TY - JOUR A1 - Rauchegger, C. A1 - Bayley, S. A1 - Schröder, Volkmar A1 - Thévenin, D. T1 - Dispersion of heavy gases - experimental results and numerical simulations N2 - The hazardous potential of accidental heavy gas releases, especially those involving flammable and toxic gases, is widely known. In order to predict the area in which these gases are in hazardous concentrations, an estimation of the dispersion of these gases must be carried out. While the hazardous area for flammable heavy gases is determined by the lower flammability limit (ca. >1 vol%), the release of toxic heavy gases can result in a much larger hazardous area. Toxic gases, even in very low concentrations (ca. <3,000 ppm), have the potential to be highly damaging. State-of-the-art dispersion models, such as the VDI Guideline 3783, can be used to estimate the dispersion of heavy gases. However, VDI 3783 gives no method for the prediction of the height and width of a heavy gas cloud, which are both required for quantitative risk analysis as well as for a possible coupling of a Lagrangian particle model with the VDI 3783 heavy gas dispersion model. Therefore, further calculation methods were used to describe these dimensions and were evaluated against experimental studies of the length, width, and height of the heavy and neutral gas field. In addition to that the influence of the source height on the heavy gas dispersion was also examined KW - Process safety KW - Heavy gas KW - Numerical simulation KW - Explosion protection PY - 2015 U6 - https://doi.org/10.1002/prs.11723 SN - 1066-8527 SN - 1547-5913 SN - 0278-4513 VL - 34 IS - 3 SP - 280 EP - 285 PB - Wiley InterScience CY - Hoboken, NJ AN - OPUS4-34756 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schalau, Bernd A1 - Rauchegger, Christian A1 - Schmidt, Dirk A1 - Thévenin, D. T1 - Einfluss der Quellhöhe auf die Ausbreitung schwerer Gase N2 - Im Rahmen von Störfallauswirkungsbetrachtungen werden oft Szenarien betrachtet, in denen Gase freigesetzt werden, die schwerer als Luft sind. Für die Berechnung der Gefährdungsbereiche wird in Deutschland oft die Richtlinie VDI 3783 eingesetzt. Die Methodik zur Bestimmung der Konzentrationsverteilung bei der Freisetzung eines Schwergases ist im Blatt 2 der Richtlinie dargestellt und basiert auf Windkanaluntersuchungen mit verschiedenen Ausbreitungsgebieten. Unter der Zielsetzung, eine möglichst konservative Abschätzung des Gefährdungsbereichs zu erhalten, erfolgte die Gasfreisetzung am Boden. In der Praxis sind aber immer wieder Szenarien zu untersuchen, bei denen die Gasfreisetzung aus Anlagenteilen über Bodenniveau erfolgt. Durch Freilandversuche sollen Anhaltswerte für die Bestimmung einer kritischen Quellhöhe, ab der eine Schwergasausbreitung nicht mehr zu betrachten ist, ermittelt werden. KW - Schwergas KW - VDI-Richtlinie 3783 KW - Gasausbreitung KW - Ausbreitungsmodelle KW - Störfallauswirkungsbetrachtungen PY - 2012 SN - 2191-0073 VL - 2 IS - 10 SP - 35 EP - 37 PB - Springer-VDI-Verl. CY - Düsseldorf AN - OPUS4-26736 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rauchegger, Christian A1 - Schröder, Volkmar A1 - Lohse, Volkmar A1 - Schmidt, Dirk A1 - Thévenin, D. T1 - Release and dispersion of heavy gases - experimental results and numerical simulations N2 - Heavy gases in large quantities are used worldwide in various industries. Past incidents, such as the liquefied gas disaster in Viareggio (2009) have shown that these materials are difficult to handle in a safe manner. According to the German Hazardous Incident Ordinance (StörfallVO 2000 - 12. BImSchV) plant operators with 'extended responsibilities' must produce a report in which they verify that, in the event of an unintentional gas release, the surrounding area will not be aversely affected. The essential elements of this report include calculations of both released mass flow and gas dispersion. Using models such as the VDI guideline 3783 (state of the art in Germany) plant operators are able to predict the characteristics of likely gas dispersions. Within the framework of the reported experimental trials, the release process of heavy gases from standard gas cylinders was investigated. Using