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STANDARD OPERATING PROCEDURE FOR SUBSLAB VAPOR SAMPLING <br /> 1.0 PURPOSE <br /> This standard operating procedure (SOP) describes the procedures for collecting subslab vapor <br /> samples using evacuated stainless-steel Summa canisters for the purpose of assessing risk to building <br /> occupants. The SOP is modified from procedures and information presented in Cal/EPA 2012 <br /> (Advisory-Active Soil Investigations); CaVEPA 2011; Cal/EPA 2010; U.S. EPA, 2006; and DiGiulio, <br /> 2003. This SOP includes (a) real-time leak-check procedures to evaluate integrity of the soil gas <br /> probe and sampling assembly during probe purging and post sampling, and (b) real-time field <br /> screening of soil gas concentrations during probe purging and post sampling. <br /> 2.0 REQUIRED EQUIPMENT <br /> • Hammer drill with 1"bit and smaller bits(slightly larger than vapor probe tubing) <br /> • Tubing for cleaning boring <br /> • Stainless-steel or Teflon vapor probe tubing with Swagelok threaded compression fitting, <br /> vapor-tight cap,and valves. <br /> • Rubber stopper or Teflon disk <br /> • Granulated bentonite,bentonite pellets and cement <br /> • Vacuum pump with adjustable rotameter for purging and leak testing <br /> • 1-Liter Summa canister for each sample <br /> • Stainless-steel sampling manifold with vacuum gauges and critical orifice flow restrictor <br /> (request that laboratory leak-check sampling manifold prior to mobilization) <br /> • Leak-check compound(e.g.helium) <br /> • Helium gas analyzer(calibrated) <br /> • Calibrated photoionization detector(PID)or other organic vapor analyzer <br /> • Isobutylene for PID calibration <br /> • Tedlar bags(for helium measurement and vapor screening) <br /> • Vacuum chamber(iron lung)for pre-and post-sampling leak-check <br /> • Leak-check enclosure(bucket with hydrated bentonite pellets [or weather stripping] for <br /> sealing enclosure to surface and openings for vapor probe tubing,helium and for <br /> sampling enclosure atmosphere) <br /> • Recordkeeping materials <br /> • Latex or nitrile gloves <br /> 3.0 PROCEDURES <br /> 3.1 Boring Clearance <br /> Prior to installing subslab vapor probes,ensure that a utility clearance has been conducted to <br /> ensure that potential subsurface utility and rebar locations have been identified and marked. <br /> 1 <br />