| 1. |
- Hansen, Rickard, 1968-
(författare)
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Study of heat release rates of mining vehicles in underground hard rock mines
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A unique study on fire safety in hard rock underground mines with focus on heat release rates of mining vehicles is presented. A literature inventory was conducted with respect to fires in underground hard rock mines, which revealed that the most common fire cause in underground mines was flammable liquid sprayed onto hot surface and the most common fire object was a vehicle. A major concern was the lack of documented fire experiments in mining vehicles and heat release rate curves. It also revealed the limited research carried out on fire safety and fire development on vehicles found in hard rock underground mines.In order to fill the gap of knowledge lack on heat release rates, fire experiments were carried out on wood cribs and wooden pallets in a model-scale tunnel with longitudinal ventilation where the distance between the fuel items were kept constant as well as varied. Different ignition criteria were applied in the ensuing calculations. It was found that the critical heat flux criterion generally showed very good agreement with the corresponding results of performed fire experiments but tended to have too short ignition times when the distance between the fuel items was increased. The ignition temperature criterion generally performed poorly compared with the measured results, but it was found that the accuracy improved considerably as the distance between the fuel items and the amount of energy accumulated on the fuel surface was increased.As a final approach, two full-scale fire experiments were carried out in an operative underground mine using a wheel loader and a drilling rig respectively. The resulting heat release rates of the experiments were compared with calculated overall heat release rates applying the different ignition criteria. It was found that the critical heat flux criterion resulted in ignition times very close to the observed ignition times. The ignition temperature criterion resulted in surface temperatures that never achieved the corresponding ignition temperatures. Some difficulties were experienced when calculating the heat release rate curve of the wheel loader, as it was difficult to accurately predict the mechanical failure of a significant part initiating the highly significant fire in the hydraulic oil. Additional heat terms were added to the heat balance, where the added flame radiation term was found to have a large impact on the output results while the heat loss terms were found to have very little effect.
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| 2. |
- He, Kun, et al.
(författare)
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Fire spread among multiple vehicles in tunnels using longitudinal ventilation
- 2023
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Ingår i: Tunnelling and Underground Space Technology. - : Elsevier. - 0886-7798 .- 1878-4364. ; 133
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Tidskriftsartikel (refereegranskat)abstract
- The characteristics of fire spread among multiple vehicles in tunnels using longitudinal ventilation were investigated by analyzing the experimental data from a series of fire tests in a 1:15 scale tunnel. Further, a simple theoretical model for gas temperature in a tunnel with multiple fire sources was proposed and used in analysis of the experimental data. The results showed that, for objects (wood piles) placed at a same separating distance downstream of the fire, the fire spread occurred faster and faster along the tunnel. Validation of the simplified temperature model for multiple fire sources was made against both model and full-scale tunnel fire tests. The model was further used to predict the critical conditions for fire spread to the second and third objects. Comparisons with the test data showed that average excess temperature of 465 K (or an equivalent incident heat flux of 18.7 kW/m2) could be used as the criterion for fire spread, and this was verified further by other model-scale tests and full-scale tests. The results showed that the critical fire spread distance monotonously increases with the heat release rate, and decreases with the tunnel perimeter. For multiple fire sources with equivalent heat release rates, as the separation distance between the first two fire sources increases, the critical fire spread distance from the second fire source to the third fire source decreases, but the total fire spread distance from the first fire source to the third one increases. If the total heat release rate at the site of a downstream fire source is greater than that at the former fire source, the critical fire spread distance becomes longer.
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| 3. |
- Kumm, Mia, 1967-, et al.
