Abstract
The pyrolysis characteristics of untreated pine and fire retardant-treated pine (Pinus densiflora) were measured by using thermogravimetric analysis according to the ASTM E1131-08 (2012) regulation. Fourier transform infrared spectroscopy was used to monitor changes in chemical groups of fire-retardant treated specimens before and after the combustion test. In addition, the microstructures of the untreated specimen and the fire-retardant treated specimen after cone calorimeter testing were determined by scanning electron microscopy. Combustion gas toxicity was evaluated according to the test method described in Naval Engineering Standard 713 (1990). The emitted combustion gases of all specimens were carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxide (NOX), and acrylonitrile. The thermal decomposition rate was reduced by about one-third that of the fire-retardant treated specimen compared to the reduction rate of the untreated specimen. These results are useful for guiding the safe utilization of fire retardant-treated wood and wood-based materials for building applications.
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Fire Properties of Pinus densiflora Utilizing Fire-retardant Chemicals Based on Borate and Phosphorus (II) – Thermal and Gas Emission Characteristics
Hyun Jeong Seo, Nam Kyun Kim, Jeong Min Jo, and Min Chul Lee *
The pyrolysis characteristics of untreated pine and fire retardant-treated pine (Pinus densiflora) were measured by using thermogravimetric analysis according to the ASTM E1131-08 (2012) regulation. Fourier transform infrared spectroscopy was used to monitor changes in chemical groups of fire-retardant treated specimens before and after the combustion test. In addition, the microstructures of the untreated specimen and the fire-retardant treated specimen after cone calorimeter testing were determined by scanning electron microscopy. Combustion gas toxicity was evaluated according to the test method described in Naval Engineering Standard 713 (1990). The emitted combustion gases of all specimens were carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxide (NOX), and acrylonitrile. The thermal decomposition rate was reduced by about one-third that of the fire-retardant treated specimen compared to the reduction rate of the untreated specimen. These results are useful for guiding the safe utilization of fire retardant-treated wood and wood-based materials for building applications.
Keywords: Fire retardant-treated wood; Thermal stability; Fire safety; Hazardous gases; Korean Pinus densiflora
Contact information: Department of Safety Engineering, College of Engineering, Incheon National University, Incheon 22012, Republic of Korea; *Corresponding author: LMC@inu.ac.kr
INTRODUCTION
The requirements of fire retardants for building materials are divided into different fire resistance, including reaction to flammability and gas toxicity. Fire-retardant chemicals, which are used in various polymer materials, are added to prevent fires and delay the spread of flame. Such treatments can be very effective for materials that require fire retardancy and fire safety (Fahy and Proulxm 2001; Kawahara and Yanagisawa 2003; Kobes et al. 2010; Stec and Hull 2011; Veen and Boer 2012). In addition, when a fire occurs, the materials should not generate even a small amount of toxic gas. Because most fire casualties and fire-related personal injuries result from the generation of toxic gases, fire retardant chemical composites should be added to the building materials. When fires occur, this is important because it is difficult for people inside a building that is on fire to escape due to the toxic substances in the combustion gases (Fahy and Proulxm 2001; Kobes et al. 2010; Stec and Hull 2011).
When fire-retardant chemicals were first used, they were classified into various types, including halogen-based, brominate-based, phosphorous-based, and other inorganic chemical species (Mfiso et al. 2014). Among these fire retardant chemicals, the use of brominated fire retardants is forbidden in Europe. Brominated fire retardants generate a large amount of toxic gases, such as hydrogen bromide (HBr), dioxins, etc., at the time of combustion (Dassari et al. 2013; Liang et al.2007; Mfiso et al. 2014). Although the use of halogen-based fire retardants is not yet regulated in Korea, studies of halogen-free fire retardants have been conducted (Jang and Choi 2009; Chung and Jin 2010; Lim et al. 2011). In this study, fire-retardant chemical composites (FRCs), including boron- and phosphorus-based chemicals, were developed by mixing using a water-based solvent (Seo et al. 2017).
