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Passive Soil Gas and Subslab Installation and Retrieval <br /> Standard Operating Procedure (SOP) <br /> Sampling Depth: 4 to 15 feet <br /> Augured Passive Soil Vapor Wells: <br /> Auger or drill a 1.5 or 2-inch diameter hole through the slab or asphalt(if present) and into the <br /> underlying soil or fill matrix to desired maximum depth(eg. 4 to 15 feet). Place 1-inch PVC <br /> pipes (i.e. vapor wells) cut to desired lengths (e.g. 4 ft and 15ft bgs). Place soil vapor well nest <br /> into the hole and insert completely to 1-inch below grade and clear soil/fill around well casing to <br /> place cement and well vault in accordance with standard well vault installation procedures. <br /> Backfill with sand filter or seal with bentonite in accordance with following illustrated diagrams <br /> in to meet your desired sampling depth requirements. Provided are drawings for screened passive <br /> soil vapor wells and open casing bottom soil vapor probes. <br /> Screened Vapor Probe Open Casing Vapor Probe <br /> Ground surface Concrete Apron min. 6-inch thickness Ground surface <br /> 1 Flush with grade or mounded �� 1 <br /> Flush mounted Flush mounted <br /> lockina well vaull lockinq well vault <br /> Annular Seal <br /> Cement with bentonite <br /> grout (permanent soil gas <br /> wells)or hydrated bentonite <br /> chips (temporary soil gas <br /> Blank casing 1 -inch <br /> diameter <br /> Transition Seal <br /> use tremie pipe to create 1-3 <br /> foot thick hydrated granular <br /> bentonite <br /> No. 2/16 Sand filter <br /> pack <br /> 0.02-inch screen Open casing at <br /> 1 -inch diameter bottom of vapor <br /> Schedule 40 PVC <br /> Length =6-12 inches T al Depth of Borehol� <br /> 4-15 feet bgs <br /> Screw on End Cap <br /> RECOMMENDED :subsurface <br /> For open casings, advance 1/2-inch soil <br /> diameter hole a min. of 6-inches to minimize <br /> plugging of casing during installation. 1/2 <br /> inch rebar may be used. <br /> Page 4 of 8 <br />