Building Design and the Fire Hazard

Building codes cover only the minimum requirements for fire safety and leave ample room for the expertise and conscience of the building designer. Providing life safety starts with securing conditions under which sufficient time is left for the occupants to escape from an incipient fire. It also involves measures that reduce the probability of exposure of the occupants to smoke and ensure their evacuation from the fire-stricken area. The safety of both life and property is served by ensuring the structural integrity of all key elements of the building even in spreading fires, but at the same time employing all available techniques to confine the fire to its place of origin

Fire analysis of steel frames with the use of artificial neural networks

The paper presents an alternative approach to the modelling of the mechanical behaviour of steel frame material when exposed to the high temperatures expected in fires. Based on a series of stress-strain curves obtained experimentally for various temperature levels, an artificial neural network (ANN) is employed in the material modelling of steel. Geometrically and materially, a non-linear analysis of plane frame structures subjected to fire is performed by FEM. The numerical results of a simply supported beam are compared with our measurements, and show a good agreement, although the temperature-displacement curves exhibit rather irregular shapes. It can be concluded that ANN is an efficient tool for modelling the material properties of steel frames in fire engineering design studies. (c) 2007 Elsevier Ltd. All rights reserved

Variable-state methods of measuring the thermal properties of solids

Two variable-state methods have been developed which both offer the advantage of producing negligible thermal disturbance in a solid during measurement. The first is a curve-fitting method. It makes use of the fact that the initial temperature rise, due to a constant flux plane heat source, at points within a certain region of a finite solid is essentially the same as that in an infinite solid. Temperature records obtained from such points thus can be analyzed with the assumption of linear heat flow, and used for calculating all thermal properties of the solid. The second is a pulse method. If a hot or cold pulse is applied to a plane surface of a specimen, the rise or drop of temperature at some distance from the surface will pass through a maximum; from the time of the maximum the thermal diffusivity can be calculated. The main advantage of this method is the ease of specimen preparation.Deux m\ue9thodes de mesure des \ue9tats variables ont \ue9t\ue9 mises au point. Toutes les deux offrent l'avantage de produire une perturbation thermique n\ue9gligeable dans les solides, durant les mesures. La premi\ue8re est une m\ue9thode bas\ue9e sur les courbes. Elle utilise le fait que l'augmentation initiale de la temp\ue9rature, due \ue0 une source de chaleur plane \ue0 flux constant, en des points situ\ue9s dans une certaine r\ue9gion d'un solide fini est essentiellement la m\ueame que celle enregistr\ue9 e dans un solide infini. Les temp\ue9ratures enregistr\ue9es en de tels points peuvent ainsi \ueatre analys\ue9es en partant de l' hypoth\ue8se d'un \ue9coulement de chaleur lin\ue9aire et utilis\ue9es pour calculer toutes les propri\ue9t\ue9s thermiques du solide. La seconde est une m\ue9thode d'impulsion. Si une impulsion chaude ou froide est appliqu\ue9e \ue0 la surface plane d'un sp\ue9 cimen l'augmentation ou la diminution de la temp\ue9rature \ue0 une certain distance de la surface traversera un maximum; on peut calculer la diffusivit\ue9 thermique \ue0 partir de la dur\ue9e du maximum. L'avantage primordial de cette m\ue9thode est qu' elle facilite beaucoup la pr\ue9paration des sp\ue9cimens.Peer reviewed: NoNRC publication: Ye

The Delphi method - a complement to research

In making fire safety decisions the designer often finds that some input variables concerning his problems are chance variables. As detailed statistical data are rarely available the designer must rely largely on his expert judgement. With the application of the Delphi method such decisions can be optimized and formalized. The essence of the Delphi method is described and its use illustrated through an example related to the assessment of fire resistance requirements.En prenant des d\ue9cisions relatives \ue0 la s\ue9curit\ue9 incendie, le concepteur se rend souvent compte que certaines donn\ue9es sont al\ue9atoires. Comme des donn\ue9es statistiques d\ue9taill\ue9es ne sont que rarement disponibles, le concepteur doit compter surtout sur son jugement d'expert. En appliquant la m\ue9thode Delphi, de telles d\ue9cisions peuvent \ueatre formul\ue9es et optimis\ue9es. Les principes de la m\ue9thode Delphi sont d\ue9crits dans cette note et l'application est illustr\ue9e par un exemple d'\ue9valuation de la r\ue9sistance au feu qui doit \ueatre exig\ue9e.Peer reviewed: YesNRC publication: Ye