Experiments were conducted with the aim of elucidating the effect of differences in the ratio Af/Ah=φ of the combustible surface area Af to the horizontal projection area Ah of a combustible on the reduction in heat release rate from supplying with water. Wood cribs (wood species: Japanese cedar) where the surface area ratio Af/Ah=φ can be easily created by changing the number of layers of stacking used for the combustibles. The main experimental parameters were "number of layers of wood cribs," "water delivered density," and "water supplying start time. In the experimental results, regardless of the number of layers of wood cribs, the heat release rate per unit area ΔQ'' that was reduced by supplying with water was proportional to the product of the water delivered density w and 1/φ (=Ah/Af). The constant of proportionality was virtually the same value (approximately 12.5 kJ/g in this experiment) for all water delivered densities and all numbers of layers of wood cribs.
The paper is intended to find out the effect of building size on the frequency of fire starting for a variety of building use types: 1. Corporate Survey of Buildings is a useful source of information on non-residential commercial building stock in Japan. 2. Fire statistics data can be used to estimate the distribution of the size of buildings within which fire started for a certain period of time, while the size distribution of the buildings at risk in Japan can be derived from Corporate Survey of Buildings for specific building use types. 3. Ignition frequency of typical building uses in Japan was found to depend heavily on the size of the building, i.e. total floor area of the building.
To establish a relationship between the floor impact sound level and driving-point impedance, a floating floor built on a wooden floor was used in the laboratory. The results are as follows: 1. The floor-impact sound-level difference for cases with a rubber-ball impact source tends to be greater than that for those cases with a car-tire impact source. 2. The difference between the driving-point impedance levels of the surface material of the floating-floor system is practically identical to the floor-impact sound-level difference in cases with a rubber-ball impact source. 3. The driving-point impedance-level difference, the flexural-rigidity-level difference, and the surface-density-level difference were defined here, and the relationships with floor impact sound level differences were compared. 4. An accurate estimate for the flexural rigidity, which is used to calculate the driving-point impedance on the surface material of the floating-floor system, is the sum of the values calculated for the individual members. 5. A floor-impact sound-level difference of 10 dB or higher was achieved at a 63 Hz band when the driving-point impedance of the surface material of the floating-floor system was increased from 2,100 to 6,700 kg/s.
Vibrations induced by multiple consecutive human footfalls on high stiffness long-span timber floor were measured and examine several performance values, the relationship between the measurements and human sensory evaluation. An experimental floor was built, on which the sensory tests were performed. It was revealed that walking vibrations induced by relatively high stiffness floors are different from relatively low stiffness floors from the point of view of strength and property. On the relatively high stiffness floors, it was inferred that walking vibration is felt as rather a consecutive long vibration at the natural frequency than stack of footfalls of each step.
Barrier-free design for the visually impaired and the elderly is growing in both importance and sophistication. Within this context, the authors of this study have sought to evaluate the accessibility of stair systems under four types of illuminations. These are: general lighting, lighting in riser, sidewall lighting, and linear lighting on edge of stair goings. This study targets young people, visually challenged people and elderly people. From this study we determined that lighting of a linear design best serves our target groups. Additionally, the authors of this study examined and determined the optimum levels of brightness for such design.
This research aims at developing a moisture expulsion exterior wall which can discharge indoor moisture to the outdoor air by the use of a humidity control material. The indoor moisture is naturally discharged using the difference in water vapor pressure between the indoor and the outdoor air in winter. In the present study, the humidity reduction effect under winter climate conditions was investigated using a field test house located in Hakusan City. And the effect of the moisture expulsion exterior wall structure was shown as a moisture expulsion quantity through one winter season.
The aim of this study is to propose pollen prevention measures in buildings by examining the mechanisms of indoor concentration decay theoretically with pollen grains as the main target, and estimate indoor concentration using theoretical formulas. We first analyzed the mechanism of the indoor pollen concentration, and verified predictive formulas based on actual measured values. Next, assuming the outdoor pollen concentration, the indoor concentration was estimated. It was shown that by making assumptions for the outdoor concentration and conditions, the indoor concentration could be estimated using a theoretical formula.
Installation of residential solid-oxide fuel cell cogeneration system (SOFC-CGS) has been promoted as an energy-saving measure. Although SOFC-CGS is becoming popular among detached housing, the installation of SOFC-CGS in apartment buildings can also be effective in reducing residential energy consumption. In this study, the effectiveness of SOFC-CGS installation in an apartment building is evaluated by considering the variation of eletricity and hot water demands in different household settings. In order to simulate the demands, parameters are formulated and randomly distributed in a 50-unit apartment building model. The reduction rate of energy consumption by SOFC-CGS installation is generated for each unit and the impact of each parameter is examined.
Frequencies and characteristics of heatstroke occurred at elementary/secondary schools were investigated by using the data of NAASH (National Agency for the Advancement of Sports and Health). The environmental factors, e.g., outdoor temperature, relative humidity and global solar radiation, were obtained at the closest meteorological observatory at the time of occurrence. 1328 cases of heatstroke were reported in the data of NAASH for the investigated schools. Of the 1328 cases, 836 were occurred at school area, i.e., schoolyard and school building. Of the 836 cases occurred at school, 533 were occurred on schoolyard, 204 were in gymnasium, 66 were in school house, and 20 were in swimming pool. Out of the 836 cases of heatstroke at school, 503 cases were occurred during athletic extracurricular activities, 104 were occurred on field day, 85 were occurred during the class of physical education. The relationships between the environmental factors, i.e., outdoor temperature, wet-bulb temperature, WBGT (wet-bulb globe temperature), and humidity ratio, and the risk factor, i.e., the odds ratio of heatstroke, were obtained. The risk factors of heatstroke for schoolyard, gymnasium, and school house, had a good correlation with WBGT, and this relationship would be used for the evidence when designing safe school environment.
Using a pedestrian tracking system on laser scanners, the big data for office-workers' trajectories can provide detailed deep insights on workplace designs. In the analysis of tracking data, it is necessary to represent them on maps so that the relationships between spatial and temporal features can be understood clearly to comprehend characteristics of their working style. In this paper, two methods to extract patterns of “Spatio-temporal activity” are described. One is the time zone extraction model, i.e. a classification model on the basis of information loss minimization model, and the other is the day scene extraction model, i.e. a latent class model using the probabilistic latent semantic indexing (PLSI). Numerical studies demonstrate the usefulness of our proposed models.