Vapor Intrusion Mitigation Systems – A simplified approach for calculating radius of influence and building specific attenuation factors
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Geosyntec developed the high volume sampling (HVS) method a decade ago (McAlary, 2010) and since that time we have conducted hundreds of HVS tests.

Geosyntec has a large data set from a variety of sites that has been evaluated using a 2-layer flow model that can calculate a radius of influence of a mitigation system based on mass flux and calculate building specific attenuation factors.  The presentation will describe a new simplified method to calculate the mitigation system radius of influence and building-specific attenuation factors using data collected during pressure-field extension testing. 

The analysis is based on three simple measurements:

  1. the extraction flow rate,
  2. cross-slab applied vacuum at a radial distance of 3 feet and
  3. cross-slab applied vacuum at a radial distance of 10 ft. 

The intent is to provide a practitioner with a rapid and useful screening level assessment of whether the benefits of reduced mitigation system costs warrant an investment in a more detailed mathematical analysis of the flow and vacuum data (McAlary, 2018).  In addition, this new approach will provide a practitioner with a way to make real-time decisions regarding placement of communication test points during pressure-field extension testing.

Publication Summary

  • Geosyntec Authors: Paul Nicholson
  • All Authors: Paul Nicholson
  • Title: RemTEC, The Remediation Technology Summit
  • Event or Publication: Event
  • Practice Areas: Vapor Intrusion Assessment and Remediation
  • Citation: Paul will present at the 2021 RemTEC Virtual Summit on March 9-11, 2021.
  • Date: March 11, 2021, 1:50-2:15 p.m. ET
  • Location: Webinar, Virtual Conference
  • Publication Type: Platform Presentation