the results of this investigation a calculation methodology has been developed which is able to predict the mass flow of a gas-phase release. As input parameters only the geometry of the gas cylinder, the material properties of the respective fluid as well as the environmental parameters such as velocity of approach and air temperature are required. In the course of modeling various approaches for nucleate boiling have been tested for their applicability. Both the calculation methodology and a comparison between the calculated and experimental results will be presented. Within the same framework of experimental trials, the dispersion process of the aforementioned heavy gases was also investigated. The dispersed gas cloud in this case was considered as originating from a continuous point source under ambient conditions. For the various trials concentrations both in the heavy gas (≥ 1 vol.-%) and in the neutral gas field (≤ 3000 ppm) were measured. In the immediate area of the release the length, width and height of the heavy gas cloud were evaluated. The experimental results, comparison calculations and the measurement techniques will be presented. T2 - 8th Global congress on process safety (GCPS) CY - Houston, TX, USA DA - 2012-04-01 KW - Heavy gases KW - Gas releases KW - Gas Dispersion KW - VDI Guideline 3783 PY - 2012 UR - https://www.researchgate.net/publication/267345315_Release_and_Dispersion_of_Heavy_Gases_-_Experimental_Results_and_Numerical_Simulations SN - 978-0-8169-1071-7 IS - Paper 104aq SP - 1 EP - 16 AN - OPUS4-25772 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rauchegger, Christian A1 - Schalau, Bernd A1 - Schmidt, Dirk A1 - Lohse, Volkmar A1 - Schröder, Volkmar A1 - Thévenin, D. T1 - Experimental results from heavy gas dispersions (R134a) N2 - Heavy gases in large quantities are used worldwide in various industries. Past incidents, such as the liquefied gas disaster in Viareggio (2009) have shown that these materials are difficult to handle in a safe manner. According to the German Hazardous Incident Ordinance (StörfallVO 2000 - 12. BIMSchV), plant operators with extended responsibilities must produce a report in which they verify that , in the event of an unintentional gas release, the surrounding area will not be aversely affected. Essential elements of this report are calculations of both the released mass flow and the gas dispersion. Using models such as the VDI guideline 3783 (state of the art in Germany) plant operators are able to predict the characteristics of likely gas dispersions. The presented experimental investigations were carried out at the BAM better understand heavy gas dispersion with high gas concentrations in the air (≥ 1 Vol.-%), as well as concentrations with approximately neutral density characteristics (≤ 3000ppm) in order to test the accuracy of the VDI guideline. The starting point for experimental trials was the heavy gas releases resulting from pipeline, vessel or standard gas bottle leaks, with mass flows of between 20 and 100 g s-1. Investigations on the gas-phase release process focused on the unsteady mass flow associated with releases from standard gas bottles. The experimental results will be used as comparative parameters for future simulations. The goal of these simulations is to develop a model with which calculation of the unsteady mass flow, based on the material characteristics for any gas, is possible. T2 - 7th Global congress on process safety - 2011 Spring meeting CY - Chicago, Illinois, USA DA - 13.03.2011 KW - Heavy gas KW - Gas releases KW - Dispersion KW - Measurement KW - VDI guideline 3783 PY - 2011 SP - 1 EP - 12 AN - OPUS4-23532 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Rauchegger, Christian A1 - Schmidt, Dirk A1 - Lohse, Volkmar A1 - Negendank, Detlef A1 - Thévenin, D. T1 - Experimentelle Untersuchungen zur Schwergasausbreitung T2 - 10. Fachtagung Anlagen-, Arbeits- und Umweltsicherheit CY - Köthen, Deutschland DA - 2010-11-04 KW - Schwergas KW - Sensortechnik KW - Experimentelle Daten PY - 2010 SN - 978-3-89746-119-2 IS - Paper M-02 SP - 1 EP - 10 CY - Frankfurt/M. AN - OPUS4-22350 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -