TY - CONF A1 - Recknagel, Christoph A1 - Spitzer, Stefan A1 - Hoppe, Johannes A1 - Wenzel, Norman A1 - Pirskawetz, Stephan T1 - SENSO JOINT - An innovative sensor system for a sustainable joint design of concrete pavements N2 - Inacceptable capability and durability of joint sealing systems but also inadequate traffic performance (noise emission; overrolling comfort) up to traffic safety aspects reflect the still enormous demand for data-based description of concrete pavements performance under heavy loading conditions. Especially the deformation behavior of concrete pavement slabs in the joint region in consideration of new pavement construction types and improved concrete mixtures meanwhile established but also under the steeply rising traffic loads is not sufficiently explored. To create a data basis for advanced design rules, evaluation methods and product standards - and with it to improve quality, durability and finally sustainability of pavements - an innovative 3-D sensor system SENSO JOINT adapted to german roadworking requirements and suitable for heavy-duty operating conditions was developed. The contribution introduced describes the development of an extensive technical solution based on the analysis of decisive loads, interactions and boundary conditions. Based on calibration data, results of laboratory testing and finally field-testing on different concrete pavement construction types the outcome of a multi-level evaluation process shall introduce the potential of the new sensor system. T2 - 9th International Conference on Maintenance and Rehabilitation of Pavements (Mairepav9) CY - Online meeting DA - 01.07.2020 KW - Concrete pavements KW - Sustainable joint sealing KW - Load quantification KW - Innovative measurement technology KW - Field validation KW - Performance design for joint systems PY - 2020 SN - 978-3-030-48678-5 SN - 978-3-030-48679-2 DO - https://doi.org/10.1007/978-3-030-48679-2 SN - 2366-2557 VL - 76 SP - 191 EP - 199 PB - Springer Nature Switzerland AG CY - Switzerland AN - OPUS4-51965 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wu, Dejian A1 - Zhao, P. A1 - Spitzer, Stefan A1 - Krietsch, Arne A1 - Amyotte, P. A1 - Krause, U. T1 - A review on hybrid mixture explosions: Safety parameters, explosion regimes and criteria, flame characteristics N2 - The hybrid mixture of combustible dusts and flammable gases/vapours widely exist in various industries, including mining, petrochemical, metallurgical, textile and pharmaceutical. It may pose a higher explosion risk than gas/vapor or dust/mist explosions since the hybrid explosions can still be initiated even though both the gas and the dust concentration are lower than their lower explosion limit (LEL) values. Understanding the explosion threat of hybrid mixtures not only contributes to the inherent safety and sustainability of industrial process design, but promotes the efficiency of loss prevention and mitigation. To date, however, there is no test standard with reliable explosion criteria available to determine the safety parameters of all types of hybrid mixture explosions, nor the flame propagation and quenching mechanism or theoretical explanation behind these parameters. This review presents a state-of-the-art overview of the comprehensive understanding of hybrid mixture explosions mainly in an experimental study level; thereby, the main limitations and challenges to be faced are explored. The discussed main contents include the experimental measurement for the safety parameters of hybrid mixtures (i.e., explosion sensitivity and severity parameters) via typical test apparatuses, explosion regime and criterion of hybrid mixtures, the detailed flame propagation/quenching characteristics behind the explosion severities/sensitivities of hybrid mixtures. This work aims to summarize the essential basics of experimental studies, and to provide the perspectives based on the current research gaps to understand the explosion hazards of hybrid mixtures in-depth. KW - Hybrid mixtures KW - Explosion protection KW - Safety characteristics PY - 2023 DO - https://doi.org/10.1016/j.jlp.2022.104969 SN - 0950-4230 VL - 82 SP - 1 EP - 54 PB - Elsevier CY - Amsterdam AN - OPUS4-56856 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spitzer, Stefan A1 - Adamus, Wojciech A1 - Askar, Enis A1 - Benke, Alexander A1 - D’Hyon, Sebastian A1 - Dyduch, Zdzislaw A1 - Dufaud, Olivier A1 - Flemming, Friederike A1 - Gehle, Nicole A1 - Hohenberger, Michael A1 - Jankuj, Vojtech A1 - Jian, Wang A1 - Krietsch, Arne A1 - Kuracina, Richard A1 - Mynarz, Miroslav A1 - Norman, Frederik A1 - Osborne, David A1 - Prodan, Maria A1 - Sandsta, Nelly A1 - Toman, Adrian A1 - Skjold, Trygve A1 - Skrinsky, Jan A1 - Szabova, Zuzana A1 - Vignes, Alexis A1 - Wingerden, Mattheus van A1 - Zhong, Shenjung T1 - Validation of a new standard for safety characteristics of hybrid mixtures: HYBRID II N2 - Safety characteristics are used for the safe operation of processes. Designing protection measures requires explosion characteristics to be determined, namely the maximum explosion pressure and the maximum rate of pressure rise. Safety characteristics of single-phase components (solid, liquid or gas) can be determined according to standards that were developed 40 years ago and are continuously improved. For hybrid mixtures containing a flammable gas and a combustible dust there has been an approach in the 80s but it has never been improved nor applied ever since (ISO 6184-3). A new approach by four German research facilities and the German Institute for standardization (DIN) with the aim of developing a new standard was launched in 2019. In 2022 the key findings led to a first international round robin test with eleven participating facilities from seven countries. The dust component was corn starch and methane was chosen as gas component. In order to strengthen the data foundation before finalizing and publishing the new standard, a second round robin test was initiated with hydrogen as gas component and lycopodium as dust. The paper will summarize the findings and their influence on the new standard. KW - Explosionsschutz KW - Anlagensicherheit KW - Konstruktiver Explosionsschutz KW - Hybride Gemische KW - Round robin tests KW - Hybrid mixtures KW - Industrial explosions KW - Safety characteristics PY - 2025 DO - https://doi.org/10.1016/j.jlp.2025.105560 SN - 1873-3352 VL - 94 SP - 1 EP - 6 PB - Elsevier Ltd. AN - OPUS4-62486 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heilmann, V. A1 - Spitzer, Stefan A1 - Dufaud, O. A1 - Hohenberger, M. A1 - Jankuj, V. A1 - Prodan, M. A1 - Zakel, S. T1 - European round robin on safety characteristics of hybrid mixtures from vapors and dusts N2 - As part of the development of a new standard testing procedure, a round robin study was conducted by six participating laboratories. This study involved the measurement of both the maximum explosion pressure and the maximum rate of pressure rise for hybrid mixtures comprising dust and vapor. Measurements were performed using a modified 20L-sphere. The primary objective of this collaborative effort was to assess the accuracy, reliability, and consistency of analytical and measurement methods across multiple laboratories, thereby increasing confidence in the obtained results. The method and protocol were developed as part of the NEX-HYS project and documented in a technical specification by the German Institute for Standardization Registered Association (DIN). The study revealed that precise pre-ignition pressure rise (PIPR) measurements and the use of a leak-free test apparatus significantly influenced the results of the measured maximum explosion pressure and maximum pressure rise rate. KW - Hybrid Explosions KW - Safety characteristics KW - Round robin KW - 20L-sphere PY - 2024 DO - https://doi.org/10.1016/j.jlp.2024.105273 SN - 0950-4230 VL - 88 SP - 1 EP - 5 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-59534 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR 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. 