ASTM D5719-13

1.1 This guide covers the use of a groundwater flow modeling code to simulate the movement of air in the subsurface. This approximation is possible because the form of the groundwater flow equations are similar in form to airflow equations. Approximate methods are presented that allow the variables in the airflow equations to be replaced with equivalent terms in the groundwater flow equations. The model output is then transformed back to airflow terms.

1.2 This guide illustrates the major steps to take in developing an airflow model using an existing groundwater flow modeling code. This guide does not recommend the use of a particular model code. Most groundwater flow modeling codes can be utilized, because the techniques described in this guide require modification to model input and not to the code.

1.3 This guide is not intended to be all inclusive. Other similar techniques may be applicable to airflow modeling, as well as more complex variably saturated groundwater flow modeling codes. This guide does not preclude the use of other techniques, but presents techniques that can be easily applied using existing groundwater flow modeling codes.