Soil Gas Testing

As some of the others have said, these guys took a very scientific approach to the inspection.  Donald did our inspection and was very thorough and patient.  I peppered him with questions throughout the 3 hour process and he was knowledgeable and amenable to answering all my queries.

I like that these guys understood the science behind soil gas testing, VOCs, pollutants, and mold are well versed in scientific journal articles, in addition to the standard building construction knowledge.

how radon enters house

The air sample and mold sample reports that came back were very detailed and compared our sample against thousands of others that the lab analyzes every year.  I talked to quite a number of different air quality vendors and glad went to the best one.

Soil-gas sampling measures the gas contained in the interstitial spaces of the soil, as opposed to directly sampling the soil matrix, above the water table.

Active soil-gas collection methods (as opposed to passive soil-gas sampling) involve pulling a vapor sample from a temporary or permanent probe inserted in the soil into a collection or analytical device. Samples are then transported to a laboratory, or in some cases they are analyzed on site.

Exterior soil-gas sampling is a screening tool used to rapidly and cost-effectively identify and delineate certain volatile contaminants in the subsurface. It is often used to ascertain the source, extent, and movement of pollutants, but it is not a substitute for groundwater sampling.

Sub-slab soil-gas sampling, where samples are taken though holes in buildings concrete slabs, is used to determine the potential for vapor intrusion. In some cases sub-slab samples are taken to determine whether to test indoor air, while in others it is conducted concurrently with indoor-air sampling to evaluate whether the subsurface is the source of indoor contaminants.

There are several types of soil-gas sampling instruments, including:

á    The Vapor Pin® is a one-of-a-kind, patented, re-useable sub-slab soil gas sampling device designed for the environmental consulting community. Traditional sub-slab soil-gas sampling methods are time consuming, expensive, and prone to leaks. Cox-Colvin designed the Vapor Pin® specifically to eliminate many of the problems associated with traditional sub-slab soil-gas sampling methods.

Vapor Pin Vapor Pin

á      Air-tight syringe. This is used to pull vapors from the soil matrix. The syringe is used to withdraw a soil-gas sample from a probe and inject it directly into an analytical instrument for on-site analysis. Some regulatory agencies require that samples collected by this method be analyzed within a few hours.

soil gas testing soil gas testing

á      Tedlar¨ bag. This requires a pump to pull the vapors from the soil. Regulatory agencies may require that samples collected by this method be analyzed within 28 to 48 hours. Bagged samples can also be drawn into sorbent tubes, which in turn undergo laboratory analysis.

Tedlar Bag

á      Glass bulb (or tube). This has openings at each end, with one end having a valve where samples can be withdrawn with a syringe. The vapor sample is collected by connecting one end of the bulb to the probe and the other to a pump. The advantage of glass bulbs is that the glass is inert; also they are easy to use. The limitations of the glass bulbs are that they break easily and can leak contaminants through the valves. Sample holding times for glass bulbs are usually no more than 24 hours.

 

soil gas testing

Leave a Reply

You must be logged in to post a comment.