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EGG Vapor Sampling (VS) Gregg In Situ, Inc. performs vapor sampling using either a post run sampling system or a specially designed filter probe attached to the piezocone. Both vapor sampling probes are pushed with the hydraulic ram on the CPT or the Ram -Set system. The post run system uses a one foot sampler that is pushed in the closed Post Run Discrete position, Figure VS. Once the sample Soil Gas Sampler In -Line interval is achieved, 1/4 inch tubing is Gas Sampler attached to a specially designed coupling mechanism and lowered down the center of the push rods. When the tubing is coupled' with the sampler, the sampler is retracted to � expose a stainless steel filter screen and the Filter sample is pulled to the surface via a vacuum.ii�i� pump, Figure VS2. After the sample has been taken, the sampler is withdrawn from the test hole, decontaminated and ready to re -deploy. The second method involves using real time lithology measurements to determine appropriate sampling locations on site. The CPT sounding is then stopped at a determined interval to collect soil gas '4 samples. The soil gas module is attached to the cone approximately two feet behind the cone tip and consists of a stainless steel Closed Open filter that is slightly inset from the module to Position Position help prevent soil smearing, Figure VS. 1/4 inch tubing is pre strung through the rods Figure VS and is attached to the sampling module. As the module is advanced, positive pressure is applied to the sample line between sample depths to purge the line and to keep the filter clear. Once the sample interval has been achieved the positive pressure source is shut off and the line is purged by the vacuum source, generally 2 to 3 times the tubing volume. The sample is then collected into either a TEDLAR bag, SUMA canister or a syringe, Figure VS2. The resulting benefit is that the sounding can continue without removing the sampler from the hole between samples.