New In-Flame Flammability Testing Method Applied to Monitor Seasonal Changes in Live Fuel

Improving the accuracy of fire behavior prediction requires better understanding of live fuel, the dominant component of tree crowns, which dictates the consumption and energy release of the crown fire flame-front. Live fuel flammability is not well represented by existing evaluation methods. High-flammability live fuel, e.g., in conifers, may maintain or increase the energy release of the advancing crown fire flame-front, while low-flammability live fuel, e.g., in boreal deciduous stands, may reduce or eventually suppress flame-front energy release. To better characterize these fuel–flame-front interactions, we propose a method for quantifying flammability as the fuel’s net effect on (contribution to) the frontal flame energy release, in which the frontal flame is simulated using a methane diffusion flame. The fuel’s energy release contribution to the methane flame was measured using oxygen consumption calorimetry as the difference in energy release between the methane flame interacting with live fuel and the methane flame alone. In-flame testing resulted in fuel ignition and consumption comparable to those in wildfires. The energy release contribution of live fuel was significantly lower than its energy content measured using standard methods, suggesting better sensitivity of the proposed metric to water content- and oxygen deficiency-associated energy release reductions within the combustion zone.

Behavior of Reactive Powder Concrete Beams Exposed to Fire

In this paper, the effect of direct fire flame and steel fiber ratio on some mechanical properties and behavior of the relationship between load and deflection of rectangular reinforced concrete beams under the influence of fire exposure was studied. Concrete specimens were exposed to fire at temperatures ranging from (25- 400 ºC). Three temperature levels of (200, 300, 400 ºC) where chosen for exposure duration of 2.0 hours. After conducting the test, it was found that increasing the proportion of steel fibers in percentages 0.5% to 1% and 1.5% decreases the mid-span deflection at service load by 33%, 50% and 37.5 and increases the ultimate load by 36.36%, 41.6% and 53% respectively. After the beams are exposed to fire, it was noticed that the maximum crack width increases with increasing fire temperature.

Fire Performance of Fly Ash-Based Geopolymer Concrete: Effect of Burning Temperature

Geopolymer concrete (GEO) is a cementless concrete produced from the reaction of an aluminosilica-rich material, in particular, fly ash, with an alkaline solution, which can either be sodium or potassium-based. In light of the potential of fly ash-based GPC as an alternative to Ordinary Portland Cement (OPC)-based concrete as a green building material, an investigation on the fire performance of GEO, in comparison to OPC-based concrete, is essential. The results of an experimental study on the fire performance of fly ash-based GEO that was subjected to a flame test using a methane burner torch, after 28 days of curing, to simulate a real fire event, are presented. Concrete specimens were exposed to a fire flame at 500 °C and 1200 °C for two hours and subsequently cooled to the ambient temperature, prior to testing. Visual inspection was performed on the specimens to observe for any cracking, spalling and change in colour. Losses of mass and residual compressive strength were measured. The results were compared with those of OPC-based reference specimens. The findings revealed that, in contrast to OPC-based concrete, the strength of GPC increased when exposed to fire at 500 °C. GEO also suffered a smaller loss of mass as compared to OPC-based concrete due to the smaller amount of loss in moisture from burning. It was also observed that no spalling had occurred on the GEO, with less cracking on the exposed surface in relation to OPC-based concrete, hence indicating that the structural integrity of GEO was successfully maintained.

A Thermal-Based Fuel-Prediction Method for Intelligent Fire Extinguisher in an Indoor Environment

Classification of fuel in the early stage of fire is important to choose the appropriate type of extinguisher for extinguishing fire. This paper proposes a method of fuel prediction based on heat information for intelligent fire extinguisher in an indoor environment. Fire flame in the early stage is first detected based on patterns of differences between consecutive thermal image frames in which temperature grows up rapidly and reveals a sharp positive slope. Then candidate flame boundaries are detected in the thermal image frames during the early stage, and boundary matching is performed among the frames. These matched boundaries are classified as fire flame and fuel class based on LSTM (Long short-term memory) for extinguisher selection. Experiments were performed with 300 samples for classification into four classes of fuel, and the results based on 9:1 training and testing ratio showed 92.142% accuracy.

