Petra Andersson

Limitations of Water Mist as a Total Flooding Agent

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.

Performance of cables subjected to elevated temperatures

The time to damage, i.e., time to short circuit, and the corresponding temperature within the cable were recorded for two different data cables and one low voltage cable when subjecting the cables to an elevated surrounding temperature. In the experiments it was found that short-circuiting occurred at a certain temperature in the core of the studied cables. The heating of the cables was modeled with the aid of computer programs for thermal analysis and an analytical solution of heat conduction. The experimental results were used to evaluate the different models. Both the analytical solution and the use of the thermal analysis programs turned out to be promising. However, both the analytical solution and the use of computer programs such as TASEF require data of the thermal properties of the cables. This is a complication as such data are not easily accessible. To some extent the thermal properties of the cables could be estimated from the experimental results.

Small and Large Scale Fire Experiments with Electric Cables under Well-Ventilated and Vitiated Conditions

Results from a series of small scale (using the DIN 53 436 tube furnace) and large scale experiments (using the IEC 60332-3 rig) are presented for two types of power transmission cables used in buildings. The results are unique in that they catalogue the production of a wide variety of organic and inorganic species under different fire conditions. The experiments were conducted to provide input to an LCA model and the specific organic species studied in detail have been chosen based on the information required by the LCA model.During the process of this study it became apparent that information concerning quantitative organic species evolution from cable fires is lacking in the open literature. This paper aims to provide such information for two specific sets of fire conditions, i.e., a well-ventilated and a vitiated cable riser fire.

Fire Performance of Selected IT-Equipment

The results from a series of large scale tests are presented to establish the fire performance of a number of common pieces of IT equipment including: computer monitors, printers and CPUs. The monitors have been tested in a fully furnished scenario in the ISO 9705 room arranged in a typical bedroom setting and in a specially constructed 4 m × 5 m room arranged in a typical classroom setting. The other pieces of equipment have been tested directly under the furniture calorimeter. This paper presents HRR for the various tests and discusses the significance of the results in terms of fire safety. A discussion of available statistical and anecdotal information is presented in this context.

Ethical aspects of undergoing a predictive genetic testing for Huntington's disease

The aim of this study was to describe the experiences of undergoing a presymptomatic genetic test for the hereditary and fatal Huntington’s disease, using a case study approach. The study was based on 18 interviews with a young woman and her husband from the decision to undergo the test, to receiving the results and trying to adapt to them, which were analysed using a life history approach. The findings show that the process of undergoing a presymptomatic test involves several closely connected ethical and medical questions, such as the reason for the test, the consequences of the test results and how health-care services can be developed to support people in this situation.

Heat Sensing Manikin Test Probe

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.

Ethical aspects of a predictive test for Huntington’s Disease: A long term perspective

Background: A predictive genetic test for Huntington’s disease can be used before any symptoms are apparent, but there is only sparse knowledge about the long-term consequences of a positive test result. Such knowledge is important in order to gain a deeper understanding of families’ experiences. Objectives: The aim of the study was to describe a young couple’s long-term experiences and the consequences of a predictive test for Huntington’s disease. Research design: A descriptive case study design was used with a longitudinal narrative life history approach. Participants and research context: The study was based on 18 interviews with a young couple, covering a period of 2.5 years; starting 6 months after the disclosure of the test results showing the woman to be a carrier of the gene causing Huntington’s disease. Ethical considerations: Even though the study was extremely sensitive, where potential harm constantly had to be balanced against the benefits, the couple had a strong wish to contribute to increased knowledge about people in their situation. The study was approved by the ethics committee. Findings: The results show that the long-term consequences were devastating for the family. This 3-year period was characterized by anxiety, repeated suicide attempts, financial difficulties and eventually divorce. Discussion: By offering a predictive test, the healthcare system has an ethical and moral responsibility. Once the test result is disclosed, the individual and the family cannot live without the knowledge it brings. Support is needed in a long-term perspective and should involve counselling concerning the families’ everyday life involving important decision-making, reorientation towards a new outlook of the future and the meaning of life. Conclusion: As health professionals, our ethical and moral responsibility thus embraces not only the phase in direct connection to the actual genetic test but also a commitment to provide support to help the family deal with the long-term consequences of the test.

Environmental Assessment of fires in products using the fire LCA model

The environmental impact of products has been increasingly discussed in recent years. In response to questions of the environmental appropriateness of, for example, technologies used to attain a high level of fire safety, a model has been developed to quantify the emissions from fires and include this into a holistic treatment of the environmental impact of a product from the cradle to the grave. This model is based on Life-Cycle Assessment (LCA) methodology but represents a significant improvement over traditional LCA models that cannot include accidents such as fires. The Fire-LCA model has been tested in three case studies: TV, cables, and furniture. This article presents the model in detail, in particular focusing on the difference between the Fire-LCA model and traditional LCA models, using examples from the case studies.

An instrument for determining the total water content in air when extinguishing fires

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.

FREIA—an expert system for fires and explosions in the process industry

FREIA is a simple tool for evaluating industrial fire safety. It considers fires and the accidental release of hazardous substances both inside and outside buildings. It gives a rough estimate on whether certain components within a room will be damaged or not. The system has been used for evaluating fire safety in both the process industry and at power plants for several years, and an example of an evaluation is presented in this paper. The system has been found to be valuable in finding weak links in the fire safety system.