| 1. |
- Andersson, Berit, et al.
(författare)
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Simulated Fires in Substances of Pesticide Type
- 1999
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In order to characterise fires in chemical warehouses, 38 medium scale experiments have been conducted. The experiments were performed in a 0.66m3 combustion chamber. On-line measurements were made of combustion gases (CO2, CO, HC and NOx), mass loss, smoke, temperatures, external radiation and phi-values. Intermittently gas and soot samples were collected and analysed for content of organic compounds and amount of soot produced. Main variables during the experiments were external radiation, fire diameter, opening configuration and ventilation condition. The medium scale was chosen in order to give a test method which is more convenient to work with, less expensive than full-scale experiments and still rather well simulates the conditions in a real fire.
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| 2. |
- Frantzich, Håkan, et al.
(författare)
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Brand och explosion
- 2003
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Ingår i: Risker i tekniska system. - 9144026641 ; , s. 275-299
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Bokkapitel (populärvet., debatt m.m.)
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| 3. |
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| 4. |
- Andersson, Berit, et al.
(författare)
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Combustion of Chemical Substances and the Impact on the Environment of the Fire Products: 1/3 Scale Room Furnace Experiments
- 1994
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report describes the results obtained from fire tests in a 1/3-scale room. The aim of the study was to investigate how changes in external radiation and oxygen supply affect the production of smoke and toxic gases. The ventilation was varied to simulate under- and well-ventilated fires. The thermal exposure to the materials was varied to simulate fires of different sizes. Fifty-nine tests were performed, with polystyrene, FR polystyrene, polypropylene, nylon and PVC. Measurements were made of the contents of O2, CO2, CO, NOx, and HC in the exhaust gases. The impact of external radiation was mainly to increase the pyrolysis rate, and thus the rate of heat release, and to drive the fire into under-ventilation. The degree of ventilation proved to have the greatest impact on the combustion efficiency. The smoke production was almost constant for polypropylene and nylon. The CO production appeared to be the most complex of the parameters to describe, and the expected increase in CO yield at low yields of CO2 could not be seen. The generation of NOx was low for the two substances without chemically bound nitrogen, but for nylon, the generation was significant. The production of low molecular weight HC was essentially constant for all three materials. Almost all the carbon was recovered in wellventilated fires, but at under-ventilated conditions, only 30% of the carbon from the he1 was detected. The toxic potency of the exhaust gases was estimated using the N-gas model, and proved to be relatively low. Lack of oxygen and the production of carbon oxide had the greatest impact on the toxicity for polystyrene and polypropylene, while NO, represented the main part for nylon. The survival fraction and the decomposition products from the original materials are not considered in the model. It can therefore not be assumed that the model reflects all aspects of the toxicity problem.
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| 5. |
- Andersson, Berit, et al.
(författare)
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Combustion products generated by hetero-organic fuels on four different fire test scales
- 2005
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Ingår i: Fire Safety Journal. - : Elsevier BV. - 0379-7112. ; 40:5, s. 439-465
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Tidskriftsartikel (refereegranskat)abstract
- The scaling of results from combustion experiments with four organic substances containing heteroatoms, carried out on four different scales, is discussed. The scales ranged from the micro-scale, using about 2 x 10(-3) kg of the substances, to large scale using about 50 kg of the substances. The content of O-2, CO, CO2, NOx, HCl, HCN and SO2 in the combustion gases were determined with special attention to the survival fractions of the tested substances and the amount of unburned hydrocarbons. The global equivalence ratio (GER) was used to describe the ventilation conditions during the experiments. The conditions were adjusted to range from under- to well-ventilated situations. It was found that the GER is not the only parameter that influences the production of combustion gases. Other parameters such as temperature and residence time also seem to be important in explaining the results. The experiments were performed as a part of the TOXFIRE project within the EC Environment programme.
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| 6. |
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| 7. |
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| 8. |
- Andersson, Berit, et al.
