WORK PLANS - Laserfiche WebLink

Home Browse Search

TO E RO E K SOP No.026,REV.1 ASSOCIATES,INC INDOOR AIR AND SUB-SLAB SOIL GAS SAMPLING METHODS PAGE 8 canister vacuum reaches 2 to 5 inches of mercury, stop the sample collection, record the time, pressure reading and note specifics on the chain-of-custody, field logbook and field data sheets. If applicable, record the laboratory-provided identification numbers for the canister and regulator (typically included as a sticker on each device). 7. Label the canister and its corresponding field data sheet with the sample number. 8. Fill out the rest of the field data sheet and chain-of-custody and document all information in a field logbook. 9. Ship or transport samples to the laboratory for analysis. SUMMA® samples do not need to be chilled after collection or during transportation. During sub-slab soil gas sampling,the SUMMA®canister sampling train is connected directly to the purged Teflon®or equivalent sampling tube.To prevent ambient air from entering the canister during sample collection,all connections must be airtight.To collect soil gas samples using this method, the following procedures are used: 1. For 4-inch concrete slabs, drill a 3/4-to 1-inch diameter hole into the slab to a depth of approximately 2 inches. If the slab is thicker than 4 inches the 3/4- to 1-inch diameter hole can be extended to 2 inches above the base of the slab. 2. Clear debris from the borehole using a brush or small shop vac. 3. Drill a smaller (e.g., 1/4-inch) diameter hole from the base of the 3/4- to 1-inch hole through the slab, extending an inch or two below the base of the slab. The size of the smaller hole is dependent on the size of the soil vapor probe or tubing used to collect the sample. 4. If obstruction such as rebar is encountered, move the sample location 2- to 3-inch from the original location. Document the proximity of floor cracks, drains, sumps, or other features to the sample location in the field logbook. 5. Clear remaining debris from the borehole using a brush or small shop vac. 6. Insert new dedicated tubing or soil vapor probe to the base of the slab, taking care not to locate the base of the tubing within or atop the fill below the slab (i.e., allow an air gap at the base of the hole to prevent the introduction of debris into the sample).