In Korea, for a fire to be considered severe, it must affect more than 60% of the area in a building. In addition, according to the statistical survey of the last 10 years since 2000 in Korea, wood and wood-based materials made up 95% of the interior building materials in newly constructed apartments and houses in Korea (Park et al. 2011; Seo et al. 2013). The fire risk of materials can be estimated based on certain factors, such as speed of flame spread, heat release rate, total heat release, and generation of combustion gas (Qian et al. 2014; Wei et al. 2015; Yew et al. 2015). According to previous studies and statistical data on personal injuries in fires, injuries caused by toxic gas inhalation were more common than burns caused by direct flames (Liang and Ho 2007; Cho et al. 2012; Stec et al. 2008; Kobes et al. 2010; Molyneux et al. 2014). Specifically, 6.78% of fire-related deaths resulted from flames in Korea (Lee 2006). Clearly, the toxic gases emitted during combustion are of greater concern than the flames themselves. However, sufficient research has not yet been conducted to determine and evaluate the toxicity characteristics of the combustion of building materials in Korea. Therefore, it is necessary to research the improvement of fire retardant performance in wood and reduce hazardous combustion gases.
In this study, the FRCs was developed by mixing using a water-based solvent as done in prior research (Seo et al. 2017). The FRCs is composed of boric acid, borax, di-ammonium phosphate, and carbonite-based chemicals. Their composition ratios are presented in the materials part of this paper. The composites were prepared via the pressure-impregnation method inside wooden specimens, and the process with pressure-impregnation proceeded in the cylinder. In addition, the microstructures of the FRC-treated wood specimens were characterized after combustion tests viascanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Thermogravimetric (TG) analysis was used to identify the expression of thermal stability. Furthermore, in accordance with the Naval Engineering Standard (NES) 713, it was determined that smoke was generated during the combustion of the FRC-treated wood and untreated wood. The objective of this study was to measure the toxic gas content and the toxicity index of the FRC-treated wood and untreated wood, and thereby to provide an initial database of the fire resistant wood-based building materials.
EXPERIMENTAL
Materials
In this experiment, Korean red pine (Pinus densiflora Siebold & Zucc.) from Pyeongchang in Gangwon, South Korea was used as a test specimen. It was prepared in the form of a 100 mm × 100 mm × 10 mm plate for FRC treatment and then redone to a size of 10 mm × 10 mm × 10 mm and a mass of 1 g ± 0.16 g to 0.25g (Fig. 1) according to the NES 713 standard (1990). The specimens were pretreated at 23.1 °C ± 1.8 °C and 49% ± 5% relative humidity and then stabilized for 3 h in a desiccator for FRC treatment. Figure 1 shows two types of untreated and FRC-treated specimens (Fire retardant treated wood by pressure-treatment; FRTW-pressure specimens). In the previous study (Seo et al. 2017), it was concluded that pressurizing FRCs was more effective in improving the fire retardant performance of wood. Therefore, in this paper, the experiment was conducted to compare FRTW-pressure and untreated test specimens. FRTW-pressure test specimens were produced with the fire retardation process by applying pressure to FRCs.
The specimens for thermogravimetric analysis were ball milled to sizes of less than 120-mesh, and they were dried for 48 h at 60 °C. The test specimens were reduced to 2 mm to 4 mm in size after the cone calorimeter test. The chemical compositions of the FRCs were the same as the previously conducted study (Seo et al. 2017). Table 1 shows the composition of the fire retardant chemicals (FRCs) used in this study and the formula of the ingredient. Among the chemical compositions of FRCs, di-ammonium phosphate and potassium carbonate were used as the main fire-retardants. The ratios given in the table are the percentages of the chemical species dissolved in water. Therefore, FRCs could be applied to wood test specimens through pressure treatment methods. Because these were not high concentrations, all of the mixtures were aqueous solutions having suitably low viscosity.
Table 1. Composition and Formula of Fire-retardant Chemicals (Seo et al. 2017)
Methods
Microstructure characterization of FRCs/P. densiflora
The microstructures of the FRTW-pressure specimen and untreated specimen after combustion testing were determined by SEM (S-3200-N, Hitachi, Tokyo, Japan) at room temperature. The specimens were observed under the acceleration voltage condition of 20 kV to collect the SEM images. In addition, FT-IR (Thermo Scientific, Nicolet 380, Madison, WI, USA) was used to monitor changes in the chemical groups inside the wood pores caused by the applied impregnation of the FRCs. The specimens were analyzed over the range of 650 cm-1 to 4000 cm-1with a spectrum resolution of 4 cm-1. The analyses were conducted to measure the char layer that was formed by foaming on the surface of the material when the specimen was burned. The test specimens were ground to a size of 100 mesh. And then those specimens were mixed with KBr powder according to tablet method.
