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Huang, C., De Grahl, J., Nessvi, K., Lönnermark, A. & Persson, H. (2019). Explosion characteristics of biomass dust: comparisonbetween experimental test results and literature data. In: : . Paper presented at Ninth International Seminar on Fire and Explosion Hazards (pp. 366-375).
Open this publication in new window or tab >>Explosion characteristics of biomass dust: comparisonbetween experimental test results and literature data
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2019 (English)Conference paper, Published paper (Refereed)
Abstract [en]

The design of explosion mitigation strategies e.g. vent design is mainly based on dust explosioncharacteristics such as the maximum explosion pressure XÇïÓ and the deflagration index n! of dustcloud, which are defined in various standards.The wood dust explosion characteristics can be directly obtained by performing standard tests, and testresults are also available in the literature. However, the parameters for one type of dust may varysubstantially in the literature. For example, the n! value for one wood dust is 11.4 times higher thananother wood dust in Gestis-Dust-Ex database. The reason for such large variation in explosionparameters is due to factors such as material properties, particle size distribution, particle shape, moisturecontent, turbulence level during tests and so on.The objectives of this paper are (i) to carry out dust explosion tests for XÇïÓ and n! for two wood dustswith well-described material parameters such as particle size distribution and moisture content accordingto European standards, (ii) to perform statistical analysis of wood dust explosion characteristics includingXÇïÓ and n! in the literature, (iii) to identify the effects of dust material parameters such as particle sizeand moisture contents on XÇïÓ and n! and (iv) to highlight the variation in XÇïÓ and n! and theimportance of obtaining knowledge about these properties of an individual dust, e.g. via dust explosiontests.

Keywords
biomass, wood dust, explosion, explosion overpressure, deflagration index
National Category
Engineering and Technology
Identifiers
urn:nbn:se:ri:diva-38809 (URN)10.18720/spbpu/2/k19-69 (DOI)9785742264965 (ISBN)
Conference
Ninth International Seminar on Fire and Explosion Hazards
Available from: 2019-05-15 Created: 2019-05-15 Last updated: 2019-05-17
Yao, Y., Li, Y. Z., Lönnermark, A., Ingason, H. & Cheng, X. (2019). Study of tunnel fires during construction using a model scale tunnel. Tunnelling and Underground Space Technology, 89, 50-67
Open this publication in new window or tab >>Study of tunnel fires during construction using a model scale tunnel
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2019 (English)In: Tunnelling and Underground Space Technology, ISSN 0886-7798, E-ISSN 1878-4364, Vol. 89, p. 50-67Article in journal (Refereed) Published
Abstract [en]

The paper presents a study on the characteristics of tunnel fires during construction. A model-scale tunnel was built and fire tests were conducted. The tunnel consists of an inclined access tunnel and a horizontal main tunnel. The main tunnel has two dead ends (excavation faces) and the only opening is from one side of the access tunnel. Propane gas burner and the fibre board soaked with the heptane were used as fuels. The flame characteristics, O 2 and CO volume fraction and gas temperature were measured and recorded. Two typical characteristics of self-extinguishment and smoke spread were found in the tunnel fires during construction. Results indicate that when a fire occurs in the horizontal main tunnel, the critical equivalence ratio for the occurrence of self-extinguishment is within 0.28–1.38 for the propane gas burner and 1.11–3.6 for the fibre board soaked with heptane. The difference is related to the burning behavior of the different fuels used. The fire location in the horizontal tunnel also has a significant influence on the fire development. A well-ventilated fire at the center of the horizontal tunnel becomes under-ventilated due to vitiation when it is located at the closed end of the horizontal tunnel. Besides, when a fire occurs at the closed end of the horizontal main tunnel, the stratification of smoke is destroyed after hitting the closed end, and then the smoke seems to spread over the entire cross section of the tunnel. The smoke spread velocity is found to be proportional to the ventilation rate. However, when a fire occurs at the closed end of the inclined access tunnel (lower end), the fire does not self-extinguish, even when the ventilation rate is 0 m 3 /s. The corresponding smoke spread velocity is higher than that in the horizontal main tunnel. The outcomes of this study provide new experimental information that contributes to improve the understanding of characteristics of tunnel fires during construction and can help firefighters to make better decisions during the rescue processes.

