TY - JOUR A1 - Spitzer, Stefan A1 - Aghaei, Siavash A1 - Askar, Enis A1 - Krietsch, Arne A1 - Salzano, Ernesto T1 - The Hazard of Soy Flour, n‑Hexane, and Their Hybrid Mixtures in the Extraction Process N2 - Soybean oil takes around half of the vegetable oil resources in the world, increasing in importance constantly. Besides, soy oil plants have experienced numerous accidents due to the coexistence of soy flour and hexane (as a solvent) in the extraction process, thus creating a hazardous environment. This study aims to find the maximum pressure, the maximum rate of pressure rise, and the minimum ignition energy of soy flour−hexane mixtures through specific experiments by varying the concentration of fuels in air and ignition mechanism (chemical igniters or exploding wires). The results have shown that soy flour alone is hard to ignite, whereas adding hexane even in small amounts increases the hazard and the severity of the explosions considerably. Eventually, the substitution of hexane with a greener and safer extraction agent should be of utmost focus. KW - Hybrid Explosions KW - Safety characteristics KW - Hexane KW - Soy Flour PY - 2024 DO - https://doi.org/10.1021/acs.iecr.4c01498 SN - 0888-5885 SP - 1 EP - 9 PB - ACS American Chemical Society AN - OPUS4-60597 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spitzer, Stefan A1 - Askar, Enis A1 - Benke, Alexander A1 - Cloney, C. A1 - D’Hyon, S. A1 - Dufaud, O. A1 - Dyduch, Z. A1 - Gabel, D. A1 - Geoerg, P. A1 - Heilmann, V. A1 - Jankuj, V. A1 - Jian, W. A1 - Krause, U. A1 - Krietsch, Arne A1 - Mynarz, M. A1 - Norman, F. A1 - Skrinsky, J. A1 - Taveau, J. A1 - Vignes, A. A1 - Zakel, S. A1 - Zhong, S. T1 - 1st international round robin test on safety characteristics of hybrid mixtures N2 - There is no applicable existing standard for the determination of safety characteristics for hybrid mixtures. While developing a new standard in a joint research project in Germany first results from parameter studies led to a standard procedure that can be adopted by laboratories that are already testing dusts in the so called 20L-sphere with as little additional effort as necessary. In fact, one of the main objectives of this research project was to keep modifications and adjustments from the generally accepted dust testing procedures as easy and minimal as possible so as to limit potential deviations from one laboratory to another. In this first round robin test on hybrid mixtures ever, with methane as gas component and a specific corn starch as dust sample, the practicality of the whole procedure, the scattering of the results and the deviation between the testing apparatuses is investigated. This paper summarizes the experimental procedure adopted and objectives of the first round-robin phase involving three of the four original German companies, plus volunteering laboratories from Australia, Belgium, Czech Republic, France, Poland and P.R. China. The results will have an impact on the new standard and may lead to robust data for later simulation purposes. KW - Hybrid mixtures KW - 20L-sphere KW - Round robin test KW - Turbulent combustion PY - 2022 DO - https://doi.org/10.1016/j.jlp.2022.104947 SN - 0950-4230 VL - 81 SP - 1 EP - 8 PB - Elsevier CY - Amsterdam AN - OPUS4-56516 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jankuj, V. A1 - Spitzer, Stefan A1 - Krietsch, Arne A1 - Bernatik, A. T1 - Safety of Alternative Energy Sources: a Review N2 - The article summarizes a short review of the literature focused on safety in the field of alternative energy sources. With an increasing orientation towards sustainable and renewable energy sources, new technologies will come to the fore. These facts must be demonstrated in occupational health and safety. Several studies focused on alternative energy sources are mentioned and show the trends for the future. Especially in the area of hydrogen and battery technologies, systems should pay attention to acquisitions as a normal part of our lives. Safety research is essential for the acceptance of cleaner, efficient, and sustainable future. T2 - Loss Prevention CY - Prag, Czechia DA - 06.06.2022 KW - Safety KW - Alternative Energy Sources PY - 2022 DO - https://doi.org/10.3303/CET2290020 SN - 2283-9216 VL - 90 SP - 115 EP - 120 PB - AIDIC CY - Milano AN - OPUS4-55030 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spitzer, Stefan A1 - Krietsch, Arne A1 - Jankuj, Vojtech T1 - Experimental Parameter Study and Inherent Scattering of Safety Characteristics of Dusts N2 - Safety characteristics are widely used in industrial processes to avoid explosive atmospheres (primary explosionprotection) or to mitigate the consequences of an explosion (constructive explosion protection). Several laboratory parameters influence the determined values when performing the test series such as the beginning pressure and the pre-ignition pressure rise, the ignition source, the ignition energy, the burning duration and volume or the concentration of the combustible substance. In the different standards for the determination of safety characteristics of dusts there is no statement about the scattering or the deviation when parameters are chosen or occur on the borders of their allowed range. Thus, two laboratories might determine values that are hardly comparable for the same given substance. This article summarizes some of the influential factors that cause a deviation and shows the inherent scattering of dust tests when all other parameters are kept constant. It also provides some advice how to minimize the deviation and the scattering with little effort. T2 - FEx23 CY - Bologna, Italy DA - 08.10.2023 KW - Safety characteristics KW - Inherent Scattering KW - Dust Explosions PY - 2023 DO - https://doi.org/10.3303/CET23104001 VL - 104 SP - 1 EP - 6 PB - AIDIC CY - Milano AN - OPUS4-58872 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spitzer, Stefan T1 - Entwicklungen zu Bestimmungsverfahren für sicherheitstechnische Kenngrößen des Explosionsschutzes für hybride Gemische N2 - Zur Bestimmung sicherheitstechnischer Kenngrößen (STK) von hybriden Gemischen (Gemisch aus mindestens zwei brennbaren Phasen, wie z.B. Staub/Gas- oder Gas/Dampf-Gemisch) existieren bislang keine einheitlichen, genormten Prüfmethoden. Die Normen und Regelwerke zur Bestimmung der STK von einphasigen brennbaren Systemen (Staub, Gas, Dampf) unterscheiden sich teilweise erheblich. Beispielsweise sind in den jeweiligen Normen für Stäube, Gase und Dämpfe unterschiedliche Zündquellen und Zündenergien definiert. Des Weiteren unterscheiden sich die in den Normen definierten Prüfabläufe bei der Gemischherstellung. Bei der Entwicklung einer einheitlichen Norm für hybride Gemische muss der Einfluss dieser beiden Parameter ermittelt werden, um die Vergleichbarkeit mit den STK der einzelnen Komponenten Gas, Staub und Dampf gewährleisten zu können und bisherige Erkenntnisse zu hybriden Gemischen interpretieren und bewerten zu können. T2 - VDI-Fachtagung "Sichere Handhabung brennbarer Stäube" CY - Online meeting DA - 04.11.2020 KW - Hybride Gemische KW - Explodierender Draht KW - Sicherheitstechnische Kenngrößen KW - Zündquellen PY - 2020 AN - OPUS4-51692 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Portarapillo, Maria A1 - Di Benedetto, Almerinda A1 - Spitzer, Stefan T1 - Turbulence effect on the determination of powders safety characteristics — A review on the experimental findings and simulation approaches N2 - Safety characteristics are widely used in the process industry to design facilities in a safe way. For powders, they are normally investigated under turbulent conditions inside a spherical test vessel, the so called 20L-sphere, to disperse the dust in air. This has been the target of many researchers to either investigate the turbulence that is present during the standardized test conditions, to compare it to quiescent conditions or to manipulate it for the comparison to other conditions. The approaches have been numerous and while the focus used to be on obtaining different experimental results it has shifted more and more to different kinds of simulations. This review gives an overview about different simulation approaches and how they can be compared. It is also an overview over the experimental findings and compares it to data obtained for three different dusts while changing the pre-ignition turbulence level in a very fine way. KW - Explosion protection KW - Dusts KW - Pressure rise KW - Ignition PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625216 DO - https://doi.org/10.1016/j.powtec.2025.120694 SN - 1873-328X VL - 454 SP - 1 EP - 19 PB - Elsevier B.V. AN - OPUS4-62521 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spitzer, Stefan A1 - Stevens, Nicole C. A1 - Krietsch, Arne A1 - Hermanns, Roy T.E. A1 - Makarova, Ekaterina A1 - Lorenzon, Ivan A1 - van Genderen, Albert C. A1 - Hessels, Conrad J.M. T1 - A first step towards a standardized iron fuel: Safety characteristics of several pure iron powders N2 - While the use of iron powder as a dense energy carrier has clear advantages over other carriers such as hydrogen and ammonia in terms of health and safety, risks may still emerge from the powder if accidentally dispersed in air during handling, transport and storage. Since the safety characteristics of dusts are affected by, among others, its particle size distribution, chemical properties and moisture content, it is hard to implement safety measures and select the most promising reduction method without a prior explosion testing. Various production and reduction methods are currently being investigated, each producing a morphologically different type of powder. In one of the key databases on safety characteristics of dusts from the Federation of the Statutory Accident lnsurance of Germany, the maximum explosion pressure ranges from non-explosible (=0) to 5.1 bar and the deflagration index goes up to 111 bar*m /s. In this work the safety characteristics of four different iron dusts, produced via three different reduction methods, are investigated using a 20-Liter sphere according to ISO/IEC 80079–20-2:2016–12 (explosibility). Three of the dusts were found to be explosible and were further tested according to EN 14034–1 (maximum explosion pressure) and EN 14034–2 (maximum rate of pressure rise). Though they were found explosible they were all categorized in dust class St1 as mildly explosible. The morphology of the powder was analyzed before the explosion tests using scanning electron microscopy and X-ray diffraction. The particle size distribution was also determined. Since the chemical properties and the moisture content are known, the findings may be applicable to implementation at larger scale without prior testing of every powder. KW - Energy carrier KW - Explosion pressure KW - Explosion protection PY - 2025 DO - https://doi.org/10.1016/j.fuel.2025.135824 SN - 0016-2361 VL - 400 SP - 1 EP - 10 PB - Elsevier BV AN - OPUS4-63446 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spitzer, Stefan A1 - Askar, Enis A1 - Hecht, Kristin A1 - Gabel, Dieter A1 - Geoerg, Paul A1 - Krause, Ulrich A1 - Dufaud, Olivier A1 - Krietsch, Arne ED - Amyotte, Paul T1 - The maximum rate of pressure rise of hybrid mixtures N2 - The maximum rate of pressure rise (dp/dt)𝑚𝑎𝑥 and the corresponding K-value of hybrid mixtures containing flammable gases and dusts are important for constructive explosion protection