Thermal characteristics of FRCs/P. densiflora
To confirm the improved thermal stability of the FRC-treated specimen compared to the untreated specimen, TG analysis (TA Instruments Inc., New Castle, DE, USA) was performed to determine the thermal characteristics of the wooden specimens. The analysis was carried out from room temperature to 800 °C, a heating rate of 10 °C /min, and under a nitrogen atmosphere at the flow rate of 100 mL/min.
Combustion gas toxicity assessment
To evaluate the toxic components of the combustion gases, the flue gas was evaluated for toxicity index according to NES 713 (1990). The NES 713 provided the concentrations of 13 different toxic gases, which are expressed as a factor of the density that is fatal to humans after 30 min of exposure time (NES 713 1990; Liang and Ho 2007). In addition, this can be quantitatively analyzed for the toxic components of the combustion gas using the test method specified in the ISO technical report (ISO/TR 16312-2). The Toxicity Test Apparatus (FESTEC Co., Seoul, Korea) was used to test the toxicity of the gases in the FRC-treated wood and the untreated wood. Figure 2 shows the test equipment and the test process.
The ignition fuel gas in the chamber was adjusted to a methane flow rate of 2 L/min and an air flow rate of 15 L/min with a burning duration that allowed a flame to be sustained. The specimens were exposed to a flame that was continuously burning. After the specimens were completely burned, a mixing fan was used to mix the gases in the chamber. Then, the mixed gases were detected using a gas detector tube (Ham et al. 2002; Kannan et al. 2005).
This enabled the identification of the amount of combustion gases produced by burning the specimens. The amounts of toxic gases (Cθ) in the combustion products were detected and estimated based on the changes in the various colors of the tube caused by the reacting gases. The formula given below was used to mathematically determine the concentration of the gas produced when 100 g of the material was burned, and the combustion products were in a chamber with a volume of 1 m3 (NES 713 1990).
The ignition fuel gas in the chamber was adjusted to a methane flow rate of 2 L/min and an air flow rate of 15 L/min with a burning duration that allowed a flame to be sustained. The specimens were exposed to a flame that was continuously burning. After the specimens were completely burned, a mixing fan was used to mix the gases in the chamber. Then, the mixed gases were detected using a gas detector tube (Ham et al. 2002; Kannan et al. 2005; Kim 2009). This enabled the identification of the amount of combustion gases produced by burning the specimens. The amounts of toxic gases (Cθ) in the combustion products were detected and estimated based on the changes in the various colors of the tube caused by the reacting gases. The formula given below was used to mathematically determine the concentration of the gas produced when 100 g of the material was burned, and the combustion products were in a chamber with a volume of 1 m3(NES 713 1990).
Cθ = (Ci × 100 × V) / m (1)
where Cθ is the final concentration of gas (ppm) in a 1 m3 volume chamber, Ci is the correct concentration of gas in the test chamber (ppm), m is the mass of the specimen (g), and V is the volume of test chamber (m3).
Equation 1 was used to calculate Cθ for each of the gases to determine the precision of replication; it is then possible to determine the averages values of the respective gases,
Toxicity Index = Cθ 1 / (Cf 1) + Cθ 2 / (Cf 2) +… + Cθ n / (Cf n) (2)
where 1, 2,…, n represents each of the gases detected and Cf is the concentration of the detected gasses that is considered fatal to humans after 30 min of exposure (ppm).
RESULTS AND DISCUSSION
Characteristics of Microstructure of the FRCs-treated Pinus densiflora S.
The SEM was used to evaluate the FRC-treated Pinus densiflora after combustion testing. Figure 3 shows the SEM images of the FRTW-pressure specimens after the combustion test. As shown, the internal structure of the carbonized wood collapsed. However, foam formed in the internal structure of the FRTW-specimen. Formation of the foam due to the FRCs was marked with a red circle in the SEM image. It swelled up as it burned inside the FRTW-pressure specimen.
The formation of foam was attributed to the combustion of phosphorus chemicals. As heat is applied to phosphorus chemicals, water vapor, metaphosphoric acid (HPO3), monobasic phosphate (HPO), oxidized phosphate (PO), and other gases are released, and then char layers are formed on the surface of the material. The foam is caused by the gas that is released as the char layer forms. According to Chung and Jin (2010), when a fire-retardant such as FRCs is impregnated into the pit openings of wood fibers, the fire-retardant swells when burned, thereby forming a char in the interior and on the surface of the wood (Chung and Jin 2010). The SEM images show that the FRCs achieved their morphology during combustion when they became impregnated inside the wood. This result also indicated that FRCs were fixed inside the wood, which positively affected the formation of the char layer (Wu et al. 2012). Figure 4 shows the reaction mechanism of the phosphorus chemicals.
