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Cold Climate Structural Fire Danger Rating System?

Maria-Monika Metallinou, Torgrim Log
2018 Challenges  
Worldwide, fires kill 300,000 people every year. The fire season is usually recognized to be in the warmer periods of the year. Recent research has, however, demonstrated that the colder season also has major challenges regarding severe fires, especially in inhabited (heated) wood-based structures in cold-climate areas. Knowledge about the effect of dry cellulose-based materials on fire development, indoor and outdoor, is a motivation for monitoring possible changes in potential fire behavior
more » ... d associated fire risk. The effect of wind in spreading fires to neighboring structures points towards using weather forecasts as information on potential fire spread behavior. As modern weather forecasts include temperature and relative humidity predictions, there may already be sufficient information available to develop a structural fire danger rating system. Such a system may include the following steps: (1) Record weather forecasts and actual temperature and relative humidity inside and outside selected structures; (2) Develop a meteorology-data-based model to predict indoor relative humidity levels; (3) Perform controlled drying chamber experiments involving typical hygroscopic fire fuel; (4) Compare the results to the recorded values in selected structures; and (5) Develop the risk model involving the results from drying chamber experiments, weather forecasts, and separation between structures. Knowledge about the structures at risk and their use is also important. The benefits of an automated fire danger rating system would be that the society can better plan for potentially severe cold-climate fires and thereby limit the negative impacts of such fires.
doi:10.3390/challe9010012 fatcat:zvegxigzavfgzd2t3prsibyr4m

Industrial Thermal Insulation Properties above Sintering Temperatures

Amalie Gunnarshaug, Maria-Monika Metallinou, Torgrim Log
2021 Materials  
Processing highly flammable products, the oil and gas (O&G) industry can experience major explosions and fires, which may expose pressurized equipment to high thermal loads. In 2020, oil fires occurred at two Norwegian O&G processing plants. To reduce the escalation risk, passive fire protection may serve as a consequence-reducing barrier. For heat or cold conservation, equipment and piping often require thermal insulation, which may offer some fire protection. In the present study, a
more » ... tive thermal insulation (certified up to 700 °C) was examined with respect to dimensional changes and thermal transport properties after heat treatment to temperatures in the range of 700 °C to 1200 °C. Post heat treatment, the thermal conductivity of each test specimen was recorded at ambient temperature and up to 700 °C, which was the upper limit for the applied measurement method. Based on thermal transport theory for porous and/or amorphous materials, the thermal conductivity at the heat treatment temperature above 700 °C was estimated by extrapolation. The dimensional changes due to, e.g., sintering, were also analyzed. Empirical equations describing the thermal conductivity, the dimensional changes and possible crack formation were developed. It should be noted that the thermal insulation degradation, especially at temperatures approaching 1200 °C, is massive. Thus, future numerical modeling may be difficult above 1150 °C, due to abrupt changes in properties as well as crack development and crack tortuosity. However, if the thermal insulation is protected by a thin layer of more robust material, e.g., passive fire protection to keep the thermal insulation at temperatures below 1100 °C, future modeling seems promising.
doi:10.3390/ma14164721 fatcat:e4sldf3lize4pjllf3nxiaigwm

Consumer Grade Weather Stations for Wooden Structure Fire Risk Assessment

Torgrim Log
2018 Sensors  
During January 2014, Norway experienced unusually cold and dry weather conditions leading to very low indoor relative humidity (RH) in inhabited (heated) wooden homes. The resulting dry wood played an important role in the two most severe accidental fires in Norway recorded since 1923. The present work describes testing of low cost consumer grade weather stations for recording temperature and relative humidity as a proxy for dry wood structural fire risk assessment. Calibration of the weather
more » ... ations relative humidity (RH) sensors was done in an atmosphere stabilized by water saturated LiCl, MgCl2 and NaCl solutions, i.e., in the range 11% RH to 75% RH. When calibrated, the weather station results were well within ±3% RH. During the winter 2015/2016 weather stations were placed in the living room in eight wooden buildings. A period of significantly increased fire risk was identified in January 2016. The results from the outdoor sensors compared favorably with the readings from a local meteorological station, and showed some interesting details, such as higher ambient relative humidity for a home close to a large and comparably warmer sea surface. It was also revealed that a forecast predicting low humidity content gave results close to the observed outdoor weather station data, at least for the first 48 h forecast.
doi:10.3390/s18103244 fatcat:rjcwuy5lu5aerde3qkg2ztyymu