measures. Since the safety characteristics of dusts and gases are determined under different conditions, there has been considerable confusion about the influence of flammable gas on the (dp/dt) of dusts and vice versa. While some investigations showed comparably higher values for hybrid mixtures, others stated that the highest value for the gas component alone is the worst case. The first part of this paper focuses on the confusion around the different statements about (dp/dt)𝑚𝑎𝑥 of hybrid mixtures and where they come from. In the second part of this paper experimental results are presented that illustrate how to clarify the different findings of past research and show what to expect as a real worst-case-value for hybrid mixtures. KW - Hybrid Mixtures KW - 20L-sphere KW - Turbulent combustion KW - Maximum rate of pressure rise PY - 2023 DO - https://doi.org/10.1016/j.jlp.2023.105178 SN - 0950-4230 SN - 1873-3352 VL - 86 SP - 1 EP - 9 PB - Elsevier CY - Amsterdam AN - OPUS4-58435 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spitzer, Stefan T1 - BAM-Monitoringkompetenz am Beispiel des Projekts INFUSE - SensoJoint N2 - BAM-Monitoringkompetenz mit Fokus auf das Datenmanagement der realen Beanspruchungen von Betonautobahnen von der definierten Datenerfassung über Datenverwaltung, Datenübertragung bis zur Datenauswertung am Beispiel des Projekts 7183-Infuse. T2 - Workshop Digitaler Zwilling CY - BAM Berlin, Germany DA - 04.06.2018 KW - Monitoring KW - Bitumen KW - Betonautobahnen PY - 2018 AN - OPUS4-45124 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - THES A1 - Spitzer, Stefan T1 - Influence of the ignition source on the Safety Characteristics of hybrid dust-gas mixtures N2 - Safety characteristics like the lower explosion limit, the highest concentration for a given substance mixed with air that does not result in a self-propagating flame, or the maximum explosion pressure, the highest pressure that can be reached after ignition for a given combustible substance mixed with air at any concentration, are widely used in the industry to either prevent an explosion or to mitigate the effects of it. Safety characteristics are not physical constants, are determined experimentally and depend on the chosen experimental parameters such as the ignition energy or turbulence. For the determination of the safety characteristics lower explosion limit (LEL), limiting oxygen concentration (LOC), maximum explosion pressure (pmax) and maximum rate of pressure rise ((dp/dt)max) of gases and vapors the gas is filled via partial pressures into a test vessel and then ignited under quiescent conditions with a weak (2 J - 20 J) ignition source. For dusts, the same safety characteristics are determined under turbulent conditions to elevate the dust homogeneously and it is ignited with two chemical igniters with an ignition energy of 1000 J each (LEL and LOC) or 5000 J each (pmax and (dp/dt)max). For the determination of safety characteristics of hybrid mixtures (a mixture containing a combustible dust and a flammable gas) there is no existing standard. In the last 40 years most of the research on their safety characteristics was performed with dust testing equipment that was modified for the addition of flammable gas. Because of the different mixing procedures of gases and dusts with air and because of different ignition energies and sources that are normally used for the standard tests of gases or dusts, the results were hardly reproducible. Statements about the different safety characteristics were contradictory and left the reader or the person responsible for designing safety measures for a process plant or a facility behind with no clear suggestion about the behavior of hybrid mixtures. This thesis is aimed on determining the influence of the different ignition sources and energies on the safety characteristics pmax, (dp/dt)max, lower explosion limit, and limiting oxygen concentration of hybrid mixtures. Several test series were conducted to characterize different standardized ignition sources, that are already in use for the determination of safety characteristics of single-phase substances (gases, liquids, dusts). The burning duration, the igniting volume and the net energy were investigated. It was shown, that the chemical igniters and the exploding wire are suitable ignition sources for the determination of safety characteristics of hybrid mixtures in general. Their burning duration was long enough to ignite dusts and quick enough, that the decay of the turbulence or sedimentation of the dusts did not occur. Both ignition sources produced comparable results for the determination of pmax, LEL and (dp/dt)max of dusts when they had the same ignition energy. A reduced ignition energy of the exploding wire and the chemical igniters did not affect the pmax and (dp/dt)max. The LEL changed with lower energies. However, for the determination of the LOC of hybrid mixtures the exploding wires with an overall energy of 2 kJ produced the best results. The influence of the different mixing procedures that have already been used for hybrid mixtures and the requirements for them were also investigated experimentally for the gas concentration and the determined safety characteristics and compared to each other. It was shown, that the partial pressure method works for mixing hybrid mixtures but the pressures should be measured very accurately and the gas concentration should be validated. Furthermore, the influence of the turbulence that is inevitable when testing dusts, on the safety characteristics of gases was determined. It was found that the chemical igniters and exploding wires produced comparable results for the determination of pmax, LEL and (dp/dt)max under turbulence. For the LOC only exploding wires with two times 1 kJ worked. Finally, the safety characteristics of hybrid mixtures were determined with different ignition energies and sources and the data were compared. It was discovered, that the pmax of hybrid mixtures was the same value than the higher determined one of the single substances while (dp/dt)max of hybrid mixtures was about 10 % to 25 % higher than the value of the stoichiometric gas mixture under turbulence. The point was found at the stoichiometric gas concentration with very little amounts of dust. To prove the key findings of this work and for the establishment of a standardized procedure for the determination of safety characteristics of hybrid mixtures, an international round robin test was conducted with eleven participating facilities in seven countries. The results were comparable within a reasonable range and are presented in this dissertation in an extra chapter. Based upon the observations in this work a reliable solution for a new standardizable ignition source to determine the safety characteristics of hybrid dust-gas-mixtures is proposed. KW - Ignition Sources KW - Hybrid Mixtures KW - Explosions PY - 2023 SP - 1 EP - 132 AN - OPUS4-58905 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jankuj, V. A1 - Mynarz, M. A1 - Krietsch, Arne A1 - Spitzer, Stefan A1 - Leipik, P. T1 - Experimental investigation of the consequences of acetylene pressure cylinder failure under fire conditions N2 - Acetylene pressure cylinders are widely used in the industrial sector for welding, flame cutting, or heating. Sometimes during work, not only with acetylene cylinders, fires occur and in this case the risk of destruction increases and the behavior of such an exposed cylinder is unpredictable. The purpose of this study is to identify those critical conditions when acetylene cylinders burst and explode in fires. In the present study, acetylene cylinders were exposed to fire conditions. For this purpose, a woodpile as a source of fire was chosen, tested, and evaluated. In addition to the fire condition, this option guaranteed reproducibility and similar conditions for all tests. The individual cylinders were equipped with thermocouples measuring the shell temperature, and half of them were prepared in order to measure the temperatures inside the cylinder. An important factor was the measurement of the amount of pressure that was achieved during the destruction of the cylinder. For this purpose, a pressure transducer was attached to the outlet of the cylinder valve. Exposed to direct fire, they can explode in 10 min, which was confirmed. The critical pressure of 40 bar has been reached in 6 min, followed by destruction after 7 min in fire. Cylinders with internal thermocouples were destroyed when lower pressure was achieved. This confirms the fact that any change of the pressure cylinder affects the original properties. After the tests, the fragments of the selected cylinders were subjected to material tests. The results obtained in these tests are the main source of information for understanding the behavior of acetylene cylinders in fire and the possibility of increasing the safety of intervening rescue services in an emergency. KW - Acetylene KW - Pressure Cylinders KW - Fire KW - Explosion KW - Fireball PY - 2022 DO - https://doi.org/10.1016/j.jlp.2022.104874 VL - 80 SP - 1 EP - 12 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-55755 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spitzer, Stefan A1 - Abed, Arkan A1 - Seifert, Alexander A1 - Salzano, Ernesto T1 - Risks from Hydrogen Carriers - Safety Characteristics of the LOHC System Toluene/Methylcyclohexane N2 - Reversible liquid organic hydrogen carriers (LOHCs) seem to be a promising solution for the transportation of hydrogen. Since no pressure or cooling needs to be applied during the transport, it is considered easier, safer and cheaper compared to pressurized gas tanks or cryogenic hydrogen on long routes and is already applied in large quantities and long distances. One simple system is methylcyclohexane and toluene. Toluene gets shipped to countries with an excess of (preferably green) energy and is charged with hydrogen to form methylcyclohexane. This is then shipped back to the place with energy and/or hydrogen demand and split into hydrogen and toluene. For toluene, some safety characteristics are available, whereas methylcyclohexane is loosely analyzed, hence safety characteristics are the basis for an appropriate approach to tackle the hazards and for the risk assessment. This paper focuses on the safety characteristics of both substances, compares the differences and points out the crucial hazards of this system, especially if the same tanks for transportation are used. T2 - 18th EFCE International Symposium on Loss Prevention and Safety Promotion in the Process Industries CY - Bologna, Italy DA - 08.06.2025 KW - Explosion protection KW - Rate of pressure rise KW - Hydrogen transport PY - 2025 DO - https://doi.org/10.3303/CET25116058 SN - 2283-9216 VL - 116 SP - 343 EP - 348 PB - AIDIC Servizi S.r.l. CY - Italy AN - OPUS4-63734 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kosár, László A1 - Szabová, Zuzana A1 - Kuracina, Richard A1 - Spitzer, Stefan A1 - Mynarz, Miroslav A1 - Filipi, Bohdan T1 - Study of the Safety Characteristics of Different Types of Pepper Powder (Capsicum L.) N2 - This research was aimed at comparing the fire characteristics of different types of pepper in the context of explosion prevention. The following characteristics were studied: explosion pressure Pmax and Kst at selected concentrations, ignition temperature of the deposited dust layer