(författare)
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Naturgas Säkerhetsnivå Riskanalys
- 1994
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna rapport har tillkommit på uppdrag av NUTEK och avser att belysa riskerna med distribution och industriell användning av naturgas. Tidigare har en rapport avseende naturgasinstallationer i hemmen utgetts [1,2]. Rapporten inleds med en allmän diskussion om risker. Vidare tas frågan om lagstiftning, tillsyn, kontroll och utbildning för naturgasanvändning i olika lander upp. Dessutom har en retrospektiv sökning efter statistik om naturgasolyckor samt incidenter gjorts. En kort genomgång av hur man beräknar konsekvenser av naturgasutsläpp görs också.
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| 9. |
- Andersson, Petra, et al.
(författare)
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An instrument for determining the total water content in air when extinguishing fires
- 1999
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Ingår i: Fire and Materials. - 1099-1018. ; 23:4, s. 187-192
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Tidskriftsartikel (refereegranskat)abstract
- n instrument suitable for measuring the total water content both as small liquid droplets and as vapour in the air, in water mist total flooding extinguishing tests, is presented. The instrument consists of a heater and a Vaisala humidity meter. The Vaisala humidity meter is capable of measuring relative humidity at temperatures up to 180°C. The instrument has a measuring range of 0-600g/m3, a sample rate of 1 L/min, a time constant of 5-10 s and an accuracy of ±40 g/m3. Accurate results are obtained when used outside the direct spray from a nozzle. If the instrument is placed in the spray the total water content can be either over- or underdetermined, depending on which part of the instrument faces the spray.
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| 10. |
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| 11. |
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| 12. |
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| 13. |
- Andersson, Petra, et al.
(författare)
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Heat Sensing Manikin Test Probe
- 2000
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Ingår i: Fire and Materials. - 1099-1018. ; 24:4, s. 195-199
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Tidskriftsartikel (refereegranskat)abstract
- A manikin test probe has been developed to simulate the thermal behaviour of human skin when exposed to thermal conditions likely to occur in fires. The threshold for second-degree burn injuries is evaluated from the temperature readings using a damage integral. The probe has been exposed to different radiation fluxes and the calculated damage criterion for second-degree burn injuries is in agreement with data from the literature on human skin and pig skin. Probes mounted on a manikin have been used to assess how the extent of burn injuries develop as a function of time on a fully dressed pilot inside a military aeroplane surrounded by a large pool fire. In another scenario burn injuries for humans inside a fire room are assessed when a super-heated water mist extinguishing system is activated.
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| 14. |
- Andersson, Petra, et al.
(författare)
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Heat sensing manikin test probe
- 2000
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Ingår i: Fire and Materials. - 0308-0501 .- 1099-1018. ; 24, s. 195-199
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 15. |
- Andersson, Petra, et al.
(författare)
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Limitations of Water Mist as a Total Flooding Agent
- 1998
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Ingår i: Journal of Fire Protection Engineering. - : SAGE Publications. - 1042-3915. ; 9:4, s. 31-50
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Tidskriftsartikel (refereegranskat)abstract
- The limitations of water mist in acting as a total flooding agent are discussed in this paper. The paper focuses on water mist consisting of droplets 1-100 µm in diameter. Water mists are very efficient as an extinguishing media if they are present in the flame. There are, however, several problems associated with introducing the water mist into the flame: the spray reaches only a short distance; small water droplets have a very short lifetime; droplets coagulate into larger droplets; large droplets hit obstacles such as walls and therefore have difficulties in being dispersed throughout the protected volume.
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| 16. |
- Andersson, Petra, et al.
(författare)
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Small scale experiments and theoretical aspects of flame extinguishment with water mist
- 1996
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The present study focuses on extinction of flames with water mist where surface cooling effects are neglected i.e. water mist as a total flooding system where the direct spray cannot reach and cool all burning items in the protected volume. The study includes a survey of the production and properties of water mist such as different types of nozzles and means to describe droplet size distribution. Properties of jets and sprays are discussed as well as water droplet movement, fall and evaporation. Three different series of experiments were conducted with different hydraulic atomising nozzles. In the first series, droplet size distribution and water spray distribution measurements for the nozzles were conducted. The measurements showed that the droplet size distribution ranged from a Sauter Mean Diameter of approximately 35 - 85 µm, all dependent on the water pressure and the configuration of nozzles. The measurements show that considerably larger droplets are formed when individual nozzles are placed together. This can be explained by a coalescence effect when droplets from the sprays of the nozzles collide. The second series of experiments were done using a tubular propane gas bumer where water and propane were mixed prior to reaching the burner outlet. Based on the tests, the specific amount of extinguishing medium required (Required Extinguishing Medium Portion, REMP = m, / m, i.e. the ratio of the agent quantity to fuel quantity consumed) is given as a quantitative measure of the efficiency of the agent. The lower the REMP value, the more efficient the agent. The water pressure ranged between 40 and 80 bar which provided for droplet sizes with a Sauter Mean Diameter in the order of 35 pm. The results show that the amount of water needed for extinguishment by weight is between 1.2 - 2,2 times the amount of propane gas. The decrease in droplet sizes decreased the amount of water needed. Another observation was that the heat release rate of the fire is not affected until extinction occurs. A REMP-value of 1,2 - 2,2 corresponds to a water content of 100 – 200 g/m3 protected volume which is in agreement with theoretical values. Finally, a series of tests were conducted in a 113 scale room using a propane gas fire. Parameters such as location of the fire, the location of the nozzle, water flow rate and the size of the room opening were varied. In these tests the water content needed was in close agreement with the values obtained from the REh4P experiments and the theoretical values. These tests also highlighted the problem of delivering the droplets to the fire. To achieve "total flooding" in an actual situation, nozzles covering the complete protected compartment, with additional nozzles under obstructions would be needed. To make droplets follow the air flows inside a room and behave more like a gaseous total flooding agent, requires droplets of a size in the order of 1 - 20 µm.
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| 17. |
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| 18. |
- Blomqvist, Per, et al.
(författare)
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An experimental study of spontaneous ignition in storages of wood pellets
- 2007
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Ingår i: 10th International Conference - Fire and Materials 2007.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This article focuses on experimental studies of self-heating characteristics of wood pellets. Controlled experiments have been conducted in physical scales from 1 dm3 to 4 m3 with wood pellets. Basket tests have been conducted according to the "crossing-point method" to derive kinetic data on the exothermic reactions responsible for self-heating and eventually spontaneous ignition. The kinetic data was used in the planning of the large-scale experiments for predictions of approximate critical temperatures. The experiments in the 1 m3 scale were set-up basically as an enlargement of the basket tests to obtain validation experiments with controlled boundary conditions in a reasonable large scale. Several experiments were conducted and spontaneous ignition was seen in the centre of the pellet bulk at an ambient temperature of 115C. The close to real-scale experiments with 4 m3 wood pellets filled in a 6 m high silo were not strictly self heating experiments, instead a core shaped heating element was allowed to initiate the pyrolysis in the pellets. Heat and gas production and transportation from the growing pyrolysis zone were mapped with a large number of measurement points in the pellets bulk and in the top of the silo. The experimental work conducted gave kinetic data on the exothermic reactions in wood pellets, insight in self heating processes, a link between different experimental scales and knowledge regarding possibilities for detection of fires in storages of wood pellets.
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| 19. |
- Blomqvist, Per, et al.
(författare)
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Fires in storages of biofuels
- 2007
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Ingår i: Fire and Materials 2007 Proceedings.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 20. |
- Bohgard, Mats, et al.
(författare)
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Arbetsmiljö vid termisk ogräsbekämpning
- 1988
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Rapporten behandlar arbetsmiljön vid termisk ogräsbekämpning. Metoden innebär att ogräset hettas upp med hjälp av gaslågor. Både stora fordonsburna och mindre handdrivna används. Det som från arbetsmiljösynpunkt är speciellt med metoden är de risker som är förknippade med gasolanvändningen. De allvarligaste problemen med de aggregat som studerats har varit heta och oskyddade plåtar, heta avgaser och brister i komponentval när det gäller slangar och kopplingar. I rapporten ges anvisningar om åtgärder för att minska riskerna avseende komponentval, säkerhetsanordningar och utbildning. Bland myndighetskrav på utrustning kan nämnas att leverentatörer ska lämna säkerhetsanvisningar på svenska samt att arbetet inte får utföras av minderåriga. Den psykosoicala miljön har också undersökts. De operatörer som intervjuats har upplevt arbetet positivt.
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| 21. |
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| 22. |
- Göransson, Ulf, et al.
(författare)
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Numerical and experimental investigation of flame spread over a PMMA surface
- 2004
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Ingår i: [Host publication title missing].
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Konferensbidrag (refereegranskat)abstract
- The objective of this study is the experimental and numerical investigation of flame spread over a PMMA surface. A series of upward flame spread tests were carried out in a cylindrical combustion room, with measurements made for gas velocity, surface temperature and surface heat fluxes. A CFD based flame spread model was then used for the simulation of the experiment. This model consists of a four-equation turbulence model, an eddy-break-up (EBU) combustion model, a discrete transfer (DT) radiation model, a statistical narrow band (SNB) gas model, a soot model, and a pyrolysis model for non-charring solids. Comparison was made between the numerical predictions and the experimental data. A reasonable qualitative agreement was found between two sets of data.
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| 23. |
- Hertz, H.M., et al.
(författare)
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High voltage measurement system based on a capacitively coupled Pockels cell
- 1987
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Ingår i: Proc. SPIE - Int. Soc. Opt. Eng. (USA). ; 701, s. 8-226
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A fiber-optical system for measurements of fast high voltage pulses has been developed. The system is based on capacitively coupled Pockels cell voltage sensor and features excellent rejection of electrical interference, large bandwidth and practically unlimited voltage range. The authors describe the principle of operation and give a preliminary discussion of the performance of the measurement system
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| 24. |
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| 25. |
- Holmstedt, Göran, et al.
(författare)
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Detector environment and detector response : a survey
- 1987
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- 1. The survey has mainly concentrated on the following items: the false alarm problem, the problem of the fire not being detected due to the fact that pre-fire heating and ventilation dominate flow inside the compartment, a description of detector sensitivity to fire signatures. engineering design methods for the siting of detectors. 2. The statistical as well as practical experience suggests that alarm systems in Sweden, follow international trends regarding rates of false alarms. 3. For existing systems, especially the older ones, introduction of a proper alarm organisation, regular training of the technical maintenance staff and/or desensitization may be appropriate measures to reduce the false alarm rate. 4. Analysis shows that desensitization of existing systems must be done with care so life hazard is still kept under control. 5. In addition to the remedies mentioned under point 3 it might be effective to revise the siting standard rules in RUS 110 in the light of the information obtained for example in the Norwegian investigation. 6. A revision of RUS 110 should also be based on scaled down physical modelling and the use of numerical modelling (field modelling) in order to investigate local flow field characteristics: the influence of beamed ceilings, ventilation in and outflow. a thermally stratified pre-fire atmosphere, etc. 7. In order to take consideration of various fire developments rates and varying ceiling heights, standard siting distance should be calculated according to the design model described in NFPA 72E Appendix C for heat detectors. 8. For smoke detectors, a more rational use of the information obtained in the EN54/9 sensitivity test standard fires should be investigated. 9. Point 3 mentioned existing systems. For new and future systems the gradual improvement in software control (alarm verification procedures. automatic compensation for regular variation in ambient conditions, automatic change of sensitivity to compensate for the gradual accumulation of dust and dirt, filtering of electronic signal spikes, checking of electric circuit integrity etc) is thought to dramatically reduce false alarm rates. 10. Efficient pattern-recognition algorithms for separating fire process environments from the aerosols produced by welding, trucks exhaust, smoking etc may be hard to produce: the aerosol characteristics are too much alike. Algorithms based on use of data from a group of sensors ("group decision") should be more reliable but may be too complex. In theory, if sensor response to monodisperse aerosols is known and with standard test fire aerosol characteristics experimentally measured, sensor output during the standard test fires should be easily calculable and a first check obtained on the discrimatory capability of pattern recognition algorithms. No information of this kind has been found.
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