The FT-IR absorption spectra of the untreated specimen and the FRTW-pressure specimen are shown in Fig. 5. The pine had the molecular formulae C6H10O5 (cellulose) and CH=CHCH2O(lignin; Korean pine) (Kim et al. 2012). In a comparison of the spectra of the two specimens, the absorbance of the FRC-treated specimen was confirmed to be lower overall. These changes resulted from the degree of infrared absorption weakening the materials (Doyle 1992). It has been reported that the type of fire retardant-treated materials had a high correlation with the elements of internal bonding force (Anderson et al. 1991a,b; Moore and Owen 2001).
Anderson et al. (1991a), Choi et al. (1987), and Wu et al. (2012) reported that the cellulose was in the range of 1250 cm-1 to 1000 cm-1, lignin was in the range of 1350 cm-1 to 1200 cm-1, and 1600 cm-1 to 1400 cm-1, respectively, and they had characteristic spectra. In addition, it was reported by Wu et al. (2012) that the spectrum showed strongly near 3400 cm-1. Based on the results of previous studies, the spectrums in this study were analyzed. The specimen surfaces are mainly composed of cellulose, hemicellulose, and lignin by made up of hydroxyl group (OH), carbon-hydrogen bond (C-H), and Carbonyl group (C=O and C-O) functional groups. The spectrum peak in the range of 3500 cm-1 to 3000 cm-1 indicates the presence of hydroxyl groups inside the materials (Colthup et al. 1964; Choi et al. 1987; Pandey and Pitman 2003). Also, it is attributed to the presence of flame-retardant agents, according to reports by Pabeliña et al. (2012). The region of 3500 cm-1 to 3300 cm-1 was assigned to the hydroxyl group. In particular, the spectrum in this range is the hydroxyl group originating from the moisture inside the material. Also, the spectrum in the region of 3400 cm-1 to 3000 cm-1 range indicates NH+ absorption in di-ammonium phosphate. In comparing the peaks of natural wood with FRTW-pressure specimen, no differences were found. According to Wen, such findings can be expected when the amount of added FRCs is small or the fixation is not good inside (Wen 2015).
The spectra of the FRC-treated specimen before and after the combustion test are shown in Fig. 6. The reason for carrying out this comparison was to find evidence as to whether impregnation of the wood had been achieved, leading to proper functioning of the fire retardant. Thermal decomposition of the wood was in progress as the temperature increased. It occurred in hemicellulose from 180 °C to 350 °C, in cellulose from 275 °C to 350 °C, and in lignin from 250 °C to 500 °C (Kim and Jeune 2009; Lowden and Hull 2013). Among the components of wood, the lignin of char is produced as a thermal decomposition product. The biggest difference in the spectrum of the specimen after combustion was the decreased spectral absorbance in the range before and after 3400 cm-1; the range of this spectrum meant that moisture was reduced. The change in absorbance means that the OH group was initially present and it disappeared. In a previous study it was reported that the absorbance disappeared at a temperature of 600 °C or more (Inoue et al. 2002). Furthermore, the spectrum around 1590 cm-1 was clearly formed, and it was determined that the aromatic ring of lignin was destroyed to form an aromatic C-H bond in agreement with the results of Lee and Lee (2008). The specificity in the spectrum of the FRTW-pressure specimen after combustion shows that the peak at 1000 cm-1 to 500 cm-1 increased very strongly. These results were related to the formation of a C-X bond (1400 cm-1 to 600 cm-1) due to the formation of char because of the carbonization of the test specimen. In addition, the peaks at 1500 cm-1 to 1100 cm-1 and 1100 cm-1 to 850 cm-1 were allocated to stretching vibration of P-O-P, and especially, peaks at 1350 cm-1 to 1100 cm-1 were allocated to stretching vibration of P=O (Wen 2015). According to the sentence described above, it was concluded that the FTIR spectra were not observed because the amount of added FRCs was small or not fixed inside the wood. However, when the results were confirmed after combustion test, it was judged that it was able to prevent fire.