from the hot surface, and minimum ignition energy. The comparison of the chemical properties of the used types of pepper was performed using TG/DSC. The results of the measurements suggest that different types of peppers exhibit different explosion characteristics. Each sample reached the maximum value of the explosion pressure and rate of pressure rise at different concentrations. The volume of the explosion chamber used also influenced the explosion characteristics. It is a consequence of the fact that the explosion characteristics strongly depend on the mechanism of action of a particular igniter. The minimum effect on the safety characteristics was observed when measuring the minimum ignition energy and the minimum ignition temperature of the dust layer from the hot surface. The results of the measurements suggest that different types of peppers exhibit different explosion characteristics. This information should then be considered in explosion prevention. KW - Dust explosions KW - Pepper samples KW - Explosion characteristics KW - Explosion protection PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605965 DO - https://doi.org/10.3390/fire7070229 VL - 7 IS - 7 SP - 1 EP - 14 PB - MDPI AG AN - OPUS4-60596 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Recknagel, Christoph A1 - Spitzer, Stefan A1 - Hoppe, Johannes A1 - Wenzel, Norman A1 - Pirskawetz, Stephan T1 - Innovative Sensorik für Fugensysteme N2 - Die zielgerichtete Weiterentwicklung von Bauteilen und Konstruktionselementen im Straßenbau hochbeanspruchter Verkehrswege unserer Infrastruktur (Bundesfernstraßen) erfordert spezielle, bauteiladaptierte technische Möglichkeiten/Sensorik zur Quantifizierung des Gebrauchsverhaltens. Bei Fugen in Verkehrsflächen stellen insbesondere langsam und schnell ablaufende Plattendeformationen infolge jahreszeitlicher und verkehrlicher Beanspruchungen maßgebende Beanspruchungszustände dar. Eine Quantifizierung dieser Einwirkungen hilft bei der Weiterentwicklung sowie auch bei der Bewertung optimierter technischer Lösungen. In Forschung kompakt 17/21 „Innovative Sensorik für Fugensysteme“ wird eine neuartige, robuste Lösung der BAM zur Datenerfassung und Bauwerksmonitoring von hochbeanspruchten Verkehrsflächen aus Beton vorgestellt. KW - Betonfahrbahndecke KW - Fugen KW - Quantifizierung realer Verformungen PY - 2021 VL - 17 SP - 1 EP - 2 PB - Eigenverlag der BASt CY - BASt, Bergisch Gladbach AN - OPUS4-54115 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Recknagel, Christoph A1 - Spitzer, Stefan A1 - Hoppe, Johannes A1 - Wenzel, Norman A1 - Pirskawetz, Stephan T1 - Optimierung von Fugensystemen - Messtechnische Grundlagen zur Ermittlung realer Beanspruchungen in situ N2 - Voraussetzung zur Aufklärung von Fugenbewegungen in hochbeanspruchten Verkehrsflächen aus Beton ist ein neues, innovatives und sensitives Sensorsystem, welches unter den Bedingungen der Autobahnpraxis schnell und sicher in entsprechend beanspruchte Bereiche installiert werden kann und in der Lage ist, stabile und hochaufgelöste Bewegungen in mehrere Raumrichtungen zu erfassen. Das durch die BAM neu entwickelte Sensorsystem ist geeignet, um direkt in die Betonfahrbahndecke integriert zu werden und sowohl über saisonale Messbereiche als auch in hoher Auflösung entsprechende Messwerte online zu erfassen und bereit zu stellen. Das für diesen Zweck entwickelte innovative Sensorsystem kann direkt in die Rollspur auf beiden Seiten der Fuge eingebaut werden und ist dafür ausgelegt, Lkw-Überfahrungen zu widerstehen. Es ist schnell und präzise genug, um die realen Bewegungen in allen drei Raumachsen in Echtzeit erfassen zu können. Dieser Forschungsbericht beschreibt das Funktions- und Wirkschema des Sensorsystems und seine Validierung im Labor- und Feldmaßstab. Dabei wird insbesondere auch die praxisgerechte Einbau- und Nutzungsmethodik vorgestellt. Auflösungsvermögen, Robustheit und Nutzerfreundlichkeit werden am Beispiel einer Konzeptstudie auf dem Testgelände DuraBASt erprobt. Es werden grundlegende Hinweise auf den dringlichen Bedarf einer gebrauchsgerechten Beschreibung des realen Verhaltens des Bauwerks Betonstraße identifiziert. Die mit dem Sensorsystem gewonnenen Daten können eine Grundlage für die Konzeption einer performance-basierten Bewertung von Fugenfüllsystemen in Betondecken von Bundesautobahnen bieten. Sie sind geeignet, die Funktionsmechanismen der verschiedenen Betonfahrbahnkonstruktionen besser zu verstehen und zielgerichtet konstruktive und materialtechnische Optimierungen und Fortentwicklungen von Fugenkonstruktionen und Fugenfüllsystemen in gebrauchsbezogener Weise zu entwickeln. Durch weitere Datenerhebung, -fusion und -analyse können Instandsetzungsintervalle und Lebensdauerzyklen besser abgeschätzt und geplant werden. KW - Betonfahrbahndecke KW - Fugen KW - Quantifizierung realer Verformungen PY - 2021 SN - 978-3-95606-590-3 SN - 0943-9323 VL - Straßenbau Heft S 153 SP - 1 EP - 173 PB - Fachverlag NW in der Carl Ed. Schünemann KG CY - Bremen AN - OPUS4-54174 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spitzer, Stefan A1 - Reitmeier, Fabian A1 - Danzi, Enrico A1 - Janovsky, Bretislav A1 - Paul, Michael T1 - The Exploding Wire: A novel ignition source for the determination of safety characteristics of dusts and hybrid mixtures N2 - For the determination of safety characteristics of dusts there are mainly chemical igniters in use. Especially for the maximum explosion pressure and the maximum rate of pressure rise there is no standard with another ignition source. The chemical igniters have the disadvantage of being very hard to obtain in most countries and they are even illegal in some. This leads to the fact, that those countries are