![]() ![]() Permeation rates increase in pressure fueling systems and decrease in suction fueling systems. A 100-foot length of two-inch diameter hose will permeate 200 to 400 gallons every year under normal temperatures, and up to 1,000 gallons if exposed to elevated temperatures along its entire length. In the hot sun, this could go as high as 500 percent of the contained volume every month.Ī two-inch diameter hose contains approximately 0.16 gallons per foot. ![]() Commercially available nitrile rubber-based hoses for curb pumps and tank trucks have been found, at equilibrium, to permeate 100 to 200 percent of their contained volume every month under normal temperatures. Over the years, we have tested a variety of hoses to find out their permeation properties. ![]() Artwork courtesy of Total Containment, Inc. Let’s take a closer look.Įxample of a piping system on a floating dock. The problems with use of rubber hose to connect the floating dock to the shore piping are primarily three-fold: excessive permeation, poor damage resistance and poor life cycle. These items are commonly used, and well accepted by most regulatory authorities. Nitrile rubber (also referred to as Buna rubber, Buna-N or butadiene-acrylonitrile rubber), tank truck hose and curb pump hose are the two most popular styles of rubber hoses used for this application. In many instances, these hoses are well in excess of 100 feet long. ![]() The conventional practice is to put an “oil-resistant elastomeric (rubber) hose” as a flexible connector between the shore and the dock. However, when the pipe hits the shore, things can really get different-especially where changes in water level are expected and the dispenser is on a floating dock (see Figure 1). Thus underground storage tank (UST) systems or aboveground storage tank (AST) systems with buried piping to the shore are almost always done in the conventional manner used in service stations and other land-based fueling facilities. Thus, permeation, pollution and system life are particularly important considerations for proper system design, and often justify the higher cost of more suitable piping systems.Ĭurrent Environmental Protection Agency (EPA), state and local regulations are very clear as to what is acceptable for the underground portion of any marina fueling system. But, many of the existing marina installations can easily put well in excess of 200 gallons per year of fuel into the water through permeation alone.Īn NPV (Net Present Value) analysis generally shows the benefit of the more expensive special marina piping systems now on the market, when system longevity and fuel loss are taken into account. After all, many claim clumsy boaters spill more fuel into the water than the worst fueling system. Marina owners (not all, but many, in our experience) often place little value on the environmental security of the marina fueling system. These systems need to be durable, permeation-resistant, flexible, fire-resistant, crush-proof, easy to install and (last but not least) economical. Especially in areas with severe periodic variation in water surface levels, such as reservoirs or oceans, the design of the marina piping system is critical to the long-term economic and environmental success of the site. With experience in designing and installing piping systems for more than 100 marina fueling facilities, we feel strongly that the piping system merits special attention and discussion. ![]()
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