Equivalent Building Dimensions

CPP Wind > What We Do > Air Modeling Services > Advanced Air Modeling > Equivalent Building Dimensions
More Accurate Than BPIP & Better Inputs for AERMOD

In many cases, AERMOD will over-predict concentrations. This is because BPIP, the standard tool for determining building dimension inputs, handles many situations poorly.

For example, in some cases BPIP will:

  • Merge nearby buildings into a single building
  • Ignore or misrepresent lattice structures
  • Mishandle buildings with a low, large footprint or complex geometry
  • Ignore the effects of terrain

CPP’s Equivalent Building Dimension (EBD) procedure avoids these mistakes by starting with an accurate model of the actual site. By testing the scale-model plume behavior, CPP experts can identify the right AERMOD-ready dimensions that match the scale-model tests. The EBD method provides more accurate and often lower concentration estimates.

Plume Dispersion With The Actual Site Structure:
Plume dispersion simulated using BPIP inputs to AERMOD:

AERMOD treats porous structures as solid. EBD studies show that the building heights of porous structures should be reduced by 40%-60% for input to AERMOD.

A scientifically-based, empirically-validated tool like EBD provides advanced modeling to facilitate the permitting process while protecting air quality. In some cases, it can offer new life to projects that have been stalled by older modelling methods.

Read Our News Article About EBD

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