Most prominent factors contributing to burn injury-related amputations: an analysis of a referral Burn Center

Amputations are un-common surgical procedures in patients with severe burn injuries. However, these patients often face extreme physical and psychological challenges that result in social stigmatization and inadequate rehabilitation facilities. A retrospective cohort study was designed for the patients admitted to the Burn Center of Adana City Training and Research Hospital (ACTRH). During the study period, a total of 2007 patients aged 0.5 to 92 years were hospitalized and treated at the burn center from January 2016 to June 2020. The incidence of amputation observed among inpatient burn injuries regardless of the etiology was 1.9%, and 87.2% were male. The univariate and multivariate logistic regression analysis was performed to detect the most prominent factors contributing to burn injury-related amputations. The cause of burns appears to be one of the main factors in the past research, and in this context, the electrical burns stand out, likewise, the fire-flame-related burns, full-thickness burns, the existence of infection, male gender, patients aged within the 18 to 64 age group, and the burn extent within the total body surface area (TBSA) range of 10 to <50% were found to be the most leading factors of amputations among patients having severe burns. Although they are rare, amputations related to burns commonly cause a decrease in quality of life. Therefore, besides increasing occupational health and safety methods for these risk groups, especially for adults of working age; also, it is essential to increase the importance and awareness of the precautions to be taken in daily life.

Steel Fiber Enhancement upon Punching Shear Strength of Concrete Flat Plates Exposed to Fire Flame

In this study, the effect of fire flame on the punching shear strength of steel fiber reinforced concrete flat plates was experimentally investigated using nine half-scale specimens with dimensions of 1500×1500 mm and a total thickness of 100 mm. The main investigated variables comprised the steel fiber volume fraction 0, 1, and 1.5% and the burning steady state temperature 500 and 600 °C. The specimens were divided into three groups, each group consists of three specimens. The specimens in the first group were tested with no fire effect to be the reference specimens, while the others of the second and third groups were tested after being exposed to fire-flame effect. The adopted characteristics of the fire test were; (one hour) burning time duration and 500 and 600 °C steady state temperature with sudden cooling process (water sprinkling directly after burning). The test results proved that exposing to direct fire effect for one hour caused a reduction in the punching shear strength with an increase in the ultimate mid-span deflection. Also, it was noticed that using steel fiber in the concrete mix leads to a significant increase in the punching shear strength for both the unburned and burned specimens. The ultimate punching load increased by about 11 and 16.6% for the unburned specimens with 1.0 and 1.5% steel fiber volume fraction, respectively, and by about 22.4 and 19% for the burned specimens at 500 °C with 1.0 and 1.5% steel fiber volume fraction, respectively. While, it was increased by about 29.2 and 21.5% for the burned specimens at 600 °C with 1.0 and 1.5% steel fiber volume fraction, respectively, as compared with the reference specimen of each group. Doi: 10.28991/cej-2021-03091751 Full Text: PDF

For the Symbolics and Semantics of “Fire” in German Phraseologisms

Phraseologisms represent the important and valuable legacy of the nation as they reflect not only cultural and historical ideology, but customs and traditions as well. The given research deals with the establishment of symbolics and semantic context of “Fire” in German phraseological units. German phraseological dictionaries are used as the research object. Fire is a guarantee of improving human lives. It is the symbol of creative energy and destructive force as well. When the fire flame is under the human control it brings warmth, light and kindness. As soon as human reveals less care towards it the fire instantly turns into a dangerous, destructive force bringing death and collapse. Fire has different symbols in different religions. In Hinduism, fire is the symbol of creativity, absolution and demolition, in Islam – birth and destruction, in Buddhism – wisdom, in Christianity it is the symbol of reanimation. Human ensures his/her welfare and safety with the help of fire. Fire is the symbol of native home, native land and family: Das heimische Feuer – native fire/hearth. Fire can figuratively express different emotions. Phraseologisms expressing love are mostly found out: Feuer der Liebe – fire of love. In a figurative way, fire also indicates such human traits as intrepidity, bravery, sympathy, goodwill, hatred, anger, enthusiasm and hope. Figuratively fire also has the mission of increasing the power of trait.

