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Mr. Jim Barton RWQCB March 29, 2013 Page 9 iii) The criterion for passing the leak test is 10 percent of the soil pump vacuum or 2.1 in Hg. 6) Remove a clean soil gas probe from the clean storage area. Probes consist of a pointed tip to which a 3-inch-long stainless steel screen and tubing connector are attached. The screen is protected by a moveable outer casing that slips over a projection on the back of the solid tip to form an air tight attachment to the tip. This seal maintains.-a closed system while the sample probe is sent downhole, and provides a mechanism to expose the screen when the sample depth is reached (by pulling up on the outer casing). a) If the probe needs to be decontaminated, the standard decontamination procedure will be followed. 7) Attach the sampling probe to new-0.25-inch-diameter Teflon tubing (tubing will not be reused). 8) Attach the other end of the Teflon tubing to the Sample T. 9) Aboveground leak test the whole sample -train (Sample T, attachments to the SUMMA canister, tubing, and probe) by applying maximum vacuum and observing whether vacuum is maintained at the maximum reading for I minute. a) If the setup fails the leak test, add Teflon tape to the sample tip connection and retest. b) The system passes .if maximum vacuum stays within 10 percent of the SUMMA vacuum or 2.1 in Hg for I minute. 10) Disconnect the Teflon sample tubing from the Sample T and pass the Teflon tubing through a sample rod until .the soil vapor tip reaches and slips into the rod annulus. 11) Continue slipping the sample tubing through successive sample rods.until the rods reach the total depth of the.borehole (2 feet above the sample depth). The rods may need to be'driven to reach the total depth. 12) When the rods need to be driven, the sample tubing is slipped through a drive cap attached to the last sample rod. Continue adding rods until the targeted sampling depth is reached. 13) Remove the drive cap from the upper sample rod,,add a pull cap, and reattach the Teflon sample tubing to the Sample T. 14) Open the valve to the sample tubing and apply vacuum using the sample pump until the maximum is reached. Leak test the downhole sampling system.