API 4775 : 2009

Abstract
1 Introduction
2 Background
3 Approach
  3.1 Conditions Simulated
  3.2 Multi-Component Mixture Vapor Source
4 Results and Discussion
  4.1 Effect of Source Concentration
  4.2 Effect of First-Order Biodegradation Rate
  4.3 Effect of Source Depth
  4.4 Effect of Building Type
  4.5 Results and Discussion for Multi-Component
      Gasoline Sources
5 Evaluation of Additional Parameters
  5.1 Effect of Soil Type
  5.2 Effect of Foundation Crack Location
  5.3 Effect of a High Moisture-Content Soil Layer
6 Discussion
  6.1 Development of a Conceptual Model
  6.2 Preliminary Screening
  6.3 Site-Specific Assessments
7 Conclusions and Recommendations
  7.1 Conclusions
  7.2 Recommendations
8 References
Appendix A - Predicted Soil Gas Pressure Field and Air
             Flow Rate into the Building
Appendix B - Plots of Attenuation Factors as a Function
             of Source Concentration, Depth and First-order
             Biodegradation Rates for Basement Scenarios
Appendix C - Plots of Attenuation Factors as a Function of
             Source Concentration, Depth and First-order
             Biodegradation Rates for Slab-on-grade
             Scenarios

Defines results from 3-dimensional numerical model simulations of vapor intrusion for petroleum hydrocarbons to assess the influence of aerobic biodegradation on the attenuation factor for a variety of source concentrations and depths for buildings with basements and slab-on-grade construction.