Thermal Properties
The TG analysis was used to measure the thermal properties of the specimens, as well as to determine mass changes in the materials based on the time-to-temperature changes. The specimens used in the TG analysis are generally ground to a size of less than 120-mesh, or cut to a size of 2 mm to 4 mm. The specimens used in this experiment were cut to a size of 2 mm or less and again ground to a size of 120-mesh or less. Figure 7 shows the TG analysis results for the thermal degradation behaviors of all the wood specimens. The mass loss rate and the values obtained by differentiating the values are shown in the graph (Fig. 5). As temperature increased, pyrolysis occurred in all of the wood specimens. First, surface burning began when the temperatures ranged between 30 °C and 100 °C According to the results of the TG analysis, the temperature ranges at which surface combustion of the material began when the temperatures ranged between 30 °C and 100 °C. For the untreated specimen, the peak differential value occurred because ignition and carbonization took place simultaneously on the surface of the wood.
When temperatures ranged from 250 °C to 400 °C, decomposition combustion progressed and pyrolysis progressed after the char layer cracked and desorption occurred. The untreated specimen showed slight pyrolysis even at temperatures below 200 °C, but pyrolysis proceeded rapidly between 350 °C and 380 °C. TG analysis is a method of thermal stability analysis in which the weight of a specimen is measured over time as the temperature changes. It provides information about chemical phenomena including thermal decomposition and solid-gas reactions (e.g., oxidation or reduction). In this study, the thermal decomposition characteristics of the material were measured. As a result of analysis, the weight residual amount of the FRTW-pressure specimen was three times higher than that of the untreated specimen.
Toxicity Index of the Combustion Gases
Table 2 shows the lethal concentrations of the harmful components of the combustion gases and the test results for all the wood specimens based on the NES 713 (1990) standard. The NES 713 (1990) standard specifies that among the combustion gases generated by a fire, carbon dioxide (CO2), carbon monoxide (CO), hydrogen sulfide (H2S), ammonia (NH3), formaldehyde (CH2O), hydrogen chloride (HCl), acrylonitrile (CH3CN), sulfur dioxide (SO2), nitrogen oxide (NOX), phenol (C6H6O), hydrogen cyanide (HCN), hydrogen bromide (HBr), and 13 different gas components and emission amounts, such as hydrogen (H), can be confirmed (Ham et al. 2002; Kannan et al. 2005; Liang et al. 2007; Kim 2016). The differences in the types of gases emitted from all three of wood specimens were not statistically significant. The types of gases released from the untreated specimens were: CO2, CO, CH2CHCN, and NOX.
Table 2. The Toxicity Concentration Fatal to Humans Based on the NES 713 (1990) Standard
However, their emissions were somewhat different. First, the amount of CO2 emitted from the untreated specimen was 88,000 ppm, which was higher than the amount emitted by the other specimens. This meant that there was a high probability of complete burning of the natural untreated wood, but it did not surpass the standard. In contrast, the CO emissions from all three of the specimens were lower than the CO2 emissions. However, compared to the total amount of released gases, the CO emissions were higher in the FRTW-pressure specimens than in the untreated specimen. The results for the FRTW-pressure specimens were determined to be due to the combustion inhibiting effect.
In the case of conventional fire retardants, bromine and fluorine are detected in the post-combustion gases. However, these were not detected in the fire-retardant chemicals used in this study. It was also confirmed that no harmful components, such as NH3 and CH2O, were present. In particular, in the case of NH3, it was the theoretical gaseous substance released during the combustion of ammonium diphosphate, but this was not detected in this experiment. This is because it is not captured in the gas detection tube when the emission of gas is less than 50 ppm. However, NOX was released from both of the FRC-treated specimens. The NOX was mainly emitted from the combustion process, and NO and NO2 have harmful effects on the human body. To suppress the generation of NOX, some methods can be used to reduce the amount of excess air or to lower the temperature at the time of combustion (Terrill et al. 1987). However, these methods are difficult to use as a practical alternative when a fire actually occurs. The best way to reduce the concentration of harmful gases emitted in a fire is to ensure that the emission of harmful gases is low when the materials are burning. Pyrolysis of di-ammonium phosphate in FRCs is thought to be the cause of the release of NOX. A small amount of NOX was also released from the untreated specimen. These results were similar to the results reported by Wilkins and Murray (1980), who found that nitrogen compounds, such as gaseous nitric acid, are released by pyrolysis of the extracts in wood when the wood is burned.
The toxicity index of the flue gas for all specimens (Fig. 8) was calculated by applying the gas detection value shown in Table 2 to Eq. 2. The toxicity index of the untreated specimen was 1.22. The toxicity index of the FRTW-pressure specimen was 1.48. The limit value of the toxicity index specified by the NES 713 standard is 5, and it is determined that the combustion gas of the material is safe when the value of toxicity index is less than 5.