Small Scale Hydrocarbon Fire Test Concept

Joachim Bjørge, Maria-Monika Metallinou, Arjen Kraaijeveld, Torgrim Log
2017 Technologies  
Structural building elements are tested in furnaces fired in accordance with the ISO 834 temperature time curve [7] : T = 20 + 345·log 10 (8·t + 1) ( • C) (1) where t (min) is the exposure time.  ... 
doi:10.3390/technologies5040072 fatcat:nhoce2nk4vh65drz4w3tc5lvwa

Erratum to: Derivative free algorithm for solving nonlinear equations

Sanjay Kumar Khattri, Torgrim Log
2012 Computing  
Log Department of Engineering, Stord Haugesund University College, Haugesund, Norway e-mail:;  ... 
doi:10.1007/s00607-012-0221-0 fatcat:upcfyqrcgrg3te54ddgjvp6kha

Study of Industrial Grade Thermal Insulation at Elevated Temperatures

Amalie Gunnarshaug, Maria Monika Metallinou, Torgrim Log
2020 Materials  
Thermal insulation is used for preventing heat losses or heat gains in various applications. In industries that process combustible products, inorganic-materials-based thermal insulation may, if proven sufficiently heat resistant, also provide heat protection in fire incidents. The present study investigated the performance and breakdown temperature of industrial thermal insulation exposed to temperatures up to 1200 °C, i.e., temperatures associated with severe hydrocarbon fires. The thermal
more » ... ulation properties were investigated using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and by heating 50 mm cubes in a muffle furnace to temperatures in the range of 600 to 1200 °C with a 30 min holding time. The room temperature thermal conductivity was also recorded after each heat treatment. Upon heating, the mineral-based oil dust binder was released at temperatures in the range of 300 to 500 °C, while the Bakelite binder was released at temperatures in the range of 850 to 960 °C. The 50 mm test cubes experienced increasing levels of sintering in the temperature range of 700 to 1100 °C. At temperatures above 1100 °C, the thermal insulation started degrading significantly. Due to being heat-treated to 1200 °C, the test specimen morphology was similar to a slightly porous rock and the original density of 140 kg/m3 increased to 1700 kg/m3. Similarly, the room temperature thermal conductivity increased from 0.041 to 0.22 W/m∙K. The DSC analysis confirmed an endothermic peak at about 1200 °C, indicating melting, which explained the increase in density and thermal conductivity. Recently, 350 kW/m2 has been set as a test target heat flux, i.e., corresponding to an adiabatic temperature of 1200 °C. If a thin layer of thermally robust insulation is placed at the heat-exposed side, the studied thermal insulation may provide significant passive fire protection, even when exposed to heat fluxes up to 350 kW/m2. It is suggested that this is further analysed in future studies.
doi:10.3390/ma13204613 pmid:33081199 fatcat:odtp2xspsbctviiapuj6voqegi

Cloud-based Implementation and Validation of a Predictive Fire Risk Indication Model

Lars Michael Kristensen, Torgrim Log, Sindre Stokkenes
2019 Norsk Informatikkonferanse  
As identified by Log [12] , it is the period during December -January when the weather is usually cold that have the highest frequency of fires in Norway.  ...  Log found [12, 13] that it is reasonable to assume that 1 kg of moisture is released daily and that older wooden houses have a lower air change rate compared to newer houses.  ... 
dblp:conf/nik/KristensenLS19 fatcat:7c2ihcpdgfc5fj22uw5c42a44y

Modeling Drying of Degenerated Calluna vulgaris for Wildfire and Prescribed Burning Risk Assessment

