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Dec 16 04 04:51p Cr.@CL CR <br />Introduction <br />916m&91-1177 p.3 <br />Tracer Tight® Method <br />of Tightness Testing for <br />Underground Storage Tank Systems <br />in Accordance With <br />Section 2644.1 <br />Enhanced Leak Detection <br />Section 2644.1 clarifies that "Enhanced" leak detection means a test method that <br />ascertains the physical integrity of an underground tank system by introduction, and <br />external detection, of a substance that is not a component of the fuel formulation that is <br />stored in the tank system." It further requires that the "test method shall be third party <br />certified, in accordance with section 2643(f), for the capability of detecting both vapor <br />and liquid phase releases from the underground storage tank system. The enhanced leak <br />detection test method shall be capable of detecting a leak rate of at least 0.005 gph or <br />less, with a probability of detection of at least 95% and a probability of false alarm no <br />greater than 5%." <br />Concept <br />Tracer Tight® is a unique method of testing underground storage systems for tightness. A <br />unique chemical called a tracer is added to the product stored in the tank. The tracer is an <br />inert chemical that evaporates readily from the fuel. After tracer is added to the system, it <br />is distributed between the vapor and liquid inside the tank. Use of the system carries the <br />tracer throughout the piping. If any small leak exists in the system, the tracer is allowed <br />to escape from the system, either as a vapor or as a dissolved component of the liquid. <br />Once outside the system, the dissolved tracer evaporates from the liquid and the tracer <br />vapors begin to migrate away from the location of the leak in all directions. After an <br />appropriate waiting period, the tracer vapors are detectable at least ten feet or more away <br />from the leak in all directions. Samples of air collected from the soil within the radius of <br />detection of the tracer reveal the leak as a presence of the tracer chemical. Because the <br />tracer chemical is not normally found in the environment or in fuel products, the Tracer <br />Tight® method is able to discriminate between previous contamination and current <br />leakage. <br />