Burning rates of objects under ceiling are increased compared to burning in an open space. To predict the burning behavior of combustibles precisely, increase of heat release rate due to heat radiation from extended flame and ceiling to fuel surface should be considered properly. For this purpose, a series of experiments was conducted using a 0.5m pool fire of lubricant oil. The fuel was burnt in an open space and under ceiling with heights ranging between 0.49 to 1.42 meters. Heat release rate and flame length were measured. When the flame did not reach to the ceiling, burning behavior was similar to that in open space. As the ceiling height was decreased, flame lengths and heat release rates were increased. A model was proposed to predict the heat release rate under ceiling using the values measured in an open geometry. First, the flame length was calculated by existing calculation formulae. Next, radiation feedback to fuel surface was calculated using the calculated flame shape. Then, heat release rate was corrected by the radiation feedback to fuel surface. However, the calculated flame lengths and heat release rates were excessive in comparison with measured values. The agreements were improved when measured flame lengths were applied instead of calculated flame length. Thus it is suggested that the prediction formula for flame length are need to be investigated further in order to improve overall accuracy.

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Portable fire extinguishers being sold in Japan hold an operation instructions label as "1) Pull pin; 2) Direct at base of flame; 3) Squeeze lever." How to operate the extinguishing agent is not shown. Shoub et al. (1957) stated that dry chemical extinguishers are most effective when operated to cover the whole flaming area at once. This operation method is not useful for flammable liquid fires having burning areas greater than the extinguisher's spray width. An objective of this study is to establish a suitable operation method to fight such a liquid fire with a single dry chemical fire extinguisher. As it is difficult to observe and analyze extinguishing agent's behavior during operation (because it is obscured by a cloud of agent), a new method is developed to indirectly measure the actually sprayed area (on the fuel surface) of extinguishing agent during a live operation. Operation experiments were done using a number of novice operators who attacked a 0.8m² n-heptane pool fire. With 66 operation experiments and analysis, it was found that a successful operation needs to meet the following three conditions:
 1) Sprayed extinguishing agent must sweep the whole burning area.
 2) Part of sprayed agent continuously hit the upper edge of fuel pan's front wall during the sweep operation.
 3) Distance (from the nozzle) to the farthest point of burning area is within the effective range.

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This research introduces a new scientific method of determining causes for fire and explosions in refuse derived fuel (RDF) by visualizing microorganism activities which cannot be seen by eye-sight. The visualizing was realized by a bacteria flora activating mapping which was made by comparing the data of temperature and oxygen concentration obtained in this experiment with optimum temperature and optimum oxygen concentration for microorganisms in the database. Several bacteria in RDF which were produced in Japan remain in dormant state during the production process, and they germinate and multiply with the presence of water. These bacteria were identified by the metagenome analysis as 10 aerobes, 7 facultative anaerobes, and 10 obligate anaerobes. Of these 27 species, 20 were identified as spore forming bacteria, and 12 as hydrogen producing bacteria. For the experiment, a 20 L insulated tank containing 10 kg RDF was used and drops of distilled water were applied from the top of the tank. Changes of temperature and gas composition with time were measured by a thermocouple and sampling probes which were inserted in the tank. Utilizing the bacteria flora activating mapping, how microorganism activities affect processes leading to fires in piles of RDF was considered.

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The authors have aimed at developing a new evacuation safety verification method based on the concept of fire risk. In this method, it is important to estimate the ratios of fire occurrence and fire spread appropriately. However, understandings for setting the appropriate values of these parameters are not sufficient. In this paper, the authors have focused on minor fires, and analyzed factors leading to the minor fires. We analyze relationships between the minor fire and the staying time, the fire alarm system installation or the total floor area by using fire statistical data of 1995 - 2008.

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