During the previous years, v~sible differences have been observed on the thermal response of a g i x n specimen placed in standard fuinaces piloted with thermocouples, The definition of a method for harmonising the severity of the heat flux absorbed by a specimen in fire resistance furnaces is necessary in order to reduce the differences observed. For several years, the project of using plate thermometers instead of thermocouples to control the furnace temperature has been examined and discussed. These new sensors can be more appropriate than thermocouples to impose to the specimen a heat impact as they seem to be largely independent of the furnace characteristics. A new zone model has been developed to calculate the heat fluxes exchanged in the furnace and the temperature of the specimen, the furnace being controlled either by thermocouples or by plate thermometers. The model's equations bring more light on the reasons why the heat flux received by a plate thermometer is weakly dependent of construction parameters. The main features of this model are described. In order to present the capabilities and lim~ts of the model, calculated results are compared to recent test results obtained on a reference specimen equipped with "calibration elements", and prediction results are given for some different specimens for which no tests have been executed, showing the advantages of plate thermometer control.
CIFI (Circulation dans un Immeuble des Fumees de l'incendie) is a computer program based on a multiroom zone model. It has been developed at CSTB for the purpose of predicting air and smoke movement in a multistorey building. In the previons versions of CIFI, the mass flows circulating from room to room through vertical openings were calculated from the differences in vertical pressure fields across these openings, but no estimate of entrainments was made. We introduced recently in CIFI a simple set of criteria in order to decide on the possibility of distributing each flow through a vertical opening between the two gaseous layers located downstream. This results in plumes and entrained flows into these plumes, which were approximately estimated. A description of our approach in given and applied to the interpretation of experiments at NBS.
In France, the design of smoke control systems for buildings open to the public commonly depends on regulatory requirements on minimal values of smoke vent areas for each building space, in natural ventilation.These regulations proved unsatisfactory for atrium buildings, and in some cases building designers as well as safety authorities must be provided with specific means for designing a smoke control system and evaluating its efficiency. This paper gives an illustration of what computer analysis can bring for this purpose, through the example of an atrium building in a new business centre near Paris (CNIT / La Defense) .Simulations of smoke movement throughout this 5-storey building containing an 18-metre high atrium were carried out with the CSTB multiroom computer code CIFI.The roughness of zonal description in the model is balanced by the capability of treating the physical system as a whole for the computer simulations. Consequently, the analysis allowed us to draw relevant information from simulation results, and then contributed to the elaboration of a reasonable agreement resulting in the acceptance of the project (the business centre has been recently inaugurated) .
Simple predictive models can be very useful for engineering applications or education in fire safety. Two aspects of compartment fires are addressed here the growing fire (risk of flashover) and the fully developped fire (fire resistance problems). For each aspect, two predictive methods are presented: a simple model needing small calculation equipment and a computer code based on a zone model. Some results are given as examples showing the possibilities and limits of these methods.
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