not able to investigate the safety characteristics or only with a high effort by sending dust samples to facilities outside the country. This article presents a novel ignition source and describes how to build it. It is also the first step to place this ignition source into the dust standards in the future. KW - Explosion protection KW - Dust explosions KW - Pressure rise PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645209 DO - https://doi.org/10.1016/j.elstat.2025.104188 SN - 0304-3886 VL - 138 SP - 1 EP - 8 PB - Elsevier B.V. AN - OPUS4-64520 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spitzer, Stefan A1 - Jankuj, V. A1 - Hecht, K. A1 - Krietsch, Arne T1 - Igniting volume of four ignition sources N2 - Several standardized ignition sources are used to determine the safety characteristics of gases, vapours and dusts. Standards indicate the source of ignition but vary in specifying other features such as the burning duration, energy or the volume in which the energy is released. Since heat is not visible under normal conditions, a schlieren technique was used to visualize the entire igniting volume and not just the flames. This article focuses on the igniting volume, compares it among the four standardized ignition sources and displays its relationship to the size of the test vessel. Differences in the ignition behaviour of the ignition sources might lead to the determination of erroneous safety characteristics and with that to the unsafe operation of processes. KW - Hybrid mixtures KW - 20L-sphere KW - Ignition sources KW - Exploding wire PY - 2023 DO - https://doi.org/10.1016/j.psep.2022.12.076 SN - 0957-5820 VL - 170 SP - 1200 EP - 1207 PB - Elsevier CY - Amsterdam AN - OPUS4-56855 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spitzer, Stefan A1 - Askar, Enis A1 - Hecht, Kristin A1 - Gabel, D. A1 - Zakel, S. A1 - Krietsch, Arne T1 - Requirements for a Hybrid Dust-Gas-Standard: Influence of the Mixing Procedure on Safety Characteristics of Hybrid Mixtures N2 - While developing a standard for the determination of safety characteristics for hybrid mixtures the authors discovered, that, beside the ignition source, the mixing procedure is the main difference between the single-phase standards for dusts and gases. The preparation of hybrid mixtures containing a flammable gas and a flammable dust in the 20 L-sphere can be realized in different ways. Either the flammable gas is filled only in the sphere or only in the dust container or in both. In previous works, almost always the first method is applied, without giving any information on the accuracy of the gas mixtures. In this work the accuracy of the gas mixtures and the results of the tests applying two methods of mixing were studied. No significant influence of the mixing method itself on the safety characteristics explosion pressure pex and the normalized rate of pressure rise (K-value) was found. Obviously, homogenization of the gas mixtures can be obtained sufficiently by the turbulence that is caused during the injection from the dust container into the explosion chamber within a short time. However, the mixing procedure has a great influence on the accuracy of the gas amount of the mixtures obtained. Without modifying the 20 L-sphere by installing precise pressure sensors, assuring its tightness and performing gas analysis, it must be expected, that the accuracy of the gas mixtures is very low. This has a significant influence on the measured safety characteristics and may lead to unsafe facilities or unnecessary expensive safety measures. KW - Hybrid mixtures KW - 20 L-sphere KW - Pre-ignition pressure rise KW - Post-injection pressure drop KW - Safety characteristics PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554610 DO - https://doi.org/10.3390/fire5040113 VL - 5 IS - 4 SP - 1 EP - 10 PB - MDPI CY - Basel AN - OPUS4-55461 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spitzer, Stefan A1 - Askar, Enis A1 - Benke, Alexander A1 - Janovsky, B. A1 - Krause, U. A1 - Krietsch, Arne T1 - Influence of pre-ignition pressure rise on safety characteristics of dusts and hybrid mixtures N2 - For the determination of the safety characteristics of dusts it is necessary to disperse the dust in the oxidating atmosphere (usually air). In the standard procedures for dusts this is realized by a partially evacuated explosion vessel (20L-sphere) in which the dust gets injected from a dust chamber pressurized with air. Shortly after that injection (60 ms) the dust cloud gets ignited under turbulent conditions, that are otherwise seen as almost ambient with 20 ◦C and about 1 bar (abs). While there has been a lot of research about the influence of the ignition delay time and the level of turbulence in the recent years little attention was paid to the pre–ignition pressure rise and the allowed variations in the standards. In the following work we showed that the allowed ranges for the pressures in the different dust standards influence the safety characteristics of dust alone severely. Even though hybrid mixtures are an emerging risk problem in an interconnected industry there is no standard for the determination of their safety characteristics. In this work it is shown that especially for the preparation of hybrid mixtures of flammable dust and gas the pressures after injection of the dust and the mixing procedure have a large influence on the composition of the tested mixtures and therefore on the safety characteristics. Considering both effects, wrong concentration of gas and wrong initial pressure, the discrepancy of safety characteristics from different facilities will be too big to applicable. The methods to overcome these weaknesses are also presented. KW - Hybrid mixtures KW - 20L-sphere KW - Pre-ignition pressure rise KW - Post-injection pressure drop KW - Safety characteristics KW - Mixing procedure PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537358 DO - https://doi.org/10.1016/j.fuel.2021.122495 VL - 311 SP - 122495 PB - Elsevier Ltd. CY - Niederlande AN - OPUS4-53735 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spitzer, Stefan A1 - Askar, Enis A1 - Krietsch, Arne A1 - Schröder, Volkmar T1 - Comparative study on standardized ignition sources used for explosion testing N2 - For the determination of safety characteristics of gases, vapors and dusts different types of ignition sources are used in international standards and guidelines. Table 1 compares technical relevant ignition sources with their main features. The paper presents test results of a comparative calorimetric and visual study between four different types of ignition sources. The ignition procedures were analyzed visually with a high-speed camera and electric recordings. In addition to that, the influence of the electrode-orientation, -distance as well as ignition energy on the reproducibility of the exploding wire igniter was tested. The exploding wire is already in use for standardized determination of safety characteristics of gases, first tests on the suitability of the exploding wire igniter for dust testing have been carried out by Scheid et al. Using the exploding wire, the ignition energy can be varied from 2 to 10 000 J (2 x 5 000 J) and thus it could be used for gases, vapors, dusts and hybrid mixtures. Moreover it can be used at high initial pressures and it is the only ignition source with an easily measurable ignition energy release. Furthermore, it does not introduce another chemical reaction into the system. Finally, a proposal for a standard ignition source for explosion tests on hybrid mixtures is derived from the test results. T2 - 13th International Symposium on Hazards, Prevention and Mitigation of Industrial Explosions CY - Online meeting DA - 27.07.2020 KW - Ignition source KW - Exploding Wire KW - Hybrid mixtures KW - Safety characteristics determination PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517908 UR - https://oar.ptb.de/files/download/5f3e662f4c93901010006dbf DO - https://doi.org/10.7795/810.20200724 VL - 13 SP - 864 EP - 875 PB - PTB Physikalisch-Technische Bundesanstalt Braunschweig AN - OPUS4-51790 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spitzer, Stefan A1 - Riesner, G. A1 - Zakel, S. A1 - Schierding, C. T1 - A New Ignition Source for the Determination of Safety Characteristics of Gases N2 - Safety characteristics are used to keep processes, including flammable gases, vapors, and combustible dusts, safe. In the standards for the determination of safety characteristics of gases and vapors, the induction spark is commonly used. However, classic transformers are hard to obtain, and replacement with new electronic transformers is not explicitly allowed in the standards. This article presents the investigation of five gases that are normally used to calibrate devices for the determination of safety characteristics, the maximum experimental safe gap (MESG), with an electronic transformer, and the values are compared to the ones that are obtained with the standard transformer. Additionally, calorimetric measurements on the net energy of both ignition sources were performed as well as open-circuit voltage measurements. It is concluded that the classic type of transformer can be replaced by the new type obtaining the same results for the MESG and introducing the same amount of energy into the system. KW - Safety characteristics KW - Ignition sources KW - MESG PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578528 DO - https://doi.org/10.3390/gases3030007 VL - 3 IS - 3 SP - 106 EP - 111 PB - MDPI CY - Basel AN - OPUS4-57852 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spitzer, Stefan A1 - Askar, Enis A1 - Krietsch, Arne A1 - Schröder, Volkmar T1 - Entwicklungen zu Bestimmungsverfahren für sicherheitstechnische Kenngrössen hybrider Gemische N2 - Zur Bestimmung sicherheitstechnischer Kenngrößen (STK) von hybriden Gemischen (Gemisch aus mindestens zwei brennbaren Phasen, wie z.B. Staub/Gas- oder Gas/Dampf-Gemisch) existieren bislang keine einheitlichen, genormten Prüfmethoden. Die Normen und Regelwerke zur Bestimmung der STK von einphasigen brennbaren Systemen (Staub, Gas, Dampf) unterscheiden sich teilweise erheblich. Beispielsweise sind in den jeweiligen Normen für Stäube, Gase und Dämpfe unterschiedliche Zündquellen und Zündenergien definiert. Des Weiteren unterscheiden sich die in den Normen definierten Prüfabläufe bei der Gemischherstellung. Bei der Entwicklung einer einheitlichen Norm für hybride Gemische muss der Einfluss dieser beiden Parameter ermittelt werden, um die Vergleichbarkeit mit den STK der einzelnen Komponenten Gas, Staub und Dampf gewährleisten zu können und bisherige Erkenntnisse zu hybriden Gemischen interpretieren und bewerten zu können. T2 - VDI-Fachtagung "Sichere Handhabung brennbarer Stäube" CY - Online meeting DA - 04.11.2020 KW - Explodierender Draht KW - Sicherheitstechnische Kenngrößen KW - Hybride Gemische PY - 2020 SN - 978-3-18-092376-5 SN - 0083-5560 VL - 2376 SP - 3 EP - 15 PB - VDI Verlag GmbH CY - Düsseldorf AN - OPUS4-51789 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spitzer, Stefan T1 - Comparative Study on Standardized Ignition Sources Part 2: Exploration of the Initial Igniting Volume of Standardized Ignition Sources for the Determination of Explosion Characteristics N2 - There are several standardized ignition sources in use for the determination of explosion characteristics of