| 1. |
- Anderson, Johan, et al.
(author)
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FDS SIMULATIONS AND MODELLING EFFORTS OF TRAVELLING FIRES IN A LARGE ELONGATED COMPARTMENT
- 2019
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In: Interflam 2019, proceedings. - : Interscience Communications. ; , s. 2085-
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Conference paper (peer-reviewed)abstract
- The present paper investigates a travelling fire scenario in an elongated structure (Length 18 m x width 6 m x height 3 m) with a controlled fire source of six pans filled with diesel (width 4 m x length 0.5 m). The fire spread is controlled manually by initiating fires subsequently in the pools. Fire Dynamics Simulator (FDS) is used to a-priori investigate variations in geometry, material data and fire load whereas simulations using the final design were performed after the test. The input to the model beside fire source and geometry are thermal material data. The FDS simulation were used to determine the appropriate size of the downstands (2 m from the ceiling in the final design) on the side to create a sufficiently one-dimensional fire spread. The post test simulations indicate that although there are a lot of variations not included in the model similar results were obtained as in the test.
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| 2. |
- Anderson, Johan, et al.
(author)
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FDS simulations and modelling efforts of travelling fires in a large elongated compartment
- 2021
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In: Fire and Materials. - : John Wiley and Sons Ltd. - 0308-0501 .- 1099-1018. ; 45:6, s. 699-
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Journal article (peer-reviewed)abstract
- The present paper investigates a travelling fire scenario in an elongated structure (Length 18 m × width 6 m × height 3 m) with a controlled fire source of six trays filled with diesel (width 4 m × length 0.5 m). The fire spread is controlled manually by initiating fires consecutively in the pools. Fire dynamics simulator (FDS) is used to a-priori investigate variations in geometry, material data and fire load, whereas simulations using the final design and measured heat release rates (HRR) were performed after the test. The input to the model beside fire source and geometry are thermal material data. The FDS simulations were used to determine the appropriate size of the downstands (2 m from the ceiling in the final design) on the side to create a sufficiently one-dimensional fire spread. The post-test simulations indicate that although there are a lot of variations not included in the model similar results were obtained as in the test.
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| 3. |
- Brandon, Daniel, et al.
(author)
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Fire Safe implementation of visible mass timber in tall buildings – compartment fire testing
- 2021
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Reports (other academic/artistic)abstract
- Five real scale fire tests of compartments constructed of cross-laminated timber (CLT) and glued laminated timber, compliant with product standards specified in current US model building code, were performed. Four of the tested compartments were designed to result in a representative and severe fire scenario in a residential fire compartment, using a probabilistic approach. The other tested compartment had additional openings and a greater opening factor, which was aimed to be representative of buildings designed for business occupancy. The interior of the compartments had surface areas of exposed mass timber that varied from approximately the area of the floor plan to approximately two times the area of the floor plan. The tests included measurements to study the internal compartment exposure, the temperature development at gypsum protected surfaces, the temperature development in the structural timber, oxygen concentrations at locations of interest and exposure to exterior surfaces of the wall and façade above the openings. The fire in the compartment with a greater opening factor had two layers of fire-rated gypsum board protection on the back wall and all other surfaces of CLT and glued laminated timber exposed. Despite having the highest peak combustion rate, this compartment fire had the least severe internal and external fire exposure. The fire decayed relatively quickly after flashover and continued to decay until the test was stopped at 4 hours after ignition. This fire resulted in less structural damage than the fires in compartments with fewer and smaller openings. The compartments with fewer and smaller openings had similar temperatures for approximately the first 10 minutes after flashover. The compartment with only the ceiling (including the glued laminated timber beam) exposed started to decay after 22 minutes of post-flashover fire and continued to decay until the end of the test at 4 hours after ignition. The other three tests had, in addition to the ceiling, significant areas of exposed wall and column surfaces. To accommodate for the extended fire duration that was expected in these configurations an extra layer of gypsum board protection was applied to the protected surfaces. The additional exposed surface areas of walls led to an increase of the fully developed fire duration by 6 - 9 minutes. One of the compartments included corners where two exposed walls intersect. Significantly increased damage was observed in the lower part of these wall corners, and an overall higher radiative exposure in the test with such corners. After more than three hours of decay, surface flaming developed on the walls in that test. The fires in the tests without such corners exhibited continual decay for the full 4-hour test duration. Post-test analysis showed that the structural damage was lower in exposed ceilings than at the bottom of the exposed walls for all tests. After the tests, remaining smoldering and hot spots were reduced using relatively small amounts of water mist. Overnight measurements to study the thermal wave going through the loadbearing structure indicated no post-test reduction of structural capacity.
