By Keith Reid

Fuel compatibility has been a core component of the underground storage tank regulations since they were finalized in 1988: “You must use an UST system made of or aligned with materials compatible with the regulated substances stored in the UST system.”

This has been a moving target as fuel composition has changed dramatically over the years to include today’s biofuel blends, and especially since these blends are being fielded at ever higher concentrations. Keeping track of specific regulatory requirements can be an enormous headache. To help tank operators keep abreast of their fueling systems EPA has developed several new information sources.

The 21-page booklet UST System Compatibility With Biofuels acts as an primer on the basic requirements of the regulation and specifically the revisions that took place in 2015. As the title suggests, it is heavily focused on contemporary biofuel blends from 10% ethanol (E10) to 100% biodiesel (B100).

The booklet includes a useful compatibility checklist broken down by general fuel type and concentration relative to such issues as system compatibility, agency notification and record-keeping. These details are expanded in a simple, but surprisingly detailed, manner to answer many the questions an operator of might have relative to such approaches as meeting a specific compatibility requirement through the use of an alternative that might be allowed by an implementing agency. It goes into such detail areas as nuanced as the compatibility of pipe dope and sealants.

One interesting point discussed was the relationship between compatibility versus functionality for release detection equipment. The brochure noted that a piece of equipment might be compatible in the sense that its components maintain their physical properties when exposed to a fuel mixture. However,  that fuel’s properties—such as ethanol’s ability to absorb water— might in some cases interfere with the equipment’s ability to actively determine the conditions inside the tank compared to a different fuel composition. Therefore, equipment must be both compatible and functional with the specific fuels. It references protocols updated in 2019 to help manufacturers to verify that their leak detection equipment meets federal performance standards for functionality.

Operator considerations when undergoing a retrofit or upgrader are also covered, and there is a linked list of additional resources that are tank operator can take advantage of to help manage compatibility. That is particularly useful, since navigating agency websites in search of specific documents can be difficult.

For even more detail, operators can visit the webpage Underground Storage Tank (UST) Technical Compendium, that covers the 2015 UST regulation and provided some of the information in the booklet. Using a FAQ format, the webpage covers the range of common considerations such as specific system requirements, walk-through inspections, release detection, compatibility and release port reporting—to name a few.

For example, relative to spill buckets, under dispenser containment sumps and containment sumps the question is asked: “Can owners and operators use ASTM E3225- 202 meet the requirements of the 2015 federal UST regulation for spill buckets and some testing?” The short answer is no, but the webpage provides an explanation for the rationale and what is required.

Or the question: “What procedures can be used to test single walled containment sumps? Is there a procedure that tests containment sumps, does not require filling the containment sump with water to 4 inches higher than the highest penetration in the sump, and is acceptable to EPA?” The answer involves multiple paragraphs including bullet points on the three options for testing containment sumps. And yes, there are alternatives.