Torgrim Log
2020 Forests  
To ensure vibrational noise dampening, the procedure as explained by Log et al. [7] was used. This included placing a 50 mm thick Styrofoam plate on the lowest grid shelf for noise dampening.  ...  To ensure vibrational noise dampening, the procedure as explained by Log et al. [7] was used. This included placing a 50 mm thick Styrofoam plate on the lowest grid shelf for noise dampening.  ...  Water Vapor Concentration in Air The exchange of humidity adsorbed, H 2 O ad , to water in the gas phase, H 2 O (g) , may be described by: For modeling purposes, the 4th order polynomials developed by Log  ... 
doi:10.3390/f11070759 fatcat:nx3z34l6cjfctltmavydhorwaq

Skin temperatures of a pre-cooled wet person exposed to engulfing flames

Torgrim Log
2017 Fire safety journal  
Log Fire Safety Journal 89 (2017) 1-6 q k δ T T h Ṫ" = ·( − )= ·∆ , q ε σ T Ṫ" = · ·( − ), rad f F S 4 4 (2) where ε f is the resulting emissivity, σ (5.67·10 −8 W/m 2 K 4 ) is the Stefan Boltzmann constant  ...  Log Fire Safety Journal 89 (2017) [1] [2] [3] [4] [5] [6] reviewers' suggestions regarding relevant literature and manuscript improvements are much appreciated; answering their questions greatly improved  ... 
doi:10.1016/j.firesaf.2017.02.001 fatcat:7m5qe7xbgbhh7laqj3p3arv3re

Study of Heathland Succession, Prescribed Burning, and Future Perspectives at Kringsjå, Norway

Anna Marie Gjedrem, Torgrim Log
2020 Land  
., husbandry, tree logging, and prescribed burning are essential for the vegetation composition [55] .  ... 
doi:10.3390/land9120485 fatcat:kfhktdhy3zajlob6vymz2npyry

Modeling Skin Injury from Hot Spills on Clothing

Torgrim Log
2017 International Journal of Environmental Research and Public Health  
The present work analyzes scald burns from hot beverages, such as coffee and tea, spilled on the lap, i.e., an incident that may occur in daily life. The Pennes bioheat equation is solved numerically for small spills wetting the clothing, i.e., the fabric prevents the spilled liquid from draining away. Temperatures are analyzed in the wetted fabric and the skin layers and the resulting skin injury is calculated based on the basal layer temperature. Parameters influencing burn severity, such as
more » ... lothing thickness, liquid temperature, removal of fabric and thermal effects of post scald water cooling are analyzed. The fabric cools the water some but represents a threat since the entrapped water results in a prolonged heat supply. The liquid temperature turned out to be the most important injury parameter, where liquid temperature of about 80-85 • C seems to be a limit for developing superficial partial-thickness burns in the present minimum case, i.e., where the liquid just wets the fabric. Spilling water in excess of just wetting the fabric, more severe burns will develop at lower liquid temperatures due to the prolonged heat supply. Higher liquid temperatures will nearly instantly develop more severe burns. It is demonstrated that removal of the clothing within the first seconds after the spill may significantly reduce the scalding severity. The general advice is therefore to avoid excessive heating of beverages and, if the beverage is spilled, to quickly remove the wetted clothing. Prolonged tempered water cooling is advised to improve the healing processes.
doi:10.3390/ijerph14111374 pmid:29137118 pmcid:PMC5708013 fatcat:ks6j6xpyrnfplckcxhe7yxaymm

