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Geosyntec O <br /> consultants <br /> 4 SUMMA CANISTER LEAK TEST <br /> Valve V-1 and V-4 will be closed and then valve V-3 (summa canister valve) will be opened to <br /> induce a vacuum on the sample train. Valve V-3 will then be closed to leave a vacuum of about <br /> 30 in Hg in the sample train. The vacuum in the sample train will be observed for a short duration <br /> (30 seconds) to ensure it does not dissipate as a final check that the sample train does not contain <br /> any leaks. Valve V-1 will then be opened and the sample collection time recorded. The vacuum <br /> gauge on the Summa canister should be monitored and closed when the residual vacuum in the <br /> canister is about 5 in Hg. <br /> 5 BLANK SAMPLES (OPTIONAL) <br /> Blank samples will be collected based on the project specific data quality objectives. <br /> An equipment blank is collected by connecting a Summa canister to a fully assembled soil gas <br /> probe(screen,tubing,and valve)prior to installation,via Swagelok fittings through a 200 milliliter <br /> per minute (mL/min)flow controller. The Summa canister valve is opened to draw the contents of <br /> the tubing and outdoor air into the canister through the probe tip and Swagelok valve. <br /> Trip blanks are required by some jurisdictions and consist of a unused Summa canister being sent <br /> by the laboratory to travel with the primary laboratory samples and then being returned to the <br /> laboratory unused. The laboratory will then proceed to analyzed the contents of the Summa <br /> canister. <br /> 2 January 2020 <br />