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APPENDIX E -FIELD PROCEDURES <br /> VAPOR EXTRACTION TEST FIELD PROCEDURES <br /> 1. During each VET, soil gas is extracted from the extraction well at a steady vacuum and <br /> flow. The extraction well is monitored for applied vacuum (with a Magnahelic pressure <br /> gage), and for flow rate (with a pitot tube and Magnahelic pressure gage). Various <br /> observation wells are monitored for any field observed vacuum response that occurred in <br /> these wells during each step of the test with the use of Magnahelic pressure gages. The <br /> vacuum is increased at distinct "steps" during each VET. Each step up in vacuum will be <br /> conducted after steady-state conditions are observed in observation wells. <br /> 2. Each step of each test will be conducted for approximately two hours or until steady state <br /> conditions in observation wells are reached, whichever comes first. Should no response <br /> be recorded in observation wells within two hours, the next step will be initiated. Vacuum <br /> measurements will be recorded on surrounding vapor extraction and groundwater <br /> monitoring wells during the conduct of each VET. <br /> 3. Soil vapor samples are collected from extraction wells during the VETS. The soil vapor <br /> samples are collected from the influent vapor stream in Tedlar bags with the use of a <br /> sample pump and quarter-inch Teflon tubing. Samples will be screened in the field using <br /> a Horiba model MEXA-554JU infrared gas analyzer. Selected samples will be retained <br /> and submitted to a laboratory for analysis. <br /> 4. Following completion of the extraction portion of a given VET, the system is shutdown, <br /> and recovery vacuum measurements are recorded at the extraction and observation <br /> wellheads. Following recovery of subsurface vacuums to pre-test values, the next VET is <br /> started. <br /> Radius of Influence Estimate <br /> The radius of influence of vapor extraction will be estimated by plotting a "best-fit" line for the <br /> observed vacuum response versus the distance from the extraction well. An observed radius of <br /> influence corresponding to a vacuum response of 0.1 in. H2O will be read from the best-fit line. <br /> The method of fitting the "best-fit" line involves the use of a linear regression of the plotted data. <br /> The linear regression analysis will calculate a y-axis intercept and a slope of the "best-fit" line, <br /> and plot the linear regression line on the distance versus vacuum response graph. <br /> FREY Environmental, Inc. 1092-01 <br />