Are you still calculating the height of your chimney with pen and paper?

Calculating the height of our chimney is always the eternal question in any project to design emission bulbs or to correct air pollution.

In large installations, this problem is solved by modeling the plume and its dispersion conditions in complex mathematical models, generally deterministic (of the Gaussian or Lagrangian type), piloted by various software such as the well-known CALPUFF, AERMOD, CTDM, etc. an underworld of the design of emission sources in which many of the companies, and even environmental consultants, may get lost.

However, small and medium-sized installations, with relatively small emission sources, usually do not have the means or the requirements of the administration to proceed with these “precise” mathematical models, and the most common is to resort to relatively simple calculation equations that always seek to establish a minimum guaranteed height that, depending on the emission conditions and the pollutants emitted, allows an adequate dispersion of the pollutants in the atmosphere.

Although it is true that, in this sense, each competent body has the capacity to regulate this calculation environment in the way that best seems to it, the calculation formula used by the 1976 regulations, the Order of October 18, 1976, as a simple method for calculating the height of chimneys for processes of less than 100 MW or emissions of less than 720 kg/h, continues to triumph. Perhaps it is because, in its relative simplicity of calculation, the formula is effective and guaranteed at the same time, not resulting in unaffordable heights for the company, or because it allows the heights to be adapted to investment objectives, but the fact is that even today many administrations still recognize it as one of the valid formulas.

Here we leave you with a generic tool that, using the 1976 formula, and correcting certain aspects of it to check for the presence of nearby obstacles that overturn the plume, will allow any company to know the approximate height at which it should design the focus of its production process. An intuitive tool with which, with four pieces of data, you will be able to have an idea of the requirements that will apply to your focus, and can even serve as a demonstration of calculation before certain public administrations.

Note that we insist that this tool is not valid for any site, some entities, such as the Basque Government, have their own mathematical tool, based on the German model, issued since 2002 in the form of a technical instruction, and others have come up with slightly more complete formulas compared to the 1976 one, so we insist that this tool that we now offer you is nothing more than a guidance tool that will have to be corroborated by the competent body.

We hope you find it useful. Click here to download it: Chimney Height Calculation