A Large number of human lives are lost in fires every year. Some of them are caused by electrical faults originated in plugs and receptacles. They usually result from overheating at poor connections or dielectric breakdown of insulating materials. This kind of dielectric breakdown is often called as a tracking phenomenon. In this paper, modified arc tracking tests were conducted on specimens carved out from polyvinyl-chloride-insulated plugs and urea-resin-covered receptacles. Temperature of the specimen and concentration of ammonium chloride solution used for the tests were varied. Leakage currents and energy consumptions were measured and the circumstantial effects on the tracking phenomena were discussed.
In order to study the inclined fire plume width and its shape influenced by cross-wind, we carried out experiments with a single fire source in an unconfined space. The inclined fire plume axis was defined based on the measured temperature, and the plume width was also defined as the distance from plume axis to the point where the temperature falls down to 1/e of the plume axis-temperature. Dependence of the fire plume width on the cross-wind velocities and traveling distance from the center of the fire source was investigated. Based on these results, in near region of the fire source, it was understood that the cross-sectional shape of the inclined fire plume swelled to the floor side. However, the cross-sectional shape of the inclined fire plume was gradually changed elliptic shape whose long axis is plume width of “horizontal direction” with the increase of the traveling distance from the center of the fire source.
Experimental study was carried out using a single circular fire source in an unconfined space to understand the behaviour of the trajectory how it depends on the cross-winds and heat release rate. The position of the trajectory was defined with the aid of the three dimensional measured temperature data in downwind field. It is observed that the trajectory oscillates with time in cross-winds. In order to estimate the plausible position of the trajectory, we employed the position where the time-averaged maximum temperatures appear. The trajectory of the inclined fire plume was modelled with logistic function, and the variables including in the model were represented by the coupled function of Froude number and dimensionless heat release rate. This model gave the good agreement with those estimated by the measured data.
When more than one hydrant against to the ordinary fire are used at the same time, the result that the water pipe network of Kobe City was experimented is analyzed with a purpose of evaluating the function and ability of the hydrant in this paper. The kobe Fire Department researched ”the combined pressure investigation of the fire fighting pump cars” on June 9, 1986 in order to evaluate the function of the hydrant against to the ordinary fire. We analyzed relations between the amount of drainage and water pressure from the drainage experiment on the water pipe network of the actual town district under the condition of the caliber size of the water pipe and the number of drainage hydrants.
This research is the one that an analysis of distributing water pipe network immediately after Southern Hyogo Prefecture Earthquake 1995 was tried. The research object is the Itayado low layer water supply district in Nagata Ward and Suma Ward where many big fires occurred simultaneously in Kobe City. The fire fighting pump car mobilized at about 6 AM immediately after the earthquake and the fire-plug in three places was used. The usage condition of the fire-plug and the parameter of the fire fighting activities were clarified in the former paper. Then, an ability of draining water off at that time has been clarified from the struck situation of the damaged water pipe.
Fire plume, ceiling-jet and the formation of hot smoke layer are most important phenomena affecting the response of fire detectors. In addition, the convective and conductive heat transfer plays an important role in the response of heat detectors, and the particulate characteristic of smoke is important in affecting the response of smoke detectors. Research papers concerning these phenomena and published between 1950 and 2003 are reviewed to help new and potential researchers of detection. Emphasis is placed on the prediction of detector's response, and the papers related to this theme directly or indirectly are selected. However, not all research papers concerning these fire phenomena are covered. Papers related to detection technology are not included.