Modeling Skin Injury from Hot Rice Porridge Spills

Torgrim Log
2018 International Journal of Environmental Research and Public Health  
The present work analyzes skin burns from spills of hot rice and milk products. The traditional Norwegian rice porridge serves as an example. By testing spills on objects emulating an arm, it was concluded that spills were seldom thinner than 3 mm, and stayed in place due to the viscosity of the porridge for more than one minute. The Pennes bioheat equation was solved numerically for such spills, including heat conduction to the skin and convective heat losses from the porridge surface.
more » ... ures were analyzed in the porridge and skin layers, and the resulting skin injury was calculated based on the basal layer temperature. Parameters influencing burn severity, such as porridge layer thickness, porridge temperature, removal of the porridge and thermal effects of post scald tempered (15 • C) water cooling were analyzed. The spilled porridge resulted in a prolonged heat supply to the skin, and the skin injury developed significantly with time. The porridge temperature turned out to be the most important injury parameter. A 70 • C porridge temperature could develop superficial partial-thickness burns. Porridge temperatures at processing temperatures nearly instantly developed severe burns. It was demonstrated that prompt removal of the hot porridge significantly reduced the injury development. The general advice is to avoid serving porridge and similar products at temperatures above 65 • C and, if spilled on the skin, to remove it quickly. After such scald incidents, it is advised to cool the injured area by tempered water for a prolonged period to stimulate healing.
doi:10.3390/ijerph15040808 pmid:29677134 pmcid:PMC5923850 fatcat:ck27mzltfvaibieywdrhgt6y74

Modeling Burns for Pre-Cooled Skin Flame Exposure

Torgrim Log
2017 International Journal of Environmental Research and Public Health  
The only research identified regarding pre-cooled wet human skin exposed to flames is the work by Log [22] where analytical solutions were used to discuss the case studied in the present work.  ... 
doi:10.3390/ijerph14091024 pmid:28880253 pmcid:PMC5615561 fatcat:xoknehmjfvby5pegj2yekaipje

Tunnel Fire Dynamics as a Function of Longitudinal Ventilation Air Oxygen Content

Sanjay Kumar Khattri, Torgrim Log, Arjen Kraaijeveld
2019 Sustainability  
Longitudinal ambient air ventilation is the most common methodology for maintaining an amicable environment in tunnels during normal operations while providing an evacuation path during tunnel fire emergencies. The present work investigates the influence of forced ventilation air oxygen concentrations on tunnel fire dynamics. Mixing inert gasses such as nitrogen, argon, or carbon dioxide with ambient air changes the ventilation air oxygen concentration. In order to quantify the influence of the
more » ... oxygen content on the critical tunnel safety parameters, multiple computational fluid dynamics (CFD) simulations were done on a reduced-size tunnel while preserving the system Froude number. Analytical expressions were developed to describe the importance of oxygen content on the tunnel fire dynamics. By employing Froude scaling, the resulting relations were extrapolated to real scale tunnels. For the ambient air ventilation, the extrapolated expressions displayed good agreement with experimental literature data. By adjusting the oxygen concentration, parameters such as maximum tunnel ceiling temperature, fire growth rate, maximum heat flux to the tunnel floor, maximum flux on the tunnel ceiling, and maximum heat release rate can be controlled. This is the case also for oxygen levels where people can survive. This may increase the possibility for evacuation and improve the conditions for firefighting, significantly improving tunnel fire safety.
doi:10.3390/su11010203 fatcat:hj3hjs3wsfgjhn2zbef44msy7q

Numerical Investigation of the Required Quantity of Inert Gas Agents in Fire Suppression Systems

Xiaoqin Hu, Arjen Kraaijeveld, Torgrim Log
2020 Energies  
Inert gas agents have the potential to be widely used in fire suppression systems due to health and safety concerns associated with active chemicals. To suppress fire while minimizing hypoxic effects in an occupied area, the discharge quantity of inert gas agents should be carefully designed to dilute the oxygen concentration to a specific threshold level. In this study, the general expressions between oxygen concentration, the discharge rate of inert gas agents, and the ventilation rate of the
more » ... air-agent mixture are derived first. Then, explicit formulas to calculate the discharge/ventilation rate and the required quantity of inert gas agents are given if the discharge rate and ventilation rate both are constants. To investigate the dilution and fire extinguishing efficiencies of inert gas agents, two scenarios with a discharge of inert gas agents into an enclosure are modeled using the Fire Dynamic Simulator (FDS). The simulation results show that the average oxygen mass fraction approximately reaches the design level at the end of the discharge period. Variation in oxygen concentration along the enclosure height is analyzed. For the scenario with a fire source, oxygen mass fraction decreases fast as oxygen is consumed by the combustion process. Thus, the fire is extinguished a little earlier than the end of the discharge period.
doi:10.3390/en13102536 fatcat:4qvzgeirnnapza6nl4i4vbjb4u
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