Fire scenarios and chemical analysis of fire products

Large fire test involving a passenger car.
Ignition source: fuel-filled sump under the engine

  

The Working Group examines fire scenarios of various sizes numerically and experimentally. From building products to room fires, we are interested in how fires and smoke start, how they spread and what the flue gases are composed of.

Various analytical methods such as Fourier transform infrared spectroscopy (FTIR) are used to determine the chemical composition of combustion gases. We investigate the effect of material properties on flue gas composition and assess the toxicity of flue gases. Components such as CO, CO₂, H₂O, CH₄, HCl, HCN, acrolein and SO₂ are qualitatively and quantitatively verified. The toxicity of flue gases is assessed using the FED (fractional effective dose) concept.

Scorched upholstery in a modified SBI set-up with coupled flue gas analysis

  

Numerical simulations using CFD (computational fluid dynamics) techniques are used to calculate the spread of fire and smoke under different scenarios. The experimental data are used as input parameters for simulations and for the validation of the numerical models. Numerical simulations are more cost effective than full scale tests when comparing fire scenarios and varying parameters.

Particularly in the investigation of unsolved fire cases, the combination of analytical investigation of fire traces and numerical simulation makes it possible to compare different fire progressions and to assess which progressions are possible and probable.

Key areas

• Modelling fire scenarios: Numerical simulation of fire development (temperature, smoke density, gas components) of various orders of magnitude from fire test stands to full scale (CFD methods, such as CFX, Fluent, FDS fire dynamic simulator), validation of the models using experimental data
• Application of numerical calculations to apartment and building fires and fires in vehicles, examining and improving fire tests
• Qualitative and quantitative flue gas analysis (FTIR spectroscopy, paramagnetic methods)
• Assessment of flue gas toxicity (CIT conventional index of toxicity, FED concept)
• Holistic, analytical examination of fire residue, particles, aerosols, condensates and combustion gases in cooperation with Divisions 1.2 and 4.2
• Examination of the composition of smoke under various combustion conditions
• Improving numerical modelling of smoke
• Delivering expert opinion on real cases of fire and fire load estimates
• Performing standards tests:
  • Fire behaviour of building materials at "medium stress levels" according to DIN EN 13823:
    Single Burning Item Test
  • Smoke development of flat samples according to EN ISO 5659-2 and ASTM E 662:
    Smoke density chamber
  • Fire behaviour of building materials at "low stress levels" according to DIN 4102 - 1:
    Small burner
  • Smoke emissions from building materials according to DIN 4102 - 1:
    DIN tube and XP2 chamber
• Participation in various national and international committees
• Care of diploma candidates, trainees and graduate students

Ongoing projects

• Innovation project: Chemical fire analysis technique
• Research project: Examining the production, spread and toxicity of smoke in bus fires, funded by the Federal Highway Research Institute (BASt)
• Research project: Quantification of smoke as a basis for simulation-based fire protection and smoke extraction concepts, funded by the of Federal Office for Building and Regional Planning (BBR), as part of the research programme "Future construction"
• BAM innovation project: Composites in fire
• BAM innovation project: Wood plastic composites

Equipment

• Numerical methods (CFD methods, such as CFX, Fluent, FDS)
• Mobile FTIR spectrometer Nicolet 380 (from ThermoFisher)
• Multi-component gas analyzer Servomex 5200 (from Servomex)
• NDIR detector IQ-1000 (from IST)

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