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| 4. |
- Brandon, Daniel, et al.
(author)
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Fire Safety of CLT Buildings with Ex-posed Wooden Surfaces : Summary Report
- 2020
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Reports (other academic/artistic)abstract
- Five real scale compartment fire tests, constructed of CLT slabs and glulam beam and column in accordance with current US product standards, were performed. The compartments had surface areas of exposed mass timber equal to up to two times the area of the floor plan. The 4 hours long tests showed that compartments with such quantities of exposed wood can exhibit continuous decay to hot-spots and embers after flashover. The tests indicate that the presence of two exposed wall surfaces in one corner should be avoided to ensure this.
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| 5. |
- Brandon, Daniel, et al.
(author)
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Predictive method for fires in CLT and glulam structures – A priori modelling versus real scale compartment fire tests & an improved method
- 2021
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Reports (other academic/artistic)abstract
- Predictive modelling of the fire duration, fire temperatures, heat release rates and the structural capacity during building fires can be used to show compliance with performance-based building code requirements. The predictive models presented in this report focusses on the post flashover fire including the decay phase and extinction of flaming combustion for mass timber structures. A priori predictions of five recent compartment fire tests have been set against experimental results and compared. After the tests, the model has been updated, mostly for increased ease of use and increased accuracy for the decay phase. The model consists of a single-zone model which uses an energy equilibrium approach to obtain gas temperatures and surface temperatures of compartment boundaries. The energy contribution of charring mass timber is included using through-depth temperature calculations of the structure and experimental relationships to determine the combustion rate. The through-depth temperatures of mass timber members also serve to provide information for structural calculations using temperature dependent reduced material properties. However, the structural calculations are out of the scope of the current report. The radiation conditions (and total thermal exposure to walls ceilings and floors) predicted by the updated model were accurately described the of recent full-scale experiments within the variations between and within the tests. The comparisons with experiments showed that the total heat is, however, underestimated in some cases and surface temperatures were underestimated in the decay phase. Local effects caused by a radiative feedback loop between surfaces that show significant char oxidation, which occurred in a part of the test, is not included in the model.
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| 6. |
- Burgén, Julia, et al.
(author)
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Safe and Suitable Firefighting
- 2022
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Reports (other academic/artistic)abstract
- The level of protection for personal protective equipment (PPE) in firefighting is important for Swedish shipowners; they want to be sure that the equipment they provide is sufficiently safe for the types of fires that can occur onboard. Shipowners also want to be updated on risks related to the carriage of alternative fuel vehicles (AFVs). Safety products and equipment used onboard ships with a European flag must be certified in accordance with the Marine Equipment Directive (MED) and follow the regulations in the International Convention for the Safety of Life at Sea (SOLAS). For fire suits, this means that they must be certified according to one of three standards listed in MED. Two of these standards cover suits used in special cases, with very intense radiant heat, and should only be worn for short periods. The third standard, EN 469, is the same standard that is referred to the PPE Regulation 2016/42, making EN 469-approved fire suits used among European firefighters ashore. However, EN 469 contains two different performance levels where the lower level is not suitable for protection against risks encountered when fighting fires in enclosures. Based on a user study and a risk assessment for AFVs, a set of suggested changes to MED and SOLAS were prepared, together with a set of recommendations for operators that were found important but not subject for regulations. A ready-to-use quick guide, containing the most important results, has been developed for operators.
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| 7. |
- Charlier, Marion, et al.
(author)
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TRAFIR: Characterization of TRAvelling FIRes in large compartments
- 2020
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Reports (other academic/artistic)abstract
- Inspection of recent fire events in large compartments reveals them to have a great deal of non-uniformity, they generally burn locally and move across floor plates over a period of time. This phenomenon which generates transient heating of the structure is idealized as “travelling fire”.A first series of tests was launched to define a fire load representative of an office building according to Eurocodes. Additional tests where the fire dynamics were controlled were launched to develop an understanding of the fire exposure to steel structures.Then, a second series of large scale tests were performed in real building dimensions. These tests had no artificial control over the dynamics, which allowed a realistic characterization of the fire. The fire load was identical for all tests, only the openings were modified.CFD numerical models were developed to reproduce the experimental campaign and to launch parametrical analyses. This allowed to provide information concerning the conditions which may lead (or not) to a travelling fire scenario.An analytical model for the characterization of a travelling fire was developed and implemented in a simple calculation tool. It allows to evaluate the fire location, the gas temperatures in the flames, the heat fluxes in the different parts of the compartment and the temperature in a steel member. In addition, the methodology is introduced in the FEM software SAFIR and OpenSees.Ultimately, a design guide was prepared including worked examples which are detailed step-by-step and for which the influence of the inputs on the results is analysed.
