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T e� SOIL VAPOR SURVEY METHODOLOGY Active Sail Vapor Sampling System TEG's proprietary, law-dead volume sail vapor sampling system has been inspected; endorsed, and is favored by all regulatory agencies who have seen it, including the E?A. The design eliminates the risk of air leakage down the soil vapor probe, ensures sample collection from the Up, and greatly facilitates decontamination procedures. Probe Construction TEG's sail vapor probes are constructed of 518 inch outer diameter chrom-moty steel, equipped with a hardened reverse-threaded steel tip. The Straiaprobe uses a larger diameter probe. Nominal lengths are 4 or 5feet, although additional lengths may be added. An inert 118 inch nyiaflow tube runs dawn the center of the probe to sampling parts beneath the tip. Probe Insertion he probe is driven into he around with ccu s truck-mounted hydrauliclvibratio nal system, an electric rotary hammer, or, with the Strataprobe. Once inserted to the desired depth, the probe is i rotated in a clockwise direction, or retracted slightly, which opens the tip and exposes the vapor i sampling pacts. This design prevents clogging of the sampling parts and cross-contamination from sails during insertion. i Sail Gas Sampling j t Soil vapor is withdrawn from the nyiaflow tubing using a small calibrated syringe connected via an i on-off valve. The first 5 dead volumes of gas are discarded to flush the sample tubing and fill it with in-situ sail vapor. The next Zo = of sail vapor are withdrawn in the syringe, plugged, and immediately transferred to the mobile lab for analysis within minutes of collection. Additional t sails vapor may be ccilected and stored in gas-tight containers as desired. _ Flushing & pecarrtamination Procedures 1 To minimize the potential for cross-ccntamination between sites, all external probe parts are cleaned of excess dirt and moisture prier to insertion. The internal nyiaflow tubing and sampling ports are flushed with hundreds of ct s of ambient air between samples. If water, dirt, or any material ,is observed in the tubing, the tubing is replaced with fresh tubing. If moderate concentrations are detected for any compound, the tubing is replacad. Sampling syringes are opened and purged to remove any volauies after =act use. If moderate cancantmticns are detected for any c--mcound, the syringe is discarded. Transdobal Environmentai Gecchemistry 11;50 Monier Park Placa, Rancho Cordova, C; 45742 ^rhone: (916) 853-aata Fax: (916) 853-8020