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 but are not standardized yet. Using the exploding wire, the ignition energy can be varied from 2 J to 10 000 J (2 x 5000 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 - Braunschweig, Germany DA - 27.07.2020 KW - Ignition source KW - Exploding wire KW - Hybrid mixtures KW - Safety characteristics determination PY - 2021 DO - https://doi.org/10.1016/j.jlp.2021.104516 SN - 0950-4230 VL - 71 IS - July SP - 1 EP - 15 PB - Elsevier CY - Amsterdam AN - OPUS4-52548 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spitzer, Stefan T1 - Influence of the pressure difference on the safety characteristics of dusts and potential ignition sources for hybrid mixtures N2 - In the standards for the determination of safety characteristics of dusts an initial pressure difference of 400 mbar (all: abs) is applied, that increases to 1013 mbar to achieve a homogeneous dust-air mixture. Since the measuring equipment accuracy is given with ± 0,1 bar the initial pressure could range somewhere between 300 and 500 mbar and the pressure increase between 500 and 700 mbar, leading to a testing pressure of 800 to 1200 mbar. This variation does not only affect the testing pressure but also the concentration of dust and the level of turbulence, leading to wrong values of Pmax, Kst and assigning them to wrong concentrations. When tests for hybrid mixtures are conducted there are more degrees of freedom leading to even higher variations. To overcome these variations a higher accuracy is demanded for hybrid mixture testing. Further, in this presentation four standardized ignition sources are presented. T2 - Global Dust Safety Conference CY - Halifax, Canada DA - 01.03.2021 KW - hybrid mixtures, ignition sources, safety characteristics PY - 2021 AN - OPUS4-53557 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jankuj, Vojtech A1 - Skrinsky, Jan A1 - Krietsch, Arne A1 - Schmidt, Martin A1 - Krause, Ulrich A1 - Kuracina, Richard A1 - Szabová, Zuzana A1 - Spitzer, Stefan T1 - Simplifying standards, opening restrictions Part I: The influence of the test vessel volume on the maximum explosion pressure of dusts N2 - Explosion characteristics are widely used in the process industries to determine the potential hazard of the used substances. In the American and European standards for determination of the maximum explosion pressure of dusts, the measured pressure is corrected if the tests are conducted in the 20L-sphere. This correction formula increases the measured values if they are above 5.5 bar g. It also causes, that the only two volumes for testing that are used are the standard 1m³ and the 20L-sphere because it is unclear whether corrections are necessary and, if so, what correction should be applied at other volumes. In this article explosion tests were performed with four different dusts, lycopodium, lignite, aluminum, and nitrocellulose, in four different vessel sizes: 20 L, 250 L, 365 L, and 1000 L to investigate the influence of the vessel size. KW - Explosion protection KW - Dusts KW - Pressure rise KW - Ignition PY - 2025 DO - https://doi.org/10.1016/j.jlp.2025.105556 VL - 94 SP - 1 EP - 7 PB - Elsevier Ltd. AN - OPUS4-62522 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spitzer, Stefan A1 - Jankuj, V. A1 - Krietsch, Arne 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 - Prag, Czechia DA - 06.06.2022 KW - Ignition source KW - Hybrid Mixtures KW - 20L-sphere PY - 2022 DO - https://doi.org/10.3303/CET2290087 SN - 2283-9216 VL - 2022 IS - 90 SP - 517 EP - 522 PB - AIDIC CY - Milano AN - OPUS4-55028 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spitzer, Stefan 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 - Braunschweig, Germany DA - 27.07.2020 KW - Ignition source KW - Exploding Wire KW - Safety characteristics determination KW - Hybrid mixtures PY - 2020 AN - OPUS4-51691 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spitzer, Stefan A1 - Recknagel, Christoph T1 - BAM-Monitoringkompetenz am Beispiel des Projekts INFUSE-SensoJoint N2 - Datenmanagement der realen Beanspruchungen von Betonautobahnen von der definierten Datenerfassung über Datenverwaltung, Datenübertragung bis zur Datenauswertung T2 - Workshop Digitaler Zwilling CY - BAM, Berlin, Germany DA - 04.06.2018 KW - Bitumen KW - Betonautobahn KW - Monitoring KW - Innovative Messtechnik PY - 2018 AN - OPUS4-45020 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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 -