- WEB EXCLUSIVE
- PE COFFEEHAUS
The EPA in a Federal Register notice on Tuesday, July 5, 2011, issued its final guidance on how owners and operators of underground storage tanks (USTs) can demonstrate compliance with the federal compatibility requirement for UST systems storing gasoline containing greater than 10-percent ethanol or diesel containing greater than 20-percent biodiesel.
The Federal UST regulation in 40 CFR part 280 addresses preventing and detecting UST system releases; the provision in 40 CFR 280.32 requires the UST system be compatible with the substance stored. As the United States moves toward an increased use of biofuels, including ethanol and biodiesel, compliance with the UST compatibility requirement becomes even more important, since biofuel blends can compromise the integrity of some UST system materials.
According to the agency, as of Sept. 30, 2010, there are approximately 600,000 regulated USTs at 215,000 facilities nationwide. Based on the size and diversity of the regulated community, the EPA believes states are in the best position to implement UST program requirements, and are therefore primarily responsible for the implementation of the UST program. Subtitle I of SWDA, as amended, allows state UST programs approved by the EPA to operate in lieu of the Federal UST program. In order for the agency to approve a state's program, that state's regulations must be at least as stringent as the federal UST regulations.
As defined, a UST system includes an underground storage tank, connected underground piping, underground ancillary equipment, and containment system, if any. Ancillary equipment includes "… any devices including, but not limited to, such devices as piping, fittings, flanges, valves, and pumps used to distribute, meter, or control the flow of regulated substances to and from an UST."
Fuel dispensers are not part of the UST system as defined by 40 CFR 280.12. This means the compatibility requirement in 40 CFR 280.32 does not apply to dispensers.
The notice notes that the EPA understands that the chemical and physical properties of ethanol and biodiesel can be more degrading to certain UST system materials than petroleum alone, so it is important to ensure that all UST system components in contact with the biofuel blend are materially compatible with that fuel. Industry practice has been for tank owners to demonstrate compatibility by using equipment that is certified or listed by a nationally recognized, independent testing laboratory, such as Underwriters Laboratories (UL). However, based on the agency's understanding of UL listings, many UST system components in use today, with the exception of certain tanks and piping, have not been tested by UL or any other nationally recognized, independent testing laboratory for compatibility with ethanol blends greater than 10 percent. In addition, the EPA is not aware of any nationally recognized, independent testing laboratory that has performed testing on UST system components with biodiesel-blended fuels. Absent certification or listing from a nationally recognized, independent testing laboratory, or other verification that equipment is compatible with anything beyond conventional fuels, the suitability of these components for use with ethanol or biodiesel blends comes into question.
Certain tanks and piping have been tested and are listed by UL for compatibility with higher-level ethanol blends. Many other components of the UST system, such as leak detection devices, sealants, and containment sumps, may not be listed by UL or another nationally recognized, independent testing laboratory for compatibility with these blends.
Although there is little information available regarding the compatibility of UST system equipment with biodiesel blends, there are known compatibility issues for pure biodiesel (B100). According to the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) Biodiesel Handling and Use Guide, Fourth Edition, "B100 will degrade, soften, or seep through some hoses, gaskets, seals, elastomers, glues, and plastics with prolonged exposure… Nitrile rubber compounds, polypropylene, polyvinyl, and Tygon materials are particularly vulnerable to B100."
In contrast, the properties of very low blends of biodiesel (B5 or less) are so similar to those of petroleum diesel that ASTM International considers conventional diesel that contains up to 5 percent biodiesel to meet its "Standard Specification for Diesel Fuel Oils" For biodiesel blends between 5 and 100 percent, there is very little compatibility information; however, NREL's handling and use guide concludes that biodiesel blends of B20 or less have less of an effect on materials and very low blends of biodiesel (for example, B5 and B2) "…have no noticeable effect on materials compatibility."
Fleet service sites have stored B20 in USTs for years, and the EPA is not aware of compatibility-related releases associated with those USTs storing B20. Based on these experiences, some states developed UST compatibility policies similar to today's final guidance, and they chose a mix of thresholds: B5, B10 and B20.
SOURCE: Federal Register