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Atmospheric dispersion

CNPP’s Fire and Environmental Laboratory carries out atmospheric dispersion modelling based on experimental values, particularly in hazard studies. Atmospheric dispersion modelling concerns:

Hot fire smoke dispersion:

  • Quantification of toxic smoke production in terms of tonnage of products. Toxic smoke production is evaluated according to CNPP fire tests background.

    Atmospheric dispersion

    Atmospheric dispersion

  • Evaluation of smoke plume caused by the fire thermal driving force.
  • Calculation of atmospheric dispersion of smoke plumes using a Gaussian model which takes into account atmospheric conditions (wind speed) and the class of atmosphere stability (Pasquill class A-F).
  • Calculation of pollutant substances concentrations on the ground based on distance from the source.
  • Analysis of the consequences in terms of air toxicity. Concentrations are compared to toxicity thresholds (references: Ministry of Ecology and Sustainable Development 2004, Ministry of Environment and Land Development 1998, American thresholds AEGLs, ERPG or IDLH) under accident conditions for each pollutant.

Cold dispersion of an accidental discharge of substance into the atmosphere:

  • Characterisation of the source according to the accidental scenario (pipe leak, groundwater evaporation, sudden seal break, etc.).
  • Calculation of atmospheric dispersion of gas clouds using an integral or 3D model. These models take into account the site atmospheric conditions based on meteorological data.
  • Calculation of pollutant substances concentrations on the ground based on distance from the source.
  • Analysis of the consequences in terms of air toxicity. Concentrations are compared to toxicity thresholds (references: Ministry of Ecology and Sustainable Development 2004, Ministry of Environment and Land Development 1998, American thresholds AEGLs, ERPG or IDLH) under accident conditions for each pollutant.

Manufacturers, trade unions ask CNPP:

  • examine the potential consequences of a fire or explosion or any other accidental event on the environment,
  • validate teh developped hypotheses thanks to mathematical models and take preventive and protection measures appropriate to the technical and economic content of the company,

either in their own security approach, or, for very specific cases, in liaison with the ministries concerned.

For example:

  • Study of the dispersion of smoke plumes generated by large fires
  • Hazard study according to classified facilities.

Contact :
Tel.: 33 (0)2 32 53 64 33
laboratoire-feu.environnement@cnpp.com