However, according to previous studies, when the toxicity index limit is applied to housing, if the toxicity index is greater than 1.5, the risk of injury or disability from a fire is higher in humans that are exposed to that environment for more than 30 min (Chauhanm et al. 2012; Seo and Son 2015). Overall, the toxicity index results demonstrated that the FRCs developed in this study had a low risk for indoor use. Based on these findings, the FRTW-pressure specimen also seemed to improve the fire safety of these building materials. However, further research is needed to reduce the amount of NOX emissions in the FRTW-pressure specimen. A further goal should be to decrease the toxicity index.
CONCLUSIONS
- The FRCs were found to work based on the SEM images of the specimens after the combustion test. Foams, which can form a char on the material surface, were formed after heat was applied during combustion. The foam was well adhered to the inside of the wood pits even after burning. This form is due to the formation of HPO and PO, which were formed by the pyrolysis of the phosphate species were belonging the FRCs. They can play a role in improving the flame retardant performance.
- Based on the FT-IR spectrums for FRTW-pressure specimen of before and after combustion test, it has been confirmed that the there was a decreased content of hydroxyl groups resulting from the evaporation of water due to combustion and an increase of NH+ due to pyrolysis of phosphate.
- The TG analysis confirmed that the FRCs used in this study were responsible for delaying the pyrolysis of the wood and for forming the char, thereby reducing the mass loss rate of wood by more than 30%.
- The FRCs produced very little noxious gas after combustion. The NOX was among the noxious gas components detected, but analysis of the overall toxicity index demonstrated that this was not problematic. Nevertheless, further studies are needed to determine the composition and composition ratios of FRCs.
ACKNOWLEDGMENTS
This work was supported by the National Research Foundation of Korea (NRF) and a grant funded by the Korean government (MSIP) (No. NRF-2016R1C1B1006636). This research was also supported by the Korea Electric Power Corporation through the Korea Electrical Engineering and Science Research Institute (Grant No. R15XA03-13).
REFERENCES CITED
Anderson, E. L., Pawlak, Z., Owen, N. L., and Feist, W. C. (1991a). “Infrared studies of wood weathering. Part 1: Softwoods,” Applied Spectroscopy 45(4), 641-647.
Anderson, E. L., Pawlak, Z., Owen, N. L., and Feist, W. C. (1991b). “Infrared studies of wood weathering. Part Π: Softwoods,” Applied Spectroscopy 45(4), 648-652.
Chauhanm, M., Gupta, B., Singh, S., Bhattacharyya, K., Singh, A. K., and Gupta, V. K. (2012). “Pretreatment of pine needles/wood particles and their composites with isocyanate prepolymer adhesive,” Polymer Engineering and Science 53(8), 1740-1750. DOI: 10.1002/pen.23436
Cho, N. W., Cho, H. D., and Oh, E. H. (2012). “A toxicity evaluation for the toxic gases of building finish materials,” Journal of the Korean Oil Chemists’ Society 29(1), 129-140.
Choi, K. S., Woo, S. I., and Chung, I. J. (1987) “A study on the pyrolysis of wood by infrared spectroscopy and thermogravimetric analysis,” Journal of the Korean Institute of Chemical Engineers 25(6), 563-569.
Chung, Y. J., and Jin, E. (2010). “Combustive characteristics of Pinus rigida treated with ammonium salts,” Journal of Korean Institute of Fire Science and Engineering, 24(5), 115-121.
Colthup, N. L., Daly, L. H., and Wiberly, S. E. (1964). Introduction to Infrared and Raman Spectroscopy, Academic Press, New York, USA.
Dassari, A., Yu, Z. Z., Cai, G. P., and Mai, Y. W. (2013). “Recent developments in the fire retardancy of polymetric materials,” Progress in Polymer Science 38(9), 1357-1387. DOI: 10.1016/j.progpolymsci.2013.06.006
Doyle, W. M. (1992). Principles and Applications of Fourier Transform Infrared (FTIR) Process Analysis (Technical Note AN–906 Rev. C.), Elsevier Science Publishers B.V., Amsterdam, Netherlands.
Fahy, R. F., and Proulxm, G. (2001). “Toward creating a database on delay times to start evacuation and walking speeds for use in evacuation modelling,” in: Second International Symposium on Human Behaviour in Fire, Boston, MA, USA.