Place, publisher, year, edition, pages
Elsevier Ltd, 2019
Keywords
Equivalence ratio, Self-extinguishment, Smoke spread, Tunnel during construction, Tunnel fire, Under-ventilated, Fires, Gas burners, Heptane, Open access, Propane, Smoke, Ventilation, Equivalence ratios, Smoke spreads, Tunnel fires, Tunnels
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-38351 (URN)10.1016/j.tust.2019.03.017 (DOI)2-s2.0-85063487886 (Scopus ID)
Note

Funding details: China Scholarship Council; Funding details: Myndigheten för Samhällsskydd och Beredskap; Funding details: RISE; Funding text 1: This work was financially supported by the Swedish Civil Contingencies Agency (MSB) and the Tunnel and Underground Safety Center (TUSC) which are gratefully acknowledged. Thanks to the advisory group consisting of numerous representatives from industry and authorities for valuable comments and support. Thanks also to Jonatan Gehandler for the support and our technicians for technical assistance in carrying out the tests. Besides, the authors would also like to acknowledge China Scholarship Council for providing Yongzheng Yao with the opportunity to study at Research Institutes of Sweden (RISE).

Available from: 2019-05-07 Created: 2019-05-07 Last updated: 2019-05-07Bibliographically approved
Lönnermark, A. (2018). Brandsäker energilagring - Sammanställning av risker och forskningsbehov.
Open this publication in new window or tab >>Brandsäker energilagring - Sammanställning av risker och forskningsbehov
2018 (Swedish)Report (Other academic)
Alternative title[en]
Fire safety of energy storage systems - Summary of risks and research needs
Abstract [en]

There is a large interest in the possibilities in storing produced energy that is not needed at that particular moment or to store energy when the cost for production of electricity is low. For this reason, different types of energy storage systems are used. With a fast development of new technologies and new forms of application for energy storage systems, it is important to also study the existing and potential risks with these types of systems.

This prestudy describes the field, its risks and needs for research. It focuses on risks associated with fire, including explosions and when relevant the production of toxic gases. Although the main focus of the prestudy is different types of energy storage systems, the report contains information also on risks associated with storage of solid biofuels and waste. This means that the report contains information on risks and needs for research for batteries, hydrogen, biogas, liquified gases, biofuels and waste.

Publisher
p. 42
Series
RISE Rapport ; 2018:42
Keywords
energy storage system, fuel, energy carrier, fire safety, biofuel, waste
National Category
Energy Systems Engineering and Technology
Identifiers
urn:nbn:se:ri:diva-36322 (URN)978-91-88695-81-9 (ISBN)
Funder
Brandforsk, 701-171
Note

Detta arbete har utförts inom förstudien Brandsäker energilagring.

Available from: 2018-11-15 Created: 2018-11-15 Last updated: 2018-11-15Bibliographically approved
Sedlmayer, I., Arshadi, M., Haslinger, W., Hofbauer, H., Larsson, I., Lönnermark, A., . . . Bauer-Emhofer, W. (2018). Determination of off-gassing and self-heating potential of wood pellets – Method comparison and correlation analysis. Fuel, 234, 894-903
Open this publication in new window or tab >>Determination of off-gassing and self-heating potential of wood pellets – Method comparison and correlation analysis
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2018 (English)In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 234, p. 894-903Article in journal (Refereed) Published
Abstract [en]

Several methods for identifying the phenomena of self-heating and off-gassing during production, transportation and storage of wood pellets have been developed in recent years. Research focused on the exploration of the underlying mechanisms, influencing factors or the quantification of self-heating or off-gassing tendencies. The present study aims at identifying a clear correlation between self-heating and off-gassing. Thus, different methods for determining self-heating and off-gassing potentials of wood pellets are compared. Therefore, eleven wood pellet batches from the European market were analyzed. For this investigation, three methods for the determination of self-heating, like isothermal calorimetry, oxi-press and thermogravimetric analysis, and four methods for off-gassing, like volatile organic compound (VOC) emissions measurements, gas phase analysis of stored pellets in a closed container by offline and by glass flask method and determination of fatty and resin acids content, were performed. Results were ranked according to the self-heating and off-gassing tendency providing a common overview of the analyzed pellets batches. Relations between different methods were investigated by Spearman's correlation coefficient. Evaluation of the results revealed an equal suitability of offline and glass flask methods to predict off-gassing tendency and indicated a very significant correlation with isothermal calorimetry for the identification of self-heating tendency. The thermogravimetric analysis as well as the fatty and resin acids determination proved to be insufficient for the exclusive assessment of self-heating and off-gassing tendency, respectively.

