constantly changing; be sure to determine which version is required in your area. Federal AST regulations are not yet in place, but it is likely that there will be legislation covering ASTs as well as underground storage tanks (USTs).

USTs must comply with federal regulations found under 40CFR Parts 280 and 281, as well as local and state regulations which may be more stringent.

Requirements include leak detection, corrosion protection and spill and overfill prevention measures. Currently, all new USTs must have leak detection systems.

2. Do local fire codes allow ASTs? For example, some codes do not allow fuel dispensing from ASTs at retail sites, but do allow fuel dispensing from ASTs for private fleets.

3. Are double-wall underground tanks required by local regulations or codes? Some jurisdictions do require double-wall USTs, which also may offer advantage of lower insurance rates.

4. Is there enough room on the property for an AST? Check the separation distances required by various codes - each code dictates how closely an AST can be located to buildings, property lines, public ways, dispensers and filling points.

5. Are fire-resistant or fire-protected tanks required? A fire-protected tank may allow reduced separation distances, offering greater flexibility in site selection. On the other hand, USTs generally are not a fire concern.

6. How important are concerns of aesthetics or vandalism? ASTs are visible and therefore are more prone to vandalism. USTs are not visible, improving the "look" of the location and decreasing the possibility of tank damage.

7. How much manpower are you willing to invest in tank maintenance? Exposure means that ASTs must be visually inspected and maintained. Open dikes collect rainwater, snow and possible debris. USTs do not require this kind of maintenance, although cathodically-protected USTs require monitoring of the cathodic protection system every three years.

8. What is the tank's desired capacity? Most codes limit the AST size, particularly for fueling applications. An AST's size and configuration will influence filling procedures, as accessibility to the tank's top is affected. Remote filling may be preferable to avoid the need to climb ladders or stairways. These considerations require more space or lower capacities. The tank's shape also will impact this decision; cylindrical tanks, while higher in profile, may be smaller in footprint than rectangular tanks, which tend to be lower with a wider footprint.

Using compartments, USTs can reduce installation and equipment costs dramatically, while providing increased storage capacity.

9. Are you able to meet the financial responsibility requirements of the EPA UST regulations? Insurance, state trust funds (if in place and solvent) and self-insurance are some means to this end. If these options are not desirable, consider an AST.

Clarification: In World Wastes, December 1997, page four, the editor reported that the city of San Diego sold its solid waste system. In fact, it was the county of San Diego, not the city.