gases, vapors and dusts. In the standards the ignition source is stated, but they vary in stating other characteristics like burning duration, energy or burning volume. Since heat is not visible under normal circumstances a Schlieren-Technique was used to make the full heating volume and not just the flames visible. While an earlier paper of the authors focused on the ignition energy and burning duration of four standardized ignition sources, this paper focuses on the initial igniting volume, the ratio between initial igniting volume and the test-vessel size and other phenomena that were observed with the Schlieren-Technique. T2 - Loss Prevention CY - Prague, Czech Republic DA - 06.06.2022 KW - Ignition source KW - Hybrid Mixtures KW - 20L-sphere PY - 2022 AN - OPUS4-55029 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spitzer, Stefan A1 - Recknagel, Christoph T1 - INFUSE - SensoJoint Entwicklung neuartiger Sensormethodik N2 - Funktionsschema einer neuartigen Messmethodik zur Ermittlung realer Beanspruchungen von Fugensystemen in hochbeanspruchten Betonfahrbahnbelägen. T2 - Bund-Länder Forschungskolloquium CY - Berlin, Germany DA - 05.07.2017 KW - Dauerhaftigkeit KW - Betonfahrbahndecke KW - Fugenproblematik PY - 2017 AN - OPUS4-41248 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spitzer, Stefan A1 - Pandal, Adrián A1 - Rodríguez, Manuel Velasco A1 - Schmidt, Martin A1 - Danzi, Enrico A1 - Dufaud, Olivier A1 - Janovsky, Bretislav T1 - Investigations on different distribution systems for dusts inside the 20L-sphere N2 - The determination of several safety characteristics for dusts requires the dispersion of it in air. This is normally conducted using two vessels, one with an overpressure holding the dust and dispersing it into the second one, where the explosion takes place, through a nozzle. This procedure has the disadvantage that some dusts cannot be conveyed through the nozzle properly. Another disadvantage is that the pressure balancing between the two vessels depends on the dust loading and especially for heavy dusts and high loadings the initial pressure inside the explosion vessel might be reduced. Flocky dusts or dusts that might be dangerous to convey through a thin nozzle with an overpressure (nano powders, zirconium) are also difficult to test according to the existing standards and may not be tested with the standard nozzles, that are so far used for the determination of safety characteristics. One very recent example, testing nitrocellulose, raised the question, whether some dusts even pose a risk being distributed and pressed through a nozzle for the testing device and, in worst case, for the operator. Previous researchers have developed alternative types of nozzles for specific types of dust, but provide limited evaluation of their performance relative to standard nozzles. Additionally, researchers have not provided sufficient geometry so that they can be reproduced by others. One alternative nozzle for the dispersion of flocky or coarse dusts is stated in the ISO standard but not described there either. This article investigates four types of nozzles: The two standard ones that are widely used already, an alternative type, that got introduced into the international standard in 2016 but is still seldomly used and one that was constructed to overcome some of the observed disadvantages. The injection curves are compared with and without dust loadings as well as the explosion characteristics. Eventually, a suggestion is given for different types of dusts. KW - Dust explosions KW - Safety characteristics PY - 2024 DO - https://doi.org/10.1016/j.jlp.2024.105492 SN - 0950-4230 VL - 92 SP - 1 EP - 12 PB - Elsevier B.V. AN - OPUS4-61697 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spitzer, Stefan A1 - Amyotte, P. A1 - Salzano, E. T1 - Explosion behavior of hybrid mixtures N2 - Flammable mixtures of dusts with gases or liquids occur in the process and energy industries. Most research about these so-called "hybrid mixtures" was, and still is, about coal dust with the admixture of methane because of their occurrence in the mining industry. In the modern industry, hybrid mixture explosions play an increasing role in many existing processes like spray-drying, or in emerging technologies like the direct reduction of iron ore with hydrogen or nuclear/fusion reactors. While some safety characteristics of one of the component substances stay the same or are unaffected by the concentrations that occur in the process, others are severely influenced by only traces of the other substance. This review paper shows in which processes and applications hybrid mixtures pose a risk and gives an overview of the research conducted in the last 150 years. Findings that are reproducible and represent current proven knowledge are stated and compared to each safety characteristic containing only solid particles, gases or liquids as combustible substances. Additionally, fundamental studies on the mechanisms of flame propagation in hybrid mixtures are reviewed. The significance of these studies in enhancing our understanding of explosion behaviors in hybrid mixtures is also discussed. An outlook on what has been missing so far in the literature, is also given comparing the knowledge of single substances with their mixtures, why this might not have been investigated, and where the challenges lie. KW - Hybrid mixtures KW - Safety characteristics KW - Combustion regimes KW - Industrial explosions PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654013 DO - https://doi.org/10.1016/j.pecs.2025.101276 SN - 0360-1285 VL - 113 SP - 1 EP - 24 PB - Elsevier CY - Amsterdam AN - OPUS4-65401 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -