EVALUATION OF THE FIRE EXTINGUISHING EFFECTIVENESS OF SPRINKLERS IN FIRES OF SELECTED FLAMMABLE MATERIALS USING COMPUTER SIMULATION METHOD

Two-scale tests, microscale and bench scale, are conducted to analyze the flammability of a flexible polyurethane foam. Microscale tests include simultaneous thermal analysis coupled to Fourier transform infrared spectroscopy, and microscale combustion calorimeter (MCC). Evolved gas components, heat release rate per unit mass, total heat release, derived heat release capacity, and minimum ignition temperature are obtained. Bench scale tests are performed on cone calorimeter. Peak heat release rate per unit area, effective heat of combustion, minimum incident heat flux for ignition, and total heat release per unit area of different incident heat fluxes are obtained. FO-category of the PU foam is estimated by multiple discriminant function analysis based on the results of cone calorimeter test. The relationship between the two-scale tests is analyzed. The minimum ignition temperatures derived from multi heating rate MCC tests are used to predict the time to ignition and compared with the results from cone calorimeter tests. This PU foam is evaluated as a high fire hazard polymer having low heat release capacity, low ignition temperature, and short ignition time.

The flame resistance properties of expandable polystyrene foams coated with a cheap and effective barrier layer

Preparation of modified epoxy resin with high hydrophobicity, low dielectric constant, toughness, and flame retardant by epoxy-functionalized siloxanes

역사마을인 한국의 하회 양동 마을은 볏짚지붕으로 된 초가집으로 구성되어 있고 일본의 역사마을인 시라가와고 또한 억새 지붕의 초가집이 존재하고 있다. 지붕재료의 연소특성은 역사마을에서 화재안전 확보를 위하여 중요하다. 본 연구에서는 착화시간(TTI), 유효연소열(Effective Heat of Combustion, EHC), 열방출율(Heat Release Rate, HRR), 총열방출율(Total Heat Release, THR), 질량손실율(Mass Loss Rate, MLR) 등을 콘 칼로리미터(ISO 5660-1)를 이용하여 측정하여 화재위험성을 평가하였다. 역사마을의 건물과 구조의 화재특성을 예측하는데 볏짚과 억새의 연소 데이터베이스가 이용될 수 있다. 연구결과, 초가지붕의 두 재료 중에서 억새가 볏짚보다 열적 위험성이 높은 것으로 나타났다. 또한 초가집 전체 연소시 최소 약 5.68 m 반경 이내의 초가집은 화재확산 가능성이 있는 것으로 평가되었다. Hahoe Village and Yangdong Village in Korea have straw-roofed houses and Shirakawa-go in Japan has silver grass-roofed houses. Combustion characteristics of these roof materials need to be identified in order to enhance fire safety in historical villages. This study used cone calorimeter (ISO 5660-1) and Flammability tester to measure combustion characteristics of thatched-roof materials to analysis hazard assessment in two historical villages. It also analyzed Time to Ignition (TTI), Effective Heat of Combustion (EHC), Heat Release Rate (HRR), Total Heat Release (THR), Mass Loss Rate (MLR) and ignition temperature. Database on combustion characteristics of straw (Oryza sativa) and silver grass (Miscanthus sinensis var. purpurascens) will be used to predict fire property of buildings and structures in historical villages. From the result, combustion data shown that Miscanthus sinensis var. purpurascens has high value than Oryza sativa for fire danger. Straw-roofed houses can be spread where is located within radius 5.68 m from straw-roofed house fires.

To study the influence of spandex on combustion behavior of textile fabrics, two kinds of nylon 6 fabrics were tested using cone calorimeter test and vertical burning test. Some key combustion parameters such as heat release rate (HRR), total heat release (THR) and rate of smoke release (RSR) were obtained from cone calorimeter test and afterflame time and damaged length from vertical burning test. Results indicated that the nylon 6 fabric containing spandex showed 21% higher HRR value. But THRs of the nylon 6 fabric containing spandex and the pure nylon 6 fabric were close. RSR curves indicated that RSR value of the nylon 6 fabric containing spandex was 73% higher than that of the pure nylon 6 fabric. The afterflame time and damaged length of the nylon 6 fabric containing spandex were much longer than that of the pure nylon 6 fabric. Spandex does accelerate the combustion behavior on Nylon fiber.

본 연구에서는 인도네시아 조림지에서 생장한 4수종의 효율적 활용방안을 마련하기 위해 콘칼로리미터법에 의해 연소특성을 조사하였다. 그 결과, 평균열방출량(<TEX>$HRR_{mean}$</TEX>)은 비중에 비례하였으며, 총열방출량(THR) 및 연소시간(FT) 등열관련 계수도 같은 경향을 나타냈다. Albizia는 열방출 시간이 짧았고, Mindi는 4수종 중 점화시간(TTI)과 연소시간(FT)이 길어져 4수종 중 연소속도가 늦었고, 열방출 시간도 가장 길게 이어져 결국은 Mangium 수종과 비슷한 총열방출률을 나타내는 것을 확인할 수 있었다. Albizia는 공시수종 중 가장 높은 비소화면적 값을 나타내어 연기발생비율이 높았고, 반대로 Mindi는 가장 낮은 비소화면적 값을 나타내 연기발생비율이 낮았다. 초기 연기방출률은 Albizia가 높았으나 이후에는 Gmelina와 Mangium 의 연기방출률이 높아져 총연기발생량이 높게 나타났다. Gmelina는 불완전연소로 인해 연소기간 중 가장 많은 일산화탄소 연기를 생성하였고, <TEX>$CO/CO_2$</TEX> 비율은 다른 수종에 비해 3배 이상 높았다. This study was performed to understand combustion properties four major Indonesian wood species such as Albizia, Gmelina, Mangium and Mindi were investigated by cone-calorimeter for better utilization of theses wood species. Heat release rate (HRR), total heat release (TSR), specific mass loss rate (SMLR), effective heat of combustion (EHC), time to ignition (TTI), flame time (FT), specific extinction area (SEA), smoke production rate (SPR) and CO compound production rate were measured. HRR, THR and FT were proportional to the density of woods. Albizia showed the highest HRR, while Mindi had the lowest HRR. For SPR, Albizia showed the highest value due to its higher SEA. On the other hand, Mindi had the lowest SPR due to a lower SEA value. The highest smoke emission was for Albizia at the beginning of combustion. After 300 seconds, smoke emission of Gmleina and Mangium was increased greatly. Mangium and Mindi showed the highest total carbon dioxide emission. Expecially, Gmelina released the highest carbon monoxide during the combustion period and presented three times higher <TEX>$CO/CO_2$</TEX> ratio than those of other species due to incomplete combustion.

Synergistic effect of expandable graphite, melamine polyphosphate and layered double hydroxide on improving the fire behavior of rosin-based rigid polyurethane foam

Fires involving electric vehicles have attracted considerable attention in the media. In particular, the toxic gases released upon combustion of electric vehicles and lithium-ion batteries has been a major concern. In this study, the results of six large-scale vehicle fire tests are presented including three electric vehicles, two internal combustion engine vehicles, and one electric vehicle with the battery pack removed. Additionally, separate battery component tests were performed. In two of the vehicle fire tests a sprinkler system was used to assess the effect of water application on the combustion gases. Furthermore, calculations of the heat release rate, peak heat release rate and total heat release were performed, as well as chemical analysis of gas and soot. Peak heat release rate and total heat release were affected by the fire scenario and vehicle model, but not significantly by the type of powertrain. Regarding the combustion gases, hydrogen fluoride represented the largest difference between electric vehicles and internal combustion engine vehicles. Additionally, battery specific metals such as manganese, nickel, cobalt and lithium were found in higher concentrations in the electric vehicle tests than in the internal combustion vehicle tests, in which larger quantities of lead were found.

The carbon fiber (CF) reinforced epoxy composites possess exceptional and distinctive properties as advanced composite materials. However, the flammability of epoxy resin and inadequate interfacial bonding between the resin and CF often impose limitations on their broader application. Herein, in order to enhance the flame retardancy of EP composites effectively, a hierarchical reinforcement was developed by facilely growing MnO2 nanosheets onto CF surface through an in situ process. Owing to their synergistic effects of physical barrier and chemical catalytic behavior, the presence of MnO2 nanosheets can effectively retard the combustion process by facilitating charring formation and suppressing heat and smoke release. Specifically, compared to the Untreated CF, the modified fiber reinforced composites exhibited significantly improved fire safety with reduction of 76.23%, 51.5% and 23.1% in peak heat release rate, total heat release and peak smoke production rate, respectively. Additionally, incorporating MnO2 nanosheets significantly enhanced mechanical properties of the composites, leading to remarkable enhancements of 41.8% in flexural strength and 28.14% in interlaminar shear strength. This study proposes an effective strategy for achieving outstanding flame retardancy and mechanical performance, thereby introducing an innovative concept for the production of high‐performance CF reinforced polymer composites.Highlights Growth of MnO2 nanoparticles enhanced the mechanical properties of the CF/EP composites. The CF‐MnO2/EP composites showed excellent flame retardancy. The flame retardant mechanism of CF‐MnO2/EP composites were analyzed. Highlight the potential application of MnO2 in the field of flame retardancy.

Experimental study on thermal performance of phase change heat storage device with rectangular shell structure

Laponite-based inorganic-organic hybrid coating to reduce fire risk of flexible polyurethane foams

In this article, some of the combustion properties of three carbonate solvent mixtures commonly used as the electrolytes of lithium ion batteries are considered by means of the ISO 5660 cone calorimeter. Experimental findings reveal that the heat release rate, the most important parameter in fire science, exhibits a significant variation among the carbonate mixtures. Other key parameters governing the fire-induced hazards such as total heat release, mass loss rate, combustion efficiency, and concentration of the major exhaust gases are also determined and analyzed. Furthermore, as some researchers argue that oxygen consumption calorimetry is likely to over-predict the chemical heat release for lithium ion cells, another thermal chemistry method based on stoichiometry for heat release rate calculation is adopted. Heat release rate results of the three carbonate solvent mixtures obtained by these two separate methods are found to be in good agreement. Thus, oxygen consumption calorimetry is considered to be an appropriate technique to determine the heat release in fires in relation to electrolytes of lithium ion batteries.

This study focuses on the increased risk of high heat release and asphyxiation (toxic gas poisoning) in the event of a fire involving polyurethane (PU)- and MDF-based building materials, which are commonly used in buildings. Among them, polyurethane (PU) building materials are very commonly used in buildings, except in Europe and some other countries, due to their excellent thermal insulation performance. Still, problems of short-term heat release and the spread of toxic gases in the event of a fire continue to occur. To overcome these problems, researchers are actively working on introducing various flame retardants into building materials. Therefore, in this study, we produced a laboratory-sized (500 mm × 500 mm) plate-like flame-retardant board that can be utilized as a building material with a lower heat release rate and a lower toxicity index. The material was made by mixing expanded graphite and ceramic binder as flame retardants in a material that is formulated based on the cellulose of waste paper, replacing the existing building materials with a hot-press method. According to the ISO-5660-1 test on the heat release rate of the plate-like flame-retardant board, the Total Heat Release (THR) value was 2.9 (MJ/m2) for 10 min, showing an effect of reducing the THR value by 36.3 (MJ/m2) compared to the THR value of 39.2 (MJ/m2) of the specimen made using only paper. In addition, the toxicity index of the flame-retardant board was checked through the NES (Naval Engineering Standards)-713 test. As a result, the test specimen showed a toxicity index of 0.7, which is 2.4 lower than the toxicity index of 3.1 of MDF, which is utilized as a conventional building material. Based on the results of this study, the cellulose fire-retardant board showed the effect of reducing the heat release rate and toxicity index of building materials in a building fire, which reduces the risk of rapid heat spread and smoke toxicity. This has the potential to improve the evacuation time (A-SET) of evacuees in fires. It is also important to show that recycling waste paper and utilizing it as the main material for building materials can be an alternative in terms of sustainable development.

Pyrolysis combustion flow calorimeter: A tool to assess flame retarded PC/ABS materials?

In order to study the influence of natural wood thickness on the flammability and fire performance, an experimental studies of fire parameters under external constant heat flux by piloted ignition of wood timber with different thicknesses (8, 10, 13, 15 mm) were conducted using cone calorimeter approach, by testing procedure prescribed in accordance with international organization for standardization. These parameters include: ignitibility, heat release rate, effective heat of combustion, total heat release, mass loss rate, smoke specific extinction area, and the yield of carbon monoxide. Four species of wood timber, namely pine, maple, oak, and walnut, were exposed horizontally under external heat flux 50 kW/m2. Thermal degradation effects of various species were observed. The obtainable data will be reported to develop a distinct national building code in Jordan and to select the suitable materials for designing of fire safety in buildings of different uses. A good compatible agreement between calculated and experimented results has been obtained. The results indicated that total heat release rate increase with increase thickness of specimen. It is observed that, the time to ignition is very small (around 12 seconds) for all species whatever the thickness is. Heat release rate for the different types of specimens with different thicknesses have been presented. Results show as the thickness of oak specimen increased: 8 mm, 10 mm, 13 mm and 15 mm, the corresponding mass loss depletions are 43%, 34%, 25%, and 21%, respectively.