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I ECOM r FIGURE 2.HAMMER DRILL WITH 7/8"MASONRY BIT 6 SAMPLING PROCEDURES 6.1 CANISTER VACUUM CHECK PRIOR TO SAMPLING The canister vacuum check will be performed for 100%of the canisters. 1. Attach the pressure gauge provided by the laboratory to the canister inlet. 1. Open valve completely. 2. Record reading. • The canister should show a vacuum of approximately-28 inches of Hg • If the canister has a vacuum of equal to or less than -25.5 inches of Hg (after adjustment for any elevation effects), then: • Label the canister with "Insufficient vacuum—No Sample"; • Set canister aside for return to the laboratory; and • Contact project manager and lab coordinator if canister failures affect field work. Close valve completely. Remove the pressure gauge. 6.2 SAMPLE TRAIN SETUP Setup the sample train configuration. The flow controller(one for each canister provided by the laboratory)will be connected to the canister inlet. • Note: Do not reuse flow controllers between locations. Each flow controller is pre-set by the laboratory to collect the sample over a two-hour period. • Flow controllers can be set to a different rate if desired by project, depending on size of container to be filled. For a 1-Liter canister set at-28 inches mercury(Hg)over a 5-10 minute period the flow rate is set at 100 to 200 ml/min. 6.3 SAMPLE COLLECTION 1. Remove the plug from the end of 1/4 line and attach a 0—0.25"Magnehelic, digital manometer, or other device for reading differential pressure. 2. Get a reading, noting whether the flow is in or out of the building.The recommended notation is: • positive sign to indicate air movement from the building into the subsurface(i.e., higher pressure in the building) • negative sign to indicate air movement from the subsurface into the building (i.e., lower pressure in the building. n--- 0 -r