Chapman Engineering pioneered a unique and powerful UST leak detection method in 1988-1989. Patented in the United States (U. S. Patent #5,003,813), this method uses a specialty porous polymer product to adsorb fuel vapors or liquids for monthly analysis and reporting. The company now provides the following UST services:

Fuel Finder™ UST Leak Detection [ View Fuel Finder™ Schematic]
This patented process gives the UST owner or operator the most sensitive and accurate leak detection service available. It is a service. No expensive equipment is required. Instead, only a minor investment is made for sampling wells followed by monthly service fees. A site is never shut down for testing. Fuel Finder™ is accepted by U. S. EPA, Texas, and most states in the U. S. An “Independent Review” to EPA specifications was conducted by Carnegie-Mellon University in 1993.

UST Compliance Checks by Trained Technicians and Engineers
Are you prepared for a regulator’s audit? State agencies, U. S. EPA, even local authorities like City Health Departments and State or Local Fire Marshals have the right to inspect your tank systems, records, and insurance policies. We can provide a “Compliance Check” that shows how ready you are, how “compliant” with the rules you are.

Cathodic Protection System Design, Installation And Testing – Not Just for UST’s!
The United States and other countries rely heavily on metal storage tank systems and pipelines for fuels and chemical storage and transport. These metal structures require protection from corrosion. Chapman Engineering designs, installs and provides ongoing testing for “cathodic protection” systems – the systems that protect such metal structures from rust or other corrosion failures. See NACE standards.

U. S. EPA and state regulatory agencies require UST systems to be properly protected against corrosion. Chapman Engineering has designed, installed, and maintained hundreds of these “CP” systems in Texas. We regularly confer with regulators.

Fuel Fingerprinting by Fuel Finder™ Laboratory Work

Chapman Engineering has for years performed evaluation of "fuel fingerprints." Other writings at this site describe gasoline and diesel fuels in some detail. To put it simply, gasoline is a mixture of up to 600 separate chemical compounds, most of which are naturally occurring in crude oils. Diesel is a mix of more 1,200 chemical compounds.

Gasoilne is typically described as a mix of compounds that fall in the "C4" to "C12" range. The "C" with number describes a molecule with that number of carbon atoms in it. The simplest C4 chemical is butane, the fluid used in most lighters. A C12 molecule is around three times larger than a C4 molecule, as it has three times more carbon atoms.

The higher the C-number, the larger the molecule, and the higher the temperature typically has to be for that chemical to evaporate, or to ignite. If gasoline is a liquid made mainly of C4 to C12 molecules (and most are between C6 and C10 in size), it is much more readily evaporated, and ignited, than diesel fuel. Diesel is made up mostly of the C12 to C28 molecule sizes, so one can quickly appreciate how much less volatile diesel must be than gasoline.

Aviation gasoline is probably the most volatile fuel mix found with any regularity at "petroleum storage tank" (PST) sites. It is a mix of C4 to C8 chemicals, and is therefore extremely volatile, and quite easy to ignite. Once ignited, it burns very rapidly.

Considering just these three fuel types, one may imagine that if each is released to the environment, changes take place in the liquid mix in different ways. Aviation gas, if spilled on a concrete tarmac, will evaporate quite quickly depending on ambient temperature and other effects, If it is leaked underground, much of the fuel mix will still evaporate and migrate away from the release point. A sample of the remaining liquid can be analyzed and compared to the original liquid. Some significant differences will be seen, but so also will there be similarities that strongly suggest the two are related.

Gasoline released to the subsurface undergoes a lot of change, much related to evaporation. Some is also related to travel distance downward through the soil column, and if ground water is encountered there is further, "preferential separation" of some compounds into ground water. So the comparison of a new gasoline to samples from underground can show some very significant differences. And, given that multiple grades of gasoline are often stored at the same site, and grades change with seaons and with different refinery "runs", and even change in composition by refiners over the years, a direct matching of a new product with released residues can be difficult. Chapman Engineering has, over the years, isolated chemical "peaks" in analysis and tied them to the addtivie complexes blended into new fuels by the branding companies.

Diesel fuel tends to weather -- that is, to change -- in the subsurface much more slowly than gasoline. But it does change. Chapman Engineering compares diesel residues by the loss -- mainly from evaporation -- of the lighter chemicals in the diesel mix, usually in the C9 to C11 range. Diesel has a very small fraction of these liquids in it as a new fuel. If they are present in a sample from the subsurface, it is likely that a new product leak is present, whether as a drip within a dispenser cabinet, from plumbing or gaskets in a submersible pump, or due to a crack in a spill protection bucket. Holes in UST's are not often found any more, provided that a system has been built since 1988, or upgraded and maintained properly.

For Texas storage tank registration records, click here.
For EPA rule requirements, click here.