Amendment of Stack Height Calculation

In the forthcoming amendment of TA Luft the nomogram as means of stack height determination is replaced by an algorithm which iteratively applies current numerical dispersion and plume rise models. The basic concept though is maintained. It guarantees "sufficient dilution" of emissions according to a special precautionary principle related definition. In effect, pollutant-specific reference concentrations (S-values) are not be exceeded in the ambient air for a set of worst case boundary conditions. The fluid mechanical prerequisites for the calculation are denoted by the legal concept of "undisturbed removal of emissions by free air flow". In its definition of insignificant mass flow, TA Luft considers emissions as diffuse emissions if they do not conform to this legal concept. For typical mass concentrations of pollutants in the waste gas flow, the new method for stack height calculation and the nomogram result in approximately equal stack heights. For low mass concentrations, stack heights according to the new method are less than nomogram stack heights. For pollutant mass concentrations as high as to by atypical nowadays at high volumetric flow rate, stack heights according to the new method are greater than nomogram stack heights.