Keywords
Carbon monoxide, Emission, Laboratory methods, Self-ignition, Storage
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-34788 (URN)10.1016/j.fuel.2018.07.117 (DOI)2-s2.0-85050894355 (Scopus ID)
Note

Funding details: 20569-4, Energimyndigheten; Funding details: 42002-1, Energimyndigheten; Funding details: 287026, EC, European Commission

Available from: 2018-08-15 Created: 2018-08-15 Last updated: 2019-02-05Bibliographically approved
Anderson, J., Sjöström, J., Lönnermark, A., Persson, H. & Larsson, I. (2017). Assessment of Self-Heating in Wood Pellets by FE Modelling. In: : . Paper presented at 12th International Symposium on Fire Safety Science. Lund Sweden.June 12–16, 2017. (pp. 14). Lund, Article ID 340.
Open this publication in new window or tab >>Assessment of Self-Heating in Wood Pellets by FE Modelling
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2017 (English)Conference paper, Published paper (Refereed)
Abstract [en]

The self-heating process in a laboratory scale experiment has been modelled using the Comsol Multiphysics software. In the simulations the gas flow and air movement in the volume and heat diffusion in the bulk were taken into account however only one reaction in the pellets bulk is considered. The input data is found from measurements of the reaction chemistry and the heat transfer properties. It is found that all relevant physics is needed in order to obtain reasonable predictions in particular the heat transfer between the bulk and the gas is important but also condensation and evaporation of moisture.   

Place, publisher, year, edition, pages
Lund: , 2017
Keywords
heat transfer; fluid dynamics; CFD; modeling; self-heating
National Category
Other Engineering and Technologies
Identifiers
urn:nbn:se:ri:diva-33323 (URN)
Conference
12th International Symposium on Fire Safety Science. Lund Sweden.June 12–16, 2017.
Note

The research leading to these results has received funding from the European Union Seventh Framework Programme (FP/2007-2013) under grand agreement n°287026.

Available from: 2018-02-27 Created: 2018-02-27 Last updated: 2019-01-22Bibliographically approved
Lönnermark, A. & Lange, D. (2017). Cascading effects during incidents: CascEff. In: Risk, Reliability and Safety: Innovating Theory and Practice - Proceedings of the 26th European Safety and Reliability Conference, ESREL 2016. Paper presented at 26th European Safety and Reliability Conference, ESREL 2016, 25 September 2016 through 29 September 2016 (pp. 18). , Article ID 181029.
Open this publication in new window or tab >>Cascading effects during incidents: CascEff
2017 (English)In: Risk, Reliability and Safety: Innovating Theory and Practice - Proceedings of the 26th European Safety and Reliability Conference, ESREL 2016, 2017, p. 18-, article id 181029Conference paper, Published paper (Refereed)
Abstract [en]

Modern socio-technical systems are increasingly characterised by high degrees of interdependencies. Whereas these interdependencies generally make systems more efficient under normal operations, they contribute to cascading effects in times of crises. Therefore, challenges for emergency preparedness and response are growing significantly. An escalating incident in such an environment can lead to severe cascading effects and quickly become extremely difficult for emergency services to handle. The more complex the environment where an incident is evolving, the more vulnerable the system, the greater the risk for escalation and cascading effects. In such instances the incident management needs to be as efficient as possible and build on up to date decision support information. New strategies, structures and methodologies are, therefore, needed to meet these new challenges, including cross border cooperation in conducting operations and providing or receiving support across borders.

Keywords
Decision support systems, Reliability, Reliability theory, Safety engineering, Cascading effects, Cross-border, Decision supports, Emergency preparedness and response, Incident Management, Normal operations, Sociotechnical systems, Emergency services
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-31087 (URN)10.1201/9781315374987-17 (DOI)2-s2.0-85016192271 (Scopus ID)9781138029972 (ISBN)
Conference
26th European Safety and Reliability Conference, ESREL 2016, 25 September 2016 through 29 September 2016
Note

Conference code: 181029; Export Date: 23 August 2017; Conference Paper

Available from: 2017-09-05 Created: 2017-09-05 Last updated: 2019-08-08Bibliographically approved
Larsson, I., Lönnermark, A., Blomqvist, P., Persson, H. & Bohlén, H. (2017). Development of a screening test based on isothermal calorimetry for determination of self-heating potential of biomass pellets. Fire and Materials
Open this publication in new window or tab >>Development of a screening test based on isothermal calorimetry for determination of self-heating potential of biomass pellets
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2017 (English)In: Fire and Materials, ISSN 0308-0501, E-ISSN 1099-1018Article in journal (Refereed) In press
Abstract [en]

For the risk for spontaneous combustion in storage of biomass pellets to be assessed, it is important to know how prone the fuel is to self-heating. There are traditional methods that are used to determine self-heating characteristics of fuels, eg, basket heating tests. The results from basket heating tests indirectly give the reactivity from a series of tests at high temperatures. This paper presents a sensitive screening test procedure for biomass pellets using isothermal calorimetry for direct measurement of the heat production rate at typical bulk storage temperatures. This method can be used to directly compare the reactivity of different batches of biomass pellets. The results could be used, eg, by storage security managers to gain better knowledge of their fuels propensity for self-heating and thereby for safer storage. A large number of tests have been performed to develop the test procedure presented. Different parameters, such as temperature, type of the test sample (powder/crushed or pellets), mass of test sample, and preheating time, have been varied. Furthermore, gas concentrations in the sample ampoule have been measured before and after some tests to study the oxygen consumption and the formation of CO and CO2. Three different types of pellets with different characteristics were tested to assess the variation in behaviour. Based on these tests, a screening test procedure is presented with a test temperature of 60°C, a sample size of 4 g, a 15-minute preheating period at the test temperature, and 24-hour test duration.

Keywords
Isothermal calorimetry, Pellets, Reactivity, Screening test, Self-heating, Wood pellets, Biomass, Calorimeters, Calorimetry, Carbon dioxide, Fuel storage, Fuels, Heating, Isotherms, Network security, Ore pellets, Pelletizing, Preheating, Reactivity (nuclear), Risk assessment, Screening, Spontaneous combustion, Technology transfer, Direct measurement, Gas concentration, Oxygen consumption, Screening tests, Test temperatures, Wood pellet, Testing
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-31124 (URN)10.1002/fam.2427 (DOI)2-s2.0-85019933108 (Scopus ID)
Available from: 2017-08-28 Created: 2017-08-28 Last updated: 2018-08-23Bibliographically approved
Lönnermark, A., Ingason, H., Li, Y. Z. & Kumm, M. (2017). Fire development in a 1/3 train carriage mock-up. Fire safety journal, 91, 432-440
Open this publication in new window or tab >>Fire development in a 1/3 train carriage mock-up
2017 (English)In: Fire safety journal, ISSN 0379-7112, E-ISSN 1873-7226, Vol. 91, p. 432-440Article in journal (Refereed) Published
Abstract [en]

To study what parameters that control the initial fire spread and the development to local flashover in a metro carriage, a total of six fire tests were conducted in a mock-up of a metro carriage that is about 1/3 of a full wagon length. They were carried out under a large scale calorimeter in a laboratory environment. The focus was on the initial fire development in a corner scenario using different types of ignition source that may lead to a fully developed fire. The ignition sources used were either a wood crib placed on a corner seat or one litre of petrol poured on the corner seat and the neighbouring floor together with a backpack. The amount of luggage and wood cribs in the neighbourhood of the ignition source was continuously increased in order to identify the limits for flashover in the test-setup. The tests showed that the combustible boards on parts of the walls had a significant effect on the fire spread. In the cases where the initial fire did not exceed a range of 400–600 kW no flashover was observed. If the initial fire grew up to 700–900 kW a flashover was observed. The maximum heat release rate during a short flashover period for this test set-up was about 3.5 MW. The time to reach flashover was highly dependent on the ignition type: wood cribs or backpack and petrol. A full developed carriage fire was achieved as a result of intense radiation from the flames and ceiling smoke layer. This was mostly dependent on the amount of fire load nearby the ignition source and how strong the vertical flame spread on the high pressure laminate boards mounted to walls and ceiling above the ignition source was, leading to a ceiling flame. In such cases, the seats alone did not contain sufficient fuel for the fire to spread within the train, and additional fuel (luggage) is required near the seats. For fully developed carriage fires, the fire starting on the seat in the corner spread to the opposite seat on the same side of the aisle, then horizontally spread to seats on the other side of the aisle, and finally a longitudinal flame spread along the carriage was observed. When and where the fire stopped or whether it reached a fully developed stage was mostly dependent on the amount of fire load nearby the ignition source and how strong the vertical flame spread on the high pressure laminate boards mounted to walls and ceiling above the ignition source was.