Ham, S. K., Kim, H., Kang, Y. G., Kim, D. H., and Yi, Y. S. (2002). “A toxicity evaluation on the toxic gases released from interior upholstery fires,” Journal of the Korean Society of Safety 17(2), 61-67.
Inoue, S., Hanaoka, T., and Minowa, T. (2002). “Hot compressed water treatment for production of charcoal from wood,” Journal of Chemical Engineering of Japan 35(10), 1020-1023. DOI: 10.1252/jcej.35.1020
ISO/TR 16312-2. (2007). “Guidance for assessing the validity of physical fire models for obtaining for fire effluent toxicity data for fire hazard and risk assessment – Part 2: Evaluation of individual physical fire models, International Organization for Standardization, Geneva, Germany.
Kannan, G. K., Gupta, M., and Kapoor, J. C. (2005). “Estimation of gaseous products and particulate matter emission from garden biomass combustion in a simulation fire test chamber,” Atmospheric Environment 39(3), 563-573. DOI: 10.1016/j.atmosenv.2004.09.041
Kawahara, J., and Yanagisawa, Y. (2003). “Organophosphorus compound in indoor environment,” Journal of Society of Indoor Environment, Japan 6, 180-181.
Kim, D. W. (2016). A Study on the Introduce of Fire Impact Assessments through Danger Analysis of City-typed Hosing, Department of Fire Protection Engineering, The Graduate School of Industry, Pukyung National University, Busan, Korea.
Kim, M. K., and Jeune, K. H. (2009). “Use of FT-IR to identify enhanced biomass production and biochemical pool shifts in the marine microalgae, Chlorella ovalis, cultured in media composed of different ratios of deep seawater and fermented animal wastewater,” Journal of Microbiology and Biotechnology 19(2), 1-7. DOI: 10.4014/jmb.0901.041
Kim, J.-Y., Kim, T.-S., Hwang, H., Oh, S., and Choi, J. W. (2012). “Chemical⋅structural characterization of lignin extracted from pitch pine with ionic liquid (1-ethyl-3-methylimidazolium acetate),” Journal of Korean Wood Science and Technology, 40(3), pp. 194-203. DOI: 10.5658/WOOD.2012.40.3.194
Kim, Y. T. (2009). A Study on the Combustion of Car Interior Materials, Department of Fire and Disaster Prevention Graduate School of Industry and Science, Kangwon National University, Samcheok, Korea.
Kobes, M., Hesloot, I., Vries, B., and Post, J. G. (2010). “Building safety and human behavior in fire: A literature review,” Fire Safety Journal 45(1), 1-11. DOI: 10.1016/j.firesaf.2009.08.005
Lee, E. P. (2006). “Analysis on the actual conditions of deaths due to fires based on annual report on the cause of death statistics in Korea,” Journal of Korean Institute of Fire Science and Engineering 20(1), 98-103.
Lee, I. J., and Lee, W. H. (2008). “Analysis of structure and physical and chemical properties of the carbonized pine wood (Pinus densiflora S. et Z) powder (Ⅰ) – Elemental analysis, SEM, N2adsorption-desorption,” Journal of the Korean Wood Science and Technology 36(4), 44-51.
Liang, H. H., and Ho, M. C. (2007). “Toxicity characteristics of commercially manufactured insulation materials for building applications in Taiwan,” Construction and Building Materials21(6), 1254-1261. DOI: 10.1016/j.conbuildmat.2006.05.051
Lowden, L. A., and Hull, T. R. (2013). “Flammability behaviour of wood and a review of the methods for its reduction,” Fire Science Reviews 2(4), 1-19. DOI: 10.1186/2193-0414-2-4
Mfiso, E., Mngomezulu, M. E., Maya, J. J., and Adriaan, S. L. (2014). “Review on flammability of biofibres and biocomposites,” Carbohydrate Polymers 111, 149-182. DOI: 10.1016/j.carbpol.2014.03.071
Molyneux, S., Stec, A. A., and Hull, T. R. (2014). “The effect of gas phase flame retardants on fire effluent toxicity,” Polymer Degradation and Stability 106, 36-46. DOI: 10.1016/j.polymdegradstab.2013.09.013
Moore, A. K., and Owen, N. L. (2001). “Infrared spectroscopic studies of solid wood,” Applied Spectroscopy Reviews 36(1), 65-86. DOI: 10.1081/ASR-100103090
NES 713 (1990). “Determination of the toxicity index of the products of combustion from small specimens of materials,” Ministry of Defense, London, UK.