(författare)
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Räddningsinsatser med och utan säker tillgång till släckvatten i spårtunnlar
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Rapporten avses att utgöra ett stöd för planering och riskbedömning inför och vid räddningsinsatser i spårtunnlar. Rapporten sammanfattar tidigare forskning och kunskap avseende branddynamik i tunnlar, räddningstjänstens förflyttning vid insats, brandsläckning i fordon samt insatshöjande åtgärder i form av såväl bärbar teknik och utrustning som permanenta installationer i tunneln.Räddningsinsatser i tunnlar har traditionellt innefattat samtidig slanguppbyggnad, baserat på tolkningen av arbetsmiljöföreskrifterna för rökdykning (AFS 2007:7) samt förfarandet vid rökdykarinsatser vid brand i byggnad. Förhållandena vid bränder i byggnader och vid bränder i tunnlar skiljer väsentligt. I en byggnad är tillgången till säker vattenförsörjning en förutsättning för rökdykarens säkerhet. I en tunnel, där ytskikten är obrännbara, brandgaserna inte ansamlas i ett begränsat utrymme och berget kyler brandgaserna längre bort från branden, är inte alltid tillgången till säker vattenförsörjning det som bäst tillgodoser säkerheten för räddningstjänstens personal när arbetsmoment som inte innefattar släckning genomförs. Detta innebär inte att kraven på säkerhet ska sänkas, utan att andra åtgärder som bibehåller eller höjer säkerhetsnivån behöver vidtas. Sådana åtgärder kan vara utökad användning av värmekamera, utökad övervakning av luftförsörjningen, tekniska installationer som stödjer orientering och vägledning samt utrustning, exempelvis spårbundna räddningstrallor, som medför snabbare förflyttning och minskad luftförbrukning.I rapporten föreslås en indelning i fyra zoner, som direkt kopplar till de branddynamiska förhållanden som råder i respektive zon. Förenklat innebär zonindelningen följande:Kall zon – Ingen risk för rökfyllnad. Ingen risk för värmepåverkan från branden.Sval zon – Viss risk för rökfyllnad. Ingen risk för värmepåverkan från branden.Varm zon – Delvis eller helt rökfylld tunnel, men liten risk för värmepåverkan från branden.Het zon – Direkt påverkan från branden. Brand eller risk för brand.Till respektive zon kopplas sedan relevanta skyddsnivåer och det arbete som bedöms kunna genomföras beskrivs. I varm zon bedöms arbete kunna genomföras utan tillgång till säkert vatten, utom i de fall syftet med arbetet är att bygga upp vattenförsörjning för senare arbete i het zon. I het zon ska alltid säker tillgång till vattenförsörjning finnas.En viktig del av en säker insats i tunnlar, med eller utan säkert vatten, är den kunskap som både den enskilde rökdykaren och de befäl som beslutar om operativa eller strategiska åtgärder behöver besitta. Rapporten ger därför både en vetenskaplig grund för beslut och pekar på indikatorer som kräver övervakning i syfte att säkerställa rökdykarnas arbetsmiljö.
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| 4. |
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Proceedings from the Eighth International Symposium on Tunnel Safety and Security, Borås, Sweden, March 14-16, 2018
- 2018
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Proceedings (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
- This report includes the Proceedings of the 8th International Symposium on Tunnel Safety and Security (ISTSS) held in Borås, Sweden, 14-16th of March, 2018. The Proceedings include 41 papers given by session speakers and 16 extended abstracts presenting posters exhibited at the Symposium. The papers were presented in 12 different sessions. Among them are Fire Safety Engineering: Cases & Incidents, Fire Safety Engineering: The Aims, Fire Detection, Explosions, Risk Analysis, Fire Safety Engineering: Case studies, Ventilation, Fire Safety Engineering: State of the Art, Fire Dynamics, Fixed Fire Fighting Systems (FFFS) and Evacuation and Human Behavior.Each day was opened by invited Keynote Speakers (in total six) addressing broad topics of pressing interest. The Keynote Speakers, selected as leaders in their field, consisted of Hans Brun, the Swedish Defence University, Dr Iain Bowman, Mott MacDonald, Canada, Dr Ying Zhen Li, RISE Research Institutes of Sweden, Dr Johan Lundin, WSP, Sweden, Allan Skovlund, Greater Copenhagen Fire Department, Denmark and Prof David Purser, Hartford Environmental Research, UK. We are grateful that the keynote speakers were able to share their knowledge and expertise with the participants of the symposium.
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| 5. |
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Proceedings from the Ninth International Symposium on Tunnel Safety and Security, Munich, Germany, March 11-13, 2020
- 2020
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Proceedings (redaktörskap) (refereegranskat)abstract
- This report includes the Proceedings of the 9th International Symposium on Tunnel Safety and Security (ISTSS) held in Münich, Germany, 11-13th of March, 2020. The Proceedings include 42 papers given by session speakers and 13 extended abstracts presenting posters exhibited at the Symposium. The papers were presented in 12 different sessions. Among them are Keynote sessions, Tunnel Safety Concepts, Fire Dynamics, Risk Analysis 1&2, Tunnel Safety Design Concepts, Poster Corner, Explosion Hazards, Active Protection 1&2, Emergency Management, Ventilation, Passive Protection and Evacuation. Each day was opened by invited Keynote Speakers (in total six) addressing broad topics of pressing interest. The Keynote Speakers, selected as leaders in their field, consisted of Anne Lehan, German Highway Research Institute, Germany, Marc Tesson, Centre for Tunnel Studies (CETU), France, Trond H. Hansen, Oslo Fire and Rescue Service, Norway, Mia Kumm, RISE, Sweden, Roland Leucker, Research Association for Tunnels and Transportation Facilities (STUVA), Germany and Rune Brandt, HI Haerter, Switzerland. We are grateful that the keynote speakers were able to share their knowledge and expertise with the participants of the symposium.
