TY - CONF A1 - Berchtold, Florian A1 - Knaust, Christian A1 - Rogge, Andreas A1 - Arnold, L. A1 - Thöns, Sebastian ED - Lönnermark, Anders ED - Ingason, Haukur T1 - Risk Analysis for Road Tunnels – A Metamodel to Efficiently Integrate Complex Fire Scenarios N2 - Fires in road tunnels constitute complex scenarios with interactions between the fire, tunnel users and safety measures. More and more methodologies for risk analysis quantify the consequences of these scenarios with complex models. Examples for complex models are the computational fluid dynamics model Fire Dynamics Simulator (FDS) and the microscopic evacuation model FDS+Evac. However, the high computational effort of complex models often limits the number of scenarios in practice. To balance this drawback, the scenarios are often simplified. Accordingly, there is a challenge to consider complex scenarios in risk analysis. To face this challenge, we improved the metamodel used in the methodology for risk analysis presented on ISTSS 2016. In general, a metamodel quickly interpolates the consequences of few scenarios simulated with the complex models to a large number of arbitrary scenarios used in risk analysis. Now, our metamodel consists of the projection array-based design, the moving least squares method, and the prediction interval to quantify the metamodel uncertainty. Additionally, we adapted the projection array-based design in two ways: the focus of the sequential refinement on regions with high metamodel uncertainties; and the combination of two experimental designs for FDS and FDS+Evac. To scrutinise the metamodel, we analysed the effects of three sequential refinement steps on the metamodel itself and on the results of risk analysis. We observed convergence in both after the second step (ten scenarios in FDS, 192 scenarios in FDS+Evac). In comparison to ISTSS 2016, we then ran 20 scenarios in FDS and 800 scenarios in FDS+Evac. Thus, we reduced the number of scenarios remarkably with the improved metamodel. In conclusion, we can now efficiently integrate complex scenarios in risk analysis. We further emphasise that the metamodel is broadly applicable on various experimental or modelling issues in fire safety engineering. T2 - International Symposium on Tunnel Safety and Security CY - Boras, Sweden DA - 14.03.2018 KW - Risk KW - Metamodel KW - CFD KW - Evacuation KW - Uncertainty PY - 2018 SN - 978-91-88695-48-2 VL - 8 SP - 349 EP - 360 AN - OPUS4-44535 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Knaust, Christian A1 - Krause, Ulrich A1 - Hofmann-Böllinghaus, Anja A1 - Schneider, U. T1 - Modeling fire scenarios in buildings with CFD N2 - In the frame of the European harmonization, new European technical standards (Eurocodes) have been developed in recent years. Classical methods, like tables and simplified analytical procedures, as well as general engineering techniques are allowed by the Eurocodes for the fire protection design. The modeling and calculation of fire scenarios with CFD (Computational Fluid Dynamics) numerical methods is one of the general engineering methods. It is nowadays still difficult to check and evaluate the CFD results for their use as technical documents for fire safety design. Analytical engineering techniques, zone models and CFD-models have been used and compared in the present work for the prediction of the fire development in a building. To solve the conservation equation for the CFD-model, the CFD-program FDS, with the mixture fraction model, and the CFD-program FLUENT, with the one step reaction model as well as with the volumetric source term model, have been used. The combustion of polyurethane is modeled in FDS by specifying the heat release rate and the stoichiometry. For the combustion in volumetric source term model, the heat release rate and the smoke release were specified with respect to the stoichiometry. The input parameter for the one step reaction model is the pyrolysis mass flow. In the one step reaction model, the transport equations for polyurethane, H₂O, N₂, O₂, CO₂, CO and C (soot) are solved and the heat of combustion is determined from the standard formation enthalpy of all the components. In volumetric source term model, the transport equation is solved for air and smoke. FDS solves the transport equation for the mixture fraction. To model the fire development, and where no literature data was available, the required material characteristics like specific heat capacity, absorption coefficient and heat of combustion were measured. In all the investigated CFD-models the heat- and species transport equation has been solved and the absorption coefficient of soot has been considered. Furthermore, the fire development has also been investigated using zone models with the programs CFAST and MRFC. Results from analytical engineering techniques (plume calculations), which were design criteria in the past, have been used as plausibility checks for the present work. The calculation results from the investigations were compared to measurements in the same building performed by the National Institute for Standards and Technology (NIST). T2 - 11th International Symposium on Fire Protection CY - Leipzig, Germany DA - 08.06.2010 KW - CFD KW - Computational fluid dynamics KW - Zone model KW - Analytical technique KW - Combustion KW - Soot model KW - FLUENT KW - FDS KW - CFAST KW - MRFC KW - Measurements PY - 2010 SN - 978-3-00-03966-2 N1 - Geburtsname von Hofmann-Böllinghaus, Anja: Hofmann, A. - Birth name of Hofmann-Böllinghaus, Anja: Hofmann, A. SP - 1 EP - 14 PB - Vereinigung zur Förderung des Deutschen Brandschutzes (vfdb) CY - Münster AN - OPUS4-23159 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hofmann-Böllinghaus, Anja A1 - Knaust, Christian A1 - Beard, A. T1 - Modelling fire scenarios in residential buildings with respect to the benefit of smoke detectors and flame retardants T2 - 12th International Flame Retardants 2006 Conference CY - London, England, UK DA - 2006-02-14 KW - Fire scenarios KW - Modelling KW - CFD KW - Fire spread KW - Smoke spread PY - 2006 SN - 0-9541216-7-8 N1 - Geburtsname von Hofmann-Böllinghaus, Anja: Hofmann, A. - Birth name of Hofmann-Böllinghaus, Anja: Hofmann, A. SP - 195 EP - 214 PB - Interscience Communications CY - London AN - OPUS4-12207 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Löhnert, Andrea A1 - Monreal, Nils A1 - Knaust, Christian A1 - Hofmann-Böllinghaus, Anja A1 - Krause, U. T1 - CFD modeling approach of smoke toxicity and opacity for flaming and non-flaming combustion processes N2 - Current engineer’s methods of fire safety design include various approaches to calculate the fire Propagation and smoke spread in buildings by means of computational fluid dynamics (CFD). Because of the increased computational capacity, CFD is commonly used for prediction of time-dependent safety parameters such as critical temperature, smoke layer height, rescue times, distributions of chemical products, and smoke toxicity and visibility. The analysis of smoke components with CFD is particularly complex, because the composition of the fire gases and also the smoke quantities depends on material properties and also on ambient and burning conditions. Oxygen concentrations and the temperature distribution in the compartment affect smoke production and smoke gas toxicity qualitatively and quantitatively. For safety designs, it can be necessary to take these influences into account. Current smoke models in CFD often use a constant smoke yield that does not vary with different fire conditions. If smoke gas toxicity is considered, a simple approach with the focus on carbon monoxide is often used. On the basis of a large set of experimental data, a numerical smoke model has been developed. The developed numerical smoke model includes optical properties, production, and toxic potential of smoke under different conditions. For the setup of the numerical model, experimental data were used for calculation of chemical components and evaluation of smoke toxicity under different combustion conditions. Therefore, averaged reaction equations were developed from experimental measurements and implemented in ANSYS CFX 14.0. KW - Fire modeling KW - Fire safety KW - Computational fluid dynamics (CFD) KW - Smoke toxicity PY - 2016 DO - https://doi.org/10.1002/fam.2340 SN - 1099-1018 VL - 40 IS - 6 SP - 759 EP - 772 PB - Wiley CY - West Sussex, UK AN - OPUS4-37514 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Krause, U. A1 - Rabe, Frederik A1 - Knaust, Christian ED - Schmidt, J. T1 - Modeling fire scenarios and smoke migration in structures N2 - Mathematical modeling of physical phenomena is an attempt to create tools which can help • to predict relevant parameters of an event at its final stage, • to predict the course of a process with time, and • to quantify the influence of System parameters, boundary conditions, material properties and so forth on the process. Applied to fire modeling the aim is either to prevent the occurrence of fires or toprevent or at least mitigate their potentially harmful consequences or to be able to reconstruct the chain of events of a fire. The first two aims, of course, are far more frequently made use of than the last one. KW - Modeling fire scenarios KW - Field models KW - Fire dynamics simulator (FDS) KW - ANSYS CFX PY - 2012 SN - 978-3-527-33027-0 DO - https://doi.org/10.1002/9783527645725.ch10 IS - Chapter 10 SP - 159 EP - 177 PB - Wiley-VCH Verlag GmbH & Co. KGaA AN - OPUS4-27738 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nandish, Ranjith A1 - Knaust, Christian A1 - Hofmann-Böllinghaus, Anja A1 - Gnutzmann, Tanja A1 - Zehfuß, Jochen T1 - Simulation of wood pyrolysis with component-based mechanism N2 - This paper presents a comprehensive fire simulation study that models the pyrolysis process of beech wood using kinetic parameters with the Fire Dynamics Simulator (FDS). The kinetic methodology is based on the application of these kinetic parameters to govern the underlying pyrolysis reactions. The primary objective was to numerically model the pyrolysis process for beech wood using both single-component (single-step, single reaction scheme) and multi-component (single-step, multi-reaction scheme) kinetic reaction schemes. The accuracy of the numerical model was validated by comparing FDS simulation results with experimental data obtained from thermogravimetric analysis (TGA) and cone calorimeter tests. This approach aids in identifying reliable kinetic reaction input parameters for modelling wood fires. A case study was included to demonstrate the implementation of the kinetic reaction schemes. Numerical results from the TGA simulations for the small-scale pure cellulose test using the single-component approach exhibit consistency with the experimental data. Furthermore, the results demonstrated that the multi-component approach more accurately replicates the shape of the experimental curve for beech wood compared to the single-component approach. However, discrepancies in the tail regions of the curves obtained from the FDS simulations showed the need for further improvement in the modelling approach, particularly regarding the exclusion of char oxidation reactions, which needs to be investigated further. KW - Simulation KW - Wood PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639272 DO - https://doi.org/10.1007/s00231-025-03571-7 SN - 0947-7411 VL - 61 IS - 6 SP - 1 EP - 14 PB - Springer Science and Business Media LLC AN - OPUS4-63927 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hofmann-Böllinghaus, Anja A1 - Knaust, Christian A1 - Krüger, Simone A1 - Raspe, Tina A1 - Deubel, Jan T1 - Detailed analysis of a smouldering fire scenario at the murder scene - experimental and numerical investigations N2 - Based on forensic evidence, a smouldering fire was observed to have occurred at a murder scene. Identification of a reasonable timeline – specifically the fire dynamics of the ignition and fire growth that occurred coincident with the death that took place – became an important focus of the criminal investigation that followed. The fire service was called when a neighbour saw a grey smoke escaping through the ventilation system of the bathrooms on the roof of the house. One flat door with elevated temperatures was found. The fire fighter who entered the flat first reported later that the flat was completely filled with smoke and all windows were closed. When the fire fighter opened the balcony door, he saw flames on the sofa that he extinguished. Then he found a body on the floor. The autopsy showed later that the victim was dead before the fire started. The police suspected that the murderer probably had deliberately set the fire to destroy evidence. One suspect had been witnessed to be in the flat approximately 2 h before the fire was detected by the neighbour. The aim of this project was to investigate how the fire most likely started and developed. KW - Fire investigation KW - Smouldering fire KW - Fire development KW - Crime KW - Numerical modelling PY - 2014 DO - https://doi.org/10.1002/fam.2222 SN - 0308-0501 SN - 1099-1018 VL - 38 IS - 8 SP - 806 EP - 816 PB - Heyden CY - London AN - OPUS4-32016 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hofmann-Böllinghaus, Anja A1 - Knaust, Christian A1 - Krüger, Simone T1 - Brandverhalten von Bauprodukten: Brauchen wir Regelungen für die Menge und Giftigkeit der Rauchgase? T2 - 57. Jahresfachtagung der Vereinigung zur Förderung des Deutschen Brandschutzes e.V. (vfdb 2008) CY - Bochum, Deutschland DA - 2008-04-27 PY - 2008 N1 - Geburtsname von Hofmann-Böllinghaus, Anja: Hofmann, A. - Birth name of Hofmann-Böllinghaus, Anja: Hofmann, A. SP - 169 EP - 178 AN - OPUS4-17755 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Eberwein, Robert A1 - Rogge, Andreas A1 - Behrendt, F. A1 - Knaust, Christian T1 - Dispersion Modeling of LNG-Vapor on Land – A CFD-Model Evaluation Study N2 - Based on methane from renewable resources, LNG is an alternative fuel for heavy and long-distance traffic in land transport. Contrary to its positive