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i 0 <br /> DTSC VAPOR SAMPLING PROCEDURE <br /> Assuming location is clear of utilities, advance vapor sampler (GeoProbe, Post a�� <br /> Run Tubing sampler) to specified depth. <br /> Retract sampler four-inches and advance ''/.tubing with connector attached down <br /> the center of the rod. <br /> Cut tubing a foot long, attach two-way stop valve (valve closed). Reverse screw <br /> the tubing until tight. <br /> Give a light tug to assure connector is seated. <br /> Apply previously hydrated bentonite to rod at ground level to seal and let stand <br /> 20 minutes. <br /> Install flow controllers to sample canister and purge canister. <br /> Install "T"fitting and two-way shut-off valves, connect with tubing. Check to <br /> assure shut-off valve closest to rod is closed, open all other two-way valves. <br /> Open purge canister briefly and close. This will pressurize the Niue. Take nale of <br /> the pressure gauge, pressure should hold. Continue for 10 n*%tBs. IfpresWe <br /> drops, tighten frttings and try again. Repeat until pressure holds for 10 rte. <br /> Once leak test is complete and 20 minutes has elapsed (far berdw*e seaq, <br /> close valve to sample canister and open down hole valve. <br /> Open purge canister, purge one to three volumes of tubing. When purge is <br /> complete, close canister and purge shut-off valve. Open valve for sampler <br /> canister and two-way valve. <br /> NOTE BEGINNING READING ON GAUGE (flow controller): it should be <br /> between 30" and 25"of mercury. <br /> Begin swabbing fittings with cotton swabs (or paper towel) dabbed with Pt% <br /> isopropyl alcohol <br /> Continue every five minutes until mercury level drops to ftve-jt ,• 'rrna <br /> we <br /> vary upon flow controller settings (norm* 30 or 60 minutes)and may als4be <br /> affected by the lithology, clays, sands, etc. <br /> EGG <br /> TO 30Vd 9NIIII2IG 993J9 ZOE0STESZ6 ZE:LO LOOZ/ET/60 <br />