This paper proposes simple equations for predicting the smoke filling time in the room of fire origin, which may be practically used to evaluate the performance of evacuation safety design of building. The simple equations were developed for the typical types of design fires, i.e. constant, t-square and their combination. Also these equations can be used for rooms having irregular ceilings, whose horizontal section areas change with height. Their prediction capabilities were verified by comparison with the predictions by BRI2002, a two-layer zone model often used as a tool for evacuation safety design. These simple equations are found to have prediction capability almost equivalent to BRI2002 for smoke filling in the room of origin.
Utilizing a zone model and a ceiling-jet model, a simple calculation method for predicting fire detector's response time is presented. The parameters are the floor area and the ceiling height of the room, the radial distance of the detector from the fire axis, time history of the heat and smoke release rates of the fire, and the response characteristics of the detector. For the heat detector, application of RTI-C model (a modified Response Time Index model) is discussed and a method utilizing two RTI's, one for the sensor element and the other for the detector body, is introduced. The method using two RTI's shows better results than the original RTI-C model, which was derived for predicting the response of sprinkler heads. In addition, a calculation method for predicting the response of rate-of-rise heat detector is presented. For the response of photoelectric smoke detector, a method utilizing a response threshold in the optical smoke concentration and a response threshold in the air velocity is introduced. It is shown that different response thresholds in the smoke concentration are needed for the smoke released from flaming sources and for the smoke released from smoldering sources respectively.
It is natural to treat a building structure as a 3D body when concerning its behavior in a fire, because fire is a phenomenon involving 3D thermal expansion. The influence that the floor slab in a fire compartment exposed to fire has on the behavior of the building structure during a fire may be extremely large, therefore, it is necessary to explore how the floor slab affects the structure when exposed to fire. In this study, the end restraint force and the displacements of the adjacent substructures are formulated by dividing structures into unitary substructures, as an approach to the problem of the increase in the number of nodes which occurs in the 3D analysis taking account of the slab. Since no basic data is available for concrete under 2D stress exposed to elevated temperatures, the thermal expansion of a floor slab is considered by conceiving the slab as a grid of intersecting beams. A method of 3D coordinate transformation, which takes the effect caused by the principal axis of component section moving from time to time into account, is proposed. Under these assumptions, an analytical method of deflection behavior concerning 3D steel frame exposed to fire that takes account of the thermal expansion of a floor slab is constructed. The theoretical results agree well with those recorded in experiments in which a full-scale frame was exposed to vehicle fire.
A series of fire resistance tests of aluminum alloy members was conducted. This study characterize temperature rise and collapse mechanism of the aluminum alloy members. Analytical expressions, based on lumped mass heat balance equation, have been developed to estimate the temperature rise of unprotected, protected aluminum members during fire. An evaluation method of critical temperature of aluminum alloy members was also proposed and compared to experimental data. The results of the calculations by these methods were found to be in a good agreement with the experimental results.