properties, the fuel contains risks from an explosion and extremely low temperatures for personal and infrastructure safety. CFD-models are suitable for doing risk analyses for arbitrary scenarios. For examining how to model for risk research the dispersion of LNG-vapor, this paper contains a model variant study, with an evaluation by experiments. This paper describes the use of the CFD-code ANSYS Fluent for simulating experiments of the ‘LNG Safety Program Phase II‘. The content of the well-documented experiments was the research of the vaporization rate of LNG on land and the dispersion of LNG-vapor in the air. Based on the comparison to two experiments, overall 12 CFD-model variants with varying thermal and turbulence parameters were examined how they affect the transient LNG-vapor dispersion in air. The definition of turbulence-boundary-condition at the domain borders had the biggest impact on modeling, followed by the turbulence model. The most accurate model variant had been applied for observing the spreading behavior of LNG-vapor in the air after evaporation on land and analyzing the influence of the LNG-composition to the dispersion. The results show that the mixture of LNG-vapor and the air in the free field is cooler than the ambient air and spreads like a heavy gas on the ground. KW - LNG KW - CFD KW - Heavy gas KW - Model evaluation PY - 2020 DO - https://doi.org/10.1016/j.jlp.2020.104116 VL - 65 SP - 104116 PB - Elsevier Ltd. AN - OPUS4-50697 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Knaust, Christian A1 - Rogge, Andreas T1 - CFD modeling of a tunnel fire by thermal coupling of fluid flow and structure N2 - The current technology allows the coupling of the temperature-dependent heat transfer mechanisms in case of fire within the structural components and at their surface by means of computational fluid dynamics (CFD). In this paper the thermal coupling of a fluid and a solid region in case of a 100 MW tunnel fire caused by a truck was carried out with CFD. The transient fire simulations were performed with the CFD program ANSYS FLUENT. The fire was modeled by the combustion of zz-heptane CrHir, using the eddy dissipation model. The fluid and the solid region were coupled by an interface. The unsteady heat conduction for the 0.4 m thick concrete structure is modeled by using the Fourier heat transfer equation. The transient thermal behavior of quartz containing concrete component was analyzed. Temperature-dependent material properties of the concrete were considered. T2 - International congress ' Fire computer modeling' CY - Cantabria, Spain DA - 18.10.2012 PY - 2012 SN - 978-84-86116-69-9 SP - 201 EP - 213 AN - OPUS4-27900 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lerena, P. A1 - Auerkari, Pertti A1 - Knaust, Christian A1 - Vela-Wallenschus, Iris A1 - Krause, U. T1 - Approaches towards a generic methodology for storage of hazardous energy carriers and waste products N2 - Energy carriers – either conventional or 'new' ones – have to be provided in large amounts to meet the requirements of permanent availability and reliable supply of electricity. Depending on their state of aggregation, energy carriers are either stored in large masses (if solid or liquid) or at elevated pressures (if gaseous). Both impose the hazard of large-scale fire, in the latter case additionally the danger of explosion or unintended release. Very similar hazards occur for wastes. Solid wastes are present in large masses and only a small part is recycled. Most of the solid wastes are used in energy conversion. The main gaseous waste is CO2. During capturing also the hazard of unintended release exists. In this article, existing approaches for safe storage and fire prevention are discussed and a generic methodology is outlined. This methodology consists of the following steps: - gaining knowledge about the behaviour of the material stored (reactivity, thermal stability, etc.), - assessing the environmental conditions for the storage site (neighbourhood, safety distances, etc.), - assessment of prospective consequences of an incident and - development of individual loss prevention conceptions. All steps require both experimental testing and theoretical considerations about accident scenarios as integral parts of the methodology. KW - Storage KW - Hazardous materials KW - Energy carriers PY - 2013 DO - https://doi.org/10.1080/13669877.2012.729524 SN - 1366-9877 SN - 1466-4461 N1 - Geburtsname von Vela-Wallenschus, Iris: Vela, I. - Birth name of Vela-Wallenschus, Iris: Vela, I. VL - 16 IS - 3-4 SP - 433 EP - 445 PB - Taylor & Francis CY - London [u.a.] AN - OPUS4-26882 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -