| 1. |
- Boulet, Pascual, et al.
(författare)
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Radiation emission from a heating coil or a halogen lamp on a semitransparent sample
- 2014
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Ingår i: International Journal of Thermal Sciences. - : Elsevier BV. - 1290-0729. ; 77:March, s. 223-232
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Tidskriftsartikel (refereegranskat)abstract
- The radiation emission of the heating coil of a Cone Calorimeter and the one of the halogen lamp of a Fire Propagation Apparatus have been studied experimentally for varying power settings. These are two standard apparatuses used for fire calorimetry. The objective is to characterize and compare the radiative flux spectrum received by a fuel sample during pyrolysis experiments. The deviation from the standard assumption of black or gray emission is discussed. It is observed that the emission of the heating coil can be approximated well to an ideal blackbody, especially in the infrared range. On the contrary, the halogen lamp emission is more complex, non gray, with an important contribution in the visible and in the near infrared ranges. The flux received by a sample exposed to these emitters is predicted using ray tracing simulations. This shows that the irradiation flux and spectrum from the cone can be accurately calculated if the coil temperature is known. The non Lambertian irradiation flux from the lamp is modeled with a combination of diffuse and collimated intensities, representing the direct emission from the lamp itself and the reflection by the mirror at the rear side. For both emitters, the irradiation is confirmed to be approximately uniform over the surface of a sample 5 cm large (maximum deviation of ±2% on the incident flux). The uniformity decreases for larger samples, but the ratio of the flux at the center to average flux is still 1.04 for standard 10 cm × 10 cm samples under the cone. For illustration purposes, the influence of the spectral characteristics of the emitter is studied in the case of a sample of PMMA, a non gray translucent medium. Using recently published measurements of PMMA absorptivity, the absorbed flux by a 3 cm thick sample is predicted. In the case of an incident flux of 20 kW/m2, the calculated average absorptivity of the sample is 0.91 under the cone, while it is 0.32 under the FPA lamp. These calculations involve absorption data of a virgin sample at room temperature and consequently the numerical results only hold for the initial instants of irradiation. However, the very large differences in radiative behavior show that important discrepancies in the pyrolysis behavior are expected between the two emitters. This might have consequences for fire testing and inter comparisons of flammability results worth further investigation.
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| 2. |
- Kinateder, Max, et al.
(författare)
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Virtual Reality for Fire Evacuation Research
- 2014
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Ingår i: Federated Conference on Computer Science and Information Systems. - 2300-5963. ; 2, s. 313-321
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Konferensbidrag (refereegranskat)abstract
- Virtual reality (VR) has become a popular approach to study human behavior in fire. The present position paper analyses Strengths, Weaknesses, Opportunities, and Threats (SWOT) of VR as a research tool for human behavior in fire. Virtual environments provide a maximum of experimental control, are easy to replicate, have relatively high ecological validity, and allow safe study of occupant behavior in scenarios that otherwise would be too dangerous. Lower ecological validity compared to field studies, ergonomic aspects, and technical limitations are the main weaknesses of the method. Increasingly realistic simulations and other technological advances provide new opportunities for this relatively young method. In this position paper, we argue that VR is a promising complementary laboratory tool in the quest to understand human behavior in fire and to improve fire safety.
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| 3. |
- Uadiale, Solomon, et al.
(författare)
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Overview of problems and solutions in fire protection engineering of wind turbines
- 2014
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Ingår i: Fire Safety Science. - : International Association for Fire Safety Science. ; , s. 983-995
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Konferensbidrag (refereegranskat)abstract
- The wind energy industry is one of today's leading industries in the renewable energy sector, providing an affordable and sustainable energy solution. However, the wind industry faces a number of challenges, one of which is fire and that can cast a shadow on its green credentials. The three elements of the fire triangle, fuel (oil and polymers), oxygen (wind) and ignition (electric, mechanical and lighting) are represent and confined to the small and closed compartment of the turbine nacelle. Moreover, once ignition occurs in a turbine, the chances of externally fighting the fire are very slim due to the height of the nacelle and the often remote location of the wind farm. Instances of reports about fires in wind farms are increasing, yet the true extent of the impact of fires on the energy industry on a global scale is impossible to assess. Sources of information are incomplete, biased, or contain non-publically available data. The poor statistical records of wind turbine fires are a main cause of concern and hinder any research effort in this field. This paper aims to summarise the current state of knowledge in this area by presenting a review of the few sources which are available, in order to quantify and understand the fire problem in wind energy. We have found that fire is the second leading cause of catastrophic accidents in wind turbines (after blade failure) and accounts for 10 to 30% of the reported turbine accidents of any year since 1980's. In 90% of the cases, the fire leads to a total loss of the wind turbine, or at least a downtime that results in the accumulation of economic losses. The main causes of fire ignition in wind turbines are (in decreasing order of importance): lighting strike, electrical malfunction, mechanical malfunction, and maintenance. Due to the many flammable materials used in a wind turbine (eg. fiberglass reinforced polymers, foam insulation, cables) and the large oil storage used for lubrication of mechanical components, the fuel load in a turbine nacelle is commonly very large. The paper finishes with an overview of the passive and active protection options and the economics (costs, revenue and insurance) of wind turbines to put in context the value of a loss turbine compared to the cost and options of fire protection. We hope that this paper will encourage the scientific community to pursue a proper understanding of the problem and its scale, allowing the development of the most appropriate fire protection engineering solutions.
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