Investigation of combustion characteristics of cotton in various environmental conditions

Fire is the uncontrolled occurrence of combustion reactions when matter combines with heat and oxygen. The basis of fire is the combination of sufficient flammable material, oxygen and heat. Fires are categorized according to the characteristics of the burning material. Cotton fires are also among Class A fires. Class A fires normally include fires of solid materials, usually organic in structure, that burn in the form of embers. Cotton is a raw material used in many sectors, especially in the textile sector. Cotton is the most important building block of the textile sector. It is the first plant whose fiber is processed. Cotton has a fibrous structure and is highly flammable. For this reason, since it is a highly flammable material in the process from collection to baling, from baling to storage, from storage to processing, from processing to fabric production, necessary fire precautions and measures must be taken throughout the organization to prevent fire. Cotton, which has high flammability, is a material that can burn with small sparks and is difficult to control after burning. In this study, cotton samples of the same weight and volume in different environmental conditions were prepared and burned in certain radii. This study aims to examine the flammability of cotton when exposed to environmental conditions based on time, the degree of change in the burning time of two different sized cotton samples with the same volume and different volume burned on different days, when the same weight is taken as the basis, the effect of humidity in the environment on the burning time, the degree of change in the burning time of cotton with the same mass whose surface area is increased and whose surface area is decreased, and whether the perceived temperature has an effect on the burning time. Visual examination of the burning event was conducted during the experiment. The following parameters were taken as basis in external environmental conditions. Air temperature Perceived air temperature Humidity Wind speed In the closed area experiment, the following parameters were taken as basis. Air temperature Humidity In our study, cotton without cotton was burned on different days. The surface diameter of the burned cotton samples was set as 12 cm and the surface diameter as 6 cm. All of the burned cotton samples were measured with a precision scale. Each sample was prepared to be 5 grams. Afterwards, the prepared cotton samples were burned in Istanbul and Adana locations. The burning status of the burned cotton samples was observed and the effect of weather conditions on burning was emphasized. In addition, in order to examine the burning status of cotton in a closed area, cotton samples prepared in the same size and diameter were burned in a closed area. A digital thermometer was used to measure the air temperature and humidity in the air in the closed environment conditions of the experiment conducted in a closed area. When the experiments conducted in Istanbul province were examined, cotton with a reduced surface area faded faster. The reason for this is that cotton has a fibrous structure and fiber contact increases as you go to the inner surfaces and allows less oxygen entry than the cotton sample with an increased surface area. The density of the cotton was increased by reducing the surface area. Cotton with an increased surface area burned longer, and since the surface area in contact with oxygen is higher due to the gaps between the cotton fibers, the burning event tended to spread to all tissues. For this reason, the burning event took a little longer. Wen-Hui Ju, who examined the burning status of cotton logistics warehouses, analyzed the fire risk of cotton logistics warehouse according to the physical and chemical properties of cotton and investigated the sources of fire hazard. As a result of the research, it was emphasized that the possibility of moisture absorption and heat release is the highest among all the causes of smoldering fire, therefore, it is important that the temperature should be below 303 K and the ambient humidity should be controlled below 70%. When the experiments conducted in the summer months in Adana province were examined, it was observed that in the air conditions where the humidity rate was 70% and above, the cotton sample with increased surface area extinguished faster and the amount of unburned cotton was higher than the samples with reduced surface area. Humidity rate is a serious parameter affecting the burning characteristics. In the experiments conducted, the burning characteristics of the cotton sample exposed to 69% and below humidity rate were the same as in Istanbul province. Due to the lower humidity rate, the cotton sample with reduced surface area and increased density extinguished faster. The cotton sample with increased surface area burned for a longer time. It was also examined how the burning characteristics of cotton proceeded in a closed area. Cotton samples of the same size and weight were burned in Adana and Istanbul locations. The parameters compared in environmental conditions were air temperature and the humidity rate they were exposed to. The air temperature and humidity rate of the current area were measured with a digital thermometer. The result is as follows. When cotton samples exposed to humidity above 70% were burned in a closed area, the cotton sample with a diameter of 12 cm faded faster than the cotton sample with a diameter of 6 cm. In the cotton sample exposed to humidity below 70%, the cotton sample with an increased surface area burned longer, while the cotton sample with a reduced surface area faded faster. Cotton burned in a closed area gave the same result as cotton burned in outdoor conditions. As a result of the experiment, the cotton sample with an increased density burned on days when the air temperature was high exhibited a smoldering burning characteristic. However, when the cotton sample whose diameter was increased and density was reduced was burned, the combustion spontaneously extinguished after a certain period of time. As Wen-Hui Ju stated in his article, it is important to keep the relative humidity of the storage areas below 70% and the temperature not to exceed 30°C. The most important conclusion we have drawn from this study is that environmental conditions have a serious effect on cotton fires. On days when the wind speed is high, the weather is hot, which causes the burning times to increase. Cotton is a highly flammable material. Even a small spark can cause a large fire. In the experiments conducted, one of the situations observed in the processes from the burning of cotton samples with reduced surface areas to their complete extinction was that most cotton samples appeared to be completely burned during the first burning process. The outer surface of the cotton sample changed color, in other words, it appeared to be burned, and there was no smoke in the cotton sample. In fact, it was as if the cotton was not burning. However, it was observed that the burning cotton sample exposed to environmental conditions burned, smoked, and continued the burning process in its inner parts when a light wind blew. One of the results obtained from the experiments is that the humidity rate being too high, exceeding 70%, causes the burning time to shorten. In the experiments conducted, it was observed that it is a material that can burn smolderingly without producing smoke. It is extremely important to consider that even a small spark can cause a fire since it has a smoldering feature. For this reason, cotton bale storage regulations should be followed in cotton factories and the necessary precautions should be taken. Cotton bales should be placed as far apart as possible. Cotton should be stored by baling so that in the event of a possible fire, cotton bales that have not shown a burning reaction can be evacuated.