Pabeliña, K. G., Lumban, C. O., and Ramos, H. J. (2012). “Plasma impregnation of wood with fire retardants,” Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 272, 365-369. DOI: 10.1016/j.nimb.2011.01.102
Pandey, K. K., and Pitman, A. J. (2003). “FTIR studies of the changes in wood chemistry following decay by brown-rot and white-rot fungi,” International Biodeterioration and Biodegradation 52(3), 151-160. DOI: 10.1016/S0964-8305(03)00052-0
Park, Y., Jun, B., Seo, J., and Kim, S. (2011). “The improvement of thermal conductivity of wood-based panel for laminated flooring used the exfoliated graphite for heating energy conservation,” Journal of the Korean Society of Living Environment System 18(6), 650-655.
Qian, X., Song, L., Bihe, Y., Yu, B., Shi, Y., Hu, Y., and Yuen, R. K. K. (2014). “Organic/inorganic flame retardants containing phosphorus, nitrogen and silicon: Preparation and their performance on the flame retardancy of epoxy resins as a novel intumescent flame retardant system,” Materials Chemistry and Physics 143(3), 1243-1252. DOI: 10.1016/j.matchemphys.2013.11.029
Seo, H. J., Kim, S., Son, D. W., and Park, S. B. (2013). “Review on enhancing flame retardant performance of building materials using carbon nanomaterials,” Journal of the Korean Society Living Environment System 20(4), 514-526.
Seo, H. J., Hwang, W., and Lee, M. C. (2017). “Fire properties of Pinus densiflora utilizing fire-retardant chemicals based on borated and phosphorus (І) – Combustion characteristics,” BioResources 12(3), 5417-5427. DOI: 10.15376/biores.12.3.5417-5427
Seo, H. J., and Son, D. W. (2015). “Hazard assessment of combustion gases from interior materials,” Fire Science and Engineering 29(4), 49-56. DOI: 10.7731/KIFSE.2015.29.4.049
Stec, A. A., Hull, T. R., and Lebek, K. (2008). “Characterisation of the steady state tube furnace (ISO TS 19700) for fire toxicity assessment,” Polymer Degradation and Stability 93(11), 2058-2065. DOI: 10.1016/j.polymdegradstab.2008.02.020
Stec, A. A., and Hull, T. R. (2011). “Assessment of the fire toxicity of building insulation materials,” Energy and Buildings 43(2-3), 498-506. DOI: 10.1016/j.enbuild.2010.10.015
Terrill, J. B., Montgomery, R. R., and Reinharde, C. F. (1987). “Toxicity evaluation of fire effluent gases from experimental fires in a building,” Journal of Fire Science 5(4), 248-271. DOI: 10.1177/073490418700500403
Veen, I., and Boer, J. (2012). “Phosphorus flame retardant: Properties, production, environmental occurrence, toxicity and analysis,” Chemosphere 88(10), 1119-1153. DOI: 10.1016/j.chemosphere.2012.03.067.
Wei, G. L., Li, D. Q., Zhuo, M. N., Liao, Y. S., Xie, Z. Y., Guo, T. L., Li, J. J., Zhang, S. Y., and Liang, Z. Q. (2015). “Organophosphorus flame retardants and plasticizers: Sources, occurrence, toxicity and human exposure,” Environmental Pollution 196, 29-46. DOI: 10.1016/j.envpol.2014.09.012
Wen, M.-Y. (2015). A Study on Development of Fire Retardant Treatment Method and Properties of Fire Retardant Wood, Department of Housing Environmental Design Human Ecology, Chonbuk National University, Jeonju, Korea.
Wilkins, E., and Murray, F. (1980). “Toxicity of emissions from combustion and pyrolysis of wood,” Wood Science and Technology 14(4), 281-288. DOI: 10.1007/BF00383455
Wu, G., Lang, Q., Chen, H., and Pu, J. (2012). “Physical and chemical performance of eucalyptus wood with impregnated chemicals,” BioResources 7(1), 816-826.
Yew, M. C., Sulong, N. H. R., Yew, M. A., Amalina, M. A., and Johan, M. R. (2015). “Influences of flame-retardant fillers on fire protection and mechanical properties of intumescent coatings,” Progress in Organic Coatings 78, 59-66. DOI: 10.1016/j.porgcoat.2014.10.006
Article submitted: August 9, 2017; Peer review completed: October 22, 2017; Revised version received and accepted: November 18, 2017; Published: November 22, 2017.
DOI: 10.15376/biores.13.1.506-521