Keywords
Commuter train carriage, Flame spread, Flashover, Heat release rate, Metro, Transportation fire, Ceilings, Flammability testing, Gasoline, Laminates, Mockups, Commuter trains, Heat Release Rate (HRR), High pressure laminates, Ignition source, Laboratory environment, Maximum heat release rate, Fires
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-30282 (URN)10.1016/j.firesaf.2017.03.016 (DOI)2-s2.0-85019034401 (Scopus ID)
Available from: 2017-08-11 Created: 2017-08-11 Last updated: 2018-08-24Bibliographically approved
Larsson, I., Lönnermark, A., Blomqvist, P. & Persson, H. (2017). Measurement of self‐heatingpotential of biomass pellets with isothermal calorimetry. Fire and Materials, 41(8), 1007-1015
Open this publication in new window or tab >>Measurement of self‐heatingpotential of biomass pellets with isothermal calorimetry
2017 (English)In: Fire and Materials, ISSN 0308-0501, E-ISSN 1099-1018, Vol. 41, no 8, p. 1007-1015Article in journal (Refereed) Published
Abstract [en]

In order to assess the risk for spontaneous combustion of biomass pellets during storage it is important to know how prone the fuel is to self-heating, i.e. to determine the reactivity. 

This article presents the results from isothermal calorimetry tests performed on 31 different biomass pellet batches. The purpose of the tests has been to characterize pellets by measuring the reactivity and investigate how the pellet composition influences the heat release rate and thereby the self-heating potential of pellets. 

The results from the tests clearly indicate that there is a significant difference in reactivity between different types of pellets. The tested high reactive pellet batches reached maximum specific heat release rates (HRRmax) of 0.61-1.06 mW/g while pellet batches with low reactivity showed HRRmax of 0.05-0.18 mW/g. The tested batches were primarily ranked based on HRRmax but an alternative ranking based on specific total heat release rate during the test period was also used for comparison. 

The test results also indicate that pine/spruce mix pellets are significantly more reactive than all other types of pellets tested and that pellets consisting of 100 % pine are more reactive than pellets consisting of 100 % spruce. Pellets produced from wine pruning/grape pomace (winery wastes), straw or eucalyptus are not very reactive compared to pellets consisting of pine/spruce. 

The results also show that the reactivity of the pellets can be reduced by either introducing certain kinds of anti-oxidants into the pellets or by extracting lipids from the raw material of pellets.

Keywords
isothermal calorimetry, biomass pellets, wood pellets, self-heating, reactivity, screening test, isoterm kalorimetri, pellets, biomassa, självuppvärmning, reaktivitet, screeningtest
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-31275 (URN)10.1002/fam.2441 (DOI)2-s2.0-85032907190 (Scopus ID)
Funder
EU, FP7, Seventh Framework Programme, 287026
Available from: 2017-09-20 Created: 2017-09-20 Last updated: 2019-01-09Bibliographically approved
Anderson, J., Lange, D., Lönnermark, A. & Mindykowski, P. (2017). Modelling in wfds of a wildfire scenario. In: 15th International Conference and Exhibition on Fire and Materials 2017: . Paper presented at 15th International Conference and Exhibition on Fire and Materials 2017, 6 February 2017 through 8 February 2017 (pp. 765-776). Interscience Communications Ltd
Open this publication in new window or tab >>Modelling in wfds of a wildfire scenario
2017 (English)In: 15th International Conference and Exhibition on Fire and Materials 2017, Interscience Communications Ltd , 2017, p. 765-776Conference paper, Published paper (Refereed)
Abstract [en]

In this paper a coarse graining process is used to subsequently model large wildland fires, starting from a model of a single tree. The models are created using Wildland Urban Interface Fire dynamics Simulator (WFDS), and it is here found that reasonable fire spread in small forests can be obtained although the results are quite dependent on grid resolution as well as moisture content. In most realistic scenarios the computational volume is rather large yielding massive amounts of data. In using WFDS a rather small grid size is needed to appropriately model the fire spread this will be a severely limiting factor in creating large models.

Place, publisher, year, edition, pages
Interscience Communications Ltd, 2017
Keywords
Fire resistance, Coarse Graining, Computational volume, Fire dynamics simulator, Grid resolution, Large models, Realistic scenario, Wildland fire, Wildland urban interface, Fires
National Category
Engineering and Technology
Identifiers
urn:nbn:se:ri:diva-38099 (URN)2-s2.0-85035798316 (Scopus ID)9781510846746 (ISBN)
Conference
15th International Conference and Exhibition on Fire and Materials 2017, 6 February 2017 through 8 February 2017
Available from: 2019-03-08 Created: 2019-03-08 Last updated: 2019-06-27Bibliographically approved
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-6758-6067

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