Field Life Easier: Soil Gas Sample Collection with Merit Labs’ Helium Shroud

Soil gas sampling is easier with Merit Laboratories’ helium shroud. Working closely with our client’s field sample collection needs in mind, Merit developed a helium shroud that makes soil gas sampling more efficient, accurate, and reproducible. And don't worry about tools or calibration in the field. Merit’s helium shroud requires no tools or field calibration. The helium shroud's quick-connect ports are proven time savers in the field. We make it easier.

The helium shroud is packaged in its own self enclosed transport container, providing clients with an easy-to-transport kit in the field. Following the instructions provided with each helium shroud, sample collection professionals are ready to sample in just a matter of minutes. Additionally, the shroud contains two helium meters allowing field staff to see the concentration in the shroud and in the line.

Merit’s helium shroud and sampling kit includes:

  • Interior helium detector (measuring in % helium using thermal conductivity)

  • Exterior helium detector (measuring in % helium using thermal conductivity)

  • Exterior flow pump 

  • Interior flow controller connection to the exterior flow pump

  • Access port in the bottom of the shroud for connection of sampling line to the flow controller

  • A 60mL syringe (to test for liquid in the well)

  • Helium tank

The helium shroud has been used by Merit’s clients for several years with great success at locations throughout the United States, from California to New York. Testing the soil gas sampling chain and well in a helium-enriched atmosphere quantifies that there has been no breakthrough of air at the sampling location, confirming that a valid soil gas sample is being collected. It should also be noted that using helium does not impact the target volatile organic compounds in laboratory testing.

Some other helium shrouds require the user to purge the well using a 60mL syringe pulled at a constant flow-rate of 200cc per minute.  This is much more difficult than it seems.  Merit alleviated this challenge by using a pump calibrated to exactly 200cc per minute allowing users to simply flip a switch and start a timer to purge the well.

After each trip to the field, the helium shroud is returned to Merit where it is inspected, cleaned, tested, and repackaged for transport.

As a national leader in environmental testing, Merit Laboratories performs laboratory testing to support air projects.  Analytical testing performed by Merit includes the analysis of Volatile Organic Compounds (VOCs) by EPA Method TO-15. Merit is NELAP-accredited for the analysis of VOCs by TO-15.  The laboratory maintains a large stock of sample collection media to support air projects, including bottle vacs, summa canisters, flow controllers and helium shrouds.  Please contact Merit to learn more about how we can support your air project testing needs.