Soil Vapor Sampling
Geoprobe® has always had a lot of experience with soil gas. Our direct push machines were initially designed specifically for soil gas sampling. Our first set of tools were manufactured to extract vapor samples from our backyard.
Before Geoprobe® tools and equipment were available, most soil gas collection was done by manually advancing NPT pipe into the ground surface using a slam bar, often followed by using a car-type jack to remove the NPT pipe. Not a pretty picture, but it got the job done.
During our early years, we developed an expendable point holder and probe rods. Once at depth, the probe rods were retracted a set distance to aid in sampling the soil vapor from the created void. A vapor sampling nipple was then attached to the top probe rod, and a sample was collected by applying vacuum to the entire rod string and evacuating a volume equivalent to a minimum of three times the system volume. Even though this was an improvement over former methods there were still some limitations and drawbacks.
And then we made it easy...
We then developed a simple, quick, cost effective method for conducting soil gas surveys. This active sampling method is based on the Post Run Tubing (PRT) system of sample collection. Using the post run tubing and PRT adapter with O-rings eliminated concerns about system leaks at threaded joints. The PRT method also decreased labor costs, time requirements, and decontamination fluids generated for sample collection.