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5.3.2 Step-by-Step Procedures for Soil Gas Sampling Using Sampling Manifolds These procedures are for a typical soil gas sampling application;actual field conditions and procedures may vary. Before you get to the field: 1. Verify contents of the shipped package (e.g., chain-of-custody, canister, particulate filter and flow controller) 2. Verify the gauge is working properly 3. Verify the initial vacuum of canister When ready to sample: Leak Check Test 1. Confirm that canister valves are closed(knob should already be tightened clockwise) 2. Remove brass caps from both the sample canister and the purge canister (unless using certified media there is no difference between the two) 3. Attach manifold to canisters 4. Confirm that there is a brass cap secured at the inlet of the manifold creating an air tight train,make sure the manifold valve above the purge canister is open, and quickly open and close the purge canister valve in order to check for leaks. If the needle on the gauge drops,your train is not airtight. In this case, try refitting your connections and/or tightening them until the needle holds steady Purging 5. Once the sample train is airtight remove the brass cap from the manifold inlet, connect the tubing from the sample port using a compression fitting and open the purge canister valve, 1/2 turn 6. Monitor integrated sampling progress periodically. *Please note, because the purge canister is Inline after the flow restrictor the line will not purge faster than at a rate of 167mis/min 7. Once the desired purge volume is met close both the manifold valve and the purge canister valve by hand tightening the knobs clockwise S. If sampling at multiple locations, the purge canister can be disconnected from the manifold and used to begin purging the next sample location without compromising the sample train 24