Fires, especially fully-developed fires, are often idealised as having a uniform temperature and gas concentrations whilst growing pre-flashover fires are commonly idealised as having two gas phase layers. With suitable simplifications the equations of a particular simplified one layer i.e. one uniform gas phase model have been adapted by redefining the terms so as to describe a suitably defined two layer model. The uniform model is thus shown to be a special case of a more general two layer model for which many of the modes of behaviour already discussed might also apply.
Dependence of the height of turbulent wall flames and the wall flame heat transfer on the fuel conditions is studied by experiments using porous line burners against walls. The flame height is represented as a function of heat release rate and fuel width. According to the data of incident heat flux to the wall surface, the wall above a fire source appears to divide into four regions following the thickness and intermittency of a luminous flame. The distribution of the incident heat flux is represented as a function of the height normalized by a scale length representing the flame height. Exploratory analysis is made to explain this result from the heat transfer mechanism. The present analysis seems to be consistent with current experimental work on wall flames.
Polycyclic aromatic hydrocarbon (PAH) contents of the particulates or sooty-tars produced during wood-combustion and -pyrolysis were investigated in simulated air (N2 : O2 v/v%) and nitrogen gas streams under heat flux in the range 1.5 - 5.0 W/cm2. The PAH contents were assessed in comparison with those of other airborne-particulates in urban and expressway tunnel atmospheres. After PAH fraction in an ultrasonic extract was preseparated by means of one-dimensional dual-band thin-layer chromatography, the PAH fraction was analyzed by method of high-performance liquid chromatography. The PAH contents for the incomplete combustion of wood was markedly higher than in wood-pyrolysis. Furthermore, the ratios of fluoranthene and pyrene to benzo (a) pyrene contents were considerably higher than in airborne particulates from the environments. The PAH contents at the former case were at the same level to the typical airborne-particulates.
Categorization of city facilities such as theaters, hospitals, bars, hotels, department stores, and railway stations, is dealt with in this paper by using 24 fire-safety-related items evaluated by experts in this field. The data was qualitative - e.g., excellent, good, fair, poor, or bad - for each item and represented graphically by colored face graphs for each facitity. Visual discrimination of these faces into groups yielded a good categorization for fire safety evaluation of city facilities and good agreement with the results obtained through numerical cluster analysis.
The Fire Center has conducted a series of full-scale tests of hotel-like rooms. The furnishings were a bed with headboard "made up" with bedding, and a wooden sidetable. The ignition source was a wastebasket. The furniture was burned in the new N. B. S. furniture calorimeter and in a 2.44 × 3.66× 2.44 high room. As an adjunct to analysis of the test results, a series of simulations of the fire tests were run using the Harvard Fire Simulation. This report describes the simulations and their results. The principal finding of the simulations was that the room had little effect in augmenting the burning of this fuel package. The simulation result was partially due to the burn algorithm used and partially due to the relatively large fire area and short assumed flame radiation extinction length. This finding might not have been true had the individual objects been smaller in area or their flames less opaque. A different burn algorithm might also have produced different results.
About 13 experiments were made with model steel-frames of three stories in which one girder, one column or both girder and column were heated to elevated temperatures at a constant heating rate by an electric furnace. These experiments made it possible to analyze thermal stresses within the steel-frame. Large thermal stresses appeared in the frame corresponding to the "binding modulus" of the frame. The structural behavior was influenced by the thermal stress generated by the heated girder more than by that of the heated column. In addition to buckling of the heated column occured.