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JAN-16-191 DIED 12:05 ID .. -X TECHNOLOGIES TEL HO:438 75 t#49e P09 <br /> of air was pumped from the extraction point. Each extraction point was <br /> tasted for a maximum of 15 minutes. <br /> The information from the Performance Test was used to determine the <br /> capture radius, the distance at which the pressure differential created <br /> by a vacuum pump is measured, in the lateral and vertical planes. The <br /> capture radius was noted by recording the vacuum gradient in neighboring <br /> probes or monitoring wells in inches of water. This procedure was <br /> performed at various flow rates at several of the probes and monitoring <br /> wells . The detection limit for the vacuum gradient was 0.005 inches of <br /> water. The effluent from the extraction points was routed through two <br /> cylinders in series, each containing 200 pounds of vapor phase activated <br /> carbon. The carbon adsorbs organic vapors from the extraction air <br /> stream, preventing discharge of contaminants into the atmosphere. <br /> Results <br /> The Performance Test was conducted on 13 March 1990 at the subject site. <br /> Extraction volumes from the probes and wells ranged from 14 to 26 cubic <br /> feet per minute (cfm) with vacuums ranging from 1 .5 to 8, 5 inches of <br /> mercury (" Kg) . The results of the Performance Test are given in Table <br /> 2. <br /> Influence was noted in both the vertical and horizontal planes. The <br /> influence in the horizontal plane was more pronounced. Capture radii of <br /> 11 feet and 23 to 41 feet were noted at the 14 to 16 feet and 32 to 34 <br /> feet below grade intervals, respectively, with extraction volumes ranging <br /> from 14 to 17 cfm. The maximum capture radius recorded at the 28 to 30 <br /> feet below grade interval was 110 feet at volumetric flow rates of 16 to <br /> 24 cfm. Influence was noted up to 110 and 147 feet between monitoring <br /> wells at extraction volumes ranging from 24 to 26 cfm. <br /> Table 2. Performance Test Data. <br /> LOCATION INFLU- EXTR PERF CAPTURE EXTR TIME <br /> ENCS RATE DEPTH RADIUS VAC <br /> ("H2O) (cfm) (feet) (feet) ("HO (min) <br /> EXTRC> MW-3 --- 26.0 28.58 3.5 <br /> J >-0, 25 32-34 23.0 �0 <br /> 0 -0.025 28-30 11 .3 0 <br /> D n 28-30 18.3 0 <br /> 8 0 14-16 28.0 0 <br /> - 5 - + <br /> 1 <br /> t <br />