Coupling of a particle analyzer to the smoke chamber
Source: BAM, Technical Properties of Polymeric Materials Division
In the transportation sector, components are tested for heat and smoke release for their specific application, such as the European rail transport standard EN 45545-2. The smoke is classified according to the optical density and toxicity of the gases, but the smoke particles are not further considered. These show a high potential risk, since particles smaller than 10 µm can enter the lungs and smaller than 2.5 µm can enter the bloodstream. Our new experimental setup - the coupling of a particle analyzer to the smoke chamber - makes it possible to additionally detect smoke particles smaller than 10 µm and to estimate their risk based on the size fractions.
In the study, industrially used smoke suppressants in a flame-retardant polyamide 6.6, which is used in the transportation sector, are examined in various fire scenarios. Based on the smoke emission and fire behavior, interactions are determined which enable a good flame retardancy and low smoke emission. The influence on particle emission is the focus of the investigation to estimate the hazard risk for people in case of a fire. This general knowledge can be used for future material developments to increase the safety of these materials in the event of fire.
It was shown that the degradation behavior of the polymer significantly influences the fire behavior and smoke emission. The interaction of flame retardant and smoke suppressant improved flame retardancy and reduced smoke density and toxicity. The mode of action of the flame retardant changed and toxic precursors were fixed in the residue by crosslinking reactions. Due to the improved barrier effect of the residue, the decomposition products remained longer in the pyrolytic zone, which reduced the particle size and smoke density.
No business as usual: The effect of smoke suppressants commonly used in the flame retardant PA6.6 on smoke and fire properties
Sebastian M. Goller, Simone Krüger, Bernhard Schartel
published in Polymer Degradation and Stability, 2023, Volume 209, Essay Number 110276.
BAM Department Safety of Structures
BAM Division Technical Properties of Polymeric Materials