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| 6. |
- Hansen, Rickard, 1968-, et al.
(författare)
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Heat release rates of multiple objects at varying distances
- 2012
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Ingår i: Fire safety journal. - : Elsevier BV. - 0379-7112 .- 1873-7226. ; 52:Aug, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes simple theoretical calculations of the overall heat release rate (HRR) of multiple objects at both constant and varying distances that have been carried out. The results were compared to both fire experiments in a longitudinal ventilated model tunnel (scale 1:15) using piles of wooden pallets placed at varying distance from each other and with model scale fire experiments (scale 1:4) conducted with piles of wooden pallets in the open. Two different methods are presented which are based on physical relations for fire spread between the piles of wooden pallets. The first method uses a critical heat flux as ignition criteria while the other method uses an ignition temperature. The method using the critical heat flux as ignition criteria shows very good agreement with the corresponding experimental results used. The method using the ignition temperature as ignition criteria did not agree well with the corresponding experimental results. The prerequisite that the burning objects should not necessarily have to be positioned at equal distances was fulfilled. The results can be used to estimate the heat release rate in full scale tunnel experiments where wooden pallets have been used as fuel.
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| 7. |
- Ingason, Haukur, et al.
(författare)
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Effects of longitudinal ventilation on fire growth and maximum heat release rate
- 2010
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- An analysis, based on two different series of model scale tests, of the effects of ventilation on maximum heat release rate and fire growth rates is presented. In both model scale test series, wood cribs of different porosity, size and numbers were used. Both ambient free burn tests and tests inside a model-scale tunnel were performed. The tunnels varied from 0.3 m to 0.6 m in width and from 0.2 m to 0.4 m in height. The longitudinal velocity varied between 0.22 m/s and 1.12 m/s. The tests show that for a higher porosity wood crib and higher velocities than 0.45 m/s, an increasing ventilation rate increases the maximum heat release rate in the range of 1.3 to 1.7 times the value measured outside the tunnel under ambient conditions. For the lower porosity wood crib and higher velocities, the corresponding increase in the maximum heat release rates was 1.8 and 2.2, respectively. For the case with a velocity of 0.67 m/s, the linear fire growth rate increased by a factor of 5–10 times compared to the free burn case, depending on the dimensions of the tunnel cross-section.
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| 8. |
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| 9. |
- Ingason, Haukur
(författare)
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Modelling of Real World Fire Data
- 2006
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Ingår i: Proceedings from 2nd International Symposium on Tunnel Safety & Security (ISTSS), 7-13, March 15-17, 2006 Madrid, Spain, 2006.
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Konferensbidrag (refereegranskat)
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| 10. |
- Ingason, Haukur
(författare)
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State of the Art of Tunnel Fire Research
- 2008
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Ingår i: Fire Safety Science2008. ; , s. 33-48
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Konferensbidrag (refereegranskat)abstract
- This paper gives an overview of the tunnel fire research, both experimental and theoretical work with the exception of computer modelling. The overview shows that the critical velocity for longitudinal flow in a tunnel is the single most well investigated fire phenomenon found in the tunnel fire research literature. This knowledge has reached a high level but there are still some areas that need to be investigated further. For example, very little work has been done on backlayering of smoke upstream a fire and cross-sectional effects on heat release rates, temperatures, flame lengths, fire spread and toxic conditions.Extensive work using model scale tunnels has contributed with new information and clarified many phenomena but the lack of good large scale experimental data is and will be a key issue in near future. This concerns mainly the correlation between heat release rate and maximum ceiling temperatures, the influence of ventilation on maximum heat release rate and fire growth rate and fire spread in and between vehicles. The extensive theoretical work which has been conducted concerning the effects of ventilation on heat release rates needs to be further investigated in large scale tests.
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