BEHAVIOR OF GLASS FIBER GEOPLOYMER BUBBLE SLABS EXPOSED TO FIRE FLAME

In the present study, eight specimens of Reinforced concrete Geopolymer bubbled slab exposed to fire flame and tested under punching shear failure with dimensions (45*45*7 cm), steel armature (Ø3@25), plastic ball diameter (4 mm) and concrete cover (1.5 cm) and the use of two percentages of fiberglass (0.5%-1%) and the variable temperatures were (150- 300- 450 ˚C) with a burning time of 30 minutes. From the results of laboratory tests, when the Geopolymer reinforced concrete bubbled slabs exposed to high temperatures, it did not occur to spalling, and the reason for that is that Geopolymer concrete has the ability to resist heat due to the fact that it's main compounds are materials burned at high temperatures. And also, it was noticed in examining a punching shear stress of the models with fibers (0.5%) that the ultimate load increased by (4.5%) for the model burned at a temperature of (150 ˚C) and a decrease in the ultimate load was (40%) for the models burned at temperatures (300 ˚C) and a decrease in the ultimate load by (30%) for the models burned at temperatures (450 ˚C). Also, it was noticed in examining a punching shear stress of the models with fibers (1%) that the ultimate load increased by (6%) for the model burned at a temperature of (150 ˚C) and a decrease in the ultimate load was (36%) for the models with temperatures (300 ˚C) and a decrease in the ultimate load by (27%) for the models burned at temperatures (450 ˚C).

The Impact of Hybrid Fibers on Punching Shear Strength of Concrete Flat Plates Exposed to Fire

This study presents an investigation about the effect of fire flame on the punching shear strength of hybrid fiber reinforced concrete flat plates. The main considered parameters are the fiber type (steel or glass) and the burning steady-state temperatures (500 and 600°C). A total of 9 half-scale flat plate specimens of dimensions 1500mm×1500mm×100mm and 1.5% fiber volume fraction were cast and divided into 3 groups. Each group consisted of 3 specimens that were identical to those in the other groups. The specimens of the second and the third groups were subjected to fire flame influence for 1 hour and steady-state temperature of 500 and 600°C respectively. Regarding the cooling process, water sprinkling was applied directly after the burning stage to represent the sudden cooling process. Generally, the obtained results exhibited a significant increase in the punching shear capacity of the fiber-reinforced slabs as compared to the corresponding no fiber-reinforced slabs even at elevated burning temperatures 600°C. The ultimate load was increased by about 16.6, 19, and 21.5% at temperatures of 25, 500, and 600°C respectively, for steel fiber reinforced slabs and by about 13.9, 27.2, and 34.6% for slabs containing two mixed types of fibers (steel and glass), as compared with the reference specimen at the same temperatures respectively. In addition, the results indicated that fibers' presence in concrete resulted in gradually punching failure with more ductile mode, whereas the failure was sudden with a brittle mode in the slabs that did not contain fibers.

Experimental investigation on the post-fire performance of reactive powder concrete columns

The increased use of reactive powder concrete (RPC) in concrete structures has attracted attention towards the structural behavior of RPC in fires. This work examines experimentally the performance of RPC and NSC columns subjected to 25% of the ultimate load and exposed to direct fire flame for a period of 30 and 60 min at various temperature levels. The paper aims to evaluate the maximum temperature level and fire duration that can be withstood by this type of concrete columns. The results show that the failure mode of RPC columns without reinforcement is a sudden shear failure, whereas the failure mode of reinforced RPC columns is a crushing failure with rupture of certain ties. The RPC columns at high temperatures spall intensively; additionally, the ultimate strength clearly decreases compared to the NSC columns at the same conditions.