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| 8. |
- Gehandler, Jonatan, et al.
(author)
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BREND 2.0 - Fighting fires in new energy carriers on deck 2.0
- 2022
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Reports (other academic/artistic)abstract
- The project BREND investigated risk with alternative fuel vehicles inside ro-ro spaces. BREND 2.0 is a continuation and has in particular investigated two of the major risks identified in BREND, namely the risk of toxic gases from electric vehicle fires and the risk of a pressure vessel explosion for fire exposed biogas or hydrogen vehicle tanks. Simulations of electric vehicle fires inside a ro-ro space based on real input fire data has been performed. Field experiments that investigate the conditions that can lead to pressure vessel explosion were made with fire exposed biogas and hydrogen tanks. Recommendations are given about how ro-ro space fires in alternative fuel vehicles, or indeed any vehicle fire, can be managed.
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| 9. |
- Huang, Chen, et al.
(author)
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Modelling thermal runaway initiation and propagation for batteries in dwellings to evaluate tenability conditions
- 2022
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Reports (other academic/artistic)abstract
- Thermal propagation is one of the major challenges when batteries will be used in dwellings in large scale. It means the exothermic reactions in the cell are out of control and can lead to a fast release of flammable and toxic gases. In a system involving a large number of cells, thermal runaway can rapidly propagate from one battery cell to the whole system, which means substantial fire and explosion risks, an event that is important to mitigate and prevent. Multi-physics simulations together with full-scale testing is a cost-effective method for designing safer batteries. This project aims at simulating thermal runaway initiation and propagation using a multi-physics commercial software GT-Suite. A battery thermal runaway model containing 12 prismatic cells based on 3-D Finite Element approach was built using GT-Suite. The computed thermal runaway time instants versus thermal runaway cell number were compared with full-scale experimental data with reasonable agreement. Quantitative sensitivity study on the model input parameters and model space and time resolutions on the computed start time instant and time duration of thermal runaway were performed. The thermal runaway model was then extended with an electric equivalent sub-model to simulate the short circuit. With the electrical model acting as the input to the thermal model, the most interesting output of the simulation is the change in temperature of the cells, dependent on the current in the cells, with respect to time. The current is determined by the value of the external resistance through which the short takes place and the voltage level of the battery pack. The obtained results from the above short circuit simulations can only be used as a starting point and not as absolute values for neither triggering the thermal model nor for accurately simulating a battery under an electrical load. Furthermore, GT-Suite was applied to simulate the gas dispersion inside a room. A comparative study of the dispersion of toxic gases during thermal runaway, utilising an arbitrary release of HCN to represent the battery gases, in a small compartment with natural ventilation was investigated and the results compared the same situation simulated in FDS. The pipe based modelling supported by GT-Suite has limited applicability and overestimated the concentrations close to the ceiling whereas the lateral concentrations where underestimated. The multi-physics model for battery thermal runaway process is promising and worth to be applied with care for designing safer batteries in combination with full-scale testing.
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| 10. |
- McNamee, Robert, et al.
(author)
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The development of façade fire testing in Sweden
- 2022
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Reports (other academic/artistic)abstract
- Façade fire testing has been high on the agenda worldwide due to the increased hazard of many occurrences of severe fire spread on façades. There is also international work going on to create a European standard for façade fire testing. In this context it is interesting to clarify what different national test methodologies are based on. This report is a review of the development that led to the Swedish standard for assessing fire performance of façades, SP Fire 105. The review starts from the development in the 1950s with assessing fire exposure from compartment fires and follows further development until 1990s. The fire exposure in the first edition of SP Fire 105 published 1985 was based on two test campaigns including external flames from room fires performed at Lund University during the late 70-ties and early 80-ties. In the early 90-ties the geometry of the air intake in the combustion chamber and the opening under the test specimen was slightly reduced leading to a lower effective thermal exposure of the façade than in the first edition of SP Fire 105. An important observation done already in the 1950s at the Swedish fire laboratory in Stockholm and in the late 1970s at Lund University was that the wind is influencing the test results when doing experiments outside.
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